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Pyrazolyl ligands in mixed metal complexes Onyiriuka, Emmanuel C. 1986

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PYRAZOLYL LIGANDS IN MIXED METAL COMPLEXES By EMMANUEL C. ONYIRIUKA  B.S.,  Adams S t a t e Colorado,  1980  M.S., U n i v e r s i t y of C a l i f o r n i a , 1982  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE  REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in  THE  FACULTY OF GRADUATE STUDIES (Department  We accept  of Chemistry)  t h i s t h e s i s as conforming  t o the r e q u i r e d  THE  standard  UNIVERSITY OF BRITISH COLUMBIA September 1986 © Emmanuel C. O n y i r i u k a , 1986  In p r e s e n t i n g  t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of  requirements f o r an advanced degree a t the  the  University  o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make it  f r e e l y a v a i l a b l e f o r reference  and  study.  I further  agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may department o r by h i s o r her  be granted by the head o f representatives.  my  It i s  understood t h a t copying or p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l gain  s h a l l not be allowed without my  permission.  Department o f  tfE.Ml _T /&~ Y  The U n i v e r s i t y of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T  1Y3  Date  /ai ^  Sifh  written  -11  -  ABSTRACT  The anions LMo(C0) isolated the N a  +  as the Na , +  (L = MeGapz^ or MeGa(3,5-Me pz) ) have been  3  2  Et^N  +  or HAsPh  salts  3  3  and the s o l u t i o n  i n THF have been d e f i n e d by a n a l y s i s of the v  salts  Ion-pair interaction  of the LMo(C0)  anion with Na  3  +  cation  i s apparent from the s p e c t r o s c o p i c evidence o b t a i n e d . anion  r e a c t e d with HC1  Mo(C0) R 3  s t r u c t u r e s of  solution  The MeGapz Mo(C0) 3  3  [MeGapzg]complexes o f  (R = Me or Ph) were o b t a i n e d .  2  2  The r e a c t i o n s of the LMo(C0)  i r spectra.  However, with Mel or PhCOCl  the type [MeGapz ]Mo(CO) (ri -COR) 3  Q  i n THF  or EtBr to g i v e the s e v e n - c o o r d i n a t e  (R = H or Et) complexes.  C  3  ions  (L = MeGapz^, HBpz  3  or  Me Gapz(02  CH CH NMe )) with a v a r i e t y of t r a n s i t i o n metal h a l i d e s p e c i e s have y i e l d e d 2  2  2  complexes with structures  of two such complexes [MeGapz ]Mo(C0) Cu(PPh ) 3  (C0) Rh(PPh ) 3  3  example  t r a n s i t i o n m e t a l - t r a n s i t i o n metal bonds.  2  have been determined.  two b r i d g i n g CO  3  and [MeGapz ]Mo3  The former complex p r o v i d e s a r a r e  of a 3:3:1, or capped o c t a h e d r a l  Mo-Cu d i s t a n c e of 2.513(9)A.  3  The X-ray c r y s t a l  s t r u c t u r e , with a s h o r t  (mean)  The l a t t e r compound d i s p l a y s one t e r m i n a l  and  l i g a n d s and a Mo-Rh d i s t a n c e of 2.6066(5)A.  T r a n s i t i o n metal-group 14 ( S i , Ge or Sn) element bonded complexes o f the type [MeGapz ]Mo(C0) M'Y 3  Si;  3  (Y = Me  3  or P h , M' 3  = Ge or Sn; Y = Me , 3  M' =  Y = M e C l , M' = Sn) have been prepared from the r e a c t i o n of the 2  MeGapz Mo(C0) 3  3  anion with the a p p r o p r i a t e organo-group 14 c h l o r i d e .  In a l l  the complexes, d i r e c t Mo-M'  (M' = S i , Ge or Sn) s i n g l e bonds are f e a t u r e d .  The [MeGapz ]Mo(C0) SnMe Cl  complex shows an i n t e r e s t i n g  3  3  i n which a t r a n s i t i o n  2  from a 3:4,  or piano s t o o l  solution  behaviour  s t r u c t u r e , to a 3:3:1, or  capped o c t a h e d r a l  arrangement, i s thought to o c c u r .  has been demonstrated i n the s o l i d compound by means o f a c r y s t a l the  'Mo-Cu' compounds d i s c u s s e d  complexes  incorporating  s t a t e f o r the  structure  3  3  3  HBpz  t r i d e n t a t e unsymmetric  3  3  The 'Mo-SnPh^' and  i n t h i s work are the f i r s t  e i t h e r the MeGapz ,  structure  [MeGapz ]Mo(C0) SnPh  determination.  the 3:3:1 arrangement has been demonstrated The novel  The 3:3:1  or C H ^ 5  examples ligands  o f such  i n which  unequivocally.  l i g a n d s Me GapzO(C H N)CH NMe2 (L~) 2  5  3  2  and Me GapzO(CgHgN)"  (_-) have been prepared and numerous t r a n s i t i o n metal  compounds c o n t a i n i n g  these l i g a n d s  2  = Mn or Re) are the f i r s t in the  examples  synthesized.  The compounds L M(C0)o (M a o  of t r a n s i t i o n metal carbonyl  which both the f a c and mer arrangements of the unsymmetric c e n t r a l metal have been found to c o - e x i s t  planar  in solution.  complexes l i g a n d about  The square  rhodium(I) complex, L_Rh(C0) has been shown to add Mel o x i d a t i v e l y ,  followed  by f a c i l e methyl m i g r a t i o n  Rh(III) acetyl  reaction  d e r i v a t i v e , L_Rh(C0Me)I.  In c o n t r a s t ,  L Rh(CO) with Mel, l e d to the s i x - c o o r d i n a t e a  product, L Rh(Me)(I)C0. a  t o produce the f i v e - c o o r d i n a t e the r e a c t i o n o f  Rh(III) o x i d a t i v e  addition  - iv TABLE OF CONTENTS Page ABSTRACT  ii  TABLE OF CONTENTS  iv  LIST OF TABLES  x  LIST OF FIGURES  xii  LIST OF ABBREVIATIONS  .  xvii  ACKNOWLEDGEMENT CHAPTER I  xxi  INTRODUCTION  1  1.1  General Introduction  1  1.2  General Techniques  14  1.2.1  Handling of Reagents  14  1.2.2  S t a r t i n g Materials  15  i)  Preparation of Trimethylgallium Me Ga  15  ii)  Preparation of Gallium T r i c h l o r i d e , GaCl ..  3  3  i i i ) Preparation of Methyldichiorogallane, MeGaCl 2  iv)  Preparation of the T r i c a r b o n y l t r i s (acetonitrile)molybdenum(O), (MeCN) Mo(C0)3 3  1.3  CHAPTER I I  Physical Measurements  16 18 20 21  THE MOLYBDENUM TRICARBONYL ANION [MeGapz ]Mo(C0)§; 3  SYNTHESIS AND CHARACTERIZATION OF ITS Na . E t N +  +  4  AND HAsPhJ SALTS, AND INVESTIGATION OF THE REACTIVITY TOWARDS ALKYL HAL IDES, PROTONATING SPECIES AND HALOGENS.  23  2.1  Introduction  23  2.2  Experimental  26  -  V -  2.2.1  Starting Materials  26  2.2.2  P r e p a r a t i o n of N a L M o ( C 0 ) MeGa(3,5-Me pz) )  (L = MeGapz ,  +  2  3  3  26  3  2.2.3  Preparation  of [ E t N ] [ M e G a p z M o ( C 0 ) ] '  2.2.4  Preparation  of [ H A s P h ] [ L M o ( C 0 ) ] "  27  +  4  3  3  +  3  3  (L = MeGapz , MeGa(3,5-Me pz) ) 3  2.2.5  2  Attempted P r e p a r a t i o n  28  3  of [MeGapz ]Mo(C0) H 3  3  using A c e t i c A c i d  29  2.2.6  Preparation  of [MeGapz ]Mo(C0) H  2.2.7  Preparation  of [MeGapz ]Mo(C0) D  2.2.8  Preparation  of [MeGapz ]Mo(C0) (Ti -C0Me)  2.2.9  Attempted P r e p a r a t i o n  3  using HCl  3  3  31  3  32  2  2  3  of [MeGapz ]Mo(C0) 3  2  (ri -C0Ph)  33  2  2.2.10  Preparation  of [MeGapz ]Mo(C0) Et  2.2.11  Attempted P r e p a r a t i o n  3  of [MeGapzo]Mo(CO)oX  and D i s c u s s i o n  2.3.1  M LMo(C0)5 M  2.4  :  Results  +  +  34  3  (X = B r , I) 2.3  30  7  36  (L = MeGapz , 3  MeGa(3,5-Me pz) ; 2  3  = Na , E t N , HAsPh ) S a l t s +  35  +  4  3  36  2.3.2  [MeGapz ]Mo(C0) H  2.3.3  [MeGapz ]Mo(C0) (ri -C0R) (R = Me, Ph)  49  2.3.4 2.3.5  [MeGapz ]Mo(C0) Et The [MeGapz ]Mo(C0) X  56 63  Summary  3  45  3  2  2  3  3  3  3  3  (X = Br, I) Complexes  63  - vi CHAPTER I I I  TRANSITION METAL-TRANSITION METAL BONDED COMPLEXES INCORPORATING PYRAZOLYL GAL LATE/BORATE LIGANDS  66  3.1  Introduction  66  3.2  Experimental  68  3.2.1  Starting Materials  68  3.2.2  Preparation  of L M o ( C 0 ) R h ( P P h ) 3  3  (where L =  2  [MeGapz ], [ H B p z ] or [Me Gapz(0CH CH NMe )])...  68  3.2.3  Preparation  of [MeGapz ]Mo(C0) Cu(PPh )  69  3.2.4  Preparation  of [MeGapz ]Mo(C0) Cu(C0)  70  3.2.5  Preparation  of [ M e G a p z ] M o ( C 0 ) P t ( M e ) ( P P h )  3.2.6  Preparation  of [MeGapZo]Mo(CO)oM'Clo  3  (M  1  3  2  2  3  3  3  2  3  3  3  = Z r or Hf)  2  3  .  70  3  T.....  71  3.2.7  Attempted P r e p a r a t i o n  of [ M e G a p z ] M o ( C 0 ) C o ( N 0 )  3.2.8  Preparation  3.2.9  Attempted R e a c t i o n of [MeGapz Mo(C0) ] Hg with S n C l Attempted D e s u l f u r i z a t i o n of H S by [MeGapz ]Mo(C0) Rh(PPh )  3  3  2  of [MeGapz Mo(C0) ] Hg 3  3  74  2  3  3  2  75  2  3.2.10  2  3  3.3  3  3  3.2.11  Attempted P r e p a r a t i o n  Results  and D i s c u s s i o n  3.3.1  LMo(C0) Rh(PPh )  76  2  of [MeGapz ]Mo(C0) Mn(C0) 3  3  5  77 78  3  3  2  (where L = [MeGapz ], [ H B p z ] , 3  3  or [Me Gapz(0CH CH NMe )])  78  3.3.2  [MeGapz ]Mo(C0) Cu(PPh )  83  3.3.3  [MeGapz ]Mo(C0) Cu(C0)  92  3.3.4  [MeGapz ]Mo(C0) Pt(Me)(PPh )  94  3.3.5  [MeGapz ]Mo(C0) M'Cl  96  3.3.6  [MeGapz Mo(C0) ] Hg  3.3.7  The  2  3.4  73  Summary  2  3  2  2  3  3  3  3  3  3  3  3  3  3  3  3  (M' = Z r or Hf)  99  2  '[MeGapz ]Mo(C0) Mn(C0) ' Complex 3  3  5  101 102  - vii CHAPTER IV  TRANSITION METAL-GROUP 14 ELEMENT BONDED COMPLEXES INCORPORATING POLY(l-PYRAZOLYL)GALLATE LIGANDS  104  4.1  Introduction  104  4.2  Experimental  105  4.2.1  Starting Materials  105  4.2.2  Preparation  of [MeGapz ]Mo(CO) SiMe  4.2.3  Preparation  of  3  3  [MeGapz ]Mo(C0) GeR 3  3  105  3  3  (R = Me, Ph)  106  4.2.4  Preparation  of [MeGapz ]Mo(C0) SnMe  4.2.5  Preparation  of [MeGapz ]Mo(C0) SnMe Cl  107  4.2.6  Preparation  of [MeGapz ]Mo(C0) SnPh  107  4.2.7  P r e p a r a t i o n of LSnMe [MeGa(3,5-Me pz) ])  3  3  3  3  2  4.3  3  3  106  3  2  3  3  (L = [MeGapz ] o r 3  108  3  4.2.8  Preparation  of [MeGapz ]SnMe Cl  Results  and D i s c u s s i o n  4.3.1  [MeGapz ]Mo(C0) SiMe  4.3.2  [MeGapz ]Mo(C0) GeR  3  (R = Me, Ph)  115  4.3.3.  [MeGapz ]Mo(C0) SnR  3  (R = Me, Ph)  117  4.3.4  [MeGapz ]Mo(C0) SnMe Cl  4.3.5  LSnY  3  3  110 3  3  3  3  3  3  109  2  3  I l l  3  122  2  (L = [MeGapz ], [MeGa(3,5-Me pz) ]", Y = Me -, 3  2  3  3  L = [MeGapz ]-, Y = M e C l ) 3  4.4  CHAPTER V  129  2  Summary  130  TRANSITION METAL DERIVATIVES OF THE UNSYMMETRIC TRIDENTATE PYRAZOLYLGALLATE LIGANDS [ M e G a p z ' 0 ( C H N ) C H N M e ] AND [ M e G a p z O ( C H N ) ]  131  Introduction  131  2  _  2  5.1  2  _  2  9  6  5  3  - viii 5.2  -  Experimental  133  5.2.1  Starting Materials  133  5.2.2  P r e p a r a t i o n o f [Me GaO(C H N)CH NMe ]  133  5.2.3  Preparation o f [Me GaO(C H N)]  136  5.2.4  P r e p a r a t i o n o f the l i g a n d N a [ M e G a p z O ( C H N ) -  2  2  3  9  2  6  2  2  +  2  CH NMe ]" 2  5.2.5  5  2  5  3  (Na L")  138  +  P r e p a r a t i o n o f the Ligand  Na [Me Gapz»0(C H N)]" +  2  9  6  (Na L")  139  +  5.3.  5.2.6  Preparation of L R e ( C 0 )  5.2.7  P r e p a r a t i o n of L M n ( C 0 )  5.2.8  P r e p a r a t i o n o f L N i (NO)  5.2.9  Preparation of L R e ( C 0 )  5.2.10  Preparation of L Mn(C0)  5.2.11  Attempted P r e p a r a t i o n o f L N i ( N 0 )  5.2.12  P r e p a r a t i o n o f Mo(MeCN) (ri -C H )(C0) Br  143  5.2.13  P r e p a r a t i o n o f L Mo(C0) (ri -C H )  143  5.2.14  P r e p a r a t i o n o f L Mo(C0) (ri -C H )  144  5.2.15  Preparation of L Rh(C0)  144  5.2.16  P r e p a r a t i o n of L R h ( C 0 )  145  5.2.17  Reaction  o f L Rh(C0) with Mel  145  5.2.18  Reaction  o f L Rh(C0) with Mel  146  5.2.19  Reaction  of L*Rh(C0) ( L * = L , L ) with  a  a  140  3  141  g  q  q  141  3  142  3  142  q  2  2  3  5  2  2  2  a  3  5  3  2  q  3  5  a  q  a  q  a  R e s u l t s and D i s c u s s i o n 5.3.1  140  3  5  3  I  2  147 148  [Me Ga0(C H N)CH NMe ] 2  q  2  2  148  - ix -  5.3.2  [Me GaO(C H N)]  5.3.3  L M(C0)  5.3.4  L Ni(NO)  5.3.5  L M(C0)  5.3.6  L*Mo(C0) (n -C H ) (L* = L ; L )  178  5.3.7  L*Rh(CO)  182  5.3.8  R e a c t i v i t y of L*Rh(C0) ( L * = L,? L ) i) With Mel ? ii) With I  2  9  a  3  6  154  2  (M = Mn; Re)  159 167  a  q  3  (M = Mn, Re)  172  3  2  3  (L* = L  5  flJ  a  q  L ) Q  2  5.4  CHAPTER VI  Summary  197  CONCLUSION AND  PERSPECTIVES  199  BIBLIOGRAPHY APPENDIX I  APPENDIX II  188 195  203 STEREO DIAGRAMS, BOND LENGTHS AND OF THE PREPARED DERIVATIVES THEORETICAL ANALYSIS  BOND ANGLES OF SOME 214  INTENSITY PATTERNS FOR MASS SPECTROMETRIC 230  -  X -  LIST OF TABLES  Table  I  Page  vCQ  (cm ) Infrared  MeGa(3,5-Me pz) , M 2  II  data f o r M L M o ( C 0 )  - 1  I r carbonyl  3  (L = MeGapz ,  +  +  3  3  = N a , E t ^ N , HAsPh* s a l t s ) +  stretching  f r e q u e n c i e s o f some LMo(C0) Me 3  (L = ^-CjjHtj, Ti-CgMe , Tc-C Hy, H B p z  complexes  39  +  5  g  MeGapz )  3>  51  3  III  Physical  data f o r the complexes LMo(C0) MY  72  IV  Physical  data f o r [MeGapz ]Mo(CO) M'Y  V  400 MHz H  VI  400 MHz *H nmr data f o r Me GaO(C H N)CH NMe  VII  400 MHz *H nmr data f o r H0(C H N) i n C D  VIII  400 MHz H  IX  Mass s p e c t r a l  data o f [Me GaO(C H N)CH NMe ]  151  X  Mass s p e c t r a l  data of '[Me GaO(CgH N)]'  154  XI  Comparison o f Ga-N and Ga-0 bond l e n g t h s i n f o u r and f i v e  3  3  3  (M* = S i , Ge, Sn)  nmr data f o r HO(C H N)CH NMe  X  5  3  2  2  5  g  nmr data  1  g  3  2  6  g  for [Me GaO(C H N)] 2  2  in C D  2  g  5  6  3  2  g  g  134  solution.  g  solution g  2  solution  in C D  2  in C D  2  6  114  6  137  solution  138  2  g  c o o r d i n a t e g a l l i u m compounds XII  Physical  158  data f o r the complexes L MT (where L a  a  = Me Gapz»02  (C H N)CH NMe ) 5  3  2  161  2  XIII  Mass s p e c t r a l  data o f [Me GapzO(C H N)CH NMe ]Mn(CO)  XIV  Mass s p e c t r a l  data o f [ M e G a p z O ( C H N ) C H N M e ] R e ( C O )  XV  Comparison o f v N Q complexes  135  2  2  5  5  3  3  values i n s e l e c t e d  2  2  2  2  165  3  166  3  f o u r - c o o r d i n a t e {MNO}  10  169  - xi -  Table  XVI  Page  Physical data f o r the complexes L MT q  (where L = Me 6apz«0(C H N)) q 2 9 b o  Q  174  c  XVII  Mass spectral data of [Me Gapz«0(C H N)]Mn(C0)  XVIII  Mass spectral data of [Me Gapz*0(C H N)]Re(C0)  XIX  Comparison of  values i n some LMo(C0) (r) -C Hg) complexes.. 178  XX  Comparison of v C Q  values i n some LRh(CO) complexes  XXI  Mass spectral data of [Me Gapz«0(C H N)]Rh(C0)  187  XXII  Mass spectral data of [Me Gapz'0(CgH N)]Rh(COMe)1  192  XXIII  Mass spectral data of [Me Gapz«0(C H N)]Rh(C0Me)I (Cont'd)  193  XXIV  Comparison of v „  196  2  g  2  9  6  6  3  2  2  9  3  6  2  g  6  values i n LRhI (C0) complexes ?  177  3  6  2  176  184  - xii -  LIST OF FIGURES  Figure  Page  1  Pyrazole  2  Deprotonation  3  Monodentate c o o r d i n a t i o n o f p y r a z o l e  3  4  C o o r d i n a t i o n modes of the p y r a z o l i d e anion  3  5  P r e p a r a t i o n of the P o l y d - p y r a z o l y l )borate l i g a n d systems  6  6  Boat conformation metal  1 of p y r a z o l e  2  of the b i s ( l - p y r a z o l y l ) b o r a t e  complex  7  7  Preparation of Me^apz^ l i g a n d  8  General  9  r e p r e s e n t a t i o n f o r the unsymmetrical t r i d e n t a t e  organogallate 9  ligand  12  Apparatus f o r the p r e p a r a t i o n of GaCl^  17  10  Apparatus f o r the p r e p a r a t i o n o f MeGaCl  11  I r spectrum of M MeGapz Mo(C0) +  3  a.  M  +  = Na  in CH C1 . 2  12  2  i n THF.  +  d.  M  +  b.  M  +  3  i n the v C Q  salts  = Na  +  19  2  i n CH C1 . 2  = HAsPh* i n C H C 1 2  region.  c.  2  M  = Et^N  +  38 3  b.  Na  +  Perturbed  c a t i o n i n THF s o l u t i o n ,  a.  Unperturbed  3  to the Mo c o o r d i n a t i o n sphere i n THF.  d e s c r i p t i o n o f CO e l e c t r o n d e n s i t y , Non-linear  anion 40  +  c.  3  anion  Proposed c a t i o n ( N a ) i n t e r a c t i o n with MeGapz Mo(C0) external  +  2  Proposed s t r u c t u r e s f o r the i n t e r a c t i o n s of MeGapz Mo(C0) anion with  13  bidentate  interaction  b.  Linear  a.  3  anion,  M.O.  interaction. 42  - xiii  -  Figure  Page  14  80 MHz H  spectrum of [ H A s P h ] [ M e G a p z M o ( C 0 ) _ ~  15  I r spectra  l  of the carbonyl  d u r i n g the r e a c t i o n 16  i n dg-acetone  +  3  3  3  s t r e t c h i n g frequency  of MeGapz Mo(C0) 3  region  observed  with Mel  3  53  nmr spectrum of [MeGapz ]Mo(C0) (ri -C0Me) i n  80 MHz H 1  2  3  2  dg-acetone s o l u t i o n 17  270 MHz  55  *H nmr spectrum of [MeGapz ]Mo(C0) Et 3  i n dg-acetone  3  solution  60  18  Various  19  Room temperature 100 MHz  isomers of the s e v e n - c o o r d i n a t e [MeGapz ]Mo(C0) Et.... 3  [MeGapz ]Mo(C0) Rh(PPh ) 3  3  3  3  62  *H nmr spectrum of 2  i n CgDg s o l u t i o n  80  20  Molecular structure  21  Proposed bonding scheme f o r [ M e G a p z ] M o ( C 0 ) R h ( P P h )  22  Possible structure  of [ M e G a p z ] M o ( C 0 ) R h ( P P h ) 3  3  3  3  3  3  of [MeGapz ]Mo(C0) Cu(PPh ) 3  81  2  3  82  2  as suggested  3  by the i r data 23  44  84  Molecular structures  of [MeGapz ]Mo(C0) Cu(PPh ) 3  3  86  3  * 24  P o s s i b l e i n t e r a c t i o n between the Mo-Cu % bond and the % of the CO l i g a n d  i n the complex [MeGapz ]Mo(C0) Cu(PPh )  88  of a l i n e a r s e m i - b r i d g i n g CO type bonding  89  3  3  3  25  The s t r u c t u r e  26  Proposed bonding scheme f o r [MeGapz ]Mo(C0) Pt(Me)(PPh )  27  80 MHz W  3  l  orbital  3  nmr spectrum of [ M e G a p z ] M o ( C 0 ) Z r C l 3  3  95  3  3  i n CgDg  solution 28  P o s s i b l e m o l e c u l a r arrangements f o r the (M' = Z r or Hf) complexes  97 [MeGapz ]Mo(C0) M'Cl 3  3  3  98  - xiv -  Figure  Page  29  I r spectrum of [ M e G a p z ] M o ( C 0 ) H f C l i n CH C1  30  P o s s i b l e m o l e c u l a r arrangement f o r the complex  3  3  3  2  solution  2  99  [MeGapz Mo(C0) ] Hg 3  31  100  2  The V  C0  CH C1 2  32  3  ^S^  0 1 1  °^ ^  n e  ^  r s  P c t r u m of [ M e G a p z ] M o ( C 0 ) S i M e i n e  3  3  3  solution  2  270 MHz H l  113  nmr spectrum of [MeGapz ]Mo(C0) GePh 3  3  in C D  3  g  6  solution 33  116  Room temperature 80 MHz *H nmr spectrum of [MeGapz ]3  Mo(C0) SnMe 3  3  i n dg-toluene  119  34  M o l e c u l a r s t r u c t u r e of [MeGapz ]Mo(C0) SnPh  35  Room temperature 80 MHz *H nmr s p e c t r a  3  3  120  3  of [MeGapz ]Mo(C0) 3  3  SnMe Cl, showing the change with time  123  2  36  P o s s i b l e m o l e c u l a r arrangements f o r the [MeGapz ]Mo(C0) 3  SnMe Cl 2  37  3  complex i n s o l u t i o n  125  Temperature dependent 300 MHz H nmr spectrum of [MeGapz ]Mo(C0) 1  3  SnMe Cl  i n dg-toluene s o l u t i o n  38  Partial  mass spectrum of [MeGapz ]Mo(C0) SnMe Cl  39  The unsymmetric o r g a n o g a l l a t e l i g a n d s  2  CH NMe ]" 2  2  126 3  3  ( L ~ ) , and [Me^apz-OCCgHgN)]  128  2  [Me Gapz*0(CgH N)2  -  3  (L~)  132  40  Molecular structure  of [ M e G a » 0 ( C H N ) C H N M e ]  41  Comparison of the Ga-N bond lengths i n the dimethyl gal 1ium  42  compounds 80 MHz H nmr spectrum of H0(C(-H^N)CH NMe  2  3  5  3  2  ?  149  2  ?  in C D fi  fi  solution...  150 152  - XV -  Figure  43  Page  400 MHz  *H nmr spectrum o f Me GaO(C H N)CH NMe 2  5  3  2  in C D  2  g  g  solution  153  44  400 MHz  45  80 MHz ti nmr spectrum o f Me Ga0(C H N) i n C D  46  Molecular structure  47  I r spectrum  9  g  g  solution  g  2  9  6  g  of [ M e G a 0 ( C g H N ) ] 2  i n the v C Q  g  region  155  solution  1  (C0) 48  *H nmr spectrum o f H0(C H N) i n C D  g  156 157  2  o f [Me GapzO(C H N)CH NMe ]Mn2  5  3  2  2  i n cyclohexane s o l u t i o n  3  160  80 MHz *H nmr spectrum o f [ M e G a p z 0 ( C H N ) C H N M e ] R e ( C 0 ) 2  5  3  2  2  in  3  Cd solution 6 6 c  49  162  c  Proposed conformation o f [Me GapzO(C H N)CH NMe ]M(CO) 2  5  3  2  2  (M =  3  Mn or Re) 50  80 MHz  163  room temperature *H nmr spectrum o f  NMe ]Ni(N0) i n CDC1 2  51  3  2  5  3  2  solution  168  Proposed mechanisms f o r the f l u x i o n a l process observed f o r [Me Gapz0(C H N)CH NMe ]Ni(N0) 2  52  [Me GapzO(C H N)CH -  5  3  2  i n the v C Q  I r spectrum  i n CDC1  2  region  solution  3  171  o f [Me Gapz0(CgH N)]Mn(C0) i n 2  g  3  cyclohexane s o l u t i o n 53  80 MHz  172  *H nmr spectrum o f [ M e G a p z 0 ( C H N ) ] R e ( C 0 ) i n C D 2  9  g  3  g  g  solution 54  80 MHz H X  C D g  55  g  a  nmr spectrum o f [ M e G a p z 0 ( C H N ) ] M o ( C 0 ) ( T i - C H ) i n 3  2  9  g  2  3  5  solution  Proposed L  175  reaction  , L ) complexes q r  180 sequence  f o r the formation o f L Rh(C0) (L  = 183  - xvi -  Figure  56  Page  80 MHz H :  nmr spectrum of [Me Gapz0(C H N)]Rh(C0) i n CgDg 2  g  6  solution 57  186  Proposed r e a c t i o n  sequence  f o r the formation o f  [Me GapzO2  (C HgN)]Rh(C0Me)1  189  g  58  270 MHz  H  l  solution  nmr spectrum of [Me2Gapz0(CgHgN)]Rh(C0Me)I  in  CDCI3 191  - xvil  -  LIST OF ABBREVIATIONS  The  f o l l o w i n g a b b r e v i a t i o n s have been used throughout  this  A  Angstrom  amu  atomic mass u n i t ( s )  Anal.  Analysis  bipy  2 , 2 ' - d i p y r i d i n e , or b i p y r i d i n e  br  broad  °C  degree C e l s i u s  Calcd.  Calculated  cf  L a t i n c o n f e r (compare)  cm""'''  wave number ( r e c i p r o c a l  COD  cycloocta-l,5-diene  thesis:  centimeters)  cont'd  continued  Cp  c y c l o p e n t a d i e n y l , CgHg  d  doublet  dd  doublet o f doublets  dec.  decrease  dppe  l,2-bis(diphenylphosphino)ethane  dppm  bis(diphenylphosphino)methane  e.g.  L a t i n exempli  gratis  EHMO  Extended Huckel  E.I  electron  impact  ( f o r example)  Molecular  Orbital  - xvm -  ethyl Fast Atom Bombardment facial Figure(s) Fourier  Transform  gram(s) hour(s) proton Hertz  ( c y c l e s p e r second)  L a t i n i d e s t (that i s ) i ncrease i nf rared magnetic resonance c o u p l i n g  constant  Me GapzO(C H )CH NMe2 2  5  3  2  Me GapzO(C H N)" 2  g  6  limited multiplet central  ( u s u a l l y metal) atom i n compound  mass t o charge  ratio  methyl 3 , 5 - d i m e t h y l p y r a z o l y l , C^HyN meridional megahertz  2  - xix -  min  minute(s)  mL  milliliter(s)  mmol  millimole(s)  MS  Mass  n  integer  nmr  n u c l e a r magnetic  P  parent  Ph  phenyl,  pKa  -log^Ka  ppm  p a r t s per m i l l i o n  pz  pyrazolyl,^ 3 ^ 2  s  singlet  sal en  bi s - s a l i c y l al dehy deethyl enedi i mi ne  t  Spectrometry  C H g  resonance  5  (Ka=acid  dissociation  constant)  triplet  THF  tetrahydrofuran  tmed  N,N,N',N'-tetramethylethyl  U.B.C.  University  UV  ultraviolet  xs  excess  of B r i t i s h  enedi amine  Columbia  approximately >  g r e a t e r than or equal to  A  reflux  TI  Greek h a p t e i n (hapto = t o f a s t e n )  TI'  monohapto  - XX -  dihapto trihapto pentahapto hexahapto nmr  chemical  shift  bridging IR s t r e t c h i n g  frequency  - xx i  -  ACKNOWLEDGEMENT  I wish to thank the f a c u l t y and t e c h n i c a l Department, e s p e c i a l l y to Dr. Steve R e t t i g would a l s o l i k e  s t a f f o f the Chemistry  (X-ray c r y s t a l l o g r a p h y ) .  I  to acknowledge the members o f my S t e e r i n g Committee; D r s .  B.R. James, D. Dolphin and M. Fryzuk f o r t h e i r very  constructive  suggestions during  Financial  the p r e p a r a t i o n  of t h i s t h e s i s .  assistance  from the Chemistry Department, i n the form o f a Teaching A s s i s t a n t s h i p i s gratefully  acknowledged.  My most s i n c e r e thanks are a l s o extended to my f a m i l y , whose support and  patience  dedicated  source o f encouragement.  This thesis i s  to them.  Finally, Alan  was a c o n s t a n t  I wish to express my g r a t i t u d e  to my r e s e a r c h  S t o r r f o r h i s guidance and support d u r i n g  s u p e r v i s o r . Dr.  the course o f t h i s work.  1  CHAPTER 1  INTRODUCTION  1.1  GENERAL  The prepared  INTRODUCTION  five-membered d i a z o l e h e t e r o c y c l i c compound, p y r a z o l e , was i n the l a t e n i n e t e e n t h  nomenclature, numbering the  direction  begins  century  [1].  By c o n v e n t i o n a l h e t e r o c y c l i c  at the protonated  of the second unprotonated  first  n i t r o g e n and proceeds i n  n i t r o g e n as shown i n F i g u r e 1.  4  F i g u r e 1.  The  t h r e e carbon atoms  Pyrazole.  (C3, C4, C5) and N2 of the p y r a z o l e  c o n t r i b u t e f o u r T c - e l e c t r o n s , and N l which  i s uninvolved  nucleus  i n the double bond  2  formation,  donates i t s e l e c t r o n p a i r , thus  n-electrons.  The c o l o r l e s s , sweetish  crystalline solid due  (n = 1 ) .  five-membered p y r a z o l e calculations  smelling  sextet of  ( u n l i k e most amines),  i s h y d r o l y t i c a l l y , o x i d a t i v e l y , and t h e r m a l l y s t a b l e ,  p a r t l y t o i t s aromatic  '4n + 2' system  c r e a t i n g an aromatic  c h a r a c t e r , s i n c e i t may be c o n s i d e r e d a Huckel The c o n s i d e r a b l e aromatic  c h a r a c t e r of the  r i n g has been borne out by molecular  orbital  by Kaufman et a l . [ 2 ] .  Upon d e p r o t o n a t i o n  of the a c i d i c  hydrogen a t t a c h e d  t o Nl (pK  = 2.53)  [ 3 ] by a p p r o p r i a t e bases, p y r a z o l e becomes the r e s o n a n c e - s t a b i l i z e d p y r a z o l i d e anion  HN  (Figure 2 ) .  N  «f  F i g u r e 2.  NaH  Deprotonation  of p y r a z o l e .  As a l i g a n d , p y r a z o l e can a c t as a n e u t r a l , monodentate,  two-electron  donor l i g a n d v i a the lone p a i r on N2 i n a s i m i l a r manner t o p y r i d i n e as shown i n F i g u r e 3.  N  F i g u r e 3.  Monodentate c o o r d i n a t i o n  With the p y r a z o l i d e anion, v i a one of t h r e e  N  i n t e r a c t i o n with  possible coordination  of p y r a z o l e .  s u i t a b l e metals can occur  modes - monodentate,  2 TI -endobidentate and exobidentate  o  o  (•)  Figure 4.  modes, r e s p e c t i v e l y ( F i g u r e 4 ) .  (b)  Coordination  p (c)  modes of the p y r a z o l i d e  anion.  4  R e l a t i v e l y few examples of monodentate c o o r d i n a t i o n of the p y r a z o l i d e anion t o t r a n s i t i o n metals [M(pz) (L-L)]  (M = P t , Pd;  2  [3,5-(CF ) pz] 3  dentate  [5].  2  ( F i g . 4 ( a ) ) have been reported e.g., L-L = dppe, b i p y , COD) [ 4 ] and ( P P h ) ( C 0 ) I r 3  On the other hand, only one example  c o o r d i n a t i o n of the p y r a z o l i d e anion  reported  i n the l i t e r a t u r e .  compound s t r u c t u r a l l y reflective  T h i s unusual  2  of TI -endobi-  ( F i g . 4 ( b ) ) , has been  bonding mode e x h i b i t e d by the  c h a r a c t e r i z e d as pzUCp  3  [ 6 ] was i n t e r p r e t e d as being  of i ) the i o n i c c h a r a c t e r of the uranium n i t r o g e n bonds as  compared t o a _i-block t r a n s i t i o n element, and i i ) t h e l a r g e r atomic of uranium.  The most  p y r a z o l i d e anion  c o o r d i n a t i o n mode i s where the  acts as an ' e x o b i d e n t a t e  which may be i d e n t i c a l stable  commonly found  or d i f f e r e n t  compounds c o n t a i n i n g such  i n the l i t e r a t u r e  (e.g.,  radius  1  bridge between two metals,  (Fig. 4(c)).  'exobidentate'  Numerous examples of bridges  have been  reported  [7-11]).  Upon c o o r d i n a t i o n t o c e r t a i n main group elements, monodentate interactions  (as d e p i c t e d i n F i g . 4 ( a ) ) of the p y r a z o l i d e anion  more p r e v a l e n t .  F o r example, c o o r d i n a t i o n t o boron gives the  p o l y ( 1 - p y r a z o l y l )borates alkanes  [ 1 2 ] ; s i m i l a r l y t o carbon,  The most widely  s t u d i e d of these  systems are the u n i n e g a t i v e formula  the p o l y ( l - p y r a z o l y l ) -  [ 1 3 ] , t o g a l l i u m the p o l y ( l - p y r a z o l y l ) g a l l a t e s  the t r i s ( l - p y r a z o l y l e t h y l )amine were obtained [15].  [R B(pz) _ ]~ n  become  4  n  [ 1 4 ] , and r e c e n t l y  by c o o r d i n a t i o n t o n i t r o g e n  main group py r a z o l y l  ligand  p o l y ( l - p y r a z o l y l )borates with the general  (where R = H, a l k y l ,  n = 0, 1, 2 ) . These are a broad  aryl,  and v e r s a t i l e  l i g a n d s whose c o o r d i n a t i v e a b i l i t y  py r a z o l y l ,  class  N C H ; 2  3  3  of u n i n e g a t i v e  i s a consequence of f a v o u r a b l e  and  5  e l e c t r o n i c and  geometric f a c t o r s .  l e d to numerous metal  The combination  of these f a c t o r s  has  complexes i n c o r p o r a t i n g the p o l y d - p y r a z o l y l ) b o r a t e  l i g a n d s , an area t h a t has been the s u j e c t of a number of review  articles  [7,16,17]. These f a i r l y  r o b u s t l i g a n d systems are r e a d i l y prepared by the  r e a c t i o n of an a l k a l i reaction  metal  borohydride with p y r a z o l e , the e x t e n t of the  being dependent on the r e a c t i o n temperature  as shown i n F i g u r e 5  [12,18]. Although  the s a l t s of a l l t h r e e anions are a i r - s t a b l e and can  stored i n d e f i n i t e l y  i n the s o l i d  polyd-pyrazolyl)borate  the s t a b i l i t y  species in solution  hydrogens a t t a c h e d to boron The  state,  of the  decreases as the number of  i s increased.  u n i n e g a t i v e b i d e n t a t e b i s p y r a z o l y l b o r a t e anion  f o r m a l l y analogous four-electron  to the 1,3-diketonate  donor l i g a n d s .  former r e a c t s with metal  (n = 2 ) , i s  i o n , both being u n i n e g a t i v e  A n o t a b l e d i f f e r e n c e between both  systems i s t h a t w h i l e v a r i o u s a s s o c i a t i v e e q u i l i b r i a t r i m e r have been observed  complexes [ 1 9 ] , the  ions to give monomeric b i s b i d e n t a t e  u s u a l l y with the [B-(N-N) -M] (M = t r a n s i t i o n  metal)  ligand  i . e . , monomer-dimer-  f o r the 1,3-diketonate metal  2  be  complexes  six-membered r i n g i n  a boat conformation as shown i n F i g u r e 6 (e.g., [ 2 0 , 2 1 ] ) .  6  F i g u r e 5.  Preparation  Of p a r t i c u l a r  of the p o l y ( 1 - p y r a z o l y l ) b o r a t e l i g a n d systems.  interest  i s the symmetrical  t r i s ( l - p y r a z o l y l )borate anion  RBpz~  uninegative, t r i d e n t a t e  (n = 1), f o r m a l l y analogous to the  7  F i g u r e 6.  well  Boat conformation of the b i s ( 1 - p y r a z o l y l )borate b i d e n t a t e metal complex.  known c y c l o p e n t a d i e n i d e  i o n (Cp") - both  being u n i n e g a t i v e , s i x -  e l e c t r o n donor l i g a n d s which are c o n s i d e r e d t o occupy t h r e e mutually c i s positions place the  i n t h e i r octahedral  metal  of Cp" l i g a n d has been found  r e s u l t i n g metal  [22] i s heatunstable  derivatives.  t o impart  succeeded i n s t a b i l i z i n g  ( I l ) - a c e t y l e n e , a l l e n e and o l e f i n  unusual  stability to  (r)-C H )CuC0 [ 2 3 ] i s t h e r m a l l y  In another  a series  The presence of RBpz^ i n  F o r example, the compound [HBpz^DCuCO  and a i r - s t a b l e , while  and a i r - s e n s i t i v e .  derivatives.  5  5  example, Clark and Manzer have  of f i v e - c o o r d i n a t e methyl platinum complexes u s i n g the t r i d e n t a t e RBpzZ  8  (R = H, Me, p y r a z o l y l , N C H ) 2  3  3  [24,25] l i g a n d s .  p l a t i n u m ( I I ) complexes are r a r e The mode o f r e a c t i v i t y of a l k y l  substitutents  Such  five-coordinate  [26-30].  o f RBpz  3  l i g a n d can be a l t e r e d by the presence  a t the C(3) and C(5) p o s i t i o n s o f each pz r i n g .  For example, the r e a c t i o n  of [ H B p z ] M o ( C 0 ) 3  3  with a r y l d i a z o n i u m  ArNg, gave the s u b s t i t u t i o n product [ H B p z ] M o ( C 0 ) ( N A r ) 3  fluorophenyl)  [31].  In c o n t r a s t ,  2  2  (Ar = m- or p-  of [ H B ( 3 , 5 - M e p z ) ] M o ( C 0 ) 2  2  [ H B ( 3 , 5 - M e p z ) ] Mo(CO) (n -C0Ar) 3  the r e a c t i o n  2  + c a t i o n A r N , y i e l d e d the novel  anion with a r y l d i a z o n i u m 2  2  cation  3  2 TI - a r o y l  3  complex  i n a c e t o n i t r i l e [ 3 2 ] , and t h e  c h l o r o m e t h y l i d e n e complex [ H B ( 3 , 5 - M e p z ) ] M o ( C 0 ) ( V - C C l ) i n C H C 1 2  2  3  2  2  [33],  respectively. The c l o s e l y r e l a t e d d i m e t h y l b i s ( 1 - p y r a z o l y l ) g a l l a t e l i g a n d i s prepared by the r e a c t i o n o f t r i m e t h y l g a l l i u m followed  by a d d i t i o n  of p y r a z o l e  with sodium  [14] as d e p i c t e d  The m e t h y l t r i s - ( l - p y r a z o l y l ) g a l l a t e MeGapz r e a c t i o n of m e t h y l d i c h l o r o g a l l i u m  3  pyrazolide  i n F i g u r e 7. l i g a n d i s prepared by t h e  with sodium p y r a z o l i d e  according  to t h e  equation below [ 3 4 ] .  MeGaCl  + 3Na pz" +  ?  c  Alkali  metal  ™ > >7 days F  Na [MeGapz.]" + 2NaCl * +  s a l t s of the p o l y d - p y r a z o l y l ) g a l l a t e  anions a r e h y g r o s c o p i c ,  white s o l i d s q u i t e u n l i k e the p o l y d - p y r a z o l y l ) b o r a t e and  moisture-stable  solids.  s a l t s which are a i r -  9  Figure  7.  Preparation  Although the c o o r d i n a t i o n ligands result  p a r a l l e l s that  of Me Gapz2 l i g a n d . 2  chemistry of the p o l y ( 1 - p y r a z o l y l ) g a l l a t e  of the boron systems, some important d i f f e r e n c e s  from the i n t r o d u c t i o n  of g a l l i u m  f o r boron i n the l i g a n d  systems.  10  A more e l e c t r o n - r i c h complexes  center i s created  [ 3 4 ] , with a g r e a t e r degree of s t e r i c  c h e l a t e d metal The  t r a n s i t i o n metal  due to the l o n g e r Ga-N  unknown i n the analogous boron systems. 2  readily  3  tris-chelating  (where M = Mo  3 'TI - a l l y l '  or W,  systems  since forcing-conditions unnecessary.  2  ideally  suited  complexes. [HBpz ]SnMe 3  (~9-ll"0 nmr  symmetry. to occupy  Crystal 3  centers  7  -allyl)  The  i n the H l  nmr  spectrum.  as Not  probes but they a l s o make s p e c t r a l  systems  systems.  are unique i n themselves, being  uninegative s i x - e l e c t r o n  The t r i p o d - l i k e  donor  l i g a n d s of  s t r u c t u r e o f these l i g a n d s i s  three m u t u a l l y c i s p o s i t i o n s  in octahedral  metal  s t r u c t u r e d e t e r m i n a t i o n s of [ H B p z ^ C o [ 3 6 ] ,  [ 3 7 ] , [HBpz ]Mo(C0) « 3  3  radical  s p e c i e s [ 3 8 ] , and  geometry  i n the above complexes.  problem of f i n d i n g  3  groups on g a l l i u m appear  l e s s c o m p l i c a t e d than i n the boron  [39] do a t t e s t to t h i s c o o r d i n a t i o n metal  3  4  2  3  high temperatures) are g e n e r a l l y  The RBpZg" and MeGapz^ l i g a n d  3 v  i n the attempted  are s y n t h e t i c a l l y much e a s i e r to prepare  X  approximate C  2  2  5  (i.e.,  tridentate,  [34].  demanding  [MeGa(3,5-Me pz) ]M(C0) (ri  3  only can these resonances a c t as H  only t r i g o n a l  f o r B-N)  transformations  = TI -C_H , * l - C H ) [35].  unique resonances at high f i e l d s  the  the  For example, the l i g a n d  Most i m p o r t a n t l y , the methyl  interpretation  chemical  [MeGa(3,5-Me pz) (0H)]~  complexes,  '^-allyl'  gallium-based l i g a n d  afforded  c o n v e r t s to the l e s s s t e r i c a l l y  'hydroxy' l i g a n d  syntheses of the  protection  bond (-2.0A c f . -1.5A  g a l l i u m - b a s e d l i g a n d s o c c a s i o n a l l y undergo  [MeGa(3,5-Me pz) ]~  i n the g a l l i u m  [MeGapz^Ni  of the l i g a n d s about the  T h i s uniqueness however poses the  a p p r o p r i a t e known systems  f o r d i r e c t comparison.  The  11  v a r i o u s known t r i d e n t a t e donor t r i p o d 1,l,l-tris(aminomethyl)ethane with are  the general  formula  l i g a n d s of C  and i t s N - m e t h y l - s u b s t i t u t e d  CH -C-(CH -Z) 3  2  3  2  3  d i v a l e n t t r a n s i t i o n metal e.g., Mn  2+ , Ni  electronically  tridentate cyclopentadienyl  TC- r a t h e r than  a-bonded  ligands, s t i l l  and MeGapz MeGapz  3  several  3  complexes provides  typical  2+  , Fe  ) . The u n i n e g a t i v e ,  i o n (Cp"), even though  the c l o s e s t approximation  to the RBpz , 3  Hence the RBpz , 3  to one another i n  complexes.  but s i g n i f i c a n t  systems came with  i t forms  of the t r i s ( 1 - p y r a z o l y l ) b o r a t e / -  and Cp" l i g a n d s are l i k e n e d t o and compared  A slight  neutral  compounds (where M =  l i g a n d s i n terms of d e r i v a t i v e c h e m i s t r y .  "isoelectronic"  2  i n c a p a b l e of forming  b i s - t r i d e n t a t e complexes analogous to the [RBpz ]M  2+  derivatives  (where Z = NH , NHMe, NMe ) [ 4 0 ]  i n a p p r o p r i a t e , being uncharged and thus,  gallate  symmetry such as t h e  3 y  d e v i a t i o n from the RBpz  the i n t r o d u c t i o n o f the novel  3  and MeGapz  unsymmetric,  3  ligand  uninegative,  tridentate,  six-electron  unsymmetric  l i g a n d s i n c o r p o r a t i n g a p y r a z o l y l moiety, i n c o n j u n c t i o n  a bifunctional grouping  donor, g a l l i u m - c o n t a i n i n g l i g a n d systems.  donor group both  being  attached  t o a dimethyl g a l l i u m  [41] ( F i g u r e 8 ) , have y e t no c o u n t e r p a r t s  pyrazolylborate  chemistry.  i n the r e l a t e d  These with  12  X = 0. Y = N orS. X = S.  F i g u r e 8.  The  ligand  recently,  pyrazolyl The active salt  General r e p r e s e n t a t i o n f o r the unsymmetrical t r i d e n t a t e organogal1 ate l i g a n d .  [HB(3,5-Me pz) (SAr)]" 2  i s the f i r s t  borate l i g a n d  Y = N.  2  (Ar = CgH -4-CH ) [42], 4  3  reported  and the only known example of a p o l y ( 1 - p y r a z o l y l )-  i n which an a d d i t i o n a l  donor f u n c t i o n a l i t y apart  from the  groups i s a t t a c h e d t o boron. unsymmetric  gal l a t e  ligands  are prepared by the r e a c t i o n  hydrogen-containing polyfunctional  of t r i m e t h y l gal 1iurn p y r a z o l y l  a c c o r d i n g t o the e q u a t i o n : -  of an  donor compound with the sodium  anion t o e l i m i n a t e  methane gas  13  Na [Me-.Gapz]" + LH *  —  +  >  Na [Me„GapzL]~ +  LH = a c t i v e h y d r o g e n - c o n t a i n i n g  In c o n t r a s t to RBpz^, MeGapz^ or Cp" exclusively  facial  flexibility  to c o o r d i n a t e to metals  to metals,  Both  X-ray  a n a l y s e s of metal  gallate  ligand  MeH  compound  systems which c o o r d i n a t e  the unsymmetric  arrangement. crystal  +  A  gallate  l i g a n d s have the  in either a facial  of these geometries  or m e r i d i o n a l  have been confirmed  structurally  complexes i n c o r p o r a t i n g the  by  unsymmetric  l i g a n d s [43,44].  Chapter  II of t h i s t h e s i s r e p o r t s on the s y n t h e s i s and  characterization  of the molybdenum t r i c a r b o n y l  MeGapz.j, MeGa(3,5-Me pz) ) as t h e i r 2  interaction reactivity  and  of the LMo(C0)  3  presents s p e c t r o s c o p i c evidence anion with the Na  of the MeGapz Mo(C0) 3  3  (L =  3  sodium, tetraethylammonium,  3  triphenylarsonium s a l t s ,  anions L M o ( C 0 )  anion toward  c h l o r i d e , p r o t o n a t i n g s p e c i e s and halogens  +  cation alkyl  and  f o r the  i n THF.  The  hai i d e s ,  benzoyl  i s also explored in t h i s  Chapter. The  reactivity  of the L M o ( C 0 )  [Me Gapz(0CH CH NMe )]) toward 2  2  2  the r e a c t i v i t y metal direct  halide  2  anions  3  3  3  Wilkinson's c a t a l y s t R h C l ( P P h ) 3  of the MeGapz Mo(CO) 3  s p e c i e s are d e t a i l e d  3  anion toward  i n Chapter  t r a n s i t i o n m e t a l - t r a n s i t i o n metal  are d i s c u s s e d , and X-ray  (L = HBpz , MeGapz ,  structural  complexes [ M e G a p z j M o ( C O k R h ( P P h J  ?  III.  a variety  also  of t r a n s i t i o n  Complexes c o n t a i n i n g  bonds i s o l a t e d  data are presented and  and  3 >  from  the r e a c t i o n s  f o r two  of the  [MeGapz-,]Mo(COLCu(PPh,).  14  Chapter IV e x p l o r e s toward Group 14  ( S i , Ge,  featuring direct  the  reactivity  Sn)  alkyl  or a r y l  3  3  organotin  s y n t h e s i s , c h a r a c t e r i z a t i o n and  determinations  of the  r e a c t i o n of [MeGapzg]"  c h l o r i d e s are a l s o  X-ray c r y s t a l  of the two  novel  and  presented  -  O(CgHgN)]", ( L ~ ) , and the t r a n s i t i o n metal Chapter, the molecular  structural  unsymmetric, t r i d e n t a t e  p y r a z o l y l g a l l ate l i g a n d s , [ I ^ G a p z ' C K C g H g N j ^ N I ^ ] , reactivity  of the  h a l i d e s p e c i e s are the s u b j e c t  reactivity  of L Rh(CO) (L  ( ~ ) , and  [Me Gapz*-  L  2  l i g a n d s towards a v a r i e t y of Chapter V.  of  In the same  = L . L ) toward methyl a q  iodide  and  iodine is also discussed.  General  Techniques  Handling  of Reagents  Since most of the m a t e r i a l s were a i r - s e n s i t i v e , were c a r r i e d LAB  is  c o o r d i n a t i o n compounds [MegGaOfCgH^NjQ^NMeg]. arid  [I^GaC^CgHgN).^, the syntheses  1.2.1  3  and  discussed. The  1.2  Complexes  compound [MeGapz2_.Mo(C0) SnPh  Compounds i s o l a t e d from the d i r e c t  [MeGa(3,5-Me2Pz) ]~ l i g a n d s with and  halide species.  t r a n s i t i o n metal-group 14 element bonds are d i s c u s s e d  X-ray c r y s t a l l o g r a p h i c a n a l y s i s of the presented.  of the MeGapZgMo^O)^ anion  out  i n a dry box  (Vacuum/Atmospheres C o r p o r a t i o n model  HE-43-2), c o n t a i n i n g p r e - p u r i f i e d  Canada), and  f i t t e d with a D r i t r a i n  l i n e equipped with  a duo-seal  a l l manipulations  nitrogen  (Linde USP,  (model HE 493),  Union  or on a high  pump (Welch S c i e n t i f i c Company).  DRI  Carbide vacuum Reactions  15  were c a r r i e d out under an i n e r t atmosphere i n the dry box or i n a nitrogen-blanketed atmosphere unless otherwise stated. AIT reaction solvents were r o u t i n e l y dried by r e f l u x i n g under N , 2  followed by d i s t i l l a t i o n according to l i t e r a t u r e methods [45,46]. The most frequently used solvents were dried as follows; THF over Na/benzophenone, and benzene over potassium by continuous r e f l u x i n g i n 2 l i t e r s t i l l pots, c o l l e c t e d p r i o r to use or stored i n the dry box under N. 2  In the case of THF, the c h a r a c t e r i s t i c blue c o l o r a t i o n of the  benzophenone ketyl radical was taken as an i n d i c a t i o n of complete dryness. The l e s s frequently used solvents CH C1 , hexane and a c e t o n i t r i l e were 2  2  dried by r e f l u x i n g over CaH , CaS0 and P °5» r e s p e c t i v e l y , followed by 2  4  2  distillation. 1.2.2 i)  S t a r t i n g Materials Preparation of Trimethylgallium, Me Ga [47] 3  HgCl 3Me Hg + 2Ga 2  ?  2Me Ga + 3Hg 3  Trimethylgallium was prepared by the gallium metal-mercury exchange method.  alkyl  T y p i c a l l y , dimethylmercury (25 g, 108 mmol) was added to  gallium metal (7.2 g, 103 mmol) and a c a t a l y t i c amount of mercuric c h l o r i d e placed i n a Carius tube. frozen to l i q u i d  The tube and i t s contents were then  nitrogen temperatures (—196°C).  The tube was then  evacuated, flame-sealed at the c o n s t r i c t i o n , and slowly warmed to room temperature.  The tube was then stored f o r about one week at ~120°C i n a  metal bomb apparatus.  At t h i s stage, the product Me^Ga, which i s a  16  colorless liquid,  had s e p a r a t e d from the mercury  d e p o s i t e d a t the bottom i s o l a t e d and condensed checked  by *H nmr  without f u r t h e r ii)  of the tube.  and excess g a l l i u m metal  The Me^Ga was  then  carefully  i n t o ampoules on the vacuum l i n e .  measurements.  I t was  Its purity  then used i n subsequent  was  reactions  purification.  P r e p a r a t i o n of G a l l i u m T r i c h l o r i d e , G a C l  2GaU) + 2Cl (g)  >  ?  3  [48]  (Ga ) (GaCl~)U) +  A  (Ga )(GaCl4)U) + C l ( g )  >  +  2  G a l l i u m t r i c h l o r i d e was Pure c h l o r i n e gas sulfuric  acid  metal  (Matheson) was  i n a gas b u b b l e r , a f t e r which  The apparatus was  The  the gas was  2  4  (m.p.  giving a colorless  170.5°C).  The  white s o l i d , g a l l i u m t r i c h l o r i d e , G a C l  3  (m.p.  liquid gave a  was  gallium  29.78°C) u s i n g a bunsen flame.  d i s a p p e a r e d upon a d d i t i o n of more c h l o r i n e , and f i n a l l y  The  liquid,  GagCl^ volatile  79°C).  r a t e of flow of the c h l o r i n e gas and the r a t e of h e a t i n g the  g a l l i u m were a d j u s t e d so t h a t most of the v o l a t i l e G a C l  deposited reacted  passed i n t o the  f l u s h e d w i t h c h l o r i n e gas, and the  gallium tetrachlorogallate, G a C l  molten  elements.  g a l l i u m m e t a l , about 22 grams  g a l l i u m r e a c t e d with the c h l o r i n e , f i r s t  The  6  d r i e d by p a s s i n g through c o n c e n t r a t e d  s l o w l y warmed to m e l t i n g (m.p.  molten  2  prepared by d i r e c t r e a c t i o n o f the  g l a s s apparatus shown i n F i g u r e 9. p l a c e d i n A.  Ga Cl  i n the c o o l e d r e c e i v e r boat C.  (essentially  100%), any  3  was  A f t e r a l l the g a l l i u m  had  sublimate i n A was  warming and f l a m e - s e a l i n g the c o n s t r i c t i o n a t B.  driven  i n t o C by  The apparatus was  then  D  >ooo E  c igure 9.  Apparatus f o r the preparation of G a C l . 3  18  evacuated and f l a m e - s e a l e d a t F. into  The crude h a l i d e was then r e - s u b l i m e d  the ampoules E, and each s e a l e d a t t h e i r r e s p e c t i v e  Assuming a 100% y i e l d  (55 grams),  each ampoule was then e s t i m a t e d . remain iii)  the weight of g a l l i u m t r i c h l o r i d e i n The g a l l i u m t r i c h l o r i d e was found to  s t a b l e i n d e f i n i t e l y when s t o r e d i n t h i s  manner,  P r e p a r a t i o n of m e t h y l d i c h l o r o g a l l a n e , MeGaCl  GaCl  3  + xsMe Si  >  4  MeGaCl  2  the g l o v e box and loaded i n t o the l e f t  joint. line,  T h i s side-arm was capped  [49]  3  3  was c r a c k e d open i n  side-arm of the apparatus shown i n  and a tap adapter f i t t e d  onto the B24  The apparatus was then evacuated v i a the tap adapter on the vacuum and bulb E was then f r o z e n i n l i q u i d  A was f l a m e - s e a l e d and the G a C l flame.  9  + Me SiCl  An ampoule c o n t a i n i n g a known q u a n t i t y of G a C l  F i g u r e 10.  constrictions.  The melted G a C l  3  3  nitrogen.  The c o n s t r i c t i o n a t  was melted by warming with a bunsen  was allowed to run down i n t o bulb E, excess  s p e c t r o g r a d e t e t r a m e t h y l s i l a n e was condensed  i n t o bulb E, and the  apparatus f l a m e - s e a l e d a t c o n s t r i c t i o n s B and C. c o n t e n t s were s l o w l y warmed to room temperature, hot water bath f o r s e v e r a l  days.  The apparatus and i t s f o l l o w e d by p l a c i n g  in a  On c o o l i n g , white c r y s t a l s of MeGaClg  were d e p o s i t e d a t the bottom o f the f l a s k .  The unreacted t e t r a m e t h y l -  s i l a n e and the t r i m e t h y l c h i o r o s i l a n e by-product were removed by r u p t u r i n g the b r e a k - s e a l a t D and condensing them i n t o a l i q u i d trap.  The white c r y s t a l s o f MeGaCl  9  isolated  nitrogen  (~95% y i e l d ) were  solvent divided  F i g u r e 10.  Apparatus f o r the p r e p a r a t i o n of MeGaCl  20  into smaller The  f r a c t i o n s and  ampoules were cracked  s t o r e d as THF open and  solutions in sealed  ampoules.  used f o r subsequent r e a c t i o n s when  needed. iv)  Preparation  o f the  tricarbonyltris(acetonitrile)-  molybdenum(O) (MeCN) Mo(C0) 3  Mo(C0)  c  + 3MeCN  M  In a t y p i c a l ~1  g Mo(C0)  6  preparation,  i n a 250  then r e f l u x e d f o r ~3  mL  few  3  compound was  3  The  THF)  3  (vCQ:  mL)  was  added t o  r e a c t i o n mixture  was  were recovered  cooled  Yellow-green,  1918(s), 1781(s)  s i n c e i t i s unstable  cm" , 1  i n almost q u a n t i t a t i v e  even under  I t i s recommended t h a t the compound  attempts at the  (~60  then used i n subsequent r e a c t i o n s no more than a  days a f t e r p r e p a r a t i o n  prepared i n small  3C0  3  s t r i p p e d o f f i n vacuo.  (MeCN) Mo(C0) 1  conditions.  (MeCNkMofCOh +  r e s u l t i n g y e l l o w - g r e e n s o l u t i o n was  solvent  1912(s), 1773(s) cm" , The  v days N  excess a c e t o n i t r i l e  The  the  a i r - s e n s i t i v e c r y s t a l s of  yield.  C  [50]  round-bottom f l a s k .  days.  to room temperature and  Nujol;  e  ~3  6  3  quantites  preparation  inert  (MeCN) Mo(C0) 3  at a time, s i n c e from our  be  3  experience,  of l a r g e r q u a n t i t i e s i n a s i n g l e  several  preparation  always r e s u l t e d i n a mixture of compounds. The  compound  most of the acetonitrile therefore  reactions  3  discussed  3  i s p r e f e r r e d as the  s t a r t i n g material  in  i n t h i s t h e s i s p r i m a r i l y because  i s a l i g a n d which has  very  little  prc-dTc  the m o l y b d e n u m - a c e t o n i t r i l e bond i n the  i s weak, and [52],  (MeCN) Mo(C0)  the a c e t o n i t i l e l i g a n d i s e a s i l y  bonding a b i l i t y  (MeCN) Mo(C0)  replaced  3  from the  3  [51];  complex complex  21  1.3  Physical  l  H  Measurements  nmr s p e c t r a were recorded on a Bruker WP-80 instrument u s i n g  F o u r i e r Transform  techniques.  A Bruker WH-400 o r a N i c o l e t - O x f o r d H-270  spectrometer was employed whenever a more d e t a i l e d spectrum was d e s i r e d .  Samples were prepared by condensing  amount o f d e u t e r a t e d s o l v e n t  (CgDg, CDCI3 or dg-acetone,  Canada Inc.; and d g - t o l u e n e , Merck Sharp s o l i d material  c o n t a i n e d i n an nmr tube.  f l a m e - s e a l e d under vacuum. residual  or enhanced  Chemical  protons o f the i n t e r n a l  resolution  the a p p r o p r i a t e  Merck F r o s t  and Dohme Canada Ltd.) onto the The nmr tube was subsequently  s h i f t s were measured r e l a t i v e t o t h e  s t a n d a r d where Q H t  =  2  «84 ppm, ^  C  H  C  =  1  6 6 2.73  ppm, r  {  C  H  ^ ^  Q  = 7.89 ppm, and *  T o l u e n e  3  _ M e = 7.91 ppm.  I n f r a r e d s p e c t r a were recorded on a Perk i n Elmer 598 double beam spectrometer.  Samples were prepared as s o l u t i o n s , u s u a l l y  in dichloro-  methane, cyclohexane  or THF (KBr and C s l s o l u t i o n c e l l s ) ,  mulls  The s p e c t r a were c a l i b r a t e d with t h e 1601 c m  (KBr p l a t e s ) .  or as Nujol - 1  band  of p o l y s t y r e n e . Mass s p e c t r a were recorded on a Kratos AES MS 50 spectrometer equipped with a d i r e c t h i g h e r m o l e c u l a r weight  i n s e r t i o n probe  and i n t e r f a c e d t o a computer f o r  (>500 amu) compounds or a VARIAN MAT CH4  spectrometer f o r low m o l e c u l a r weight  (<500) compounds.  i n t e r p r e t a t i o n o f f r a g m e n t a t i o n p a t t e r n s was s i m p l i f i e d comparison  o f the observed  intensity  In g e n e r a l , by d i r e c t  p a t t e r n s t o the t h e o r e t i c a l  p a t t e r n s generated by computer s i m u l a t i o n from the n a t u r a l abundances o f the elements.  intensity  isotopic  22  Crystallographic  d e t e r m i n a t i o n s were conducted  u s i n g g r a p h i t e monochromated Mo-K diffractometer.  a  crystals  r a d i a t i o n on an Enraf-Nonius  T h i s work was performed  Crystallography Laboratory.  on s i n g l e  CAD4-F  by Dr. S. R e t t i g o f the U.B.C.  Stereodiagrams  and r e l a t e d bond d i s t a n c e s and  a n g l e s are c o l l e c t e d i n Appendix I . Elemental Microanalytical  a n a l y s e s were performed Laboratory.  by Mr. P. Borda o f the U.B.C.  23  Chapter  II  THE MOLYBDENUM TRICARBONYL ANION  [MeGapz ]Mo(C0) ; 3  SYNTHESIS AND CHARACTERIZATION OF THE N a , E t ^ N +  3  AND HAsPhJ SALTS,  +  AND INVESTIGATION OF THE REACTIVITY TOWARDS ALKYL HALIDES, PROTONATING SPECIES AND HALOGENS.  2.1  INTRODUCTION  The u n i n e g a t i v e , alkyl,  aryl,  analogous MeGapz  3  tridentate,  pyrazolyl,  react  (Cp~)  yielding  R B ( 3 , 5 - M e 2 P z ) 2 , MeGapz^)  N C H ) 2  3  gives  3  The  directly  CpMo(C0)  anion  3  the n - a l l y l another  reacts  with  Differences  o f LMo(C0)  and P h B p z derivatives allyl  3  3  with  halides  in behaviour:  (L = R B p z , 3  3  and i s o l a b l e  (R = H,  3  of CO.  t o give the  allyl  in  There  contrast  some-  halides  In c o n t r a s t ,  a-allyl  is,  t o the  as  pyrazolyl,  the  complex  o n l y upon UV i r r a d i a t i o n [55,56].  the  and  i n b e h a v i o u r are  anions w i t h  loss  3  to  tris(acetonitrile)-  anion,  3  [ L = RBpz  [54])]  CpMotCO^ft-allyl)  difference  or  o f t h e t y p e LMo(C0)  which decarbonylates  derivative  notable  [34],  the n - a l l y l  CpMo(C0) (a-allyl), 3  3  RBpz^ (R = H,  F o r example t h e RBpz  t o t h e CpMo(C0)  [53,54].  reaction  [ 5 3 ] , MeGapz  anions  analogous  the tetraethylammonium s a l t s observed.  ligand.  w i t h molybdenum h e x a c a r b o n y l  molybdenum t r i c a r b o n y l  times  donor ligands  N2C3H3), and MeGapz^ show many s i m i l a r i t i e s  cyclopentadienyl  ligands  six-electron  to  give  however, numerous  24  seven-coordinate cyclopentadienyl complexes generally denoted as CpMl_  4  [57], r e l a t i v e l y few of such d e r i v a t i v e s are known f o r the p o l y ( l pyrazolyl )borate complexes.  The reported examples of seven-coordinate  p o l y ( l - p y r a z o l y l )borate complexes are [HBpz ]Mo(C0) R 3  3  [53], [HBpz ]W(C0) (CS)I [ 5 8 ] , [RBpz ]TaMe Cl 3  2  3  recently [HBpz ]Mo(C0) X 3  3  (R = H, Me, E t )  (R = H or pz) [59], and most  (X = H, Br, I) [60]. The e l e c t r o n i c nature of  3  the HBpz ligand has been shown t o be considerably d i f f e r e n t from that of 3  the Cp" ligand i n that the former hybridizes the metal o r b i t a l s i n t o an octahedral d i s p o s i t i o n much more e f f e c t i v e l y than does the Cp" ligand [36,60].  The propensity of the molybdenum t r i c a r b o n y l  incorporating the RBpz  3  complexes  ligand t o remain p r e f e r e n t i a l l y six-coordinate i s  manifested i n the s t a b i l i t y of the radical species [HBpz ]Mo(C0) * [38], 3  3  i n contrast, t o the analogous CpMo(C0) » [61], and (ri-CgMeg)Mo(C0) [62] #  3  3  radical species which are unstable with respect t o t h e i r [CpMo(C0) ] and 3  [(ri-CgMeg)Mo(C0) ] dimer precursor. 3  2  2  Comparison of the chemistry of  compounds incorporating the RBpz , MeGapz and Cp" ligand systems was 3  3  therefore considered t o be i n s t r u c t i v e e s p e c i a l l y where the coordination number about the central metal atom i s greater than s i x .  The 3:4 or  "four-legged piano s t o o l " structure i s the paradigm f o r seven-coordinate CpMI_ complexes of group 5 and 6 t r a n s i t i o n metals [63]. 4  At the inception of t h i s work, only one type of molybdenum TI -acyl complex incorporating the t r i d e n t a t e poly (1-pyrazolyl )borate l i g a n d , [HB(3,5-Me pz) ]Mo(C0) (n -C0R) 2  2  3  2  (R = Ph, C H NMe -p, C H CF -p, C H Me-p, g  4  2  g  4  3  g  4  25  C H g  1 1  The o t h e r examples are [ H B p z ] M o ( C 0 ) ( T f - C 0 R )  ) [ 3 2 ] was known.  Me, Ph) [64,65] and t h e i r phosphine adducts t h i s work.  of the r e l i e f  of s t e r i c  (R =  reported d u r i n g the course of  In the l a t t e r examples, the authors  the combination  2  3  concluded t h a t  c o n g e s t i o n and o r b i t a l  hybridiza-  2 t i o n f a v o r e d the t r a n s f o r m a t i o n of [HBpz ]Mo(C0) R 3  [HBpz ]Mo(C0) (T] 3  -COR)  2  effects  (relief  potentially  [ 6 5 ] . We  of s t e r i c  3  reasoned  t h a t the combination  c o n g e s t i o n and o r b i t a l  s t a b i l i z e the i s o e l e c t r o n i c ,  t o the r\ -acyl  complex  of both  h y b r i d i z a t i o n ) could  isostructural  [MeGapz ]Mo3  2 ( C 0 ) ( T ) -COR) 2  (R = Me, Ph) complexes i n a manner s i m i l a r t o the boron  system. The LMo(C0)  3  (L = MeGapz , MeGa(3,5-Me pz) ) anions 3  i s o l a t e d as t h e i r N a , E t ^ N +  i n t e r a c t with the N a  +  +  2  and HAsPh  3  3  salts.  have been  The LMo(C0)  anions  3  c a t i o n i n THF, and i r s p e c t r o s c o p i c evidence f o r  this  a n i o n - c a t i o n i n t e r a c t i o n i n THF i s presented and d i s c u s s e d .  this  result  c o n s t i t u t e s the f i r s t  of the LMo(C0)  (L = RBpz  3  3  3  3  3  (C0) R 3  as THF.  anion toward a l k y l  s p e c i e s and halogens  dissociative  The general  h a l i d e s , benzoyl  has been i n v e s t i g a t e d .  (R = H, E t ) have been prepared  exhibit  involvement  o r MeGapz ) anion i n i o n - p a i r i n g with c a t i o n s  i n b a s i c and p o l a r s o l v e n t s such [MeGapz ]Mo(C0)  reported o b s e r v a t i o n of the  Thus,  phenomena  i n THF.  reactivity  of the  chloride, protonating  The compounds  [MeGapz ]Mo3  and the hydride has been shown t o The compound  [MeGapz ]Mo3  2 (C0) (TI -COMe), a product  of f a c i l e  presented  An X-ray  2  and d i s c u s s e d .  alkyl crystal  t o CO m i g r a t i o n r e a c t i o n , i s structural  d e t e r m i n a t i o n of the  26  [HAsPh ] [MeGa(3,5-Me pz) Mo(C0) ]~ s a l t  is currently  +  3  2  3  3  P a r t s of t h i s c h a p t e r have been submitted  2.2  in progress.  for publication  [66].  EXPERIMENTAL  2.2.1  Starting  Materials  Triphenylarsonium chloride chloride HCl(g)  (Strem C h e m i c a l s ) ,  (Eastman Organic C h e m i c a l s ) , e t h y l  (Matheson),  chloride  bromide ( A l l i e d  as s u p p l i e d .  the m e t h y l t r i s ( 1 - p y r a z o l y l ) g a l l a t e Na MeGapz dimethyl-l-pyrazolyl)gallate previously.  Glacial  acetic acid  sodium s a l t s of methyltris(3,5as  +  2  iodide  stored  2  3  benzoyl  N a [ M e G a ( 3 - 5 - M e p z ) ] ~ [35] were prepared  Methyl  over P 0g and  The  [ 3 4 ] , and  +  distillation  Chemicals),  DBr(g) (Merck Sharpe and Dohme), methanol and  ( F i s h e r S c i e n t i f i c ) were used  described  tetraethylammonium  3  ( F i s h e r S c i e n t i f i c ) was  over mercury d r o p l e t s  ( A l l i e d Chemicals)  was  dried  before  by  use.  d r i e d a c c o r d i n g to l i t e r a t u r e  methods [ 4 5 ] , 2.2.2  P r e p a r a t i o n of N a L M o ( C 0 )  (L = MeGapz , MeGa(3,5-Me pz) )  +  N a L " + (MeCN) Mo(C0)  3  3  +  3  A 30 ml  T  H  >  F  3  a l i q u o t of Na MeGapz +  3  s o l u t i o n of (MeCN) Mo(C0)  same s o l v e n t .  reaction  The  3  c h a r a c t e r i s t i c of the  mixture was  (MeCN) Mo(C0) 3  3  3  Na LMo(C0)~ + 3MeCN +  (~0.51 mol)  added to a s t i r r e d  2  3  ligand solution (0.154 g, 0.510  stirred until  s t a r t i n g material  i n THF  was  mmol) i n the  the V ^ Q bands had  disappeared.  27  The  s o l v e n t s were then allowed t o evaporate  amber c o l o r e d s o l i d The  salt  Both Na  of the d e s i r e d  Na [MeGapz Mo(C0) ]~. +  3  2  3  3  precluded s a t i s f a c t o r y  by t h e i r s o l u t i o n  3  3  cm" ; I R ( C H C 1 ) \> :  C Q  :  1895(s), 1775(s),  1888(s), 1760(br) c m .  1  H  -1  CQ  NMR  l  T ( C H ) C 0 = 7.89 ppm, 9.58s (Ga-Me); 3.83t 3  of these  a n a l y s e s , however they were c h a r a c t e r i z e d  IR(THF) v  +  2  The pronounced i n s t a b i i t y  i r and *H nmr s p e c t r a .  For Na [MeGapz Mo(CO) ]": 2  3  by a s i m i l a r method.  +  s a l t s were very a i r - s e n s i t i v e .  MHz):  salt,  N a [ M e G a ( 3 , 5 - M e p z ) M o ( C 0 ) ] ~ was prepared  salts  +  product  from t h e mixture t o give an  1720(s)  ( d - a c e t o n e , 80 g  ( p z - H ) ; 2.35d  (pz-H );  4  2  5  3 2.00d  (pz-H ).  (^HCCH  ~  =  ^  2  Z  ^  ^  0 r  P  Z  r o t o n s  IR(THF) v  For N a [ M e G a ( 3 , 5 - M e p z ) M o ( C 0 ) ] " : +  2  3  3  1710(s) cm" ; I R ( C H C 1 ) v : 2  6  (pz-Me ); 2.2.3  1890(s), H  l  1765(s),  NMR  = 7.89 ppm, 9.54s (Ga-Me); 7.78s  2  4.38s  3  (pz-H ). 4  P r e p a r a t i o n of [ E t N ] [ M e G a p z M o ( C 0 ) ] ~ +  4  Na MeGapz +  3  + (MeCN) Mo(C0)  Na MeGapz Mo(C0)  3  +  3  3  T  + Et N Cl"  T  H  4  THF s o l u t i o n  added a 60 ml a l i q u o t  H  3  F  Na MeGapz Mo(C0) +  3  >  +  i r spectrum  + 3MeCN  +  4  3  The r e a c t i o n mixture was s t i r r e d  3  [ E t N ] [ M e G a p z M o ( C 0 ) ] " + NaCl  of (MeCN) Mo(C0)  of the Na MeGapz  which time t h e s o l u t i o n  >  F  3  +  3  To a s t i r r e d  THF.  3  7.19s (pz-Me );  5  : 1  QQ  x(CH ) C0  ( d - a c e t o n e , 80 MHz):  C Q  1885(s), 1745(br) cm" .  1  2  *)  3  3  3  3  (0.309 g, 1.02 mmol) was  (~1.20 mmol) l i g a n d s o l u t i o n i n at room temperature  of the mixture  overnight at  indicated  complete  28  formation  +  3  An equimolar MeOH was  amount of Et_,N Cl~  collected  stirred  and  [Et N] [MeGapz Mo(C0) _f 3  d e t e r i o r a t e with  IR(CH C1 ) v 2  ppm,  3  2  C  :  Q  dried  H  -1  The  salt.  r e s u l t i n g cloudy  The y e l l o w p r e c i p i t a t e  This s a l t  yellow  was  i s unstable  (d -acetone, g  2.27d  4  2  3  H  C  C  270  MHz):  (pz-H );  i n a i r and  1885(s),  x(CH ) C0 = 3  1.92d  5  = ~2  H  v ^ :  IR(Nujol)  1  (N-CH -CH ); 6.41br (N-CH -CH ) ( J 2.2.4  THF)  -1  i n vacuo t o give the d e s i r e d product  (pz-H );  3  cm ,  mmol) d i s s o l v e d i n ~5 ml  1760(br) cm" ;  NMR  l  9.57s (Ga-Me); 3.8H 2  1720  time.  1890(s),  1730(s) cm .  1775,  solution.  i n ~40% y i e l d .  +  solutions  salt  f o r another hour.  by f i l t r a t i o n  4  1895,  (0.169 g, 1.02  +  added t o the carbonyl  s o l u t i o n was  1752(s),  (vCQ  of the Na MeGapz Mo(CO)~  Hz f o r pz  2  (pz-H ); 3  7.89  8.57br  protons.)  P r e p a r a t i o n of [ H A s P h ] [ L M o ( C 0 ) ] " (L = MeGapz +  3  3  3>  MeGa(3,5-Me pz) ) 2  3  Na LMo(C0)~ + HAsPh Cl" +  T  3  To the s t i r r e d was  THF  solution  added s o l i d H A s P h C l ~  heated  3  F  >  [ H A s P h ] [ L M o ( C 0 ) ] " + NaCl +  3  3  of Na MeGapz Mo(C0)  (~0.85 mmol) s a l t  +  3  g 0.85  mmol).  under n i t r o g e n at r e f l u x temperatures  s o l u t i o n was yellow  (0.29  H  The  3  r e s u l t i n g mixture  overnight a f t e r which the  cooled and the s o l v e n t removed i n vacuo.  residue was  e x t r a c t e d with  benzene and  The  filtered.  resulting  Upon e v a p o r a t i o n  of the benzene s o l v e n t c o n t a i n i n g the e x t r a c t s , a y e l l o w s o l i d obtained. afforded  R e c r y s t a l l i z a t i o n from C H C l / h e x a n e 2  golden y e l l o w  needles  2  was  was  (1:1) mixed s o l v e n t s  of the d e s i r e d [ H A s P h ] [ M e G a p z M o ( C 0 ) ] ~ +  3  3  3  29  s a l t i n -90% y i e l d .  The s a l t [ H A s P h ] [ M e G a ( 3 , 5 - M e p z ) M o ( C 0 ) ] " was +  3  2  3  3  p r e p a r e d v i a a s i m i l a r procedure except t h a t t h e r e s i d u e was e x t r a c t e d with CH C1 2  2  and hexane was added to the C H C 1 2  filtrate.  2  i s o l a t i o n o f the p r o d u c t w i t h o u t benzene s o l v a t i o n .  T h i s enabled the  Both o f the above  s a l t s a r e c o n s i d e r a b l y more s t a b l e e i t h e r as s o l i d s or i n s o l u t i o n the c o r r e s p o n d i n g N a or E t ^ s a l t s  respectively.  +  A n a l . C a l c d . F o r [HAsPh ] [MeGapz Mo(C0) ]"« 0.75 CgHg:  C, 5 1 . 2 6 ; H,  +  3  3.91;  N, 1 0 . 1 1 .  Found:  IR(THF) v  1  v  C Q  3  3  C, 5 1 . 4 1 ; H, 3.54; N, 9 . 9 4 .  1 8 9 0 ( s ) , 1750(br) c m " ;  C Q  3  2  (pz-H );  2.05s  3  (As-__).  (J  (pz-H );  1  CQ  2  C, 5 1 . 8 3 ; H, 4 . 6 7 ;  (pz-Me );  4.38s  2.2.5  3  IR(CH C1 ) v : 2  1  T ( C H ) C 0 = 7.89 ppm, 9.55s  3  3  2  1885(s),  CQ  1 8 8 5 ( s ) , 1750(br) c m " . H NMR ( d g - a c e t o n e ,  80 MHz):  3  (Ga-Me);  2  ( p z - H ) ; 2.09s 4  (As-Ph);  l  7.80s  ( p z - M e ) ; 7.21s 5  2.61s ( A s - H ) .  Attempted P r e p a r a t i o n of [MeGapz ]Mo(C0) H u s i n g A c e t i c 3  A THF s o l u t i o n o f the N a MeGapz Mo(C0)  3  +  3  glacial  acetic acid.  benzene and f i l t e r e d .  3  Acid  s a l t was a c i d i f i e d  The r e a c t i o n m i x t u r e was s t i r r e d o v e r n i g h t ,  s o l v e n t removed under vacuum.  :  = ~2 Hz f o r pz p r o t o n s . )  H C C H  C, 5 2 . 4 3 ; H, 4 . 8 0 ; N, 9 . 2 2 .  1740(br) c m " ; IR(THF) v :  C Q  5  +  3  Found:  v  2.35d ( p z - H ) ; 1.98d  4  A n a l . C a l c d . For [ H A s P h ] [ M e G a ( 3 , 5 - M e p z ) M o ( C 0 ) ] " : N, 9 . 8 1 .  2  *H NMR ( d g - a c e t o n e , 80 MHz):  (Ga-Me); 3 . 8 3 t  ( A s - P h ) ; 2.58s  2  1  1  -u(CH ) C0 = 7.89 ppm, 9.56s  IR(CH C1 )  1 8 9 0 ( s ) , 1755(br) c m " ; I R ( N u j o l )  :  1 8 8 5 ( s ) , 1 7 6 0 ( s ) , 1735(s) c m " .  :  than  with and the  The r e s u l t i n g r e s i d u e was e x t r a c t e d w i t h  O r a n g e - y e l l o w s o l i d s were r e c o v e r e d upon  e v a p o r a t i o n o f the benzene s o l v e n t c o n t a i n i n g the e x t r a c t s .  Both the i r  30  and  H nmr data  for this  product  i n d i c a t e d the presence of perhaps two  compounds.  IR(THF):  IR(C H ):  1950, 1935, 1912, 1810 cm" .  g  1960, 1930, 1910, 1810, 1895, 1775, 1725 cm' . 1  1  1 2  X  H NMR  (dg-acetone, 80 MHz):  x ( C H ) C 0 = 7.89 ppm, 10.14s, 9.63s (Ga-Me); 3.88t, 3.83t 3  2.33d The  (pz-H );  2.05d, 1.90d ( p z - H ) .  5  i r  bands at 1895, 1775, 1725 cm"  Na MeGapz Mo(C0) +  3  suggestive  3  protonate  protonation  protonating  as the p r o t o n a t i n g Preparation  H  = ~2 Hz f o r pz p r o t o n s . )  those  obtained  (see s e c t i o n 2.2.2).  of the MeGapz Mo(C0) 3  s p e c i e s may be necessary repeated  This i s  anion  3  f o r the  by a c e t i c  to f u l l y  using the strong  acid  of [MeGapz ]Mo(C0) H using HCl  3  solution  C  2.40d,  species. 3  3  + HCl (g)  +  An  C  The r e a c t i o n was then  Na MeGapz Mo(C0)  The  4  i n THF, and one s e t of s i g n a l s  1  s t a r t i n g material  of incomplete  the anion.  H  compared q u i t e well with  salt  a c i d ; hence a s t r o n g e r  2.2.6  (J  3  i n t h e *H nmr spectrum,  HCl,  (pz-H );  2  3  T H F  >,  MeGapz Mo(C0) H + NaCl 3  3  equimolar amount of HCl(g) (~0.5 mmol) was condensed i n t o a THF c o n t a i n i n g t h e Na MeGapz Mo(C0) +  3  3  (~0.51 mmol) s a l t  under vacuum.  r e a c t i o n mixture was warmed up t o room temperature and the r e s u l t i n g  orange s o l u t i o n was s t i r r e d vacuo, and the r e s u l t i n g of the hexane f i l t r a t e  f o r ~2 h.  r e s i d u e e x t r a c t e d with  of t h i s  hexane.  removed i n  Upon  containing the e x t r a c t s , a i r - s e n s i t i v e  s o l i d s of the d e s i r e d hydride decomposition  The s o l v e n t was then  s p e c i e s were obtained  compound occurs  evaporation orange  i n ~60% y i e l d .  i n the b a s i c and weakly  polar  Slow  31  solvent,  THF.  F o r example, t h e i r spectrum of t h e h y d r i d e  showed t h e p r e s e n c e the acid-base  of t h e MeGapz^Mo(C0)  dissociation  anion  3  species  i n THF  presumably emanating  from  o f t h e Mo-H bond i n t h e M e G a p z ^ M o ( C O ^ H  complex. Anal. 16.48.  Calcd.  Found:  f o r MeGapz Mo(CO) H 3  C, 3 7 . 2 1 ;  H, 3 . 6 2 ; N, 1 6 . 4 1 .  1 9 0 8 ( s ) , 1808(s) c m " .  1928(s),  1  = 7 . 8 9 ppm, 9 . 9 0 s  l  (Mo-IH).  ( HCCH  2.2.7  Preparation  J  of  ~  =  2  H z  f  containing under  o  r  p  z  resulted  f o r ~2 h .  i n an o r a n g e  MeGapz Mo(C0) D 3  the  3  product  anion,  acid-base similar  sticky  product  displayed  anion  3  e  C  o  n  s  T(CH ) C0 3  2  (pz-H ) 3  ')  M  >  N  MeGapz Mo(C0) D 3  3  i n t o a MeCN  as i t s H A s P h  3  salt  of t h e dark  solid.  g  g  3  solution  ( 0 . 5 0 g , 0 . 6 6 mmol)  This  orange  product  reaction is  very  i n THF s o l u t i o n ,  characteristic  of the d e u t e r i d e  mixture  air-sensitive  The s o l u t i o n  indicated the formation  However, bands  the i r spectrum of  of t h e M e G a p z M o ( C 0 ) 3  species.  species  3  Evidently, 3  in the hydride  ir  of t h e e x p e c t e d  o f t h e Mo-D bond i n t h e M e G a p z M o ( C 0 ) D  observed  + HAsPh Br"  m i x t u r e was warmed t o room t e m p e r a t u r e a n d  in C H  to those  dissociation  to that  t  5  i n a m a t t e r of m i n u t e s .  deuteride.  in addition  300 M H z ) :  3  Work-up  deteriorate  spectrum of t h i s  o  o f D B r ( g ) was c o n d e n s e d  The r e a c t i o n  and s o l u t i o n s  r  3  3  then s t i r r e d  P  1952(w),  ):  ( p z - H ) ; 2.16d  4  3  the MeGapz Mo(C0)  vacuum.  1 4  [MeGapz ]Mo(C0) D  3  excess  G  ( p z - H ) ; 2.50d  +  A slight  IR(C H  H NMR ( d - a c e t o n e ,  [HAsPh ] [MeGapz Mo(C0) ]" + DBr(g) 3  C , 3 7 . 6 7 ; H, 3 . 9 2 ; N,  g  (Ga-Me); 3.60t  18.50s  • 0.5 C g H ^ :  3  3  (Section 2.2.6)  complex is  32  operative cm" .  i n THF  solution.  IR(CH C1 ):  1  2  2  IR(C H ): 6  1935(s), 1910(s), 1845(w), 1380(w)  g  1940(s), 1905(m), 1838(w) cm" .  1905(s), 1830(m), 1380(w); 1885(s), 1770(br) the c r y s t a l l i z a t i o n  of t h i s  c h a r a c t e r i z a t i o n was  cm" . 1  Persistent  attempts  product were u n s u c c e s s f u l ; hence no  at  further  performed. 2  2  3  Na MeGapz Mo(C0)3 + Mel +  T  H  >  F  3  To a THF Na  salt  +  orange-red  solution was  then s t i r r e d  The  1  of the MeGapz Mo(C0) 3  Mo(C0) Me' i n s o l u t i o n . 3  MeGapz Mo(C0) 3  probably  3  r e s i d u e was  e x t r a c t e d with  added t o the  1920  and  CH C1 9  9  After stirring  2  and  filtrate.  at  ~1570  i n t e r m e d i a t e 'MeGapZgbands due  t o the  f o r ~4 days, i s  i n THF.  vacuum.  filtered.  the  presumably  1  of the  reaction  removed under 2  cm"  after stirring  of t h i s  CH C1  1955  a-methyl  However, the presence  of a low y i e l d  dark  at which  weak a b s o r p t i o n band appeared  of a t r a n s i e n t  and the u n r e a c t e d Mel were then  resulting  bands i n the V ^ Q region of  anion i n THF.  anion i n s o l u t i o n , even  indicative  hexane was  1  3  The  i n a d d i t i o n t o the V ^ Q bands  cm" ,  bands observed at 1970,  emanated from the presence  (1.28 mmol) anion as  3  f o r about 2 days  showed new  and 1855  mixture f o r another 2 days, a new cm" .  2  i n the same s o l v e n t .  of the mixture  at ~1970, 1920  characteristic  2  3  3  r e a c t i o n mixture was  the spectrum  MeGapz Mo(C0) (n -C0Me) + Nal  c o n t a i n i n g the MeGapz Mo(C0)  added excess Mel  stage the i r spectrum  red  1940(s),  P r e p a r a t i o n of [ M e G a p z ] M o ( C 0 ) ( T ] - C 0 M e )  2.2.8  its  IR(THF):  1  The  The  solvent  resulting  An equal  dark-  amount of  Upon e v a p o r a t i o n of the mixed  33  CHgClg/hexane s o l v e n t s , a i r - s e n s i t i v e were o b t a i n e d i n ~30%  b r i c k - r e d c r y s t a l s of the  yield.  A n a l . C a l c d . For [ M e G a p z ] M o ( C 0 ) ( r i - C 0 M e ) :  C, 34.95; H,  2  2  3  17.48.  Found:  C, 35.10, H,  1855(s), 1570(w) cm" . 1  ppm,  1  H  3.16  NMR  17.15.  (dg-acetone,  IR(CH C1 ): 2  T(CH ) C0 =  80 MHz):  (pz-H ); 3  6.60s (-COMe). i n a 2:1  P-2C0 , P-3C0 , and P-3C0-Me +  (J  +  H  C  C  H  ratio.  3  7.89  2  2.06d,  5  = ~2  Hz f o r pz protons.)  MS:  P,  (P = p a r e n t )  +  N,  1980(s),  2  4  r i n g protons appeared  Pyrazolyl  P-Me , P-C0 , P-C0-Me ,  +  +  +  +  ion s i g n a l s were d i s p l a y e d .  Attempted P r e p a r a t i o n of [MeGapz ]Mo(C0) (T) -C0Ph)  2.2.9  2  2  3  9  THF  +  Na MeGapz Mo(C0) 3  Excess solution  benzoyl  f o r ~2  chloride  i n THF  then  f l a s k was  3  [MeGapz ]Mo(CO) (n -COPh) + NaCl 3  was  2  added p o r t i o n - w i s e to a  (~0.35 mmol) s a l t .  h a t which stage the i r spectrum  the complete  o i l and  The  3  s l o w l y poured  off.  e x t r a c t e d with C H C 1 2  2  The and  Hexane was  dark  solid  filtered.  3  added to the  residue l e f t  sufficient  The  very low y i e l d  of t h i s experiment.  f o r o b t a i n i n g an i r spectrum.  cm"  1.  mixture  solution  anion.  The resulting  behind i n the  Work-up of the C H C 1 2  c o n t a i n i n g the e x t r a c t s a f f o r d e d dark b l u e c r y s t a l s i n very low y i e l d .  THF  reaction  of the dark  consumption of the MeGapz Mo(C0)  removed under vacuum.  discouraged r e p e t i t i o n  1535(w)  — — — > ~*C 0  3  s o l v e n t was  product  + PhCOCl  +  heated  filtrate  3  of the Na MeGapz Mo(C0)  indicated  dark  N,  3.12;  9.30s (Ga-Me); 3.63t, 3.53t ( p z - H ) ; 2.46d, 2.24d ( p z - H ) ;  1.95d  was  product  (<5%)  of t h i s  However the y i e l d IR(CH C1 ): 2  2  2  of the product was  1965(s),  1820(s),  34  2.2.10  P r e p a r a t i o n of [MeGapz ]Mo(C0) Et 3  Na MeGapz Mo(C0) 3  3  3  + EtBr  — [ M e G a p z  A 5 0 - f o l d excess of EtBr i n THF was the Na MeGapz Mo(C0) +  3  was  stirred  stirring vacuo.  (~0.68 mmol) s a l t  at r e f l u x temperatures, The r e s u l t i n g  reddish-brown  solids  3  resulted  ( p z - H ) 8.15br 3  pz protons.) was  observed  N, 16.33. 1  ppm;  removed i n  E v a p o r a t i o n of  i n a dark-brown  9.53s  2  H  NMR  1  (Ga-Me); 3.81  (Mo-Et-C_H_ ); 6.32br 3  2  1970(s),  (pz-H );  4  (Mo-Et-C_H_ ). 2  (J  H  C  C  5  H  c o r r e s p o n d i n g t o the P-3C0-Et  +  ion were  compound.  observed.  16.98.  1930(s),  g  ( p z - H ) ; 2.36  of t h i s  N,  ( d - a c e t o n e , 270  MHz): 1.97  - unresolved f o r  E x c e s s i v e fragmentation i n d i c a t i v e of thermal i n the mass spectrum  afforded  or i n s o l u t i o n .  C, 36.39; H, 3.44;  IR(CH C1 ) :  sticky  The compound i s  c o n d i t i o n s e i t h e r as a s o l i d 3  mixture  f o l l o w e d by another day of  of the product i n low y i e l d s .  1890(s), 1755(br) cm" .  2  The  2  C, 36.55, H, 3.28,  ( C H ) C 0 = 7.89  t o a s o l u t i o n of  out of CH^Cl /hexane mixed-solvents  3  1  + NaBr  i n the same s o l v e n t .  A n a l . C a l c d . For [MeGapz ]Mo(C0) Et:  1820(s) cm" ;  E t  e x t r a c t e d with benzene.  from the e x t r a c t s  u n s t a b l e even under i n e r t  Found:  3  a f t e r which the s o l v e n t was  r e s i d u e was  Recrystal1ization  ] M o ( C 0 )  added dropwise  f o r ~1 day at room temperature  the benzene s o l v e n t solid.  3  3  decomposition  However, weak s i g n a l s  35  2.2.11  Attempted  P r e p a r a t i o n of [MeGapz ]Mo(C0) X 3  3  (X = B r , I)  Bromine (0.14 g, 1.7 mmol) i n THF was reacted with Na MeGapz Mo(C0) +  3  (0.85 mmol) s a l t the  solution  i n THF.  i r spectrum  3  The r e a c t i o n mixture was s t i r r e d o v e r n i g h t and of the mixture at t h i s stage showed t h r e e new V^Q _I  bands at 2010, 1975, 1930 cm removal  as expected f o r the product.  i n vacuo, e x t r a c t i o n  of the r e s i d u e with Q-^C^ and  r e c r y s t a l 1 i z a t i o n from CH C12/hexane mixed s o l v e n t s 2  The  i r spectrum  gave a y e l l o w s o l i d .  of the y e l l o w s o l i d showed t h r e e bands  cm" , CH C1 ; 2010, 1975, 1930 cm" , THF) i n the v C Q 1  spectrum.  2  The *H nmr spectrum  and dg-acetone compound.  attempts  1980, 1900  of t h i s y e l l o w s o l i d product i n both CDC1 ^  i n d i c a t e d decomposition of the expected  Repeated  (2010,  region of the  1  2  Solvent  at o b t a i n i n g a n a l y t i c a l l y  [MeGapz ]Mo(C0) Br 3  3  pure samples  of the  product were u n s u c c e s s f u l . Similarly, with  reaction  of i o d i n e  (0.108 g, 0.85 mmol) d i s s o l v e d  an equimolar amount of Na MeGapz Mo(C0) +  3  solid.  The i r spectrum  3  s a l t i n THF gave a dark red  of the s o l i d product showed t h r e e V^Q bands as  expected f o r the product but repeated r e c r y s t a l 1 i z a t i o n  out of  CHgC^/hexane s o l v e n t mixtures d i d not y i e l d an a n a l y t i c a l l y compound. cm" . 1  H  1  IR(THF): NMR  2015, 1972, 1928 cm" ; I R ( C H C 1 ) : 1  2  (dg-acetone, 80 MHz): 5  2  pure  2015, 1978, 1925  T ( C H ) C 0 = 7.89 ppm, 9.59s 3  2  3.87br ( p z - H ) ; 2.38br ( p z - H ) ; 2.03br ( p z - H ) . 4  i n MeCN  3  (Ga-Me);  36  2.3  R e s u l t s and D i s c u s s i o n  2.3.1  M LMo(C0)~ (L = MeGapz , MeGa(3,5-Me pz) ; M +  3  2  3  +  = N a , E t N , HAsPh*) +  +  4  salts The  p h y s i c a l phenomenon of i o n - p a i r i n t e r a c t i o n s o f group 1 and 2  c a t i o n s with  the carbonyl  w e l l - documented.  F o r example, the c r y s t a l  [CpMo(C0)3] Mg (C H N) 2 +  2  oxygen o f t r a n s i t i o n metal c a r b o n y l a t e s  5  5  has been  s t r u c t u r e s of  [ 6 7 ] , and [ ( C o ( s a l e n ) ) N a C o ( C O ) ~ T H F ] [68] have +  4  2  ?+ indicated and  Na  +  i n t e r a c t i o n s of the t r a n s i t i o n metal c a r b o n y l a t e s with  c a t i o n s i n the above complexes.  of t r a n s i t i o n metal carbonyl  anions  metal amalgam, or d i r e c t metal  A very common mode o f p r e p a r a t i o n  f o r f u r t h e r s y n t h e t i c purposes i s by  r e d u c t i o n s of the metal carbonyl  i n b a s i c , low p o l a r i t y , donor s o l v e n t s , t y p i c a l l y THF. carbonylate  anion/alkali  extensively  i n these  the Mg  precursors  T r a n s i t i o n metal  or a l k a l i n e e a r t h c a t i o n i n t e r a c t i o n s occur  systems.  The f i r s t  quite  i r s p e c t r o s c o p i c evidence f o r  i o n - p a i r i n g between a l k a l i - m e t a l c a t i o n s and metal carbonyl  anions i n  s o l v e n t s of moderate p o l a r i t y was r e p o r t e d sometime ago by E d g e l l e t a l . [69]. [70]  Since that o r i g i n a l salt,  analyses  r e p o r t and subsequent work on the N a C o ( C 0 )  of THF-solution  q u i t e s u c c e s s f u l l y to unravel CpFe(C0)  2  [71,72],  spectroscopy  +  V^Q i r s p e c t r a have been employed  a l k a l i - m e t a l c a t i o n i n t e r a c t i o n s with  and CpMo(CO)" (M = C r , Mo, W) [73] a n i o n s .  i n the v r n  4  region i s p a r t i c u l a r l y  Infrared  v a l u a b l e i n the study o f  37  interactions  involving direct  c o n t a c t of a n i o n ( s )  where the geometry of the f r e e c a r b o n y l a t e  anion  and c a t i o n ( s ) e s p e c i a l l y i s perturbed  by the  cation. The LMo(C0) prepared  3  salts.  HAsPh^ s a l t s .  C  3 y  i n THF s o l u t i o n , As an i l l u s t r a t i v e (M  +  3  3  shown i n f i g u r e 11. symmetry  g  for C  symmetry  s  sodium Na ,  3  MeGapz Mo(C0)  +  4  The i r s p e c t r a of the s a l t s  i n Ch^Clg  +  t h r e e s t r o n g bands were observed example, the s o l u t i o n +  1  3  anion  3  3  g  C  3 v  symmetry  symmetry  salts  ( T a b l e 1) shows the presence of a low frequency i n THF.  r e g i o n are  i n THF. i n the  Since vCQ  of the f r e e  upon p e r t u r b a t i o n by  A comparison o f the V ^ Q values  +  Na LMo(C0)Z s a l t s  salt  +  + A" modes), t h r e e bands are expected  c a t i o n i n THF.  +  bands i n THF i s s u g g e s t i v e  of the Na MeGapz Mo(C0)  has been reduced t o C  f o r the N a  i n the v C Q  +  4  The presence of t h r e e  anions.  i r s p e c t r a o f the  = N a , E t N , HAsPhJ) s a l t s  f o r the anion (2A  f o r the f r e e  the N a  +  have been  tetraethylammonium E t N , and  +  r e g i o n o f the spectrum, e v i d e n t l y the i n i t i a l 3  anions  s t r u c t u r e (A + E modes) as expected  M [MeGapz Mo(C0) ]"  of C  as t h e i r  2  d i s p l a y e d two s t r o n g bands i n the V ^ Q r e g i o n , c o n s i s t e n t with a  symmetrical However,  3  and i s o l a t e d  triphenylarsonium solution  (L = MeGapz , MeGa(3,5-Me pz) )  f o r the M L M o ( C 0 ) +  band f o r the  3  38  Figure 11.  Ir spectrum of M MeGapzoMofCO)? salts in the vCO region. a. M = Na in THF. b. M = Na in CH C1 . c. M = E t N in CH C1 . d. M = HAsPhJ in CH C1 . +  +  +  +  2  +  2  2  2  2  2  4  +  39  Table I.  v M  ( c m ) I n f r a r e d Data f o r M L M o ( C 0 ) - 1  C  Q  +  MeGa(3,5-Me pz) 2  +  SOLVENT  Na MeGapz Mo(C0)  CHgCl  +  3  3  Na MeGa(3,5-Me p z ) M o ( C O ) +  2  3  3  3  3  1760  1890  1755  1890  1750  THF  1885  1750  CH 2 C 1 2  1885  1740  2  HAsPh^MeGa(3,5-Me pz) 2  3  1710  1765  1890  2  2  +  1760  1765  2  A' (CO««-M )  1720  1890  CH C1  3  E  1775  1890  THF HAsPh MeGapz Mo(C0)  A"  1745  2  3  l  1885  CHgCi  CH C1  +  A  1888  2  THF Et N MeGapz Mo(C0)  A'  1895  THF  Mo(C0)~  3  4  THF  3  3  = N a , E t N , HAsPh* s a l t s ) .  +  COMPOUND  4  (L = MeGapz ,  +  40  The low frequency  band observed  oxygen perturbed by the N a Mo-C0"'Na . +  +  i n THF i s i n d i c a t i v e of a carbonyl  cation  i n an i n t e r a c t i o n o f the type  Such an i n t e r a c t i o n would l e a d to a c o l l a p s e o f the 'E'  v i b r a t i o n o f the  symmetry  of the unperturbed  anion  give the 'A'" and A' c o n t a c t modes o f the Cs symmetry  ( f i g u r e 12a) to o f the p e r t u r b e d  anion as shown i n f i g u r e 12b.  Me  Me  < 0 f ) O ><0(p> AK  Mo  Mo"  '3v  r  i g u r e 12.  A, • E  Na  C  R  : A' • A* • A'lcontact)  Proposed s t r u c t u r e s f o r the i n t e r a c t i o n s o f MeGapz-jMofCO)^ on. a n i o n with Na c a t i o n i n THF s o l u t i o n , a. Unperturbed anio b. Perturbed anion.  In t h i s type o f i o n - p a i r i n g e x t e r n a l to the c a r b o n y l a t e c o o r d i n a t i o n sphere,  s u b s t a n t i a l n - e l e c t r o n d e n s i t y i s expected  to r e s i d e i n the r e g i o n  41  of the l o n e p a i r s on the oxygen i n v o l v e d i n the i n t e r a c t i o n [ 7 4 ] . A molecular o r b i t a l  d e s c r i p t i o n o f the CO e l e c t r o n d e n s i t y i n t h i s  i n t e r a c t i o n i s shown i n f i g u r e 1 3 a .  In the p i c t u r e , t h e N a c a t i o n  is  +  p o s i t i o n e d f o r maximum i n t e r a c t i o n w i t h the e l e c t r o n d e n s i t y i n both the a and % o r b i t a l s .  In any c a s e , whether the arrangement i s o f a l i n e a r t y p e  ( f i g u r e 13b), or n o n - l i n e a r  ( f i g u r e 1 3 c ) , t h i s i n t e r a c t i o n would, of  c o u r s e , tend t o i n c r e a s e the CO bond o r d e r i n the n o n - i n t e r a c t i n g Mo-CO groups w i t h c o n c o m i t a n t decrease i n the CO bond o r d e r i n the Mo-C0*» Na #  group.  This p o l a r i z a t i o n of electrons  (electronic-drift)  m o l e c u l a r o r b i t a l , r e g i o n towards the M o - C 0 * " N a  * r e i n f o r c e the dn;(Mo) ->• n  +  +  i n the it-bonding  i n t e r a c t i o n s i t e , would  + (-C0**»Na ) backbonding component.  would be a decrease i n the  The r e s u l t  v a l u e f o r the CO group i n v o l v e d i n the  cation-anion contact i o n - p a i r i n g .  A l t e r n a t i v e l y , the  v a l u e s f o r the  CO groups not i n v o l v e d i n the i n t e r a c t i o n w i t h the N a c a t i o n would be +  i n c r e a s e d due to decreased c o m p e t i t i v e backbonding a b i l i t y by the CO groups f o r the Mo metal d e l e c t r o n s . The i r data f o r the Na L.Mo(C0) +  with t h i s observation.  3  s a l t s i n THF (Table I ) a r e i n a c c o r d  The s o l u t i o n i r spectrum o f the [Et_,N] [MeGapz Mo+  3  ( C 0 ) ] ~ s a l t i n THF i s r a t h e r i n t e r e s t i n g s i n c e i t d i s p l a y e d one s t r o n g 3  band a t ~1890 c m  - 1  , and a second c o n t i n u o u s broad band w i t h two o r more  maxima c e n t e r e d a t ~1765 c m  - 1  .  T h i s o b s e r v a t i o n may be s u g g e s t i v e o f some  p e r t u r b a t i o n o f the MeGapz^MofCO)^ a n i o n C c o n t a c t o f t h e anion w i t h the Et_jN c l e a r whether the E t ^ N in t h i s case.  +  +  3 v  symmetry, emanating from some  c a t i o n i n THF s o l v e n t .  I t i s not  c a t i o n i n t e r a c t s w i t h one o r more c a r b o n y l  However, an X - r a y c r y s t a l  oxygens  s t r u c t u r e study o f the r e l a t e d  42  F i g u r e 1 3 . Proposed c a t i o n (Na ) i n t e r a c t i o n w i t h MeGapz3Mo(CO)o a n i o n , e x t e r n a l to the Mo c o o r d i n a t i o n sphere i n THF. a . M.O d e s c r i p t i o n o f CO e l e c t r o n d e n s i t y , b. L i n e a r i n t e r a c t i o n , c. Non-linear i n t e r a c t i o n . [ M e N ] [ C p C r ( C 0 ) 3 _ " complex [ 7 5 ] has r e v e a l e d some e l e c t r o s t a t i c +  4  i n t e r a c t i o n between the Me^N c a t i o n and the CpCrfCO)^ anion i n the above +  salt.  The v .  v a l u e s f o r Na MeGapzJto(CO); (1895, 1775, 1720 c m ' , THF) +  1  43  compare n i c e l y with the V ^ Q values (vCQ  reported  (CO)^  salt  1796,  1743 cm" , THF) [73] r e s p e c t i v e l y .  recent  1  [67], and ( v  1  with c a t i o n s  review a r t i c l e s  The  +  1893, 1775, 1749 cm" , p y r i d i n e ) 1  carbonylates  independently f o r the Na CpMo-  i n low p o l a r i t y s o l v e n t s  has been d i s c u s s e d i n  [76,77]. +  3  3  3  This  i s i n d i c a t i v e of a symmetrical  in solution. in solution.  C  3 v  groups to be  s t r u c t u r e f o r the  S i m i l a r *H nmr s p e c t r a were obtained Detection  measurement of the perturbed  studies  pyrazolyl  d i s p l a y i n g one s i g n a l f o r each of the p y r a z o l y l r i n g proton  resonances.  unlikely  1899,  H nmr spectrum of the [ H A s P h ] [ M e G a p z M o ( C 0 ) ] ~ s a l t i n  equivalent,  studied  Q  I o n - p a i r i n g o f t r a n s i t i o n metal  dg-acetone s o l u t i o n ( f i g u r e 14) shows a l l the three  anion  C  of the asymmetry i n d i c a t e d by i r  anion  on the NMR time s c a l e .  f o r a l l the s a l t s  ( f i g u r e 12) i n THF would be r a t h e r  Oxygen-17 and carbon-13 nmr s p e c t r a l  have i n d i c a t e d , however, t h a t the l i f e t i m e of any one o f the  e q u a l l y probable C p M o ( C 0 ) C 0 " » * * N a 2  solution  i s shorter  +  i n t e r a c t i o n s i n the Na CpMo(C0) +  3  than the time s c a l e of an o b s e r v a b l e event using nmr  techniques  ( c a . 10  particular  i o n s i t e may be taken as the mean l i f e t i m e o f a c o l l i s i o n  and  i s on the order  spectroscopy ~10"  U  s) [ 7 7 ] .  of 1 0 "  1 1  The lower l i m i t o f the l i f e t i m e o f a  s [78], o b v i o u s l y  detectable  by i r  s i n c e the e x c i t e d s t a t e l i f e t i m e of an i r experiment i s  s [79].  salt  pair,  45  2.3.2  [MeGapz ]Mo(C0) H 3  3  I t was r e p o r t e d o r i g i n a l l y  that a c i d i f i c a t i o n  of [RBpz ]Mo(C0) 3  H, or p y r a z o l y l , N C H ) anions with a c e t i c a c i d y i e l d e d 2  3  3  [ R B p z ] M o ( C 0 ) H [53] a c i d s . 3  Similarly,  3  initially glacial  [55].  3  y e l l o w powdery s o l i d two in  3  3  from  3  anion  attempted  3  3  3  salt solution  +  isolated  the *H nmr spectrum 3  of the Na MeGapz Mo(C0)  Both the s o l u t i o n  compounds i n s o l u t i o n  MeGapz Mo(C0)  base CpMo(C0)  The p r e p a r a t i o n of [MeGapz ]Mo(C0) H was  by a c i d i f i c a t i o n  acetic acid.  the c o r r e s p o n d i n g  the weak a c i d CpMo(C0) H i s  r e a d i l y o b t a i n e d by p r o t o n a t i o n of the c o r r e s p o n d i n g with a c e t i c a c i d  (R =  3  with  i r and *H nmr s p e c t r a of t h e  the r e a c t i o n  i n ~2:1 r a t i o  i n d i c a t e d the presence of  (two Ga-Me s i g n a l s were  i n a 2:1 r a t i o ) .  observed  An incomplete p r o t o n a t i o n o f the  anion was t h e r e f o r e suspected.  A comparison o f the i r and  *H nmr data f o r the mixture, with those o b t a i n e d f o r the Na MeGapz Mo(C0) +  3  salt  ( s e c t i o n 2.2.2), confirmed  t h a t the s p e c i e s r e s p o n s i b l e f o r the  weaker s e t of s i g n a l s emanated from The  [MeGapz ]Mo(C0) H hydride s p e c i e s . 3  t h a t the MeGapz Mo(C0) 3  CpMo(C0) acid  the unreacted  s t r o n g e r s e t o f s i g n a l s was suspected 3  3  3  anion  t o protonate  required to f u l l y To t e s t t h i s  protonate  Na MeGapz Mo(CO) +  3  to have a r i s e n  from  3  salt.  the expected  I f t r u e , then the s u g g e s t i o n would be  i s perhaps a weaker base than the analogous  a n i o n , the i m p l i c a t i o n  suffices  3  being t h a t under c o n d i t i o n s where a c e t i c  the CpMo(C0)  3  anion, a s t r o n g e r a c i d would be  the MeGapz Mo(CO) 3  3  anion.  h y p o t h e s i s , the r e a c t i o n was repeated u s i n g the s t r o n g e r  acid, HCl(g), for a c i d i f i c a t i o n .  An orange-yellow  air-sensitive  s o l i d of  46  the d e s i r e d  complex, [MeGapz ]Mo(C0) H, 3  was obtained i n good y i e l d s .  3  compound d i s p l a y e d t h r e e s t r o n g bands and one weak band 1808 cm" , hexane), i n the 1  /hydride  This  (1952, 1928, 1908,  region of the i r spectrum.  These  bands were c l o s e t o those observed f o r one of the s p e c i e s suspected t o be the hydride i n the product mixture from the a c e t i c a c i d 1935, 1912, 1810 cm" , C g H ^ ; 1  s e c t i o n 2.2.5).  compound such as [MeGapz ]Mo(C0) H, 3  3  as b e f i t s a complex p o s s e s s i n g C  three  reaction  (1950,  F o r a 7-coordinate bands are expected i n the i r  symmetry  (2A  1  + A " ) , c o n s i s t e n t with a  s  3:4 o r 'four-legged piano s t o o l ' s t r u c t u r e .  The c l o s e l y  related  CpMo(C0) H (2030, 1949, 1913 cm" , C S ) [ 5 5 ] , and [HBpz ]Mo(C0) H  (2000,  1905, 1880 cm" , N u j o l ) [53] compounds have been shown t o d i s p l a y  three  1  3  2  3  3  1  v^g bands i n t h e i r i r s p e c t r a , without accompanying V case.  q  ^ bands i n each  Thus, one of the f o u r bands observed f o r the [MeGapz ]Mo(C0) H 3  complex must  be due t o the Mo-H s t r e t c h i n g  The replacement  implies that corresponding  virtually  i n v o l v i n g hydrogen. a l l the p o t e n t i a l  v i b r a t i o n i n the molecule.  F o r a pure (where  energy i n v o l v e d  in a shift  stretching)  of deuterium f o r hydrogen attached t o a  i n frequency by a f a c t o r of /2 o r 1.414  v (M-H)/v(M-D) ~ /2 Harmonic o s c i l l a t o r approximation) [ 8 0 ] . which of the f o u r bands observed f o r the [MeGapz ]Mo(C0) H 3  Mo-H s t r e t c h i n g  'pure'  i n the  normal mode i s a s s o c i a t e d with the M-H bond  s t r e t c h i n g mode, s u b s t i t u t i o n results  3  of hydrogen by deuterium i s a well-known technique  f o r studying v i b r a t i o n s  metal  M  3  To e s t a b l i s h  i s due t o the  v i b r a t i o n , the d e u t e r i d e s p e c i e s [MeGapz ]Mo(C0) D  prepared and i t s s o l u t i o n  3  i r obtained.  The s o l u t i o n  (i.e.,  3  was  i r spectrum of t h e  47  molybdenum the v C Q  deuteride  showed t h r e e bands (1935, 1910, 1845 cm" , CgHg) i n  r e g i o n , and a weak band a t ~1380 cm" . 1  ~1952 cm"  E v i d e n t l y , the band a t  i n the [MeGapz ]Mo(C0) H compound had s h i f t e d to lower wave-  1  3  3  numbers by a f a c t o r of ~/2 j u s t by s u b s t i t u t i o n o f deuterium f o r hydrogen i n the molybdenum a t 1952 cm"  1  hydride  complex.  i n the hydride  compound were a s s i g n e d  Based on t h i s o b s e r v a t i o n ,  complex, and 1380 cm"  to Mo-H  and Mo-D  the bands  i n the d e u t e r i d e  1  stretching vibrations  respectively. The  i r spectrum of the [MeGapz ]Mo(C0) H o r [MeGapz ]Mo(C0) D i n THF 3  solution  i s interesting  are a l s o d i s p l a y e d .  i n t h a t the  3  3  bands o f the MeGapz Mo(C0) 3  anion  3  T h i s i s thought to a r i s e from the acid-base  d i s s o c i a t i o n of the Mo-H solvent.  3  or Mo-D  bond i n the p o l a r and weakly b a s i c THF  This l a t t e r observation,  a s t r o n g a c i d to f u l l y  protonate  i n c o n j u n c t i o n with  the MeGapz Mo(C0) 3  3  the requirement o f  anion,  suggests t h a t  [MeGapz ]Mo(C0) H i s more p r o t o n i c and l e s s h y d r i d i c than the analogous 3  3  CpMo(C0) H. 3  earlier,  T h i s c o n c l u s i o n i s a t odds with  i . e . , t h a t MeGapz  3  and HBpz  the trend e s t a b l i s h e d  l i g a n d s are b e t t e r  3  than the Cp" l i g a n d as judged from the h i g h e r V^Q values anion  compared to e i t h e r HBpz Mo(C0)  respectively.  3  electron-donors f o r CpMo(C0)  [53] or MeGapz Mo(C0)  3  3  [34] anions  3  I f t h i s argument h o l d s , then the only l o g i c a l  t h a t the s i x - c o o r d i n a t e MeGapz Mo(C0) 3  to i t s s e v e n - c o o r d i n a t e cyclopentadienyl  system.  hydride  3  anion  3  conclusion i s  i s more s t a b l e with  respect  than i s the case i n the analogous  S i m i l a r observations  compound were r e p o r t e d d u r i n g the course  on the [HBpz ]Mo(C0) H [60]  of t h i s work.  3  3  48  The  H nmr  displayed  one  equivalent 18.5  T.  spectrum of the  [MeGapz ]Mo(C0) H i n dg-acetone s o l u t i o n 3  3  s e t of s i g n a l s f o r the p y r a z o l y l  r i n g protons, i n d i c a t i n g  p y r a z o l y l r i n g s i n the above complex, and  It is evident,  the above complex symmetry f o r the  a Mo-H_  however, t h a t the pz groups are  ( i r showed three complex).  Since  resonance a t  inequivalent  bands, c o n s i s t e n t with a  C  $  seven-coordinate complexes of t h i s  are known f o r t h e i r f l u x i o n a l behaviour i n s o l u t i o n , i t i s probable the present  compound i s s t e r e o c h e m i c a l l y  interconversion the 3:4  of the CO  ligands 3  (X = H,  interconversion  of l i g a n d s  3  3  some stage p l a c e  symmetrical  3:3:1  equalization *H  nmr  in solution.  the H l i g a n d i n the  Br,  I) [60] must be o p e r a t i v e i n the  or  basal  plane of  in solution.  plane of the 3:4  s t r u c t u r e would  s t r u c t u r e , l e a d i n g to  1  of the environments of the pz r i n g s ; hence, one structure in solution.  3 v  groups.  i s a r a p i d r o t a t i o n of the  The  x , a considerably  CpMo(C0) H (Mo-H 3  -12.8  Mo-]_  chemical  shift  reasonable to s p e c u l a t e electron-donor  field  the  'MeGapz ' moiety about 3  the  environments  and  [HBpz ]Mo(C0) H 3  3  3  species. 3  for  x [53];  [MeGapz ]Mo(C0) H and  however, t h a t s i n c e the MeGapz  than the HBpzZ l i g a n d [ 3 4 ] ,  -13.3  to r a t i o n a l i z e the  [HBpz ]Mo(C0) H hydride 3  (Mo-H  3  It is d i f f i c u l t  3  3  p o s i t i o n than those r e p o r t e d  d i f f e r e n c e between the 3  sees i n  A l t e r n a t i v e l y , and  3  T) [55]  analogous CpMo(C0) H and  the  resonance f o r [MeGapz ]Mo(C0) H appeared at  higher  T [60]), respectively.  Such  the Ga*»*Mo a x i s , g i v i n g a  'capped-octahedral  experiment a dynamic C  of the pz  Mo-H  Thus,  basal  Ga«»»Mo a x i s , r e s u l t i n g i n the e q u a l i z a t i o n of the chemical  13.02  that  3  the H l i g a n d along  perhaps l e s s l i k e l y ,  18.5  type  s t r u c t u r e of [MeGapz ]Mo(C0) H, s i m i l a r to t h a t observed f o r  [HBpz ]Mo(C0) X  at  and  non-rigid  in  large the  It i s  ligand i s a  the proton i n the  present  better  49  [MeGapz-jlMofCCO^H compound most l i k e l y effect  from the e l e c t r o n - r i c h Mo  c e n t e r i n the  I t i s noteworthy t h a t the c r y s t a l (r]-C Me )Mo(C0) H [81] compound has 5  5  3  According  inferred  authors  concluded  'hole' i n the Mo pyramid was  t h a t the geometrical  3  stool'  2  3  r e p o r t , i t was  anion with Mel  geometry, and  nmr  molecule the  v e r t e x of the  square  'missing' H atom.  the  complex, HBpz Mo(CO) Me 3  t h a t the product  3  o f the  above  2 complex [ H B p z - ^ M o f C O ^ T i -COMe), no  d e t e c t a b l e q u a n t i t i e s of the a-methyl i r and  f o r the  s t a t e d t h a t the r e a c t i o n o f  gave the a-methyl  2 i n f a c t an TI - a c y l  molecule.  Ph)  R e c e n t l y , C u r t i s e t a l . communicated  r e a c t i o n was  et a l .  not l o c a t e d , i t s  f a c t s obtained  ' f o u r - l e g g e d piano  2  HBpz Mo(C0)  analogous  r e c e n t l y been r e p o r t e d by Leoni  i n t e r p r e t e d to be the r e s u l t o f the  In an e a r l i e r  The  s t r u c t u r e of the  [MeGapz ]Mo(C0) (n -C0R) (R = Me,  [53].  complex.  atom c o o r d i n a t i o n sphere a t a basal  3  shielding  from the geometry of the remainder of the  were c h a r a c t e r i s t i c o f a  2.2.3  greater  to the a u t h o r s , even though the H atom was  p o s i t i o n was The  experiences  complex being observed  f o r the complex were c o r r o b o r a t e d  in solution.  definitively  by  an  2 X-ray s t r u c t u r e d e t e r m i n a t i o n in  the  solid  [53,64],  state [64].  In an attempt to c l a r i f y  the r e a c t i o n o f the i s o e l e c t r o n i c ,  anion with Mel actual  showing the presence  was  investigated.  pathway of such  the above  isostructural  Of p a r t i c u l a r  a reaction.  o f an TI - a c y l  interest  Is the a-methyl  geometry  observations  MeGapz Mo(CO) 3  to us was  the  complex  '[MeGapz ]Mo(C0) Me' formed a t some stage, and rearranged to g i v e the 2 2 TI - a c y l complex [MeGapz-,]Mo(CO) (ii -COMe)? In order to observe t h i s 3  3  ?  3  50  a-methyl  intermediate, i f  formed at a l l , the r e a c t i o n was c a r r i e d out  THF and m o n i t o r e d at room temperature by s o l u t i o n i r s p e c t r o s c o p y .  in  The  r e s u l t s o b t a i n e d i n d i c a t e t h a t the a-methyl complex i s formed but 2 r e a r r a n g e s t o g i v e the TI - a c y l complex as the f i n a l the e q u a t i o n s  product a c c o r d i n g  to  below:-  Me6apz Mo(C0)3 + xsMel  "*"> THF  3  [MeGapz Mo(C0) Me] 3  3  THF  Y 2 [MeGapz ]Mo (CO) ( TI -COMe) 3  2  Thus, a f t e r s t i r r i n g the r e a c t i o n m i x t u r e a t room temperature f o r ~2 d a y s , the i r spectrum of the s o l u t i o n showed t h r e e new 1920 and 1855 c m " . 1  bands a t 1970,  The t h r e e bands i n t e n s i f i e d a f t e r s t i r r i n g the  r e a c t i o n m i x t u r e f o r a n o t h e r 2 d a y s , a f t e r which a d d i t i o n a l produced no change i n the i r spectrum.  stirring  The presence of the  c h a r a c t e r i s t i c of the u n r e a c t e d MeGapz Mo(C0) 3  bands  a n i o n , even a f t e r  3  stirring  the r e a c t i o n m i x t u r e f o r 4 d a y s , i s i n d i c a t i v e o f the low y i e l d o f r e a c t i o n i n THF a t room t e m p e r a t u r e .  this  The i r spectrum o f the b r i c k - r e d  c r y s t a l s i s o l a t e d from t h i s r e a c t i o n showed two s t r o n g bands a t 1980, 1855 c m " , and a weak band a t 1570 c m " . 1  cm"  1  1  The v  C Q  bands a t 1970, 1920 and 1855  observed d u r i n g the r e a c t i o n are thought to have emanated from the  presence o f a t r a n s i e n t a-methyl solution.  'MeGapz Mo(C0) Me' 3  T h i s p a t t e r n i s c h a r a c t e r i s t i c of C  3  g  intermediate  in  symmetry M(C0) X groups 3  51  which t y p i c a l l y (2A  show t h r e e V^Q bands i n t h e i r  + A") modes expected.  1  compared w i t h II below.  These v  C  Q  values f o r 'MeGapz Mo(C0) Me' a r e 3  bands r e p o r t e d f o r r e l a t e d  The presence  i r c o n s i s t e n t with the t h r e e  a-methyl  3  complexes i n T a b l e  o f o n l y two bands i n s t e a d o f the expected  three  bands i n the (ii-CgHg)Mo(CO) Me compound was i n t e r p r e t e d as being due t o 3  the c o i n c i d e n c e o f two bands [ 5 5 ] . Table  II.  I r carbonyl complexes  stretching  3  (L = T) -CgHg, TI -CgNteg, T t - C H , HBpz , MeGapz ). g  COMPOUND  v  c o  (cm  - 1  7  3  3  )  Reference  (Ti-C H )Mo(C0) Me  2020,1937  (Ti-C Me )Mo(C0) Me  2014,1929 ( C g H )  82  (Tt-C H )Mo(C0) Me  2024,1945,1911  83  [HBpz ]Mo(C0) Me  1985,1970,1948  5  5  5  3  5  9  3  7  3  [MeGapz ]Mo(C0) Me 3  The  3  presence  band a t 1570 cm"  o f two sharp 1  (CC* )  55  4  12  3  3  from  f r e q u e n c i e s o f some LMo(C0) Me  1848,1830,1800  (Nujol)  1970,1920,1855  (THF)  53 T h i s work  bands a t 1980 and 1855 c m , and a weak - 1  i n the i r spectrum  the r e a c t i o n o f MeGapz Mo(C0) 3  3  o f the b r i c k - r e d c r y s t a l s with Mel, suggested  isolated  t h a t the p r e s e n t  o  compound  i s indeed the TI - a c y l  2  ( C 0 ) ( T I -COMe). 2  structural [84,85].  compound with the f o r m u l a t i o n  2  Complexes a r e d e s c r i b e d as T) - a c y l  d e t e r m i n a t i o n o r from  [MeGapz ]Mo3  compounds e i t h e r  from  2 -1 i r s p e c t r a [ Q Q (TI - a c y l ) < 1600 cm ] V  =  The metal-bonded T ^ - a c e t y l groups (TI M-C(O)R) u s u a l l y 1  at h i g h e r f r e q u e n c i e s i n the i r (>1600 cm" ) [85,86]. 1  An X-ray  absorbed structural  52  determination has  indeed  1983,  of the i s o e l e c t r o n i c ,  revealed that this  1856,  1570  cm"  with  those  observed  1570  cm" ,  CH^C^) complex.  1  i s an TI - a c y l  observed  1  isostructural  [HBpz ]Mo(C0) (TI -COMe) 3  2  complex [ 6 4 ] .  The  bands a t  f o r t h i s complex are i n c l o s e agreement [MeGapz ]Mo(C0) (Ti -C0Me) (1980,  f o r the p r e s e n t  1855,  2  2  3  A plausible  r e a c t i o n sequence f o r the  2 of the p r e s e n t r\ - a c y l  formation reaction  sequence, CO m i g r a t i o n with  bond of the a-methyl 2 TI - a c y l  intermediate  subsequent i n s e r t i o n  3  3  experiment.  2  ligand i s equally viable.  the above routes  is operative solely  Mechanistic  In  i n t o the Mo-Me  3  Methyl  m i g r a t i o n onto  It is difficult  to d i s c u s s which  on the r e s u l t s o b t a i n e d  s t u d i e s on the c l a s s i c  c a r b o n y l a t i o n of  from  actually  and  carbon  of a c o o r d i n a t e d CO  decarbonylation anion with species  step was  PhCOBr.  By  group.  It is clear,  use  of  bonds to the  however, t h a t a  i n v o l v e d i n the r e a c t i o n of the  HBpz Mo(C0) 3  3  C - l a b e l l e d PhC*0Br as the s t a r t i n g h a l i d e 2 2 i n t h e i r p r e p a r a t i o n of the TI -benzoyl [ H B p z ] M o ( C 0 ) ( T i -COPh) 1 3  the metal  2  3  compound, C u r t i s e t a l . [65] c l e a r l y is lost  Molecular Orbital  showed t h a t t h e r e i s s u b s t a n t i a l bond but a very weak Mo-0 2  2  complexes.  In t h i s  (EHMO) treatment,  initially  on  same paper, u s i n g the  authors  double-bond c h a r a c t e r i n the Mo=C(acyl)  bond; hence they  [ H B p z ] M o ( C 0 ) ( T i - C 0 R ) (R = Me, 1 6 - e l e c t r o n Mo  e s t a b l i s h e d t h a t the CO  in a decarbonylation process.  the Extended Huckel  3  subsequently  this  alkyl-  [ 8 5 ] , have shown, t h a t i t i s  group t h a t migrates  final  the  (pentacarbonyl)manganese by C a l d e r a z z o the a l k y l  this  'MeGapz Mo(C0) Me' would g i v e the 2  complex [ M e G a p z ] M o ( C 0 ) ( n -COMe).  c o o r d i n a t e d CO of  complex i s shown i n f i g u r e 15.  Ph)  suggested  c o u l d be regarded  t h a t the compounds as  stabilized  53  1855 2000 F i g u r e 15.  i8oo  1600 (crrf 1 )  I r s p e c t r a o f the carbonyl s t r e t c h i n g frequency r e g i o n observed d u r i n g the r e a c t i o n of MeGapz,Mo(CO); w i t h Mel.  54  The in  [ M e G a p z ] M o ( C 0 ) 2 ( T i -COMe) compound  H nmr spectrum o f the p r e s e n t  dg-acetone s o l u t i o n  3  ( f i g u r e 16) i s c o n s i s t e n t  with the f o r m u l a t i o n as  2 an TI - a c y l pattern one  complex.  i n d i c a t i n g that  pyrazolyl  ically  The p y r a z o l y l  rigid  protons o f the l i g a n d  two o f the p y r a z o l y l  r i n g being d i f f e r e n t . structure  This  in solution.  appear i n a 2:1  groups a r e e q u i v a l e n t  with  i s s u g g e s t i v e o f a stereochem-  The a c e t y l  COMe s i g n a l  i s also  a t 6.60 x .  displayed  Much c u r r e n t  i n t e r e s t has been d i r e c t e d 2  chemical  r e a c t i v i t y o f t h e TI - a c y l  possible  r o l e o f these s p e c i e s i n the m e t a l - c a t a l y z e d  carbon monoxide [87,88,89].  metal  towards the p r e p a r a t i o n and  The f a c i l e  complexes p a r t l y due t o t h e hydrogenation o f  alkyl  t o CO m i g r a t i o n observed i n 2 the f o r m a t i o n o f the p r e s e n t [MeGapz ]Mo(CO) 2 (Ti -COMe) compound and t h e 2 analogous [ H B p z ] M o ( C O ) 2 ( T i -COMe) [64] complex are unprecedented i n e i t h e r CpMo(C0) R o r CpMo(C0) (a-C0R) c h e m i s t r y . In f a c t t o our knowledge, t h e 2 h y p o t h e t i c a l CpMo(C0) 2 (Ti -COR) (R = Me, Ph) complexes have never been 3  3  3  3  reported. [90]  However, a r e l a t e d  2 tungsten complex, CpW(CO)(HCCH)(ri -COMe)  has been r e p o r t e d but no d e f i n i t i v e s t r u c t u r a l  data a r e a v a i l a b l e . 2  data f o r the p r e s e n t [ M e G a p z ] M o ( C 0 ) 2 ( T i -COMe) complex  Mass s p e c t r a l displayed  3  signals  P-C0-C0Me , P-3C0 +  Interestingly,  a t t r i b u t a b l e t o the P , P-Me , P-C0 , P-C0Me , P-2C0 , +  +  and P-2C0-C0Me  +  +  (P = p a r e n t ) ions  the above mass s p e c t r a l  those r e p o r t e d f o r the i s o s t r u c t u r a l  +  +  +  respectively.  data a r e i n p e r f e c t 2  agreement with  [ H B p z ] M o ( C 0 ) 2 ( T ) -COMe) compound 3  [65]. Similarly,  reaction  o f the MeGapz,Mo(CO)Z anion with PhCOCl  gave a  56  dark blue its  product, a l b e i t  i n very  i r spectrum (1965, 1820  low y i e l d ,  and 1535 c m ,  2  3  well  with  that obtained  The  f o r the complex  [ H B p z ] M o ( C 0 ) ( r i - C 0 P h ) (1965, 1852, 2  2  3  CHgCl )  -1  p r o d u c t , [ M e G a p z ] M o ( C 0 ) ( r ] -COPh).  and c h a r a c t e r i z e d  T) -benzoyl  as the  2  s o l e l y by  2  i r data f o r t h i s compound compare structurally  1490 cm" ,  characterized  CH C1 ) [65].  1  2  2  Thus, i t appears t h a t the tendency of the a-donor e l e c t r o n s at the n i t r o g e n octahedral ligands the  LMofCO-jR  arrangement.  3  3  together  [60],  S i m i l a r reasoning  the t r a n s f o r m a t i o n  (C0) (TI -C0R)  (R = Me,  2  HBpz Mo(C0) * [ 3 8 ] , and 3  3  " l e g s " of the piano  was  invoked by C u r t i s e t a l . [65] i n  of [ H B p z ] M o ( C 0 ) R 3  3  to [HBpz ]Mo3  complexes.  [MeGapz ]Mo(C0) Et 3  The the  Ph)  species,  i n the s u c c e s s f u l  compound were found to be compressed  rationalizing 2  s t r u c t u r e of  quasi-six-coordinate  compound, where the f o u r  s t r u c t u r e of the l a t t e r  bulk of the  In f a c t the HBpz^ l i g a n d has been shown to  of the paramagnetic r a d i c a l  i n the HBpz Mo(C0) Br  2.3.4  to the  s i x - c o o r d i n a t i o n over s e v e n - c o o r d i n a t i o n  isolation  stool  and the s t e r i c  of the s e v e n - c o o r d i n a t e 3:4  (L = MeGapz^, HBpz^) s p e c i e s  2  also  about the metal c e n t e r  the t r a n s f o r m a t i o n  LMO(C0) (TI -COR) promote  localized  donor s i t e s of the l i g a n d s MeGapz^ and HBpz^, to promote  coordination  favor  as  3  r e a c t i o n of the MeGapz Mo(C0) 3  metal-alkyl  bonded  compound i s u n s t a b l e inert conditions. solution,  3  anion with e t h y l  [MeGapz ]Mo(C0) Et 3  3  derivative.  and decomposes on storage  However, the decomposition  bromide  The  afforded  red-brown  a f t e r a few days even under i s much more r a p i d i n  the i r spectrum of s o l u t i o n s of t h i s e t h y l  derivative clearly  57  showing the presence of the anion MeGapz Mo(C0) . 3  spectrum of the e t h y l 1820 cm' , 1  ively.  compound i n C H g C l  i n a d d i t i o n to two v  The l a t t e r  C Q  The s o l u t i o n i r  3  shows v  2  C Q  bands a t 1970,  bands at 1890 and 1755 c m  two bands are c h a r a c t e r i s t i c o f the  1930,  respect-  - 1  MeGapz Mo(C0) 3  3  anion, presumably due to slow decomposition of the [MeGapz ]Mo(C0) Et 3  compound i n s o l u t i o n probably by p - e l i m i n a t i o n  In  3  (see scheme below).  the scheme, the decomposition of the Mo-Et bond i n v o l v e s a f a c i l e  P-hydride m i g r a t i o n t o form the h y d r i d e [MeGapz ]Mo(C0) H 3  e x p u l s i o n of e t h y l e n e . species  D i s s o c i a t i o n of the Mo-H  3  s p e c i e s with  bond i n the above h y d r i d e  ( s i m i l a r to t h a t d i s c u s s e d i n s e c t i o n 2.3.2, p 45) would then  e x p l a i n the presence of the MeGapz Mo(C0) 3  3  anion i n the s o l u t i o n i r  spectrum o f the p r e s e n t [MeGapz ]Mo(C0) Et compound. 3  3  58  I t Is i n t e r e s t i n g t h a t the i r spectrum of the c l o s e l y [HBpz ]Mo(C0) Et 3  vCQ  3  bands (1980, 1960,  indicating The  complex,  r e p o r t e d e a r l i e r by Trofimenko, d i s p l a y e d  1850,  1835,  1816  cm" , 1  t h a t they d i s p l a y o n l y two strong were observed f o r the CpMo(C0) Et 3  CpCr(C0) Et  (2012, 1933 cm" ,  appearance of only two v C Q d e r i v a t i v e s may  result  (2016, 1932  f o r the  3  4  respectively.  The  ethyl  similar  compound are c o n s i s t e n t with a  C  g  or 'four-legged piano  spectrum of [MeGapz ]Mo(C0) Et 3  3  in  ( f i g u r e 17), d i s p l a y e d one s e t of s i g n a l s f o r the pz  p r o t o n s , i n d i c a t i n g e q u i v a l e n t pz r i n g s i n the complex. methylene  [55] and  complex.  room temperature *H nmr solution  CC1 )  bands  r e g i o n o f the i r spectrum  + A " ) , and again s u g g e s t i v e of a 3:4  stool' structure  dg-acetone  1  two  from the c o i n c i d e n c e of two bands with  3  1  cm" ,  [91] complexes  The t h r e e bands observed i n the  (2A  For example,  bands f o r the above c y c l o p e n t a d i e n y l  f o r the p r e s e n t [MeGapz ]Mo(C0) Et  The  N u j o l ) [ 5 3 ] , perhaps  analogues are i n t e r e s t i n g i n  bands.  pentane)  1  3  symmetry  five  a s i m i l a r tendency to decomposition f o r the boron compound.  i r s p e c t r a of r e l a t e d c y c l o p e n t a d i e n y l  energies.  related  protons of the e t h y l  resonances c e n t e r e d a t 8.15 of the p r e s e n t complex  The methyl  and  group appeared as u n r e s o l v e d broad  x and 6.32  x respectively.  The nmr  spectrum  i s d i f f e r e n t from t h a t r e p o r t e d f o r the analogous  59  [HBpz ]Mo(C0) Et 3  the  [53] complex.  3  l a t t e r complex appeared  at 8.60  protons of the l i g a n d appeared interpreted  Although the methyl  by the author as i n d i c a t i v e  s t r u c t u r e with the e t h y l  group  peaks of  x , r e s p e c t i v e l y , the pz  T and 6.38  i n a 2:1  and methylene  pattern.  T h i s o b s e r v a t i o n was  of a s t e r e o c h e m i c a l l y  probably e q u i d i s t a n t from two  rigid of the pz  groups. There are perhaps  three possible  interpretations  r e s u l t s f o r the [MeGapz ]Mo(C0) Et complex. 3  "capped axis  e q u i v a l e n t pz groups protons.  Such a symmetrical  Secondly, a r i g i d 3:4  case r a p i d  Thirdly,  rotation  of the  interconversions  or C  3 v  a r i g i d 3:3:1  l y i n g along the  'MeGapz^' moiety about the G a » « M o  first  between the v a r i o u s isomers  The  (three  bands were observed i n the i r; a r i g i d 3:3:1  s o l u t i o n would show only two d i s c o u n t e i t h e r the second  3:4  of the 3:4  bands).  t o a 3:3:1  3  2  average  on the i r data structure i n  I t i s d i f f i c u l t , however, t o  or the t h i r d p o s s i b i l i t y  [ 9 2 ] , a complex which  arrangement  structure  process i n  can be d i s r e g a r d e d based  since  However, from our e x p e r i e n c e with the r e l a t e d  [MeGapz ]Mo(C0) SnMe Cl  resonances.  complex as shown i n f i g u r e 18, with an  possibilty  both are e q u a l l y compound  showed a t r a n s i t i o n from a  i n s o l u t i o n , the second p o s s i b l i t y most  accounts f o r the observed *H  nmr  axis  #  s t r u c t u r e predominating due t o a f l u x i o n a l  3  principal  o r 'four-legged piano s t o o l ' s t r u c t u r e i n  solution.  probable.  or  s t r u c t u r e would give  set of s i g n a l s f o r the pz proton  the [ M e G a p Z g J ^ C O J g E t  3:3:1  nmr  hence one set of s i g n a l s are d i s p l a y e d f o r the pz  would lead t o e q u i v a l e n t  of  Firstly,  o c t a h e d r a l " s t r u c t u r e with the Et group  of the molecule.  which  3  of the *H  results  likely  i n the present Mo-Et complex.  In  F i g u r e 17.  270 MHz  H nmr spectrum o f [MeGapz ]Mo(CO) Et 3  3  i n dg-acetone s o l u t i o n .  61  the Mo-Sn complex, the observed e q u i v a l e n c e of the pz groups i n the arrangement was  the Ga»**Mo a x i s .  H  and  1 3  C  of the 'MeGapz ' moiety about 3  It i s worthy of mention t h a t C u r t i s and Shiu  one set of e q u i v a l e n t l  by a r o t a t i o n  rationalized  reported  pz rings and one set of e q u i v a l e n t CO groups i n the  nmr s p e c t r a f o r the [HBpz ]Mo(C0) X 3  3  (X = H, Br, I) complexes i n  s o l u t i o n from room temperature t o -80°C [ 6 0 ] .  This observation  interpreted  of dynamic C  by the authors as being i n d i c a t i v e  the complexes i n s o l u t i o n . solid  3:3:1  A 3:4  3 y  was  symmetry f o r  s t r u c t u r e f o r the boron complexes i n the  s t a t e has been confirmed by a s i n g l e  crystal  X-ray s t r u c t u r a l  d e t e r m i n a t i o n of the [ H B p z ] M o ( C 0 ) B r compound by the same authors [ 6 0 ] . 3  It  i s noteworthy that  3  i n the CpMo(C0) Et 3  compound the methyl and  methylene group s i g n a l s were u n r e s o l v e d , apppearing at 6.0 the valence i s o e l e c t r o n i c C p C r ( C 0 ) E t 3  complex [ 9 1 ] , the methyl and  methylene group s i g n a l s were r e s o l v e d , appearing at 8.89 respectively.  The c r y s t a l  structure  of the CpMo(C0) Et 3  determined, and i s i n accord with a 3:4 solid  % and 6.39  %  complex has been  structure f o r this  complex i n the  state [93]. The mass spectrum of [MeGapz ]Mo(C0) Et was 3  excessive fragmentation, i n d i c a t i v e  3  of thermal  under the mass s p e c t r o m e t r i c c o n d i t i o n s . corresponded t o t r a c e s i g n a l s  c h a r a c t e r i z e d by  instability  CpMo(C0) R 3  (R = H, Me,  of the compound  The h i g h e s t mass observed  a t t r i b u t a b l e t o the P-3C0-Et  thermodynamic study of the C O - i n s e r t i o n i n t o the Mo-R  bond  % [ 5 5 ] , but i n  +  ion.  A  recent  bond i n the  E t ) compounds [ 9 4 ] , has concluded t h a t the Mo-Et  i s weaker than the Mo-Me bond  (CO i n s e r t i o n i n t o the Mo-Et bond i s ~3  62  Mo  o° o C  C  s  E t  b  c  d  C  F i g u r e 18.  V a r i o u s isomers of the s e v e n - c o o r d i n a t e  [MeGapz ]Mo(CO) Et. 3  3  63  kcal/mol more f a v o u r a b l e than i n t o the Mo-Me bond). transition-metal  d e r i v a t i v e s which  However, methyl  l a c k P-hydrogen atoms are k i n e t i c a l l y  more s t a b l e than the e t h y l compounds having p-hydrogen atoms. combination  of these f a c t o r s i s probably r e s p o n s i b l e  The  f o r the i n a b i l i t y  to  2 form the r\ - COEt d e r i v a t i v e as well pattern  observed f o r the present [MeGapz ]Mo(C0) Et compound i n the mass 3  spectrometer under e l e c t r o n impact 2.3.5  as the e x c e s s i v e f r a g m e n t a t i o n  The The  3  conditions.  [MeGapz ]Mo(C0) X (X = Br, I) complexes 3  3  r e a c t i o n of the molybdenum t r i c a r b o n y l anion with halogens,  as  shown below, MeGapz Mo(C0) 3  3  + X  T  H  F  2  >  X = Br , 2  was  used i n an attempt  complexes.  MeGapz Mo(C0) X + 3  I  3  2  to prepare the [MeGapz ]Mo(C0) X 3  Yellow (X = Br) and dark  X"  (X = Br, I)  3  red (X = I) s o l i d s ,  sparingly  i n most o r g a n i c s o l v e n t s , were i s o l a t e d from these r e a c t i o n s . p e r s i s t e n t attempts  at obtaining  consistently unsuccessful. nmr  and  i r spectra  3  3  T h i s was  However,  pure products were  very d i s c o u r a g i n g  s i n c e both the *H  of the r e a c t i o n products i n d i c a t e d the presence of the  expected h a l i d e s p e c i e s . [HBpz ]Mo(C0) X  analytically  soluble  In c o n t r a s t , the i s o e l e c t r o n i c , i s o s t r u c t u r a l  (X = Br, I) compounds have been prepared and one of them  (X = Br) s t r u c t u r a l l y c h a r a c t e r i z e d [ 6 0 ] . 2.4  Summary  The LMo(C0)  3  (L = MeGapz  3>  MeGa(3,5-Me pz) ) anions have been 2  i s o l a t e d and c h a r a c t e r i z e d as t h e i r Na , +  Et N A  3  +  and HAsPht s a l t s .  Anion-  64  cation has  i n t e r a c t i o n of the MeGapz Mo(C0) 3  been d e s c r i b e d  represents  the  importantly, LMo(C0)  and  first  the  supported by  isolation  first  The  hydride  3  evidence f o r the  3  3  protonate  species  most the  been prepared  but  anion  3  and i s required  to  under c o n d i t i o n s where a c e t i c  the analogous CpMo(C0)  3  anion.  The  [MeGapz ]Mo(C0) H d i s s o c i a t e s i n the 3  weakly b a s i c s o l v e n t , THF.  study  in polar  +  3  the MeGapz Mo(C0)  hydride  involvement of  found t h a t a s t r o n g a c i d such as HCl  to f u l l y  This  s a l t s and,  the N a c a t i o n  complex [MeGapz ]Mo(C0) H has  protonate  bond of the  3  THF  THF.  I t was  suffices  cation in  +  evidence.  +  characterized. fully  the Na  i r spectroscopic  anions i n i o n - p a i r i n t e r a c t i o n s with  3  and  of the M MeGapz Mo(C0)  reported  weakly b a s i c s o l v e n t s such as  acid  anion  3  polar  3  These r e s u l t s taken t o g e t h e r  Mo-H but  i n d i c a t e the  s e v e n - c o o r d i n a t e [MeGapz ]Mo(C0) H compound i s more d e s t a b i l i z e d with 3  respect  3  to i t s s i x - c o o r d i n a t e d  the analogous c y c l o p e n t a d i e n y l The  anion  MeGapz Mo(CO) , than i s the 3  case i n  3  system.  r e a c t i o n of MeGapz Mo(CO) 3  3  anion  with  Mel  was  found to proceed p  via  a a-methyl  'MeGapz Mo(C0) Me' i n t e r m e d i a t e 3  3  to g i v e the  TI - a c y l  2 compound [MeGapz ]Mo(C0) (Ti -COMe) as 2  3  poorly-coordinating the  r a t e of the m i g r a t o r y  allowing CO and  s o l v e n t , THF  spectroscopic  CO  the f i n a l  as the  trile,  the  The  use  of the  use  have  of  the  retarded  i n the above r e a c t i o n , thereby  a-methyl  i n s e r t i o n r e a c t i o n s have been shown to be Bergman [ 9 5 ] .  The  r e a c t i o n medium may  i n s e r t i o n step  d e t e c t i o n of the  product.  intermediate.  Migratory  'solvent-catalyzed'  polar, highly coordinating,  r e a c t i o n medium used by C u r t i s e t a l . , may  by  Wax  acetoni-  have c a t a l y z e d  the  65  t r a n s f o r m a t i o n of the 'HBpz Mo(C0) Me' a-methyl 3  i n t e r m e d i a t e to [HBpz ]Mo-  3  3  ( C O ) ( T I -COMe) [17] p r e v e n t i n g d i r e c t o b s e r v a t i o n o f t h i s 2  The t r a n s f o r m a t i o n of the a-methyl 2 the TI - a c y l favoured ability  derivative  intermediate.  'MeGapz Mo(C0) Me' i n t e r m e d i a t e to 3  3  2 [MeGapz-^MofCO^Ti -COMe) i s b e l i e v e d to be  by a combination  o f the r e l i e f  of s t e r i c  of the a-donor e l e c t r o n s l o c a l i z e d  congestion  and the  on the n i t r o g e n s of the MeGapz  3  l i g a n d t o promote o c t a h e d r a l c o o r d i n a t i o n . The r e a c t i o n of the MeGapz Mo(C0) 3  seven-coordinate  3  anion with  [MeGapz ]Mo(C0) Et a-ethyl 3  3  EtBr y i e l d e d the  compound.  No evidence  f o r the  2 migratory  CO i n s e r t i o n  observed  in this  i n t o the Mo-Et to form an TI -COEt product was  reaction.  I t i s not c l e a r a t t h i s stage why an a c y l  complex was o b t a i n e d with Mel but not with E t B r . reactivity  between both  of these a l k y l  The d i f f e r e n c e i n  h a i i d e s i s probably  Mo-R and Mo-CO bond s t r e n g t h s i n the [MeGapz ]Mo(C0) R 3  compounds.  The r a t e of a l k y l  to a c y l  3  formation  related  to the  (R = Me, Et)  r e a c t i o n i s known to be  dependent on the s t r e n g t h s of the M-C ( a l k y l ) and M-CO bonds i n the starting alkyl CpMo(C0) R 3  and  I t i s worthy of mention, however, t h a t the  (R = Me, E t ) compounds  phosphites  CpMo(C0) (DC0R 2  complex [ 9 6 ] .  have been shown to r e a c t with  phosphines  to a f f o r d the s t a b l e c r y s t a l l i n e a c y l complexes (L = phosphines,  phosphites)  v i a CO i n s e r t i o n  reactions  [97]. The p r e p a r a t i o n o f the compounds attempted and s p e c t r o s c o p i c evidence formation.  However,  were u n s u c c e s s f u l .  [MeGapz ]Mo(C0) X 3  was gathered  3  (X = Br, I) was  to support  a l l attempts a t o b t a i n i n g a n a l y t i c a l l y  their pure  products  66  CHAPTER I I I TRANSITION METAL - TRANSITION METAL BONDED COMPLEXES INCORPORATING  3.1.  PYRAZOLYL GALLATE/BORATE  Introduction  The  uninegative,  tridentate, chelating RB(pz)  p y r a z o l y l ) , MeGapz^ and [ M e G a p z ( 0 C H C H N R ) ] ~ 2  2  2  being s i x - e l e c t r o n donors, are f o r m a l l y ion  LIGANDS  (Cp").  The r e a c t i v i t y  documented [34,98-100]. ligand  systems.  [HBpz ] Rh (C0) 3  2  2  formulation,  analogous to the 3  electron  Differences  (R = H, a l k y l ,  (R = H, Me) l i g a n d  2  o f the LMo(C0)  systems toward a number o f three  3  donor l i g a n d s  2  2  [102], and ( r ) - C H ) R h ( ^ - C 0 ) ( C 0 ) 5  2  2  2  array  ligands  [101],  of h e t e r o b i m e t a l l i c  complexes  (compounds having  bonds between two d i s s i m i l a r m e t a l s ) ,  Much c u r r e n t  research  no such complexes a r e  has been d i r e c t e d towards  complexes with t r a n s i t i o n m e t a l - t r a n s i t i o n reasoned t h a t c o o p e r a t i v e the r e a c t i v i t y  incorporation  and t r i s ( 1 - p y r a -  i s t h a t w h i l e the former i s found i n an  known f o r the t r i d e n t a t e p o l y p y r a z o l y l b o r a t e / g a l l a t e  influence  3  they d i s p l a y markedly d i f f e r e n t geometry.  z o l y l ) b o r a t e / g a l 1 ate  metal-metal  has been w e l l  [103] have s i m i l a r  One obvious d i f f e r e n c e between the c y c l o p e n t a d i e n y l  extensive  cyclopentadienyl  are sometimes observed between these 3  5  systems,  anions o f the above l i g a n d  While the compounds [ M e G a p z ] R h ( n - C 0 ) 3  aryl,  metal  ligands. heterobimetallic  bonds, p a r t l y s i n c e  e f f e c t s between the d i f f e r e n t metal o f such complexes [104-113].  centers  For example,  o f both e a r l y and l a t e t r a n s i t i o n metals i n t o the same  i t is may  67  dinuclear  compound might lead to systems capable of a c t i v a t i n g and  polarizing studies  substrates  such as CO [114-118].  o f simple b i n u c l e a r  design and s y n t h e s i s potential The  catalytic  species  I t i s a l s o argued  may well  of l a r g e r heterometallic applications  provide useful  that  clues  c l u s t e r species  i n the  with  [107,119,120].  p r e s e n t study was undertaken with the primary o b j e c t i v e of  isolating  heteronuclear  ( o r mixed-metal) compounds i n c o r p o r a t i n g the  HBpz^, MeGapz^, and [Me Gapz(OCH CH NMe )]~ l i g a n d systems i n which 2  transition the on  2  metal-transition  The evidence f o r  bond between the d i f f e r e n t metals i s based  accepted c r i t e r i a  f o r such bonds.  distance  c l o s e to the sum of the van der Waals r a d i i  revealed  by X-ray s t u d i e s ,  a metal-metal  spectroscopic  That i s , a metal-metal of the two metals as  evidence and/or the n e c e s s i t y of  bond t o p r o v i d e each metal with a reasonable number o f  valence e l e c t r o n s  (generally  16 or 18) [114].  A number o f t r a n s i t i o n m e t a l - t r a n s i t i o n been prepared by the r e a c t i o n of LMo(C0)  3  metal bonded complexes has  (L = HBpz , MeGapz , Me,,Gapz3  (0CH CH NMe )]~) anions with a v a r i e t y of t r a n s i t i o n metal 2  2  Results  2  of the a n a l y s e s c o n f i r m  i n these compounds i n a d d i t i o n  to carbonyl  f i r s t examples of h e t e r o b i m e t a l l i e bonded complexes i n c o r p o r a t i n g  3  halide  the presence o f d i r e c t metal-metal  bonding environments [76,121-123],  ligands.  direct  2  metal bonds are f e a t u r e d .  presence of a metal-metal the g e n e r a l l y  2  species. bonds  groups i n a number of d i f f e r e n t  Thus, these compounds c o n s t i t u t e the transition metal-transition  the t r i d e n t a t e  metal  pyrazolylborate/gallate  The Mo-Cu bonded complex p r o v i d e s a r a r e example of a 3:3:1 or  'capped o c t a h e d r a l  1  structure.  68  The [MeGapz ]Mo(C0) Rh(PPh ) 3  3  3  complex prepared and discussed i n t h i s  2  chapter, was tested as a potential reagent f o r the d e s u l f u r i z a t i o n of at ambient temperatures,  but no noticeable a c t i v i t y was  observed.  h^S  Parts  of t h i s chapter have been published elsewhere [124]. 3.2  Experimental  3.2.1  Starting Materials The ligand Na [Me Gapz(0CH CH NMe )]~ was prepared as a THF s o l u t i o n +  2  2  as described elsewhere [41].  2  2  K HBpz~ [125], [CuCl ( P P h ) ]  [126],  +  3  4  PtCl(Me)(COD) [127], Co(N0) I [128], and Mn(C0) Br [129] were prepared 2  l i t e r a t u r e methods.  5  RhCl(PPh ) 3  3  (Strem chemicals), CuCl, H g C l  2  by  (M&B  Chemicals), CO (Linde Union Carbide), Z r C l ^ , H f C l ^ (Merck-Schuchardt) and HS  (Matheson), were used as supplied.  2  3.2.2  Preparation of LMo(C0) Rh(PPh ) 3  3  2  (where L = [MeGapz ], [HBpz ] or 3  3  [Me Gapz(0CH CH NMe )]) 2  2  2  2  Na LMo(C0) + R h C l ( P P h ) +  3  3  T H F 3  >  LMo(C0) Rh(PPh ) + PPh + NaCl 3  3  2  3  The Na L~ l i g a n d s o l u t i o n (-0.40 mmol i n 100 ml THF) was +  added to a  s t i r r e d s o l u t i o n of an equimolar amount of (MeCN) Mo(C0) (~0.10 g, 3  mmol) i n the same solvent. molybdenum complex i n THF ligand s o l u t i o n .  The  +  3  0.40  The i n i t i a l yellow c o l o r a t i o n of the changed to an amber c o l o r on a d d i t i o n of the  reaction mixture was s t i r r e d f o r ~2 days during  which time the amber c o l o r i n t e n s i f i e d . Na LMo(C0) was  3  The  r e s u l t i n g s o l u t i o n of  reacted d i r e c t l y with R h C l ( P P h ) 3  3  (0.37 g, 0.40  mmol),  69  added as a s l u r r y stirred  red r e a c t i o n mixture was  f o r a f u r t h e r 2 days and then the s o l v e n t was removed i n vacuo to  a f f o r d a dark and  i n ~100 ml THF.. The dark  red-black r e s i d u e .  the s o l u t i o n  gave an o i l y  filtered.  The r e s i d u e was e x t r a c t e d with benzene  E v a p o r a t i o n of the s o l v e n t from the f i l t r a t e  red-black m a t e r i a l which was r e c r y s t a l l i z e d  from  CH C1 /2  2  hexane to g i v e a i r - s t a b l e dark-red c r y s t a l s of the d e s i r e d product i n approximately 60% y i e l d . in Table I I I . Rh(PPh ) 3  -890  2  Physical  The mass spectrum  data f o r these complexes a r e c o l l e c t e d  of the complex  d i s p l a y e d s i g n a l s due to the P-PPh  (based on  6 9  G a and  9 8  [MeGapz ]Mo(C0) 3  3  i o n ( P = parent ion) a t +  3  Mo).  In the p r e p a r a t i o n o f the complexes L M o ( C 0 ) R h ( P P h ) 3  [ H B p z ] or [MeGapz ]), y e l l o w c r y s t a l l i n e 3  3  vCQ:  1980 cm"  3.2.3  (Calcd.:  2  C, 64.31; H, 4.34.  Found:  (CHgClg)) were a l s o i s o l a t e d  1  2  (where L =  samples o f the complex  3  RhCl(C0)(PPh )  3  C, 63.73; H, 4.27;  i n -5% y i e l d .  P r e p a r a t i o n o f [MeGapz ]Mo(C0) Cu(PPh ) 3  4Na [MeGapz ]Mo(C0) +  3  3  3  + [CuCl(PPh ) ] 3  3  T H F 4  >  4[MeGapz ]Mo(C0) Cu(PPh ) + 4NaCl 3  A solution  o f the N a [ M e G a p z ] M o ( C 0 ) +  3  3  salt  prepared as d e s c r i b e d above ( s e c t i o n 3.2.2). of [ C u C l ( P P h ) ] 3  produced stirred vacuum.  4  3  3  (1.7 mmol) i n THF was  A one-quarter molar amount  (0.61 g, 0.43 mmol) was added t o the r e a c t i o n mixture and  an immediate rusty-orange c o l o r . f o r approximately  T h i s r e a c t i o n mixture was  one day b e f o r e the removal  o f s o l v e n t under  The r e s u l t i n g orange r e s i d u e was e x t r a c t e d with C H C 1 9  ?  and the  70  mixture  filtered.  Hexane was added t o the f i l t r a t e  allowed t o evaporate  slowly.  Golden-yellow  air-stable  p r o d u c t , [ M e G a p z ] M o ( C 0 ) C u ( P P h ) , were produced 3  3  i n approximately 60% y i e l d .  included  i n Table I I I f o r the complex.  3.2.4  P r e p a r a t i o n of  Na [MeGapz ]Mo(C0)  3  + CuCl  3  A suspension of CuCl solution  3  C0(g) was bubbled  color.  through  ^ ^> THF  [MeGapz ]Mo(C0) Cu(C0)  9  3  3  salt  3  The r e a c t i o n mixture  was s t i r r e d  The s o l v e n t was then  removed under vacuum  Slow e v a p o r a t i o n of the benzene  a f f o r d e d the product, [MeGapz ]Mo(C0) Cu(C0), 3  deteriorate  i n low y i e l d s  s l o w l y with time.  f o r ~4 h.  f o r another 2 h at which stage t h e  and the residue e x t r a c t e d with benzene.  air-stable solid  + NaCl  (0.85 mmol) i n THF and produced an  the mixture  brown c o l o r had i n t e n s i f i e d .  filtrate,  data are  3  C Q  +  rusty-brown  Pertinent physical  (0.08 g, 0.85 mmol) i n THF was added t o a  of Na [MeGapz ]Mo(C0)  immediate  of the  [MeGapz ]Mo(C0) Cu(C0)  +  3  crystals  from the c o n c e n t r a t e d  3  solutions  and the mixed s o l v e n t s  3  as a y e l l o w  (~20%).  S o l u t i o n s of t h i s  compound  Physical  data f o r the complex are given i n  Table I I I . 3.2.5  P r e p a r a t i o n of [ M e G a p z ] M o ( C 0 ) P t ( M e ) ( P P h ) 3  3  3  PPh Na [MeGapz ]Mo(C0) +  3  3  + PtCl(Me)(COD)  3  > -COD THF [ M e G a p z ] M o ( C 0 ) P t ( M e ) ( P P h ) + NaCl 3  3  3  71  To a s t i r r e d  solution  of Na [MeGapz ]Mo(C0)  salt  +  3  3  (0.350 mmol) i n  THF, was added PtCl(Me)(COD) (0.123 g, 0.350 mmol) d i s s o l v e d i n THF. r e a c t i o n mixture was  stirred  f o r ~1 h, a f t e r which the s t a b i l i z i n g  PPh-j (0.091 g, 0.350 mmol) d i s s o l v e d mixture.  i n THF was  The s o l u t i o n was then s t i r r e d  The  ligand  added s l o w l y t o the  f o r ~4 days.  At t h i s  s t a g e , the  s o l u t i o n i r spectrum of the mixture i n d i c a t e d completion of the r e a c t i o n . The s o l v e n t was then removed i n vacuo and the r e s u l t i n g brown r e s i d u e e x t r a c t e d with CH C1 . 2  Hexane was  2  added t o the CH C1 2  filtrate  2  e v a p o r a t i o n of the CH C1 /hexane mixed s o l v e n t s a f f o r d e d dark 2  crystals  brown  2  of the product i n ~50% y i e l d .  Elemental  (1:1), and  a n a l y s i s and *H nmr data  i n d i c a t e d a methylene c h l o r i d e s o l v a t e d complex as the product. complex i s s t a b l e as a s o l i d  but u n s t a b l e i n s o l u t i o n .  Anal. Calcd. For [MeGapz ]Mo(C0) Pt(Me)(PPh )'CH Cl : 3  3.13;  N, 8.21.  Found: 1  ppm,  9.50s (Ga-Me); 4.18t  PPh-;  9.45s (Pt-Me, J  J  1  i y 5  3.2.6  3  3  C, 38.05; H, 2.90; N, 8.57.  1900s, 1815s, 1785s cm" .  X  H  NMR  2.35d  4  (pz-H ); 5  - 72 Hz);  Q  3  + M'C1  3  3  T 4  of Na [MeGapz ]Mo(C0) +  3  2  2  C Q  :  x ( C H ) C 0 = 7.89 3  pz-H  2  obscured by  3  2.13m, 2.50m (PPh,).  H  F  >  3  3  (M  1  = Z r or Hf)  [MeGapz ]Mo(C0) M'Cl  An equimolar amount of M'Cl^ d i s s o l v e d solution  v  IR(CH C1 )  H,  J  3  +  C, 38.72;  2  g  (pz-H );  , Pt-Me  2  ( d - a c e t o n e , 80 MHz):  P r e p a r a t i o n of [MeGapz ]Mo(C0) M'Cl  Na [MeGapz ]Mo(C0)  The  3  i n THF was  i n the same s o l v e n t .  3  3  + NaCl  added t o a s t i r r e d The  resulting  cloudy  Table III.  Physical Data for the Complexes LMo(C0),MY.  L  M  MeGapz  c  HBpz  Y  (PPh )  Rh  3  3  (PPh ) Rh 1.0 CH C1 3  3  2  Me Gapz(OCH CH NMe ) 2  2  2  2  3.88 4.07  7.67 7.58  1873,1772,1758 (1897,1763,1744)  2  53.23 53.49  3.80 3.83  7.60 7.73  1871,1772,1757 (1863,1772,1766)  4.65 4.72  3.96 3.83  1852,1762,1737  2  54.26 54.52  (PPh ) 3  GaMe  pz-H  10.00s  2.70d  4.06t  2.89d  2.05m 3.04m  -  2.71d  4.24t  2.96d  2.09m 5.71s 3.04m CH C1 solvate  b  b  3  pz-H  4  pz-H  5  PPh  3  Other -  2  10.42s 10.29s  e  2.32d  2  3.69t obscurred 2.60m 8.07s by PPh 7.09s signals NMe 3  2  2  46.96 46.91  3.41 3.43  10.61 10.54  1898,1798 (1890,1805,1780)  15.08 15.45  2010,1955,1810 (1898,1880, 1772,1745sh)  MeGapz  Cu  MeGapz  Cu  CO  30.15 30.78  2.15 2.85  MeGapz  Zr  Cl  29.64 29.00  2.34 2.87  30.01 29.80  3.75 3.65  3  3  3  Hf 1,5 C H  MeGapz3  6  3  3  "3  2015,1920,1895  9.55 9.51  = 2483 cm" , 1  2015,1915,1895  9.42s  2.02d  3.69t  2.19d  9.45s  1.71d  3.66t  2.20d  10.10s  2.19d  4.18t  3.08d  10.07s  2.15d  4.18t  3.09d  e  e  b  b  2.45m  14  a s=singlet, d=doublet, m=multiplet, sh=shoulder and t=triplet. B H  2  53.82 54.04  PPh  c v  1 a H nmr  co  2  Rh  2  -1 v (cm ) CH C1 (Nujol)  ANALYSIS CALCD/FOUND C H N  e (CD ) C0 solution, T(CH ) C0 = 7.89 ppm, J 3  2  3  2  b CgDg solution, TC H =2.84 ppm, J g  HCCH  6  =2Hz for pz protons.  HCCH  =2Hz for pz protons,  73  r e a c t i o n mixture was s t i r r e d f o r ~ 1 day a f t e r which the s o l v e n t was removed under vacuum. CH C1 2  2  CH C1  2  2  (M  1  The residue was e x t r a c t e d with benzene (M  = Hf) and the s o l u t i o n f i l t e r e d .  filtrate.  1  = Zr),  Hexane was added t o the  E v a p o r a t i o n of the s o l v e n t s a f f o r d e d y e l l o w s o l i d s of  the products i n ~60% y i e l d .  The complexes are unstable as s o l i d s and  s o l u t i o n s d e t e r i o r a t e with time even under i n e r t visibly  from b r i g h t y e l l o w t o dark green.  benzene  (M' = Z r ) , and hexane (M  1  conditions,  The complexes were i s o l a t e d as  = Hf) s o l v a t e s  data f o r the complexes are compiled  turning  respectively.  i n Table I I I .  Satisfactory  Physical analysis  f o r C and H were obtained f o r the Mo-Zr complex but the N analyses were i n c o n s i s t e n t each time the sample was analyzed. 3.2.7  Attempted P r e p a r a t i o n of [ M e G a p z ] M o ( C 0 ) C o ( N 0 ) 3  3  Equimolar amounts of Na [MeGapz ]Mo(C0) +  3  were reacted i n THF.  orange c r y s t a l s  3  Analytical,  agreement with t h a t  3  v  :  N Q  2  C, 30.74; H, 2.65; N, 20.85. 1665s cm" .  H  1  2  residue  i r and *H nmr data f o r  of the compound  reported p r e v i o u s l y [ 3 4 ] .  2  A n a l . C a l c d . F o r [MeGapz ]Mo(C0) N0: Found:  s o l u t i o n and C o ( N 0 ) I  Work-up of the r e s u l t i n g  (~60% y i e l d ) .  t h i s product were i n p e r f e c t [MeGapz ]Mo(C0) N0  salt  A f t e r s t i r r i n g the r e a c t i o n mixture o v e r n i g h t , t h e  s o l v e n t was removed under vacuum. yielded  3  2  NMR  l  C, 30.79; H, 2.57; N, 20.96.  IR(CH C1 ) v 2  (CgDg, 80 MHz):  2  C Q  :  2020s, 1930s cm" ;  xCgHg = 2.84 ppm, 10.03s  (Ga-Me); 4.28t, 4.10t ( p z - H ) ; 3.10d, 2.95d ( p z - H ) ; 2.63d, 2.23d 4  ( HCCH J  2:1  =  ~  ratio.)  2  ,  0 H  z  f  o  r  p  z  P  r o t o n s  5  -)  (  T n e  1  Pyrazolyl  (pz-H ).  protons appeared i n a  3  74  The mass spectrum o f t h i s compound the parent  d i s p l a y e d s i g n a l s c o r r e s p o n d i n g to  ( P ) i o n a t -469, i n a d d i t i o n to P-C0 , P-2C0 , P-2C0-N0 i o n +  +  s i g n a l s a t 441, 413, and 383 mass u n i t s  +  +  (based on ^ G a and 9  9 8  Mo),  respectively. In order to o b t a i n a d d i t i o n a l  evidence as to the i d e n t i t y  of t h i s  product, the r e a c t i o n was repeated, t h i s time employing the Na [MeGa(3,5+  Me pz) ]Mo(C0) 2  3  s a l t as the s t a r t i n g m a t e r i a l .  3  A g a i n , orange c r y s t a l s  were i s o l a t e d as the product o f the r e a c t i o n . f o r t h i s compound Mo(C0) N0. 2  80 MHz):  were c o n s i s t e n t with the f o r m u l a t i o n [MeGa(3,5-Me pz) ]2  IR(CH C1 ) v 2  2  C Q  :  2020s, 1920s; v  xCgHg = 2.84 ppm, 9.75s  3 (pz-H ); 4.58s, 4.40s  7.35s  Both the i r and *H nmr data  N Q  :  1650 c m .  *H NMR  -1  3  (CgDg,  (Ga-Me); 8.20s, 7.60s (pz-Me ); 8.09s, 5  4 (pz-H ).  (The pz proton and methyl  resonances  appeared i n a 2:1 r a t i o . ) Thus, i t appears t h a t the C o ( N 0 ) I reagent i s a c t i n g p r i m a r i l y as a 2  n i t r o s y l a t i n g agent i n these 3.2.8  reactions.  P r e p a r a t i o n o f [MeGapz Mo(C0) ] Hg 3  2Na [MeGapz ]Mo(C0) +  3  3  3  + HgCl  T  H  2  >  F  2  One-half molar amount o f H g C l  2  +  cloudiness resulted cloudy vacuo.  indicating  s o l u t i o n was s t i r r e d  3  3  2  (0.115 g, 0.425 mmol) was added to a  THF s o l u t i o n o f the N a [ M e G a p z ] M o ( C 0 ) 3  [MeGapz Mo(C0) ] Hg + 2NaCl  3  salt.  An almost immediate  p r e c i p i t a t i o n o f NaCl.  The y e l l o w brown  o v e r n i g h t and the s o l v e n t then removed i n  The r e s i d u e was e x t r a c t e d with benzene.  The benzene f i l t r a t e was  75  c o n c e n t r a t e d and supernatant  liquid  slowly poured  o f f , leaving  a i r - s e n s i t i v e o f f - y e l l o w c r y s t a l s of the d e s i r e d product Anal. Calcd. Found:  For [MeGapz Mo(C0) ] Hg: 3  C, 28.05;  3  presence  of the Ga-Me s i g n a l  observed  in either  3.2.9  IR(CH C1 ) v C Q : 2  The *H nmr spectrum  1  of the compound showed the  but s i g n a l s due to the pz protons were not  CU  3  [MeGapz Mo(C0) 3 ] 2 Hg 3  + SnCl  T  H  F  2  spectrum  2  3  3  [MeGapz Mo(C0) ] SnCl . 3  3  2  2  [CpFe(C0) ] 2  2  SnCl  attempts  2  2  2  + Hg(s)  The s o l u t i o n i r  orange brown s o l i d o b t a i n e d from t h i s r e a c t i o n was r e g i o n o f the spectrum.  with a v a r i e t y o f s o l v e n t s f a i l e d  pure product, hence no f u r t h e r c h a r a c t e r i z a t i o n was Although  2  [MeGapz Mo(CO) l SnCl  devoid o f a b s o r p t i o n bands i n the recrystallization  SnCl  i n THF d i d not r e s u l t i n the expected  r e a c t i o n product  o f the dark  2  (0.602 g, 0.530 mmol) with an  3  amount o f S n C l  3  >  R e a c t i o n o f [MeGapz Mo(C0) 3 ] 2 Hg  replacement  2020m, 1985m,  2  or d..-acetone s o l u t i o n . C C 6 6 6 Attempted R e a c t i o n o f [MeGapz Mo(C0) ] Hg with  equimolar  i n ~60% y i e l d .  C, 27.56; H, 2.12; N, 14.84.  2  H, 2.33; N, 14.99.  1952m, 1890s cm" .  behind  i s known to i n s e r t  and [ C p M o ( C 0 ) ] 3  Repeated to give the  attempted.  i n t o the M-M bonds i n the dimers  [130], and the f a c t t h a t both Hg and Sn form  2  s t r o n g c o v a l e n t bonds with t r a n s i t i o n metals  [131], the Mo-Hg-Mo bond i n  the p r e s e n t compound [MeGapz ](C0) Mo-Hg-Mo(C0) [pz GaMe] may be too 3  s t r o n g , thereby complex.  3  p r e v e n t i n g the replacement  3  3  o f Hg with S n C l  2  i n the  76  3.2.10  Attempted d e s u l f u r i z a t i o n of H S by [ M e G a p z ] M o ( C 0 ) R h ( P P h ) 2  3  3  3  2  D u r i n g the c o u r s e of t h i s work, the f i r s t q u a n t i t a t i v e f o r m a t i o n o f m o l e c u l a r hydrogen H  2  v i a a b s t r a c t i o n of s u l f u r from H S by the dimer 2  [ P d X ( n - d p p m ) ] (X = C l , B r , I; dppm = b i s ( d i p h e n y l p h o s p h i n o ) m e t h a n e ) 2  2  2  [ 1 3 2 ] was communicated i n p r e l i m i n a r y f o r m .  I t was t h e r e f o r e of  t o us t o see i f  [MeGapz ]Mo(C0) Rh(PPh )  the h e t e r o b i m e t a l l i c complex  3  3  interest 3  2  would e f f e c t a s i m i l a r t r a n s f o r m a t i o n of H S i n t o m o l e c u l a r hydrogen H 2  a c c o r d i n g t o the scheme shown below.  2  77  A or  H S 2  E  low  •  T.  LM  • H  2  However, the r e a c t i o n of the Mo-Rh complex w i t h H S i n C H C 1 2  ambient temperatures r e s u l t e d i n a b l a c k s o l i d .  2  The s o l u t i o n i r  2  at  spectrum  o f the b l a c k s o l i d i n d i c a t e d a non-carbonyl c o n t a i n i n g compound as the p r o d u c t , w h i l e the *H nmr spectrum i n CgDg o r dg-acetone d i s p l a y e d a sharp Ga-Me s i g n a l pyrazolyl  i n the g a l l i u m a l k y l r e g i o n but t h e r e was no e v i d e n c e of  r i n g p r o t o n resonances i n the spectrum.  the  Attempts a t the  p u r i f i c a t i o n of t h i s p r o d u c t were u n s u c c e s s f u l . 3.2.11  Attempted P r e p a r a t i o n of  The MeGapz Mo(C0) 3  3  [MeGapz ]Mo(C0) Mn(C0) 3  3  5  (0.51 mmol) anion was r e a c t e d w i t h Mn(C0)gBr  (0.154 g , 0.510 mmol) i n THF.  The r e a c t i o n m i x t u r e was s t i r r e d f o r ~2  d a y s , a f t e r which the s o l v e n t was removed under vacuum and the r e s i d u e e x t r a c t e d w i t h benzene.  E v a p o r a t i o n of the benzene  c o n t a i n i n g the e x t r a c t s gave a dark s t i c k y s o l i d .  resulting  filtrate  T h i s dark s o l i d was  78  washed with hexane and solid  g  nmr  1 2  2045, 2035, 2015,  C Q  ( C D , 80 MHz): g  xCgHg = 2.84  6  2.14br (pz-H Analytically  3.3  dark  product. IR(C H ) v :  *H  the hexane-washings d i s c a r d e d l e a v i n g behind a  ). pure  The  pz-H  2000, 1980,  ppm,  resonance  was  10.03  1930,  1900,  1875  (Ga-Me); 4.05br  obscured  cm" . 1  (pz-H ); 4  by the s o l v e n t peak.  samples of the product c o u l d not be o b t a i n e d .  R e s u l t s and D i s c u s s i o n  3.3.1  LMo(C0) Rh(PPh ) 3  3  2  [MeGapz ], [HBpzg],  (where L =  3  or  [Me Gapz(0CH CH NMe )]) 2  The  2  2  2  r e a c t i o n s of the a n i o n i c l i g a n d s [MeGapz ]Mo(C0) , 3  [ H B p z ] M o ( C 0 ) , and 3  3  [Me Gapz(0CH CH NMe )]Mo(C0) 2  catalyst, RhCl(PPh ) , 3  3  2  i n THF  2  2  resulted  3  3  with W i l k i n s o n ' s  i n the displacement of the c h l o r o  l i g a n d , the f o r m a t i o n of molybdenum-rhodium bonds, and the l o s s of t r i p h e n y l p h o s p h i n e from  the rhodium c o o r d i n a t i o n sphere.  The  crystalline  products are a i r - s t a b l e but s o l u t i o n s of the complexes decompose on exposure  to a i r .  [MeGapz ]Mo(C0) 3  RhCl(C0)(PPh ) 3  of  2  3  In the experiment  ( u s i n g e i t h e r the [ H B p z ] M o ( C 0 ) 3  was  i s o l a t e d , presumably being produced 3  anion s t a r t i n g  Physical ir v  r n  or  anion) a small amount of the y e l l o w c r y s t a l l i n e m a t e r i a l  a t r i p h e n y l p h o s p h i n e from R h C l ( P P h )  tricarbonyl  3  3  by a CO  v i a displacement  l i g a n d of the molybdenum  material.  data f o r the complexes are l i s t e d  f r e q u e n c i e s i n d i c a t e the presence  i n T a b l e I I I p. 72.  of both t e r m i n a l and  The  bridging  79  carbonyl the  groups i n the compounds.  The room temperature  H nmr data f o r  complexes c o n t a i n i n g t h e 'MeGapz^' and 'HBpz^' l i g a n d s  equivalence  of the three p y r a z o l y l  observed  f o r the r i n g protons  although  showing sharpening  clearly  suggest  rings s i n c e only one s e t of s i g n a l s i s  (see f i g u r e 19).  Low temperature s p e c t r a ,  of these proton s i g n a l s , d i d not d i s t i n g u i s h  any d i f f e r e n c e between t h e t h r e e p y r a z o l y l  rings.  The room  temperature ti nmr spectrum of the [ M e G a p z ( O C H C H N M e ) ] M o ( C 0 ) R h ( P P h ) l  2  complex i s c o n s i s t e n t with a f a c i a l gallate  ligand  signals  being  2  ligand  recorded.  A complicated  complex.  A meridional  l i g a n d would give an A X 2  The  3  3  2  about the molybdenum c e n t e r , with two Ga-Me and two N-Me spectral  2  in this  2  c o o r d i n a t i o n of the unsymmetric  the -CH CH - group, l e n d i n g f u r t h e r support 2  2  crystal  2  p a t t e r n was observed  for a facial  for  organogal 1 ate  c o o r d i n a t i o n of the unsymmetric  p a t t e r n (two t r i p l e t s ) f o r t h e -CH CH ~ group. 2  s t r u c t u r e of the [ M e G a p z ] M o ( C 0 ) R h ( P P h ) 3  3  3  shown i n f i g u r e 20, and c o n s i s t s of d i s c r e t e molecules  2  2  complex i s  separated  by normal  van d e r Waals d i s t a n c e s . The  structure clearly  u n i t , which, although  shows the presence  significantly  of a t e r m i n a l  n o n - l i n e a r (173.9(5)A),  removed from the Rh c e n t e r ( R h * " C ( l ) , 2.845(5)A) t o suggest interaction. recorded  at 1879 c m  different, angles  are both  (Nujol).  clearly  respectively  significantly  at Mo.  - 1  i s too f a r any b r i d g i n g  f o r the h i g h e s t V^Q value  The two remaining  Mo-CO u n i t s ,  although  i n b r i d g i n g range of t h e Rh c e n t e r with Mo-C-0  of 167.4(4) and 153.2(4)° and Rh«««C d i s t a n c e s of 2.334(5) and  2.079(5)A is  T h i s CO l i g a n d presumably accounts  Mo-C(l)-0(l)  (v  values 1758, 1772 cm' ). 1  C Q  non-linear i n this  s t r u c t u r e with  The G a » " M o - R h  an angle  unit  of 161.59(3)°  81  Figure  It solid  is  Molecular  also evident  state  postulate  20.  that  structure of  [MeGapz ]Mo(C0) Rh(PPh )  the p y r a z o l y l  rings  and t o e x p l a i n t h e s o l u t i o n  that a rapid  fluxional  3  is  the  'MeGapz ' 3  likely,  Ugand  i n which  a b o u t t h e Ga-**Mo  there  is  rapid  axis,  interchange  there  pyrazolyl  rings.  is  is  of  necessary in  in  the  to Two  rotation  perhaps  the d i f f e r e n t  2  solution.  a rapid  and a n o t h e r ,  t h r e e CO l i g a n d s , w i t h c o n c o m i t a n t e q u a l i z a t i o n o f three  it  taking place  s u c h p r o c e s s e s may be e n v i s a g e d , one i n w h i c h  3  are non-equivalent  *H nmr d a t a  process  3  roles  of  more of  the environments of  the the  82  The rhodium complex reported here i s very similar to the one reported e a r l i e r by Carlton et a l . [104],  These authors reported the structure of  substitutes the 'MeGapz ' ligand of the present complex. 3  The s i m i l a r i t y  of the two complexes i l l u s t r a t e s once more the interchangeable i t y of the 'n-CgHg' and 'MeGapz-j' ligand systems [34]. The Mo-Rh bond distance of 2.6066(5)A ( c f . 2.588(1 )A in the Ti-CgHg complex) in the present compound i s well below the estimated  single bond distance of 2.8-3.OA and suggests  some multiple bond character between the two transition metals. A bonding scheme similar to that proposed by Carlton et a l . would give an 18-electron count to the Mo atom and a 16-electron count to the Rh center.  In this picture (figure 21), in addition to two bridging CO  o Figure 21.  Proposed bonding scheme for [MeGapz~]Mo(CO).,Rh(PPh.,)  83  groups, a double component overall  bond between the two t r a n s i t i o n metals, with one  being a Rh+Mo d a t i v e l i n k ,  c o n s t i t u t e s an i n t e g r a l  p a r t o f the  m o l e c u l a r framework, and i s c o n s i s t e n t with the observed Mo-Rh  bond l e n g t h i n the p r e s e n t complex. Such d a t i v e i n t e r a c t i o n s between metals have been proposed number o f h e t e r o b i m e t a l l i c complexes [107,133,134]. different the  In keeping with the  r o l e s o f the carbonyl l i g a n d s , the C-0 bond l e n g t h s i n v o l v i n g  'bridging' ligands  (1.190(5) and 1.175(6)A) are s i g n i f i c a n t l y  than t h a t o f the unique  t e r m i n a l CO l i g a n d  framework possesses a b u t t e r f l y  (1.154(6)A).  arrangement as seen  T)-CgHg complex [104] with the Rh-C-Mo d i h e d r a l  longer  The Rh(p.-C0) Mo 2  i n the analogous  angle o f 156° compared with  i n the Ti-CgHg compound.  161° 3.3.2  [MeGapz ]Mo(C0) Cu(PPh ) 3  3  3  The r e a c t i o n o f the [MeGapz ]Mo(C0) 3  [CuCl(PPh )] 3  anion.  data f o r the complex are compiled The s o l u t i o n  i r spectrum  s u g g e s t i v e o f a symmetrical The p o s i t i o n s of these  (C0) (HAsPh 3  +  4  3  product  C  i s a i r - s t a b l e but  r a p i d l y on a i r - e x p o s u r e .  The p h y s i c a l  i n Table I I I p. 72.  f o r t h i s complex shows two 3 v  bands  (A + E modes) s t r u c t u r e (1898 and 1798 c m ,  h i g h e r than those observed  (Et N  of a yellow c r y s t a l l i n e  The s o l i d m a t e r i a l  s o l u t i o n s o f the complex decompose  3  anion with the t e t r a m e r  from the displacement o f the c h l o r o l i g a n d by the  molybdenum t r i c a r b o n y l  slightly  3  i n THF l e d t o the i s o l a t i o n  4  which r e s u l t e d  (C0)  for a  -1  bands f o r the complex.  CH C1 2  2  f o r the uncomplexed anion  salt)  (1890 and 1760 cm" ,  CH C1 2  2  s o l u t i o n ) and  salt)  (1890 and 1750 cm" ,  CH C1  2  solution).  1  are c l o s e i n v a l u e to the v  solution) are  1  2  [MeGapz ]Mo3  [MeGapz ]Mo-  These  3  results  v i b r a t i o n s , r e c o r d e d some time e a r l i e r by  84  (1897 and 1761 cm" , MeCN s o l u t i o n ) . d i s p l a y s t h r e e bands i n the v 1780 c m " , N u j o l ) .  C Q  In the s o l i d s t a t e the Cu complex  r e g i o n of the spectrum (1890, 1805 and  These c o u l d a r i s e e i t h e r from a s p l i t t i n g of the  1  mode observed i n the s o l u t i o n spectrum, or from s l i g h t l y d i f f e r e n t environments f o r the two independent m o l e c u l e s .  'E'  packing  From the c r y s t a l  s t r u c t u r e data d i s c u s s e d below, one of the c a r b o n y l groups of the unprimed m o l e c u l e i s i n v o l v e d i n a p o s s i b l e C-H»»*0 i n t e r a c t i o n . ir  spectrum of the uncomplexed c a r b o n y l anion i n the  [ E t N ] [ M e G a p z M o ( C 0 ) ] d i s p l a y e d two v 3  3  N u j o l ) as expected from i t s C  3 y  state  salt  bands (1885 and 1730 c m " ,  +  4  The s o l i d  1  C Q  symmetry.  These v a l u e s again compare  c l o s e l y w i t h those r e p o r t e d f o r the analogous boron s p e c i e s i n the [ E t N ] [ H B p z M o ( C 0 ) ] " (1890 and 1750 c m " , KBr d i s c ) [ 6 0 ] . +  4  A structure  1  3  salt  3  c o n s i s t e n t w i t h the i r data of the Mo-Cu complex i s shown below.  co  Figure 22.  P o s s i b l e s t r u c t u r e of the [ M e G a p z ] M o ( C 0 ) C u ( P P h ) complex as suggested by the i r d a t a . 3  3  3  85  In  the scheme, the Mo c e n t e r r e t a i n s an 1 8 - e l e c t r o n count  assumed t h a t the CO groups of the molybdenum t r i c a r b o n y l t h e i r t e r m i n a l c h a r a c t e r to the molybdenum atom. Mo+Cu, between the two t r a n s i t i o n metals moiety  a 14-electron  The  anion  retain  The s i n g l e donor bond,  g i v e s the Cu of the C u ( P P h ) I  +  3  count.  nmr data of [MeGapz ]Mo(C0) Cu(PPh ) i n CgDg s o l u t i o n a t room 3  temperature  3  3  are c o n s i s t e n t with a symmetrical  s o l u t i o n , being s i m i l a r to the uncomplexed anion p. 44) except  nmr spectrum  [MeGapz ]Mo(CO) 3  f o r the presence  3  (HAsPh  of the P P h  s i g n a l s i s d i s p l a y e d f o r the p y r a z o l y l pyrazolyl  i f i ti s  groups i n the complex.  s t r u c t u r e f o r the complex i n o b t a i n e d f o r the  3  salt)  ( f i g u r e 14, s e c t i o n  3  ligand.  Only  2.3.1  one s e t o f  protons, i n d i c a t i n g e q u i v a l e n t  The chemical  shift  data from  the *H  nmr  r e s u l t s compare q u i t e well with those measured f o r the uncomplexed anion [MeGapz ]Mo(C0) 3  3  The c r y s t a l  (HAsPh  3  salt)  (see s e c t i o n 2.2.4  p. 29).  s t r u c t u r e of the [MeGapz ]Mo(C0) Cu(PPh ) complex i s 3  3  3  shown i n f i g u r e 23 and again c o n s i s t s of d i s c r e t e molecules normal  separated by  van der Waals d i s t a n c e s .  The only i n t e r m o l e c u l a r c o n t a c t o f any p o s s i b l e s i g n i f i c a n c e i s a C-H-'-O i n t e r a c t i o n a s s o c i a t i n g p a i r s of unprimed molecules i n v e r s i o n c e n t e r a t (0,0,1/2) [ C ( 3 0 ) - H ( 3 0 ) - " 0 ( 2 ) 3.424(9), H " » 0 = 2.55A, C-H«-«0 = 151°]. statistically  significant  l e n g t h s and angles  (-x, -y, £ - z ) , C«««0 =  Apart from  s e v e r a l small but  d i f f e r e n c e s between the c o r r e s p o n d i n g bond  (Appendix  two c r y s t a l l o g r a p h i c  about the  I ) , the most n o t a b l e d i f f e r e n c e between the  independent  molecules  of [MeGapz ]Mo(C0) Cu(PPh ) i s 3  3  3  86  Figure 23.  Molecular structures of [MeGapz ]Mo(C0) Cu(PPh ). 3  in the orientation of the PPh the molecule  3  ligand.  3  The conformation  3  about the Cu-P  in  denoted by unprimed atom labels i s about 4° from staggered  compared with a value of 26° in the second molecule.  The complex  [MeGapz ]Mo(C0) Cu(PPh ) i s valence isoelectronic with the Rh compound, 3  3  3  [MeGapz ]Mo(C0) Rh(PPh ) 3  3  3  2  discussed in section 3.3.1.  However, the Cu  complex i s of much higher symmetry, possessing an approximate 3-fold axis along the near-linear C(4)-Ga»*»Mo-Cu-P atomic arrangement (mean angles: C-Ga«««Mo = 178.0(3), Ga»"Mo-Cu = 175.2(6), and Mo-Cu-P = 176.1(9)°).  In  this s o l i d state structure the three pyrazolyl rings are equivalent, t h i s being  consistent with the *H nmr  results already discussed above.  The three CO ligands are e s s e n t i a l l y symmetrically placed with mean bond angles Mo-C-0 of 170.1(5), 170.7(1), and 172.1(6)A, Cu-C-0 of  87  117.0(1), 117.5(3) and 118.5(1)°, and mean bond lengths Mo-C of 1.973(7), 1.964(6) and 1.966(6)A, C u « " C  of 2.247(13), 2.298(23) and 2.415(5)A.  These X-ray data, however, do suggest c e n t e r and the carbonyl interaction type  some i n t e r a c t i o n  groups, although  i s not c l e a r .  Obviously  s i n c e the Mo-C-0 angles  the exact  between the Cu  nature  the i n t e r a c t i o n  of t h i s  i s of a s e m i - b r i d g i n g  are not f a r removed from  linear.  Numerous recent p u b l i c a t i o n s have documented and d i s c u s s e d types  of b r i d g i n g CO i n t e r a c t i o n s  i n h e t e r o b i metal l i e t r a n s i t i o n  complexes [76,121-123,135 and r e f e r e n c e s t h e r e i n ] .  metal  metal  The present Cu  compound does not appear t o f i t i n t o the category electron-rich  different  of a d i s t a l  c e n t e r (the Cu c e n t e r has a 1 4 - e l e c t r o n  count)  * donating  e x c e s s i v e charge i n t o the CO TC  dTc-dTc bonding occurs i n t e r a c t i o n with (ri-CgHg)2Mo2(C0)  orbitals  [123].  Although, i f  between the Cu and the Mo c e n t e r s , then an  the CO groups s i m i l a r t o t h a t p o s t u l a t e d f o r the complex 4  [76,136] may be p o s s i b l e .  Such an i n t e r a c t i o n  between a  * Mo-Cu rc-bond and the TC i n f i g u r e 24 (p. T h i s type  orbital  of a CO l i g a n d  i s shown s c h e m a t i c a l l y  88).  of i n t e r a c t i o n would, of course, tend t o lengthen the C-O  bond, and, with a mean C-O bond d i s t a n c e of 1.164A, the carbonyl do d i s p l a y s l i g h t l y ligands. type  The present  bonding  by Horwitz  l o n g e r bonds than  u s u a l l y found  f o r t e r m i n a l CO  s t r u c t u r e does not meet the requirements  ( f i g u r e 25 p. 8 9 ) .  These  requirements  ligands  f o r n-CO  were r e c e n t l y  reviewed  and S h r i v e r [ 7 6 ] .  Thus, the Cu-0 d i s t a n c e s the Cu-C d i s t a n c e s approximately  (2.945(5) - 3.143(5)A) are much l o n g e r than  (2.234(6)-2.419(6)A), l e a d i n g t o Q values of  2.14 - 2.16 (where Q = exp[D(Cu-C)/D(Cu-0)], D = d i s t a n c e ) .  Figure 24.  *  P o s s i b l e i n t e r a c t i o n between the Mo-Cu n bond and the n o r b i t a l of the CO l i g a n d i n the complex [MeGapz ]Mo(C0) Cu(PPh ). 3  3  3  These Q v a l u e s p r o v i d e a measure of the e x t e n t of i n t e r a c t i o n of Cu w i t h the C and 0 ends of the CO l i g a n d s , but are much lower than expected f o r a s t r o n g n-CO type i n t e r a c t i o n [ 7 6 ] .  In a d d i t i o n , the  frequencies  observed f o r the complex are a l l much h i g h e r than the expected v a l u e o f ~1650 c m  - 1  f o r a n-CO g r o u p .  89  M  -M  n-co 0  fi=  = 2 2 - 3-3  exp[D(M-C)/D(M'-0)] (where  Figure  25.  D = distance)  The s t r u c t u r e o f a l i n e a r s e m i - b r i d g i n g  Perhaps the bonding i n the p r e s e n t complex regard  recent  a complex  donor bond  to s e m i - b r i d g i n g  2  strong ligands  5  i n addition  originally  i n t e r a c t i o n between the d i s t a l (Cr-CO  i s more s u b t l e .  M.O. c a l c u l a t i o n s [105] on the complex  (n-C0) Rh(C0)(T)-CgH ),  ( b r i d g e ) , 1.902(7)A,  postulated  In t h i s  (Ti-CgHg)(CO)Crto c o n t a i n  a Cr+Rh  CO i n t e r a c t i o n s [107], suggest a Rh c e n t e r  and the b r i d g i n g CO  Rh-CO ( b r i d g e ) , 2.200(7)A), with a net  bond o r d e r c l o s e t o z e r o between the metal  atoms (Rh»--Cr,  S i m i l a r c a l c u l a t i o n s on the p r e s e n t system may well  2.757(2)A).  be i n v a l u a b l e i n  d e t e r m i n i n g the major bonding i n t e r a c t i o n s r e s p o n s i b l e separation.  CO type bonding.  f o r the s h o r t Mo-Cu  90  I t i s again i n t e r e s t i n g to compare s i m i l a r complexes i n t h i s area. Carlton e t a l . [104] have provided s t r u c t u r a l data on two d i f f e r e n t forms of the complex (ri-CgHgMCO^CufPPh-^, and suggest some semi-bridging i n t e r a c t i o n s i n v o l v i n g the two metals and two of the CO ligands.  Three  important differences occur with the [MeGapz ]Mo(C0) Cu(PPh ) complex. 3  F i r s t , only one PPh  3  3  ligand i s attached to the Cu center, making the  3  molecule valence i s o e l e c t r o n i c with the [MeGapz ]Mo(C0) Rh(PPh )2 compound 3  (see section 3.3.1).  3  3  Second, the present structure has three  roughly  equivalent CO groups, whereas i n Carlton's tungsten compounds one of the three CO groups i s c l e a r l y terminal to tungsten.  T h i r d , the mean Mo-Cu  distance of 2.513(9)A i s considerably shorter than e i t h e r of the W-Cu distances of 2.771(1) and 2.721(1)A reported by Carlton e t a l . Given that the r a d i i for Mo and W are very s i m i l a r at ~1.61A (the M-M distances i n ( T I - C H ) ( C 0 ) M - M ( C 0 ) ( T I - C H ) are 3.222(5)A for M = Mo [137] and 3.24(1) A 5  5  3  3  5  5  for M = W [138]), these differences i n bond lengths suggest a much stronger Mo-Cu i n t e r a c t i o n i n the present complex.  Indeed, the observed  Mo-Cu distance i s s i g n i f i c a n t l y shorter than the estimated single Mo-Cu bond length of ~2.7 — Cu-P  2.8A. Another noticeable difference occurs i n the  distances i n the two complexes.  Thus the compound reported here  displays a mean Cu-P distance of 2.196(3)A, somewhat shorter than the corresponding  mean distance of 2.299(12)A reported for the two c r y s t a l l i n e  forms of (Ti-C H )W(C0) Cu(PPh ) . 5  5  3  3  2  Recently, s t r u c t u r a l data were provided  for the (ri-C H )Mo(C0) Cu(tmed) (tmed = N, N, N', 5  5  3  N'-tetramethylethylene-  diamine, Me NCH CH NMe ) compound by Doyle et a l . [139]. ?  9  ?  ?  Even though  91  d i f f e r e n t metals were i n v o l v e d and d i s s i m i l a r both s t e r i c a l l y  and  the  l i g a n d s on  electronically,  the Cu were q u i t e  the  o v e r a l l geometry of  l a t t e r molecule i s s u r p r i s i n g l y s i m i l a r to t h a t of one ( r i - C r j H g M C O ^ C u f P P h . ^ isomers r e p o r t e d reported  by Doyle and  'four-legged addition  the W complexes r e p o r t e d  piano s t o o l '  to a Cu-M  semi-bridging  CO  by C a r l t o n .  configurations  (M = Mo  or W)  about the Mo  The  5  ( C 0 ) B r [60]  5  (ri-C H )W(C0) Au(PPh ) [140] 5  The  3  5  W-Au  3  s t r u c t u r e analogous to t h a t d e p i c t e d  three  positions. reported  CO  l i g a n d s and  3  the  of the  possibility  [MeGapz ]Mo3  arrangement  the Au  with  (ri-CgHg)W u n i t at the  as a 3:4  for [HBpz ]Mo(C0) Br.  a capped o c t a h e d r a l  a minimum i n the  had  been  These authors  3  i n t e r e s t i n g aspects which prompted  of o b s e r v i n g  apex  basal  piano s t o o l , has  3  the  piano  3  Shiu  very  atom r e p l a c i n g  'four-legged  s t r u c t u r e , s i n c e c a l c u l a t i o n s by Kubacek e t a l . [141] arrangement r e p r e s e n t s  3  the Au(PPh ) grouping occupying the  A s i m i l a r structure, described  [60] mentioned t h a t one  [HBpz ]Mo-  i n f i g u r e 23,  'MeGapz ' l i g a n d and  r e c e n t l y by C u r t i s and  study, was  present  Thus, i n s t e a d of a  atom the arrangement adopted i s t h a t of a  the  the  compound d i s p l a y s an  s t o o l ' , or a d i s t o r t e d square-pyramid with the and  two  i n the  and  3  from t h a t found f o r Mo-Cu complex.  'ri-CgHg' l i g a n d r e p l a c i n g the the Cu  and  3  (C0) Cu(PPh ) structure.  symmetrical  or W atoms i n  (2.513(9)A vs. 2.592A) to  complexes are worthy of comparison with  3  different  have  Mo-Cu d i s t a n c e  3  s t r u c t u r e s of the  3  complex  (T)-C H )Mo(C0) Cu(tmed) compound.  t h a t of the The  Both the Mo  bond with a s i n g l e t e r m i n a l  groups r e s p e c t i v e l y . 3  the  by C a r l t o n  [MeGapz ]Mo(C0) Cu(PPh ) complex i s comparable 3  of  the  their  (3:3:1)  shown t h a t  p o t e n t i a l energy s u r f a c e  for  this  92  analogous ( T ) - C H ) M I _ 5  5  complexes whose global  4  minimum (ground s t a t e ) i s  always the ' f o u r - l e g g e d piano s t o o l ' , or 3:4 the p r e s e n t copper complex t h i s 3:3:1  [MeGapz ]Mo(C0) Cu(PPh ) 3  capped o c t a h e d r a l  Finally,  structure.  3  I t appears t h a t  c l o s e l y approaches  3  arrangement. ( r ] - C H ) F e ( C O ) A u ( P P h ) [142]  the s t r u c t u r e of the complex,  3  5  3  3  has many f e a t u r e s s i m i l a r to those of the Mo-Cu complex presented I t has been proposed t h a t the bonding i n t h i s  here.  i r o n complex r e s u l t s from  the Lewis base ( r ) - C H ) F e ( C 0 ) donating a p a i r o f e l e c t r o n s to the Lewis 3  5  3  a c i d A u ( P P h ) , and does not n e c e s s a r i l y  i n v o l v e any d i r e c t  +  3  between  interaction  the Au atom and the CO l i g a n d , the geometry of the complex  d i c t a t e d by t r a n s i t i o n metal b a s i c i t y .  being  If t h i s reasoning i s c o r r e c t  then  the Au c e n t e r a t t a i n s a 1 4 - e l e c t r o n count and the Fe-Au s e p a r a t i o n o f 2.519(1)A 3.3.3  results entirely  from the Fe+Au d a t i v e  bond.  [Me6apz ]Mo(C0) Cu(C0) 3  3  The i n t r o d u c t i o n of the HBpz  ligand  3  o f t e n known to have a s t a b i l i z i n g  i n p l a c e of the CgHg l i g a n d i s  e f f e c t on the r e s u l t i n g complex.  example, w h i l e the compound ( T ) - C H ) C U C 0 [23] decomposes 5  5  rapidly  at room  temperature even under i n e r t c o n d i t i o n s , the analogous [HBpz ]CuC0 3  i s a white, c r y s t a l l i n e  a i r - and h e a t - s t a b l e s o l i d .  attempts a t the i s o l a t i o n unsuccessful  [143]  Even though p r e v i o u s  of the analogous [MeGa(3,5-Me2pz) ]CuC0 3  were  [144], i t was open to s p e c u l a t i o n as to whether the 'MeGapz  l i g a n d would s t a b i l i z e  the compound [MeGapz ]Mo(C0) Cu(C0), 3  3  with the re-acceptor CO l i g a n d a t t a c h e d to the a l r e a d y Cu metal c e n t e r i n the 'PPhJ  For  especially  electron-deficient  (assuming the Cu has a 1 4 - e l e c t r o n count s i m i l a r to t h a t  d e r i v a t i v e d i s c u s s e d i n s e c t i o n 3.3.2).  3  93  R e a c t i o n of the [MeGapz ]Mo(C0) 3  anion with CuCl  3  i n the presence of  CO r e s u l t e d  i n the y e l l o w [MeGapz ]Mo(C0) Cu(C0) compound as  Analytical,  i r and *H nmr data f o r t h i s compound are c o l l e c t e d  III p. 72.  The s o l u t i o n i r spectrum  i n the v C Q  3  r e g i o n of the spectrum  the Cu metal  would not be expected  expected.  3  i n Table  of t h i s compound showed three bands  (2020, 1955, 1810 cm" , 1  CH C1 ). 2  Since  2  to donate e l e c t r o n d e n s i t y e f f i c i e n t l y  * to the TC link  system of i t s CO l i g a n d , the backbonding present i n the Cu-CO  i s r e l a t i v e l y weak and consequently  f o r the h i g h e s t v C Q  value at 2010 c m .  t h i s CO l i g a n d probably  accounts  The two other bands a t 1955 and  -1  1810 cm~ must be due to the three s y m m e t r i c a l l y p l a c e d CO l i g a n d s on the 1  Mo atom (assuming  a complex i s o s t r u c t u r a l  which i s d i s c u s s e d i n s e c t i o n 3.3.2).  to [MeGapz ]Mo(C0) Cu(PPh ) 3  3  3  higher v C Q  The s l i g h t l y  values  o b t a i n e d f o r the p r e s e n t complex compared to those recorded f o r [MeGapz ]Mo(C0) Cu(PPh ) 3  3  3  to g r e a t e r withdrawal  (1898 and 1798 cm" , 1  of e l e c t r o n d e n s i t y from  CHgCI ), are presumably due 2  the Mo atom to the Cu atom  i n the [MeGapz ]Mo(C0) Cu(C0) complex. 3  The  3  nmr data f o r t h i s Cu-CO complex are c o n s i s t e n t with a  symmetrical  C  s t r u c t u r e i n s o l u t i o n , and d i s p l a y one s e t of  3 v  resonances  f o r the p y r a z o l y l  protons, being i n d i c a t i v e of e q u i v a l e n t p y r a z o l y l  groups.  nmr data compare q u i t e well with those recorded f o r the  These  [MeGapz ]Mo(C0) Cu(PPh ) compound, and suggest 3  3  isostructural the f a c i l e  3  to the 'Cu(CO)' d e r i v a t i v e .  replacement  t h i s complex may  indeed be  S u p p o r t i v e evidence comes from  of the CO l i g a n d of the complex  [MeGapz ]Mo-  (COKCu(CO) by PPh-, l i g a n d to g i v e the [MeGapz,jMo(COkCu(PPh.J  3  compound.  94  3.3.4  [MeGapz ]Mo(C0) Pt(Me)(PPh ) 3  3  3  The PtCl (Me)(COD) (COD = 1,5-cyclo-octadiene, TC-1 ,5-CgH^) complex, previously reported as unreactive toward RBpz ligand unless the very 3  tightly-bonded COD ligand is f i r s t activated by a strong oxidant such as AgPFg via halogen abstraction [24,145], was recently shown to be reactive toward Me Gapz ligand in the absence of a strong oxidant [ 1 4 6 ] . 2  2  S i m i l a r l y the [MeGapz ]Mo(C0) 3  3  anion reacted with PtCl(Me)(C0D) without  the AgPFg, but in the presence of the s t a b i l i z i n g PPh l i g a n d , to form the 3  complex [MeGapz ]Mo(C0) Pt(Me)(PPh ) with the elimination of the chloro 3  3  and COD ligands.  3  A n a l y t i c a l , i r and *H nmr data for t h i s complex are  l i s t e d in section 3.2.5 (p. 71). The i r spectrum of the [MeGapz ]Mo(CO) Pt(Me)(PPh ) compound showed 3  3  3  three strong bands (1900, 1815, 1785 c m , CH C1 ) in the v  region.  - 1  2  2  C Q  If  one terminal and two bridging CO groups are assumed to be present in t h i s compound as suggested by the i r data, then a bonding scheme between the Mo atom and the Pt metal center can be proposed. shown in f i g u r e 26.  Such a bonding scheme i s  In t h i s bonding scheme, the Mo atom is provided with  an 18-electron environment with the Pt having a 16-electron count i f a double Mo=Pt bond exists in the complex.  This is not unusual, since  18-electron environments are common f o r Mo in low oxidation s t a t e s , and s i m i l a r l y 16-electron states are not exceptional for P t ( I I ) complexes. The V^Q values recorded for the present Mo-Pt complex are in good agreement with those reported for the closely related compound s t r u c t u r a l l y characterized as (ri-C H )Mo(CO) Pt(H)(PPh ) 5  1828, 1797 c m " , KBr disc) [112]. 1  5  3  3  2  (v  C Q  :  1916,  According to the X-ray s t r u c t u r a l  95  F i g u r e 26.  analysis, is  Proposed bonding scheme f o r  the usual  strongly  [MeGapz ]Mo(C0) Pt(Me)(PPh ).  s q u a r e - p l a n a r environment  distorted  i n the l a t t e r complex.  3  3  3  found f o r P t ( I I ) compounds T h i s arrangement  was  r a t i o n a l i z e d by the authors as being due to m i n i m i z a t i o n of s t e r i c r e p u l s i o n s between the bulky phosphine groups The  room temperature *H nmr spectrum o f the  (PPh ) complex  i n dg-acetone  the compound.  A rapid  3  a x i s might e x p l a i n The Pt-Me s i g n a l  solution  rotation  [MeGapz ]Mo(C0) Pt(Me)-  i n d i c a t e d e q u i v a l e n t pz groups i n  the observed e q u i v a l e n c e o f the pz groups  was a l s o d i s p l a y e d Pt-satellites  U n f o r t u n a t e l y , the a c t u a l  3  3  (J  in solution.  i n the spectrum a t ~9.45-c with the  c * 72 H z ) . Pt-Me  1 Q  i y o  s t r u c t u r e of the p r e s e n t Mo-Pt  not be c o n f i r m e d s i n c e attempts to o b t a i n c r y s t a l s  X-ray s t r u c t u r a l  3  o f the 'MeGapz ' moiety about the Ga*"Mo  195 accompanying  could  i n the complex.  s t u d i e s were u n s u c c e s s f u l .  complex  suitable for  96  3.3.5  [MeGapz ]Mo(C0) M'Cl 3  The  3  reaction  3  quite  anion and  3  by the  reasonably s t a b l e  3  usual  room temperature *H pz  resulted  complexes.  physical  nmr  a *H  of the  groups i n s o l u t i o n .  symmetrical  nmr  s o l u t i o n would be groups i n d i c a t e d  3:3:1  structure  ( f i g u r e 28a)  with the  *H  nmr  of  *H  nmr  spectrum.  A l t e r n a t i v e l y , the  *H  nmr  r e s u l t s can  ( f i g u r e 28b)  i n which a r a p i d  about the  Ga»**Mo axis might e q u a l i z e  days. the  Interestingly, of  f o r both complexes. f o r the  the the  the A  complexes i n of the  a l s o be e x p l a i n e d  r o t a t i o n of the  the  the  spectrum f o r  observed e q u i v a l e n c e  the  structure  the  decompose  spectrum almost superimposable t o t h a t  consistent by  but  72)  complexes i n d i c a t e d The  Mo-Zr compound, s u g g e s t i n g i d e n t i c a l s t r u c t u r e s rigid  III p.  tube turned dark green i n 3  spectra  the  compounds  methods (Table  Mo-Zr complex i n CgDg s o l u t i o n i s shown i n f i g u r e 27. Mo-Hf complex had  The  in  For example, a CgDg y e l l o w s o l u t i o n  Mo-Zr complex i n a f l a m e - s e a l e d nmr  presence of e q u i v a l e n t  3  M'Cl^  as s o l i d s under i n e r t c o n d i t i o n s ,  readily in solution.  The  3  Hf)  [MeGapz ]Mo(C0) M'Cl  have been c h a r a c t e r i z e d are  = Z r or  of [MeGapz ]Mo(C0)  mixed t r a n s i t i o n metal  and  (M'  3  by  a  pz  3:4  'MeGapz ' moiety 3  environments of the  pz  rings  in  complexes. As  i n the  MorZr and  *H  nmr  results discussed  above, the  i r spectra  Mo-Hf compounds were almost i d e n t i c a l , p r o v i d i n g  evidence f o r the  similarity  i n the  structures  of both  the  additional  of both compounds.  The  ir  98  3:4  3:3:1  F i g u r e 28.  P o s s i b l e m o l e c u l a r arrangements f o r the [MeGapz3]Mo(C0)3M'Cl3 (M = Z r or Hf) complexes. 1  s p e c t r a of the [MeGapz ]Mo(C0) M'Cl (M' 3  three  3  s t r o n g bands i n the V ^ Q r e g i o n .  f o r the complexes i n s o l u t i o n . (C0) HfCl 3  3  3  = Zr or Hf) complexes d i s p l a y e d T h i s i s s u g g e s t i v e of C  A typical  complex i s shown i n f i g u r e 29.  i r spectrum f o r the  g  symmetry [MeGapz ]Mo3  99  1  2200  F i g u r e 29.  The is  2000  1900  1700  I r spectrum o f [ M e G a p z ] M o ( C O ) H f C l 3  presence of only t e r m i n a l i n d i c a t i v e of d i r e c t Mo-M'  accompanying b r i d g i n g CO  (M'  = Zr or Hf)  ligands.  s u i t a b l e f o r X-ray c r y s t a l  T h i s was  rather discouraging  3  in CHgCl  2  (CT ) 1  solution.  i n t e r a c t i o n s with  However, a l l attempts at s t r u c t u r e analyses  especially  o f the t i t a n i u m group metals with M-M' Hf) bonds have been r e p o r t e d  3  1600  V ^ Q bands i n the i r s p e c t r a of the  crystals  3.3.6  1800  i n the l i t e r a t u r e  no  isolating  were u n s u c c e s s f u l .  since r e l a t i v e l y (M = Cr, Mo  complexes  or W;  few d e r i v a t i v e s M  1  = T i , Zr or  [114].  [MeGapz Mo(C0) ] Hg 3  An  extensive  3  2  a r r a y of metal-metal  known i n c y c l o p e n t a d i e n y l  chemistry.  [HBpz Mo(CO) ] [38] i s known with 3 2 2  bonded dimers and  c l u s t e r s are  In c o n t r a s t , only one  such dimer,  the t r i d e n t a t e p o l y ( 1 - p y r a z o l y l J b o r a t e  100  l i g a n d c o o r d i n a t e d on more than one m e t a l . f a c t t h a t X-ray s t r u c t u r a l a Mo=Mo t r i p l e elusive  Even more i n t e r e s t i n g  a n a l y s i s o f t h i s complex showed  i s the  the presence o f  bond, r a t h e r than the expected Mo-Mo s i n g l e bond i n the  [HBpz-jMofCO^l, compound.  Metatheticai resulted  reaction  o f the Na MeGapz Mo(C0) +  3  i n the o f f - y e l l o w , a i r - s e n s i t i v e  good y i e l d .  The s o l u t i o n  3  s a l t with H g C I  i n THF  2  compound [MeGapz Mo(C0) ] Hg i n 3  i r spectrum o f t h i s  product showed  3  four  (2020, 1985, 1952, 1890 cm' , CHgClg) i n the t e r m i n a l  v  above i r data are i n good agreement t o those r e p o r t e d  f o r the  1  C  Q  2  bands  region.  The  [(ri-CgH,-)Mo(C0) ] Hg compound by the two independent groups o f F i s c h e r and 3  Noack  2  [147], and by Burl i t c h  t h e i r spectra  and F e r r a r i  i n terms o f a s i n g l e  [148].  These authors  interpreted  isomer with a skew c o n f i g u r a t i o n  o f the  M O ( C 0 ) ( T I - C H ) groups about the Mo-Hg-Mo system i n the [ ( n - C H ) M o 3  (C0) ] Hg 3  2  5  5  5  complex.  The i r r e s u l t  f o r the p r e s e n t  [MeGapz Mo(C0) ] Hg 3  complex i s perhaps s u g g e s t i v e o f the a d o p t i o n o f a 3:3:1 a r r a y MeGapz Mo(C0) 3  3  5  3  2  f o r the  groups about a l i n e a r Mo-Hg-Mo backbone i n the compound as  shown below ( f i g u r e 3 0 ) .  101  The mass spectrum of the compound [MeGapz Mo(C0) ] Hg was 3  3  2  characterized by extensive low fragment ions, usually i n d i c a t i v e of thermal decomposition of the sample under electron impact ( E . I ) conditions.  However, the monomeric MeGapz Mo(C0) ion fragment was 3  3  observed at -467, in addition to MeGapz Mo(C0) , MeGapz Mo(C0) , and +  3  MeGapz Mo  +  3  2  3  fragment ions at 439, 411 and 383 mass units (based on  69 Ga,  go  Mo), r e s p e c t i v e l y .  The most intense signals in the spectrum were those  a t t r i b u t a b l e to the MeGapz Mo(C0) Mo fragment ion at -565. +  3  3  I n t e r e s t i n g l y , a s i m i l a r fragmentation pattern has been observed in the mass spectrum of the compund [ ( T I - C H ) M O ( C 0 ) ] 5  5  3  by King [ 1 4 9 ] .  2  The *H nmr spectrum of the [MeGapz Mo(C0) ] Hg complex i s rather 3  3  2  strange, in that a sharp Ga-Me signal was displayed in the gallium a l k y l region but the pz proton resonances were not observed in e i t h e r dg-toluene, CgDg or dg-acetone s o l u t i o n .  Attempts to obtain suitable  c r y s t a l s for X-ray crystal structure analyses were unsuccessful. 3.3.7  The '[MeGapz ]Mo(C0) Mn(C0) ' Complex 3  3  5  The preparation of the compound [MeGapz ]Mo(C0) Mn(C0)g was attempted 3  3  by the reaction of the MeGapz Mo(C0) anion with Mn(C0)gBr. 3  3  Spectral data  obtained on the black s o l i d i s o l a t e d from the reaction indicated the desired compound to be present in the product mixture.  The s o l u t i o n  ir  spectrum of the black s o l i d in cyclohexane showed v C Q bands at 2045, 2035, 2015, 2000, 1980, 1930, 1900 and 1875 c m " , i n d i c a t i v e of terminally bound 1  CO groups.  This v C Q pattern observed compares quite well to the bands  reported for the analogous (r)-CcH,-)Mo(C0) Mn(C0) ?  q  complex [150,151].  102  Unfortunately a l l  attempts to i s o l a t e an a n a l y t i c a l l y  [MeGapz ]Mo(C0) Mn(C0)g were u n s u c c e s s f u l 3  3  not undertaken.  and f u r t h e r i n v e s t i g a t i o n s  I t i s probable t h a t the compound  would adopt a capped o c t a h e d r a l  pure sample o f were  [MeGapz ]Mo(C0) Mn(C0) 3  arrangement, s i n c e severe  3  5  steric  i n t e r a c t i o n s between the pz r i n g s and the CO groups a t t a c h e d to the Mn atom would most l i k e l y stool' 3.4  p r e c l u d e the adoption of a ' f o u r - l e g g e d  geometry of the ( r i - C H ) M o ( C 0 ) M n ( C 0 ) 5  5  3  5  complex  piano  [152].  Summary  The mixed t r a n s i t i o n metal  complexes L M o ( C 0 ) R h ( P P h ) 3  3  2  (L =  [MeGapz-j], [ H B p z ] , o r [Me Gapz(OCH CH NMe )]) have been prepared and 3  characterized.  2  2  2  2  One of the above f o r m a l l y u n s a t u r a t e d  bimetallic  complexes, [ M e G a p z ] M o ( C 0 ) R h ( P P h ) , has been s t r u c t u r a l l y 3  3  and d i s p l a y s one t e r m i n a l  3  2  and two b r i d g i n g CO l i g a n d s .  characterized,  Double bonding  between the Rh and Mo i s proposed with one of the bonds being a d a t i v e link  (Rh=±Mo). The h e t e r o b i m e t a l l i c  complexes [MeGapz ]Mo(C0) CuY 3  CO) f e a t u r i n g Mo-Cu bonds have a l s o been prepared.  3  (where Y = PPh  3  structure analysis.  the Cu c e n t e r .  3  The three CO l i g a n d s are e s s e n t i a l l y  to Mo, with the p o s s i b i l i t y  or  The s t r u c t u r e of the  compound [MeGapz ]Mo(C0) Cu(PPh ) has been determined by X-ray 3  3  crystal  terminally  bound  of some weak s e m i - b r i d g i n g i n t e r a c t i o n s with  T h i s Mo-Cu complex p r o v i d e s a r a r e example of a 3:3:1, or  capped o c t a h e d r a l  structure.  The MeGapz Mo(C0) 3  o f the s t a b i l i z i n g  3  anion  r e a c t e d with PtCl(Me)(C0D) i n the presence  PPh, l i g a n d , e l i m i n a t i n g the c h l o r o and COD  l i g a n d s to  103  give  the h e t e r o b i m e t a l l i c compound [ M e G a p z ] M o ( C 0 ) P t ( M e ) ( P P h ) , i n which 3  Mo-Pt bonding i s f e a t u r e d . complex c o u l d  Unfortunately  not be confirmed due  3  the a c t u a l  to the  3  s t r u c t u r e of  l a c k of success i n  this  obtaining  s u i t a b l e c r y s t a l s f o r X-ray s t r u c t u r a l a n a l y s i s . The  complexes [ M e G a p z ] M o ( C 0 ) M ' C l 3  prepared from the  (M'  3  = Zr or Hf)  r e a c t i o n of the MeGapz Mo(C0)  starting halide species. ligands  3  3  The  presence of only  i s i n d i c a t i v e of d i r e c t Mo-M'  (M'  complexes without accompanying b r i d g i n g CO  3  have been  anion and  the  terminally-bonded  = Zr or Hf) ligands.  M'Cl^ CO  i n t e r a c t i o n s i n the  104  CHAPTER IV  TRANSITION METAL-GROUP 14 ELEMENT BONDED COMPLEXES INCORPORATING POLY(1-PYRAZOLYL)GALLATE LIGANDS  4.1  Introduction The  reactivity  of the t r i c a r b o n y l  anions LMo(C0)  [HBpz-j], or [Me2Gapz(0CH2CH2NMe2)]) toward a v a r i e t y  (L = [MeGapz^],  3  of t r a n s i t i o n metal  h a l i d e s p e c i e s t o produce novel t r a n s i t i o n m e t a l - t r a n s i t i o n metal compounds was  explored  i n Chapter I I I .  i n v e s t i g a t i o n i n t o the s i m i l a r i t y analogous CpMo(C0)  As part  of an on-going  of the MeGapz Mo(C0) 3  3  anion and the  a n i o n , the behaviour of the MeGapz Mo(C0)  3  3  3  anion  toward a number of group 14 ( S i , Ge, Sn) element organo h a l i d e s s t u d i e d ; and the r e s u l t s from the study w i l l Chapter. single  Complexes  containing direct  be d i s c u s s e d  [MeGapz ]Mo(C0) SnPh 3  3  t r a n s i t i o n metal-group 14 element  d e t e r m i n a t i o n i n the s o l i d shown t o be n o n - r i g i d experiment.  The 3:3:1  by means of a c r y s t a l  3  state.  has been  i n the present  bonds have been i s o l a t e d , and confirmed s t r u c t u r a l l y  complex  bonded  The complex  f o r the  structure  [MeGapz-^MotCO^SnMegCl  i n s o l u t i o n by a v a r i a b l e temperature *H o r capped octahedral  nmr  arrangement has been  demonstrated f o r the compound s t r u c t u r a l l y  c h a r a c t e r i z e d as  [MeGapz ]Mo(C0) SnPh  Thus, the above compound  3  3  3  c o n s t i t u t e s the f i r s t LM(C0) M'R 3  3  M' = S i , Ge,  i n the s o l i d  state.  reported s t r u c t u r e f o r complexes  of the type  (where L = ( T ) - C H ) , [ H B p z ] , or [MeGapz ]; M = C r , Mo, 5  or Sn; R = a l k y l  5  3  or a r y l ) .  was  3  or W;  105  The  p r e p a r a t i o n and  organotin  c h a r a c t e r i z a t i o n of the s i x - c o o r d i n a t e  complexes LSnMe^ (L = [MeGapz^], [ M e G a ( 3 , 5 - M e p z ) ] ) , and 2  3  [MeGapz ]SnMe C1 compound are a l s o d e s c r i b e d i n t h i s c h a p t e r . 3  have been p u b l i s h e d elsewhere  the  P a r t s of  2  t h i s chapter 4.2  tri-  [92].  Experimental  4.2.1  Starting materials Me-jSiCl, Me GeCl, Ph GeCl 3  Chemicals),  (Strem  3  Ph SnCl  Chemicals),  (Alpha Chemicals) and M e S n C l  3  2  Me SnCl  (Aldrich  3  2  (PCA  Chemicals) were  used as s u p p l i e d . 4.2.2  P r e p a r a t i o n of  Na MeGapz Mo(C0)  3  3  + Me SiCl  +  3  [MeGapz ]Mo(C0) SiMe  3  T  To the molybdenum t r i c a r b o n y l was  added M e S i C l 3  H  F  3  3  3  3  3  (0.35  (0.038 g, 0.350 mmol) i n the same s o l v e n t . was  was  r e s i d u e was  removed i n vacuo. Evaporation  The  mmol) i n  inert conditions i f l e f t  e x t r a c t e d with benzene  s o l i d s of the d e s i r e d product  f o r a few  i n Table  THF  The  s t i r r e d o v e r n i g h t a f t e r which the s o l v e n t  T h i s compound i s u n s t a b l e as a s o l i d  compound are l i s t e d  + NaCl  3  and  of the benzene s o l v e n t from the f i l t r a t e  the e x t r a c t a f f o r d e d y e l l o w yield.  [MeGapz ]Mo(C0) SiMe  anion MeGapz Mo(C0)  r e s u l t i n g r e a c t i o n mixture  filtered.  >  3  IV.  days.  and  containing  i n moderate  i n s o l u t i o n even under  P e r t i n e n t p h y s i c a l data  for this  106  4.2.3  Preparation  of [MeGapz ]Mo(C0) GeR 3  Na MeGapz Mo(C0) +  3  Me GeCl  Na MeGapz Mo(C0) +  3  3  overnight  resulting  + R GeCl  T  H  >  F  3  (R = Me, Ph)  3  [MeGapz ]Mo(C0) GeR 3  3  (0.13 g, 0.85 mmol) was added t o a s t i r r e d  3  stirred  3  3  (0.85 mmol) s a l t  i n THF.  + NaCl  3  solution  of t h e  The r e a c t i o n mixture was  a f t e r which the s o l v e n t was removed under vacuum.  orange residue was e x t r a c t e d with benzene and f i l t e r e d .  benzene s o l u t i o n  The The  c o n t a i n i n g the e x t r a c t s was then c o n c e n t r a t e d t o give  orange needles of the d e s i r e d product  [MeGapz ]Mo(C0) GeMe 3  3  3  i n moderate  yield. The compound Ph GeCl  [MeGapz ]Mo(C0) GePh 3  3  as the s t a r t i n g m a t e r i a l .  3  isolated  3  was prepared s i m i l a r l y  Orange c r y s t a l s  i n approximately the same y i e l d .  complexes are a i r - s e n s i t i v e  solids  occurs s l o w l y  Physical  in solution.  Both  of t h i s  using  product were  of the above Mo-Ge  and d e t e r i o r a t i o n  of the compounds  data f o r the complexes are c o l l e c t e d  i n Table IV. 4.2.4  P r e p a r a t i o n of [MeGapz ]Mo(C0) SnMe 3  Na MeGapz Mo(C0) +  3  3  + Me SnCl  The Na MeGapz Mo(C0) with  an e q u i m o l a r amount  solvent.  T  H  3  +  3  3  3  F  >  3  [MeGapz ]Mo(C0) SnMe  (0.353 mmol) s a l t of Me SnCl 3  3  solution  3  3  + NaCl  i n THF was reacted  (0.070 g, 0.353 mmol) i n the same  The cloudy, dark orange, r e a c t i o n mixture produced was s t i r r e d  f o r ~2 days a f t e r which the s o l v e n t was removed i n vacuo t o a f f o r d a dark  107  orange-brown o i l y filtered.  residue. This  Upon slow e v a p o r a t i o n  orange c r y s t a l s  residue was e x t r a c t e d with  of the s o l v e n t from the f i l t r a t e ,  of the d e s i r e d product  were recovered  Analytical,  dark  i n ~70% y i e l d .  compound i s s t a b l e under n i t r o g e n but decomposes s l o w l y air.  n-hexane and  The  on exposure t o  i r and *H nmr data f o r the complex are compiled i n  Table IV. 4.2.5  Preparation  of [MeGapz ]Mo(C0) SnMe Cl 3  Na MeGapz Mo(C0)  + Me SnCl  +  3  An THF,  3  2  3  T  equimolar amount of M e S n C l 2  was s l o w l y  mmol) s a l t . tricarbonyl  [MeGapz ]Mo(C0) SnMe Cl 3  3  2  The i n i t i a l anion  overnight  Slow e v a p o r a t i o n  orange  To a s t i r r e d  from c o n c e n t r a t e d  benzene and f i l -  + Ph SnCl  s o l u t i o n i n ~50% y i e l d .  complex are i n c l u d e d i n Table IV.  3  3  The r e a c t i o n  of the s o l v e n t from the f i l t r a t e y i e l d e d y e l l o w  of [MeGapz ]Mo(C0) SnPh  +  3  d u r i n g the r e a c t i o n .  residue was e x t r a c t e d with  P e r t i n e n t p h y s i c a l data f o r t h i s  Na MeGapz Mo(C0)  (0.880  a f t e r which the s o l v e n t was removed i n  of the d e s i r e d product  Preparation  3  amber-yellow c o l o r of the s t a r t i n g molybdenum  darkened s l i g h t l y  tered.  + NaCl  (0.193 g, 0.880 mmol) d i s s o l v e d i n  2  3  The r e s u l t i n g  was  >  +  vacuo.  crystals  F  added t o a THF s o l u t i o n of the Na MeGapz Mo(C0)  mixture was s t i r r e d  4.2.6  H  2  2  3  T  H  F  3  >  3  [MeGapz ]Mo(C0) SnPh 3  THF s o l u t i o n of the Na MeGapz Mo(C0)  3  +  3  added an equimolar amount of Ph SnCl 3  3  3  + NaCl  (0.353 mmol) s a l t  (0.136 g, 0.353 mmol) d i s s o l v e d  108  i n the same s o l v e n t .  The r e s u l t i n g cloudy r e a c t i o n mixture was  f o r 2 days a f t e r which the s o l v e n t was  removed  r e s i d u e remaining was e x t r a c t e d with C H C 1 2  of hexane was evaporate  added to the f i l t r a t e  slowly.  of y e l l o w was liquid  decanted  behind.  and f i l t e r e d .  sticky  An equal  amount  s o l i d with some v i s i b l e t i n g e  T h i s mixture was washed with CHgCI  and the  2  o f f s l o w l y to l e a v e behind b r i g h t - y e l l o w a i r - s t a b l e  c r y s t a l s of the d e s i r e d product [MeGapz ]Mo(C0) SnPh 3  yield.  The dark y e l l o w  and the mixed s o l v e n t s were allowed t o  A chocolate-brown  left  2  i n vacuo.  stirred  Pertinent physical  3  i n approximately  3  40%  data f o r t h i s complex are presented i n T a b l e  IV.  4.2.7  P r e p a r a t i o n o f LSnMe  3  (L = [MeGapz ] or  Na L~ + Me SnCl +  T  H  F  3  Na MeGapz  (0.88 mmol) was  +  i n THF.  3  >  LSnMe  3  removed under vacuum.  benzene and f i l t e r e d .  2  3  3  + NaCl  r e a c t e d with Me SnCl  The r e s u l t i n g cloudy s o l u t i o n was  the s o l v e n t was  [MeGa(3,5-Me pz) ])  3  (0.18 g, 0.90 mmol)  s t i r r e d o v e r n i g h t a f t e r which  The r e s i d u e was  then e x t r a c t e d w i t h  Slow e v a p o r a t i o n of the benzene s o l v e n t c o n t a i n i n g  the e x t r a c t s a f f o r d e d c o l o r l e s s , a i r - s e n s i t i v e c r y s t a l s of the d e s i r e d [MeGapz ]SnMe 3  3  compound i n ~50% y i e l d .  The compound [MeGa(3,5-Me pz) ]SnMe 2  an i d e n t i c a l  procedure  3  3  was  prepared  in similar y i e l d  s t a r t i n g with the [MeGa(3,5-Me pz) ]~ 2  S o l u t i o n s of the above complexes are u n s t a b l e e s p e c i a l l y solvents  3  ligand.  in chlorinated  (CH^CI , CHC1 ) and a l s o i n acetone. 2  3  A n a l . C a l c d . For [MeGapz ]SnMe : 3  3  C, 34.71; H, 4.67.  Found:  C,  by  109  3 4 . 9 3 ; H, 4 . 1 9 . H  NMR (CgDg, 270 MHz): xCgHg = 2.84 ppm, 10.45s  l  (Ga-Me); 9.81s ( S n - M e ) ; 4 . 0 0 t ( p z - H ) ; 3.29d ( p z - H ) ; p z - H 4  5  obscured by  3  3  s o l v e n t peak.  ( J u r r u  ~ 2 Hz f o r pz p r o t o n s . )  M U t M  ( J  1  i i y  1  ,  Q  Sn-Me  J  1  1  AA/  =50  7  Sn-Me  Hz.) A n a l . C a l c d . For [MeGa(3,5-Me pz) ]SnMe »0.5 C H : 2  6.29.  Found:  C, 4 6 . 3 4 ; H, 6 . 3 5 .  A  3  3  g  C, 4 6 . 1 2 ; H,  6  H NMR (CgDg, 80 MHz):  xCgHg = 2.84  ppm, 10.41s (Ga-Me); 9.83s ( S n - M e ) ; 7.93s ( p z - M e ) ; 7.71s ( p z - M e ) ; 3  5  3  4.38s ( p z - H ) .  ( J  4  1  1  i i y  , J  Q  1  Sn-Me  1  = 50 H z . )  7  ^'Sn-Me  S a t i s f a c t o r y a n a l y s i s was o b t a i n e d f o r C and H i n both complexes but the N a n a l y s e s were i n c o n s i s t e n t each time the compounds were a n a l y z e d . 4.2.8  P r e p a r a t i o n of [MeGapz ]SnMe Cl 3  Na MeGapz~ + M e S n C l +  2  To M e S n C l 2  2  2  T H F 2  >  [MeGapz ]SnMe Cl + NaCl 3  2  (0.193 g, 0.880 mmol) d i s s o l v e d i n THF, was added a 50 ml  a l i q u o t o f the Na MeGapz +  3  ( 0 . 8 8 mmol) s a l t s o l u t i o n i n the same s o l v e n t .  The r e s u l t i n g r e a c t i o n m i x t u r e t u r n e d c l o u d y as NaCl p r e c i p i t a t e d .  To  ensure complete p r e c i p i t a t i o n , the r e a c t i o n m i x t u r e was s t i r r e d o v e r n i g h t a f t e r which the s o l v e n t was removed under vacuum and the r e s i d u e e x t r a c t e d with C H C 1 . 2  2  Slow e v a p o r t i o n o f the C H C l 2  2  s o l v e n t c o n t a i n i n g the  e x t r a c t s , gave c o l o r l e s s f l a k y c r y s t a l s of the d e s i r e d compound i n ~50% y i e l d . decomposes i n s o l u t i o n .  [MeGapz ]SnMe Cl 3  T h i s compound i s u n s t a b l e i n a i r and s l o w l y  2  110  Anal. 16.39.  Calcd.  Found:  F o r [MeGapz ]SnMe Cl«0.5 CH C1 : 3  C. 29.51; H, 3.97; N, 15.87.  xCgHg = 2.84 ppm. (pz-H ); 5  2  2.43d  C, 29.27; H, 3.71; N,  2  2  A  H NMR  (CgDg, 80 MHz):  9.95s (Ga-Me); 9.15s (Sn-Me ); 3.98t  (pz-H ); 4  2  (pz-H ). 3  (J  H  C  C  H  = 2 Hz f o r pz protons.) ( J  n  3.08d  g  Sn-Me J  1  1  iA/  = 50 Hz.)  7  Sn-Me  4.3  Results  and D i s c u s s i o n  Continued  i n t e r e s t i n the chemistry  1 4 - t r a n s i t i o n metal  of compounds f e a t u r i n g group  bonds stems p a r t l y from the hope of f i n d i n g u s e f u l  c a t a l y t i c systems and a l s o from i n t e r e s t i n the s t r u c t u r a l , s p e c t r o s c o p i c and  bonding p r o p e r t i e s  of t h i s  c l a s s of compounds [153,154].  chemistry of the c y c l o p e n t a d i e n y l studied quite extensively.  compounds of group 14 elements has been  In c o n t r a s t , the use of  poly(1-pyrazolyl )borate/gallate  ligands  unexplored.  Recently,  as the f i r s t  s t r u c t u r a l l y characterized  [37].  The present  the  MeGapz  the  reactivity  3  direct  i n group 14 c h e m i s t r y  the compound [HBpz ]SnMe 3  work was t h e r e f o r e  ligand t o include 3  3  six-coordinate  3  trialkyltin  Nicholson complex  anion toward a v a r i e t y of group 14  with the hope of i s o l a t i n g  i s two-fold:  by  designed t o extend the chemistry of  t r a n s i t i o n metal-group 14 element covalent  this expectation  was reported  is virtually  group 14 elements and furthermore t o e x p l o r e  of the MeGapz Mo(C0)  element h a l i d e s p e c i e s  The  firstly,  complexes f e a t u r i n g bonds.  The b a s i s f o r  the valence o r b i t a l s  of group 14 2  3  3  elements are known t o be e n e r g e t i c a l l y compatible with the d sp , dsp and dsp  orbitals  of t r a n s i t i o n metals and hence s t a b l e  a-bonds are r e a d i l y  Ill  formed between these secondly  elements and  t r a n s i t i o n metal  the p r o p o s i t i o n t h a t metals capable  organometallic  of forming  compounds would a l s o be capable  to o t h e r metals [156,157].  Thus, 1:1  s p e c i e s [155];  and  c-bonded  of forming  covalent  r e a c t i o n s of MeGapz Mo(C0) 3  bonds anion  3  with a v a r i e t y of group 14 element organo h a l i d e s p e c i e s have y i e l d e d y e l l o w - o r a n g e c r y s t a l l i n e products  i n which d i r e c t molybdenum-group  element c o v a l e n t bonds are f e a t u r e d . air-stable unstable time.  S o l u t i o n s of a l l the complexes d e t e r i o r a t e slowly  presence of a d i r e c t s i n g l e c o v a l e n t bond between  molybdenum atom and question  has  of one  compound r e p r e s e n t s type LM(C0) M'R 3  M'  the a p p r o p r i a t e  3  the f i r s t  = S i , Ge,  or Sn;  R = Me  [MeGapz ]Mo(C0) SiMe 3  The  3  3  (T)-C H )MO(C0) 5  5  non-basic  3  obtainable  anion with  in  3  This  latter the  [ H B p z ] , or [MeGapz ]; M = Cr, 3  or Ph),  and  3  a l s o provides  Mo,  a r a r e example  structure.  3  (ri-CgHg)(Mo(C0) SiR  r e p o r t e d as being  or Sn)  s t r u c t u r a l l y c h a r a c t e r i z e d complex of  of a 3:3:1, or capped octahedral 4.3.1  3  with  structure  of the complexes, [MeGapz ]Mo(C0) SnPh .  (where L = (i-CgHg),  3  by the c r y s t a l  are  the  group 14 element ( S i , Ge,  been demonstrated u n e q u i v o c a l l y  determination  or W;  complexes are moderately  s o l i d s , except f o r the Mo-Si and Mo-Ge d e r i v a t i v e s which  to a i r .  The  The  14  3  (R = a l k y l  or a r y l ) complexes have been  v i a s a l t e l i m i n a t i o n r e a c t i o n of  the a l k y l  or a r y l  silyl  s o l v e n t s such as cyclohexane [154].  the  h a l i d e only i n  An e a r l i e r attempt a t  o b t a i n i n g these M o - s i l y l d e r i v a t i v e s by the same s a l t e l i m i n a t i o n route i n basic  s o l v e n t s such as THF,  d e r i v a t i v e s were o b t a i n e d  proved u n s u c c e s s f u l  [157].  However,  these  v i a an amine e l i m i n a t i o n r e a c t i o n between  112  ( T I - C H ) M O ( C 0 ) H and M e S i - N M e i n 5  5  3  3  2  THF under CO p r e s s u r e [158], and  from the r e a c t i o n of K ( T I - C H ) M O ( C 0 ) +  5  s o l v e n t [159].  The l a t t e r  reaction of ( T ) - C H ) M O ( C 0 ) 5  the n u c l e o p h i l i c solvent.  5  halide  Judicious  5  3  and H S i B r i n the absence o f 3  report attributed  the u n s u c c e s s f u l  anion and R^SiCl  3  metathetical  i n THF to c o m p e t i t i o n  i o n and the molybdenum t r i c a r b o n y l  selection  also  between  anion i n t h i s  of s o l v e n t s has been emphasized i n the  p r e p a r a t i o n of molybdenum-silicon compounds s i n c e p o l a r s o l v e n t s have the tendency to c l e a v e the Mo-Si reaction  bond i n the complexes [160,161,162].  of the MeGapz Mo(C0) 3  yellow, a i r - s e n s i t i v e  anion with M e S i C l  3  3  [MeGapz ]Mo(C0) SiMe 3  3  *H nmr data f o r t h i s compound are c o l l e c t e d  Analytical,  i n Table  The i r spectrum of the [ M e G a p z ] M o ( C 0 ) S i M e 3  i n THF has y i e l d e d the  complex.  3  3  3  this  g  symmetry  in CH C1 2  2  solution  5  5  3  [ 6 0 ] , but d i f f e r s (R = Me,  bands,  (2A' + A" modes) f o r the complex i n s o l u t i o n .  r e g a r d , the p r e s e n t complex  (TI-C H )MO(C0) X  i r and  IV, p. 114.  ( f i g u r e 31), shows the presence of t h r e e s t r o n g t e r m i n a l suggesting a C  The  resembles the halogen  In  derivatives  (X = C l , Br or I) [ 5 5 ] , and [ H B p z ] M o ( C 0 ) X (X = Br or I) 3  from the methyl and e t h y l  derivatives  (rt-C,-H )Mo(C0) R  The v  bands observed f o r  E t ) [ 5 5 ] , which show only two bands.  the p r e s e n t [ M e G a p z ] M o ( C 0 ) S i M e 3  3  3  C Q  5  (2015, 1920, 1895 cm" , 1  3  3  C H C 1 ) complex 2  2  are i n good agreement with those r e p o r t e d f o r the analogous (ri-CgHg)Mo(C0) SiMe 3  (1974, 1955, 1890 cm" , 1  3  N u j o l ) [158] compound.  The  terminally  bonded CO groups suggested by the i r data of the complex are i n d i c a t i v e o f the presence o f a d i r e c t  s i n g l e c o v a l e n t bond between  i n the p r e s e n t [ M e G a p z ] M o ( C 0 ) S i M e 3  3  3  compound.  the Mo and Si atoms  113  2000 Figure 31.  The v CH C1 2  C Q 2  1§feo  1600  ^cTn") 1  r e g i o n o f the i r spectrum o f [ M e G a p z ] M o ( C O ) S i M e solution. 3  3  3  in  The H nmr spectrum o f the p r e s e n t Mo-Si complex i n d i c a t e d e q u i v a l e n t A  p y r a z o l y l groups and hence i s s u g g e s t i v e o f a 3:3:1 symmetrical f o r the complex i n s o l u t i o n , c o n t r a r y t o the C ir results. firstly,  g  structure  symmetry i n d i c a t e d by the  There are two p o s s i b l e e x p l a n a t i o n s f o r t h e *H nmr r e s u l t s :  a symmetrical 3:3:1 arrangement i n s o l u t i o n would g i v e e q u i v a l e n t  environments f o r the pz g r o u p s .  S e c o n d l y , a 3:4 s t r u c t u r e i n which  there  i s r a p i d r o t a t i o n o f the ' M e G a p z ' grouping about the Ga»»»Mo a x i s would 3  a l s o be c o n s i s t e n t w i t h the observed e q u i v a l e n t environments f o r the pz groups i n s o l u t i o n .  The l a t t e r p o s s i b i l i t y i s f u r t h e r supported by the i r  r e s u l t s d i s c u s s e d above.  T a b l e IV.  Physical  Data f o r  [MeGapz,]Mo(C0),M'Y  ANALYSIS  v  CALCD/FOUND M'  Y Me  SI  •0.17  Ge  •1.0  Ge  •2.0  36.97  3.99  15.22  37.15  4.00  14.80  39.92  4.08  6  39.78  3.84  55.76  4.22 . 9.08  6  55.07  4.28  9.63  30.51  3.34  13.35  31.13  3.45  13.65  6  6  Ph  6  3  C H  3  C H 6  M e  N  3  3  Sn).  (cnf )  *H nmr  1  CH.CI-  H  C H  Me  Sn  C  (M' = S I , Ge,  (Nujol) 2015,1920,1895  b  2015,1920,1892  b  2015,1922,1898  b  GaMe  M'Me  pz-H  9.95  10.08s  4.15t  3.05d  2.14d  9.88s  9.43s  4.19t  3.08d  2.14d  4.15t  3.04d  2.13d  10.10s  2.77  2020,1970,1870  a  9.86s J  12.93  2018,1912,1890  1  i  1  1  27.72  2  2.74  13.00  (1989,1905,1880)  4.09t  , J  Sn-Me  a  i i ; ,  Me Cl  9.01s q  A 9.93s J  Sn  5  pz-H  3  Ph  3  2.38m 2.93m  l i 3  27.70  pz-H  4  1  1  1 A  4.12t  « 52 Hz, J  Sn-Me  BIO.00s  2.36d  'Sn-Me  8.73s  0  2.91d => 50 Hz  7  1  1  1 A ,  8.96s  2.95d  2.40d  = 50 Hz  7  Sn-Me  4.19t  3.07d  2.17d  4.14t  2.73d  2.12d  9.11s  Sn  Ph  3  45.62  3.31  10.50  44.98  3.32  10.42  1.86d (1990,1900,1875)  b  9.98s  2.65m 2.93m  a  In <L-toluene  (t  b  In CgDg s o l u t i o n  (T  A  3:3:1  B  structure.  = 7.91 ppm)  M  c  h  J  = 2.84 ppm)  3:4* s t r u c t u r e  ( F i g . 36)  urrM  * ^.0  s = singlet,  H z  ^  o r  P  z  P  r  d • doublet,  o  t  o  n  s  -  t = triplet,  m = multlplet  115  4.3.2  [MeGapz ]Mo(C0) GeR 3  3  3  (R = Me, Ph)  The r e a c t i o n of the anion MeGapz Mo(C0) 3  3  w i t h R GeCl (R = Me, Ph) 3  h a l i d e s p e c i e s a f f o r d e d the [MeGapz ]Mo(C0) GeR 3  orange, a i r - s e n s i t i v e s o l i d s .  3  A n a l y t i c a l and s p e c t r o s c o p i c data f o r  complexes are given i n Table IV, p. 114. complexes d i s p l a y e d t h r e e s t r o n g v C Q + A") f o r the complexes i n s o l u t i o n . p r e s e n t [MeGapz ]Mo(C0) GeMe 3  [MeGapz ]Mo(C0) GePh 3  3  3  complexes as y e l l o w -  3  The s o l u t i o n i r  s p e c t r a of  bands s u g g e s t i v e of C The  bands observed f o r 1  £  2  the  symmetry (2A  g  (2015, 1920, 1892 c m " , C H C 1 )  3  the  the  and  (2015, 1922, 1898 c m " , C H C 1 ) complexes are  in  1  3  2  2  good agreement w i t h those r e p o r t e d f o r the analogous  (ri-C H,-)Mo{C0) GeMe 5  3  (1999, 1929, 1905 c m " , CgHg) [163] and ( r i - C H ) M o ( C 0 ) G e P h 1  5  5  1918 c m " , CCl^) [157] compounds, r e s p e c t i v e l y . 1  1  3  For a l l  3  3  (2008, 1925,  of the above  c y c l o p e n t a d i e n y l Mo-Ge d e r i v a t i v e s , the a u t h o r s c o n c l u d e d t h a t t h e r e i s a d i r e c t c o v a l e n t bond between the Mo and Ge c e n t e r s w i t h no i n t e r a c t i o n s the CO l i g a n d s w i t h the Ge atom.  of  I t appears, l i k e l y t h a t a s i m i l a r  bonding arrangement i s o p e r a t i v e i n the p r e s e n t  [MeGapz ]Mo(C0) GeR 3  3  3  complexes based on the i r data o b t a i n e d f o r the compounds. The room temperature  nmr spectrum of the [ M e G a p z ] M o ( C 0 ) G e P h 3  CgDg s o l u t i o n i s shown i n f i g u r e 3 2 .  3  3  A g a i n , one s e t of s i g n a l s was  d i s p l a y e d f o r the p y r a z o l y l p r o t o n s s u g g e s t i n g e q u i v a l e n t environments the pz r i n g s .  for  E v i d e n t l y , s i m i l a r r o t a t i o n of the 'MeGapz ' moiety about 3  the G a * " M o a x i s (see S e c t i o n 4 . 3 . 1 ) might a f f o r d a r a t i o n a l e f o r o b s e r v e d H nmr r e s u l t s . 1  [MeGapz ]Mo(C0) GeMe 3  in  3  3  the  A s i m i l a r ^ti nmr spectrum was o b t a i n e d f o r  complex.  These compounds [MeGapz ]Mo(C0) GeR  Me or Ph) p e r s i s t i n s o l u t i o n f o r o n l y a few d a y s .  3  3  3  the (R =  For example, the room  116  117  temperature  H nmr  CgDg s o l u t i o n , from  spectrum  of the same [MeGapz ]Mo(C0) GePh 3  i n a flame s e a l e d nmr  those d i s p l a y e d i n the i n i t i a l  s i g n a l s are presumably sample i n s o l u t i o n .  due  3  tube, showed new spectrum  a f t e r 5 days.  to o b t a i n c r y s t a l s  s t r u c t u r e d e t e r m i n a t i o n s were u n s u c c e s s f u l .  4.3.3.  [MeGapz ]Mo(C0) SnR  The  3  (R = Me,  r e a c t i o n of the MeGapz Mo(C0) 3  y i e l d e d yellow-orange 3  These  new of the  Ph) anion with Me SnCl  3  3  and PhgSnCl  c r y s t a l l i n e products of the Mo-Sn bonded s p e c i e s  [MeGapz ]Mo(C0) SnR . The complexes are moderately 3  different  s u i t a b l e f o r X-ray  crystal  3  signals  compound i n  to peaks a r i s i n g from the decomposition  Attempts  3  3  air-stable  3  s t a t e but s o l u t i o n s d e t e r i o r a t e on exposure  i n the  to a i r . A n a l y t i c a l  and  s p e c t r o s c o p i c data f o r these complexes are presented i n T a b l e IV p. It is interesting  to compare the compounds with those r e p o r t e d by  and Graham i n which the MeGapz  3  ligand  114.  Patil  i s r e p l a c e d by the Cp~group [157].  In both s e r i e s of compounds only t e r m i n a l v C Q ir  solid  bands are d i s p l a y e d i n the  s p e c t r a , i n d i c a t i v e of d i r e c t Mo-Sn i n t e r a c t i o n without accompanying  b r i d g i n g CO  ligands.  s t r o n g t e r m i n a l CO  In the case of the c y c l o p e n t a d i e n y l complexes, t h r e e  bands were observed  i n each case whereas the  compounds r e p o r t e d here show d i f f e r e n t p a t t e r n s . complex g i v e s one weak and two complex d i s p l a y s one The pyrazolyl  nmr  Thus, the  two  'SnPh ' 3  s t r o n g V^Q v i b r a t i o n s , whereas the  'SnMe ' 3  s t r o n g and two weak V^Q bands.  data f o r the  'SnPh ' and 3  'SnMe ' complexes show a l l three 3  groupings to be e q u i v a l e n t i n s o l u t i o n , d i s p l a y i n g only one s e t  of s i g n a l s f o r the p y r a z o l y l symmetrical  r i n g s p r o t o n s , and are hence i n d i c a t i v e of a  s t r u c t u r e f o r the complexes.  The  room temperature  *H  nmr  118  spectrum of the  [MeGapz ]Mo(C0) SnMe  shown i n f i g u r e  33.  The  to the P-3C0  3  816,  3  together  P-3C0 , and +  thermal  3  of the  The  X-ray c r y s t a l  presented here r e p r e s e n t s s t r u c t u r e of t h i s type,  data.  figure  34.  The  at  m/e  ions P-C0 , P-2C0 , +  +  greater  'SnMe ' d e r i v a t i v e 3  1  being  but,  i r and  *H  3  approximate £  The  3  data  X-ray  3  3  reported  [MeGapz ] moiety r e p l a c e s above.  nmr  3  arrangement p r e d i c t e d on  m o l e c u l e , which has  Mo  type  [MeGapz ]Mo(C0) SnPh  b e l i e v e to be the f i r s t  given  M =  the m o l e c u l a r arrangements  s t r u c t u r e of the complex  formulation  or Sn;  f o r complexes of the  based p r i m a r i l y on  what we  = Ge  r a t h e r s u r p r i s i n g l y , no  or a r y l ) ,  i n which the  a n a l y s i s c o n f i r m s the 3:3:1 nmr  to the  bonded d e r i v a t i v e s (where M  (where R = a l k y l  l i g a n d i n the general  the  conditions.  proposed f o r these s p e c i e s [154].  parent  +  3  X-ray s t r u c t u r a l data have been r e p o r t e d 3  to the  the parent ion s i g n a l , P ,  'SnPh ' compound over the  been s t u d i e d q u i t e e x t e n s i v e l y  3  s i g n a l s due  displayed  Perhaps these v a r i a t i o n s r e f l e c t the  +  (r)-CgHg)M(C0) M'R  but  compound  3  In c o n t r a s t , the mass spectrum of  chemistry of M-M'  has  3  ~ 544,  complex d i s p l a y e d  P-3C0-Me .  under e l e c t r o n impact  or W)  3  with prominent s i g n a l s due  stability  The  complex i n dg-toluene s o l u t i o n i s  3  [MeGapz ]Mo(C0) SnMe  ion at m/e  +  were not observed.  +  [MeGapz ]Mo(C0) SnPh ~  3  mass spectrum of the  s i g n a l s due ion P  3  the ^-CgHg  structure  the b a s i s of  the  symmetry, i s shown i n  120  The s t r u c t u r e i s s i m i l a r to t h a t r e c e n t l y r e p o r t e d  f o r the compound  [MeGapz ]Mo(C0) Cu(PPh ) [124] (see a l s o s e c t i o n 3.3.2 p. 86) but i s 3  3  3  d i f f e r e n t from the 3:4 o r 'four-legged  piano stool  1  s t r u c t u r e s of the  r e l a t e d molecules (n-C H )Mo(CO) Sn(Cl ) [ ( r i - C H ) F e ( C 0 ) ] 5  5  3  5  5  2  [ H B p z ] M o ( C 0 ) B r [ 6 0 ] , and (ri-C H )Mo(C0) Et [ 9 3 ] . The 3  3  5  s p e c i e s with the T ) - C H 5  5  5  3  r e p l a c i n g MeGapz  The s t r u c t u r e of the [MeGapz ]Mo(C0) SnPh terminal  carbonyl  multi-metal 5  a 3:3:1 s t r u c t u r e due to the bulky F e - c o n t a i n i n g  presence o f three  [164],  on Mo, and the [ ( r ) - C H ) F e ( C 0 ) ]  3  groupings r e p l a c i n g the Me groups on Sn, may well  3  2  3  3  be i n c a p a b l e  5  2  of adopting  substituents. complex c l e a r l y  shows the  groups with bond angles o f 169.7(3),  172.1(3), and 172.7(3)° f o r the Mo-C-0 u n i t s , the s l i g h t d e v i a t i o n s  from  121  linearity  being d i r e c t e d away from the Sn c e n t e r and probably  the p r o x i m i t y of the phenyl of 1.154(4), 1.139(3), and terminal  carbonyl  groups on the Sn atom.  groups and  the Mo-C  above parameters show t h a t one from the other two.  from o v e r a l l  C^ m o l e c u l a r  symmetry and  The and  the sums of van  Ga««»Mo-Sn u n i t with  as expected  groups d i f f e r s  can  phenyl  groups on Sn,  the Mo  center.  The  an angle  [93,137,165,166]. distance reported  The  5  in  C««»0 =  infinite  radii. of 178.49(1)° i s e s s e n t i a l l y  the expected  (1.39  the  r e s p e c t to the three CO  linear  distant  l i g a n d s on  f o r the  present  d i s t a n c e of 3.00A based  + 1.61 A) f o r the two  (2.891(5)A) f o r the complex  2  atom i n t h i s m u l t i - m e t a l  atoms  As  [(t)-C H )Mo(CO) ]Sn(Cl)5  5  3  i n the s t r u c t u r e d e s c r i b e d h e r e i n , the  complex i s i n a p s e u d o t e t r a h e d r a l  Sn  environment.  Cameron and  Prout  the complex  (ri-CgHg^MofSnBrgjBr i n which the Sn atom i s i n a d i s t o r t e d  trigonal  [167]  C-HvO  d i s t a n c e i s , however, comparable to the f i r s t Mo-Sn  [ ( r i - C H ) F e ( C 0 ) ] 2 [164]. 5  l i n k i n g molecules  Mo-Sn d i s t a n c e of 2.8579(3)A observed  of the c o v a l e n t r a d i i  departure  = 2.39,  groups, w h i l s t e c l i p s i n g  are staggered with  complex i s c o n s i d e r a b l y s h o r t e r than on the sum  signifi-  be a s c r i b e d to a weak H---0  bipyramidal  of 3.411A.  and  A l l o t h e r i n t e r m o l e c u l a r d i s t a n c e s are  der Waals  the p l a n a r p y r a z o l y l  for  The  T h i s r e p r e s e n t s the most s i g n i f i c a n t  3.326(4)A, C-H---0 = 162°, C-0--H = 156°]  g r e a t e r than  bond d i s t a n c e s  bonding arrangement.  of the carbonyl  along the b a x i s .  by  d i s t a n c e s of 1.967(3), 2.000(3),  hydrogen bond [C(10)-H(10) •••0(1) (x, 1/2-y, z-1/2),  c h a i n s extending  C-O  1.141(3)A are a l s o i n the range expected  1.994(3)A are c o n s i s t e n t with a t e r m i n a l CO  cantly  The  caused  have r e p o r t e d a Mo-Sn d i s t a n c e of 2.691(4)A f o r  environment with a f o u r t h , l o n g , Sn»»»Br  A s i m i l a r environment f o r the Sn atom has  interaction  been r e p o r t e d f o r  122  the complex ( b i p y ) (Cl ) M o ( C 0 ) ( S n M e C l ) , i n which the Mo-Sn d i s t a n c e 3  2  of  2.753(3)A was i n t e p r e t e d as i n d i c a t i v e of some m u l t i p l e bond c h a r a c t e r [168].  The same a u t h o r s r e p o r t e d the s t r u c t u r e of the  tungsten-tin  complex ( M e S ( C H ) S M e ) ( C l ) W ( C 0 ) ( S n M e C l ) i n which the W-Sn d i s t a n c e 2  2  3  of  2  2.759(3) was argued to r e f l e c t the s i m i l a r i t y of the W and Mo c o v a l e n t radii  [169].  In both of these s t r u c t u r e s t h e r e i s a b r i d g i n g Cl  between the metal c e n t e r s , w i t h a l o n g Sn-Cl 4.3.4  ligand  distance.  [MeGapz ]Mo(C0) SnMe Cl 3  3  2  The 1:1 r e a c t i o n of MeGapz Mo(C0) 3  a n i o n and M e S n C l  3  2  y e l l o w c r y s t a l l i n e product [ M e G a p z ] M o ( C 0 ) S n M e C l . 3  3  2  2  r e s u l t e d i n the  T h i s complex  is  a i r - s t a b l e i n the s o l i d s t a t e but s o l u t i o n s d e t e r i o r a t e s l o w l y w i t h t i m e . The s o l u t i o n i r spectrum of t h i s compound d i s p l a y s one weak and two s t r o n g v  C Q  These v  v i b r a t i o n s (2018, 1912, 1890 c m " , C H C 1 ) . 1  2  2  and Graham [ 1 5 7 ] .  v a l u e s compare  (ri-C H )Mo(C0) SnMe Cl  q u i t e w e l l w i t h those r e p o r t e d f o r the analogous compound by P a t i l  C Q  5  5  3  2  The presence of o n l y t e r m i n a l  bands i n the i r spectrum o f the p r e s e n t [MeGapz ]Mo(C0) SnMe Cl 3  3  compound  2  i s i n d i c a t i v e of d i r e c t Mo-Sn i n t e r a c t i o n w i t h o u t accompanying b r i d g i n g CO ligands.  However, the presence of t h r e e  the p r e s e n t complex i s s u g g e s t i v e o f a C  bands i n the i r g  spectrum of  symmetry f o r the compound i n  solution. The room temperature *H nmr spectrum of [MeGapz ]Mo(C0) SnMe Cl 3  i n t e r e s t i n g s i n c e i t changes w i t h time and s o l v e n t .  3  2  ( F i g u r e 35 shows the  change, w i t h t i m e , i n the spectrum of the complex i n d g - t o l u e n e . s i m i l a r e f f e c t was observed u s i n g C D fi  fi  is  or CDClo as s o l v e n t s ) .  A  Thus,  123  JJu B  r  1  f  3 Figure  T 35,  T  T  lb r(ppm)  Room temperature 80 MHz H nmr s p e c t r a o f [ M e G a p z ] M o ( C 0 ) S n M e C l , showing the change w i t h time: i n i t i a l spectrum ( t o p ) , a f t e r 1 day (middle), and a f t e r 5 days (bottom). (A) 3:3:1 s t r u c t u r e , (B) 3:4 s t r u c t u r e . 3  3  2  124  initially  the  spectrum shows two  s e t of s i g n a l s structure  as  is consistent  'sets' of  signals.  with a symmetrical  shown i n f i g u r e 36A,  3:3:1  s i m i l a r to t h a t  rotation  Mo-Sn bond i n s o l u t i o n would give the  of e q u i v a l e n t  pyrazolyl  In the  'set'  yet  second  the  pyrazolyl  difficult  signals  of s i g n a l s  groups, as well  groups on  the  atom.  as p o s s i b l y  A rotation  a x i s might a f f o r d a r a t i o n a l e  3  groups i n t h i s  grouping i n the  Cp MoH ^-Cu[HBpz ] 2  2  the  3  pyrazolyl  compounds.  weaker s e t of of  signals  gradually  the  3  this  consistent  2  the  with the  d i s a p p e a r s and  structure  the  and  equivalence  spectra  of  of  these  for  the  t h e r e remains only one  set  structure.  rearrangement p r o c e s s i s  i s warmed up  Ga»»*Mo  of  MHz  *H  nmr  further  spectrum of  the  compound i n dg-toluene shown i n f i g u r e 37.  solution  3:3:1  nmr  the  Me  the  5  species responsible  temperature dependent 300  3  spectrum, as  3  i n terms of a 3:3:1  [MeGapz ]Mo(C0) SnMe Cl  two  A similar rotation  room temperature *H  proposed i n t r a m o l e c u l a r  supported by  between the  been invoked to e x p l a i n  event, with time, the  signals, explicable The  has  piano  inequivalent  observed e q u i v a l e n c e of  3  and  is  MeGapz^ moiety about the  second arrangement.  groups i n the  In any  pattern  'four-legged  distinguishing  f o r the  pattern  non-equivalent This  or  free  2  expected to g i v e  of the  the  observed  complexes [ H B p z ] M o ( C 0 ) 2 ( T i - C H ) [170]  [171]  2  would be  for  'SnMe ' grouping.  Sn-Me groups are  even a s t a t i c 3:4,  ( f i g u r e 36B)  pyrazolyl  pyrazolyl  a s i n g l e t f o r the two  capped-octahedral  In t h i s arrangement  groups seemingly remain e q u i v a l e n t .  s t o o l ' arrangement  HBpz  the  to r a t i o n a l i z e s i n c e  Sn  and  117).  intense  established  (see  about the  4.3.3, p.  most  or  'SnPh ' d e r i v a t i v e 3  section  The  to ~80°C, the  predominates s i n c e  the  s e t of rate  In signals  of  the  125  Figure  36.  P o s s i b l e m o l e c u l a r arrangements f o r the [MeGapz3]Mo(CO)oSnMe2Cl complex i n s o l u t i o n : (A) 3:3:1 s t r u c t u r e , (B) 3:4 s t r u c t u r e .  rearrangement process would be more r a p i d a t high temperatures. solution  i s cooled  3:3:1 s t r u c t u r e intensity  down, the s e t o f s i g n a l s e x p l i c a b l e  As the  i n terms o f the  decrease i n i n t e n s i t y with concomitant i n c r e a s e i n  f o r the s i g n a l s a t t r i b u t a b l e to the 3:4 s t r u c t u r e , u n t i l  -80°C, the system shows only  one s e t o f s i g n a l s c o n s i s t e n t  at ~  with the 3:4  126 A  80*c B  -80c  I  0  '  Figure 37.  I  2  1  1  1  1 4  1  6  8  10  r(ppm)  Temperature dependent 300 MHz H nmr spectrum of A  [MeGapz ]Mo(C0) SnMe Cl 3  3  2  in dg-toluene  solution.  127  structure.  The above b e h a v i o u r i s not s u r p r i s i n g s i n c e the 3:4 o r  ' f o u r - l e g g e d piano s t o o l ' s t r u c t u r e has been shown to be the most s t a b l e point  (ground s t a t e ) i n the p o t e n t i a l  complexes [ 1 4 1 ] . f o r the  Interestingly, Patil  energy s u r f a c e f o r  (ri-C H )ML 5  5  4  and Graham [157] r e p o r t a s i n g l e t  ' S n M e ' p r o t o n s i n t h e i r CpMo(C0) SnMe Cl complex f o r which they 2  3  s p e c u l a t e a 3:4 o r piano s t o o l  s t r u c t u r e , s i m i l a r t o t h a t demonstrated f o r  the complexes ( r i - C H ) M o ( C 0 ) E t 5  5  2  [ 9 3 ] , and ( T ) - C H ) M o ( C 0 ) M n ( C 0 )  3  5  5  3  5  [152],  respectively. The mass spectrum o f the p r e s e n t [MeGapz ]Mo(C0) SnMe Cl 3  displayed a strong parent i o n , P , +  signal  +  2  a t m/e ~ 6 5 0 .  s i g n a l s due t o the P - C 0 , P - 2 C 0 , P-3C0-Me +  3  +  and P - 3 C 0  +  complex  In a d d i t i o n i o n s were a l s o  o b s e r v e d , the l a t t e r being the s t r o n g e s t i n the spectrum.  The  relative  i n t e n s i t i e s of the l i n e s i n these s i g n a l s agreed w e l l w i t h a computer-generated p r o f i l e ,  t a k i n g i n t o account the r e l a t i v e abundances  the n a t u r a l l y o c c u r r i n g i s o t o p e s o f Mo, Ga, Sn, and Cl  (see f i g u r e 3 8 ) .  of  Iff  Sf 6f 4f  ro  co  2f f  I | I I II  I I I II  52f  Figure 38.  | I  64f  68f  P a r t i a l mass spectrum o f [MeGapz ]Mo(CO) SnMepCl. Inset: computer generated p r o f i l e o f s i g n a l f o r ions c o n t a i n i n g Ga, Mo, Sn, and Cl atoms. 3  3  129  4.3.5  LSnY  (L = [MeGapz ]", [MeGa(3,5-Me pz) ]", Y = 3  2  Me ;  3  3  L = [MeGapz ]", Y = MepCl) 3  The  complexes LSnY were prepared by the  l i g a n d with e i t h e r Me SnCl 3  The  The  of the  LSnMe  3  H  nmr  2  analyses f o r C,  d i f f e r e n t each time. A  colorless, flaky, air-sensitive  The  spectra  and  H;  pyrazolyl may  be  of the  t o the  Sn  atom.  groups i n d i c a t e d  by the  *H  nmr  r a t i o n a l i z e d by a rapid in solution.  f o r X-ray s t r u c t u r a l structure reported  six-coordinate groups.  by  clear.  rotation  The  of the of the  pyrazolyl  tridentate  seemingly compound  equivalent [MeGapz ]SnMe Cl 3  3  d e t e r m i n a t i o n proved u n s u c c e s s f u l .  An 3  and  t i n bonded t o t h r e e methyl  confirms the groups and  the  crystals  X-ray  analogous compound [HBpz ]SnMe  N i c h o l s o n [37],  2  'MeGapz ' moiety about  However, attempts t o i s o l a t e s u i t a b l e  d e t e r m i n a t i o n of the recently  was  complexes showed a l l three of the  ligand  Ga**»Sn axis  N content  reason f o r t h i s d i s c r e p a n c y i s not  groups i n each compound t o be e q u i v a l e n t , s u g g e s t i n g c o o r d i n a t i o n of the  consistently  3  however, the  crystals.  conditions.  (L = [MeGapz ], [MeGa(3,5-Me pz) ]) complexes  3  appropriate respectively.  complexes were u n s t a b l e even under i n e r t  gave s a t i s f a c t o r y  The  of the  or Me^SnC^ s t a r t i n g m a t e r i a l s ,  compounds were i s o l a t e d as  Solutions  reaction  3  was  presence of t o three  a  pyrazolyl  130  4.4  Summary The r e a c t i o n  with a v a r i e t y  of the molybdenum  featured.  solution  anion,  [MeGapz ]Mo(C0) 3  of group 14 ( S i , Ge, Sn) o r g a n o h a l i d e s has y i e l d e d  o f complexes i n which d i r e c t Mo-M' are  tricarbonyl  (M 3  complex shows an i n t e r e s t i n g  2  behaviour i n which a t r a n s i t i o n from a 3:4, or piano  structure, occur.  to a 3:3:1, or capped-octahedral  The s t e r e o c h e m i c a l  structure  n o n - r i g i d i t y of the above  3  3  'SnMe^Cl'  temperature *H nmr  has been demonstrated i n the s o l i d  [MeGapz ]Mo(C0) SnPh  3  stool  arrangement, i s thought to  i n s o l u t i o n was demonstrated by a v a r i a b l e The 3:3:1  a series  = S i , Ge, Sn) s i n g l e c o v a l e n t bonds  1  The [MeGapz ]Mo(C0) SnMe Cl 3  3  compound by means of a c r y s t a l  state  derivative experiment.  f o r the  structure  determination. The l i g a n d s  [MeGapZg] and MeGa(3,5-Me pz) ] 2  study to form the e l u s i v e  six-coordinate  3  have been used i n t h i s  o r g a n o t i n complexes, LSnMe  [MeGapz ] or [MeGa(3,5-Me pz) ]) and [MeGapz ]SnMe Cl. 3  2  3  3  2  3  (L =  131  CHAPTER V  TRANSITION METAL DERIVATIVES OF PYRAZOLYLGALLATE LIGANDS AND  5.1  THE  UNSYMMETRIC TRIDENTATE  [Me Gapz'0(C H N)CH NMe ]~ 2  5  3  2  2  [Me Gapz'0(C H N)]~ 2  9  6  Introduction  The  first  organogallate  of a new  c l a s s of unsymmetric t r i d e n t a t e c h e l a t i n g  l i g a n d s was  introduced  sometime ago  [41].  systems, c o n t a i n i n g a p y r a z o l y l group, t o g e t h e r with moiety, both coordinate  attached  facially  compounds [172,173,174].  square-planar dinitrosyl  Rh(I)  a Afunctional  Meridional  c e n t e r has  t r a n s i t i o n metal  been demonstrated f o r f o u r - c o o r d i n a t e  s p e c i e s [175,176], and  the novel  five-coordinate iron  2  2  2  2  isomers have been s t r u c t u r a l l y  2  2  [44].  [43].  multidentate  the p y r a z o l y l and  2  I t has  2  2  2  l i g a n d systems i n c o r p o r a t i n g both  the  Metal  d e r i v a t i v e s of pyridyl  groups have been the s u b j e c t of r e c e n t p u b l i c a t i o n s [177,178].  been i n f e r r e d  p r o p e r t i e s than capability  2  Both  c h a r a c t e r i z e d f o r the  c o o r d i n a t i o n compound [ M e G a p z ( 0 C H C H N H ) ] N i  functional  carbonyl  c o o r d i n a t i o n of the above l i g a n d  complex [ M e G a ( 3 , 5 - M e p z ) ( 0 C H C H N M e ) ] F e ( N 0 )  fac and mer  donor  to a dimethyl g a l l i u m u n i t , have been shown to  i n a v a r i e t y of o c t a h e d r a l  systems to the metal  These l i g a n d  t h a t although  p y r i d i n e [177],  [179].  The  pyrazole  has  stronger  a-donor  the former has weaker r t - a c c e p t o r  many novel  aspects  d i s p l a y e d by  the compounds  132  incorporating general  area  t h i s c l a s s of l i g a n d prompted f u r t h e r i n v e s t i g a t i o n i n t o of unsymmetrical  an amino-pyridyl l i g a n d system.  uninegative  moiety as well  organogallate  as a fused  This chapter describes  the  quinolyl  ligands  to  include  'aromatic' u n i t i n  synthesis  of the  the  ligands  the  L~, a  and  L~  derived  from 2 - ( d i m e t h y l a m i n o m e t h y l ) - 3 - h y d r o x y p y r i d i n e ,  8-hydroxyquinoline  r e s p e c t i v e l y , and  v a r i e t y of t r a n s i t i o n metal  Figure  39.  The  halide  2  2  Thus, r e a c t i o n s of the  new  by  the  usual  toward a  ligands  [Me^apz-CKCgH^N)-  [Me Gapz-0(C H N)]" ( L ~ ) . 2  l i g a n d s L~,  halide species y i e l d e d a diverse  been c h a r a c t e r i z e d  reactivity  species.  unsymmetric o r g a n o g a l l a t e  CH NMe ]" ( L ~ ) , and  t i o n metal  details their  and  g  6  L~ with a v a r i e t y of  transi-  range of compounds which have  p h y s i c a l methods.  The  reactivity  of  the  133  complexes L Rh(CO), L Rh(CO) toward a q  methyl  a l s o described  s t r u c t u r a l study  be a methyl (Me)(I)C0  and an X-ray  iodide  crystal  oxidative  i s i n progress.  molecular structures  a d d i t i o n product  The p r e p a r a t i o n ,  5.2.1  of what i s thought t o  D^Gapz'OtCgH-jNjQ^NMe^Rh-  properties,  crystal  compounds are a l s o p r e s e n t e d .  2  work have been submitted f o r p u b l i c a t i o n 5.2  and m o l e c u l a r i o d i n e i s  and  of the [Me^a'O^H-jNjCH^Me,,], and  [Me Ga*0(CgHgN)] coordination 2  iodide  P a r t s of t h i s  [180,181].  Experimental  Starting  Materials  Sodium p y r a z o l i d e pyrazole  was prepared  by r e a c t i n g sodium hydride  (K and K l a b o r a t o r i e s ) i n THF.  manganese pentacarbonyl  Nickel  nitrosyl  iodide  bromide [182], rhenium t e t r a c a r b o n y l  ( A l f a ) with [128],  chloride  dimer [183], and M o ( M e C N ) ( r ) - C H ) ( C 0 ) B r  [184] were prepared a c c o r d i n g  t o l i t e r a t u r e methods.  c h l o r i d e dimer,  3  2  hexacarbonyl pyridine used  2  Rhodium d i c a r b o n y l  ( A l d r i c h ) , 8-hydroxyquinoline  distillation  5.2.2  5  molybdenum  (Strem C h e m i c a l s ) , i o d i n e , 2-(dimethylaminomethy 1)-3-hydroxy-  as s u p p l i e d .  droplets.  3  Methyl  iodide  bromide  were  ( F i s h e r S c i e n t i f i c ) was d r i e d by  from phosphorus pentoxide  Allyl  (Eastman O r g a n i c Chemicals)  and s t o r e d  over a few mercury  (Eastman Kodak Co.) was d i s t i l l e d  before use.  P r e p a r a t i o n of [Me GaO(C H N)CH NMe ] 2  Me Ga + H0(C H N)CH NMe 3  5  3  2  5  2  3  — — >  2  2  [Me GaO(C H N)CH NMe ] + MeH 2  5  3  2  2  134  To a THF s o l u t i o n o f 2 - ( d i m e t h y l a m i n o m e t h y l ) - 3 - h y d r o x y p y r i d i n e  (1.34  g , 8 . 8 mmol) was added t r i m e t h y l g a l l i u m (1.01 g , 8.8 mmol) i n the same solvent.  The r e a c t i o n m i x t u r e was r e f l u x e d under N  methane gas (-2 d a y s ) .  2  until cessation  of  The s o l u t i o n was then c o o l e d t o room t e m p e r a t u r e  and the s o l v e n t removed under vacuum. w i t h benzene, and f i l t e r e d .  The r e s u l t i n g r e s i d u e was e x t r a c t e d  Slow e v a p o r a t i o n of the benzene  solvent  c o n t a i n i n g the e x t r a c t s a f f o r d e d a i r - and m o i s t u r e - s e n s i t i v e p a l e y e l l o w c r y s t a l s o f the d e s i r e d p r o d u c t .  Y i e l d -80%.  A n a l . C a l c d . f o r Me Ga0(C H N)CH NMe : 2  Found:  5  3  2  C, 4 8 . 0 5 ; H, 6 . 7 6 ; N, 1 0 . 9 6 .  Mp 62°C. C, 4 7 . 8 5 ; H, 6 . 8 3 ; N, 1 1 . 1 6 .  2  The NMR data f o r t h i s complex and  the hydroxy s t a r t i n g m a t e r i a l are c o m p i l e d i n T a b l e s V and VI (see a l s o f i g u r e s 42 and 4 3 ; pp. 152 and 1 5 3 ) , r e s p e c t i v e l y .  Table V  400 MHz *H NMR Data f o r H 0 ( C H N ) C H N M e 5  3  2  2  in C D g  6  solution.  135  x(ppm)  *  t  J(Hz)  Assignment  -  8.15(s) 6.33(s)  H  b  H  3.20(dd)  4.0(8.0)  2.86(dd)  2.0(8.0)  1.85(dd)  2.0(6.0)  c  -  -1.45(s)  * xCgHg = 2 . 8 4 ppm; s = s i n g l e t ; * Ring protons  T a b l e VI  400 MHz  A  are  dd = d o u b l e t  doublets.  unassigned.  H NMR D a t a f o r M e G a O ( C H N ) C H N M e 2  5  3  2  2  a  H c  of  2  Me b  2  i n CgDg s o l u t i o n .  136  * x(ppm)  t  J(Hz)  Assignment  -  10.29(s) 8.39(s)  -  6.40(s)  -  3.14(dd)  H  a  H  b  H  4.0(8.0)  2.74(d)  8.0  1.99(dd)  2.0(4.0)  * xCgHg = 2.84 ppm;  s = singlet;  d = d o u b l e t ; dd = d o u b l e t of d o u b l e t s  Ring protons are unassigned. 5.2.3  P r e p a r a t i o n of [ M e G a 0 ( C H N ) ] 9  Q  Me Ga + H0(C H N) 3  g  fi  9  — — — >  6  The c o o r d i n a t i o n compound  [Me GaO(C H N)] 2  g  6  [Me Ga0(C HgN)] was prepared by the method 2  g  d e s c r i b e d above ( s e c t i o n 5.2.2), u s i n g 8 - h y d r o x y q u i n o l i n e material. yield.  The a i r - s e n s i t i v e  as s t a r t i n g  lemon y e l l o w product was i s o l a t e d  i n ~85%  Mp 63°C.  A n a l . C a l c d . f o r [Me GaO(C HgN)]: 2  Found:  + MeH  g  C, 54.58; H, 4.61; N, 5.97.  the hydroxy  C, 54.16; H, 4.92; N, 5.74.  The NMR  s t a r t i n g m a t e r i a l are compiled  a l s o f i g u r e s 44 and 45, pp. 155 and 156).  data f o r t h i s compound and  i n T a b l e s VII and VIII (see  137  Table VII  400 MHz H l  NMR Data f o r H0(C H N) i n C D  x(ppm)  g  J(Hz)  3.24(dd)  4.0(8.0)  3.00(dd)  2.0(8.0)  2.81(m)  8.0(32.0)  2.47(dd)  2.0(8.0)  1.60(dd)  2.0(4.0)  6  g  6  solution.  Assignment  1.46(s)  * -cCgHg = 2.84 ppm; s = s i n g l e t , dd = d o u b l e t of d o u b l e t s ; m = m u l t i p l e t . * R i n g p r o t o n s are u n a s s i g n e d .  138  Table V I I I  400 MHz lH NMR Data f o r [ M e G a O ( C H g N ) ] 2  9  J(Hz)  x(ppm)  2  i n CgDg s o l u t i o n .  Assignment  9.90(s) 3.58(dd)  4.0(8.0)  3.31(dd)  2.0(8.0)  2.71(m) 2.61(dd)  2.0(4.0)  2.57(dd)  2.0(8.0)  tCgHg = 2.84 ppm; s = s i n g l e t ; dd = d o u b l e t o f d o u b l e t s ; m = m u l t i p l e t . R i n g protons a r e u n a s s i g n e d . 5.2.4  P r e p a r a t i o n o f the l i g a n d Na [Me Gapz«0(C H N)CH NMe ]~ (Na L ) 2  Me Ga + Na -pz~ +  3  T H F  >  5  3  2  Na [Me Gapz]" +  3  2  a  139  N a [ M e G a p z ] " + H0(C H N)CH NMe +  3  5  3  2  T  H  >  F  2  Na [Me Gapz«0(C H N)CH NMe ]" +  MeH  +  2  Trimethylgallium sodium p y r a z o l i d e  (4.86  r e a c t i o n mixture was THF  to 500  ml  (6.20  g, 54.0  g, 54.0  stirred  mmol) i n ~50  ml  h.  flask.  The  THF  An  was  3  until  The  r e a c t i o n mixture was  the e v o l u t i o n of methane gas  cooled  s o l u t i o n was  standard  t r a n s i t i o n metal  halide  Preparation  2  >  T H F  _  6  stirred  (~2  12.96 N  days).  2  The flask.  subsequent r e a c t i o n s with metal  2  Na L~ standard +  halide  +  +  prepard by a method i d e n t i c a l  r e s u l t i n g yellow  (Na L~)  Na [Me Gapz'0(CgHgN)r +  s e c t i o n 5.2.4, using 8 - h y d r o x y q u i n o l i n e as the  A l i q u o t s of the  standard  in a volumetric  +  3  in  then d i l u t e d with  r e f l u x e d under  ligand Na [Me Gapz«0(CgH N)]  +  +  ml  The  species.  of the  l i g a n d Na L~ was  THF.  s o l u t i o n were used i n subsequent r e a c t i o n s with  N a [ M e G a p z ] " + HOfCgHgN)  The  to 250  added to  (1.973 g,  ceased completely  then d i l u t e d with THF  A l i q u o t s of t h i s  5.2.5  had  2  added to a  s o l u t i o n of 2 - ( d i m e t h y l a m i n o m e t h y l ) - 3 - h y d r o x y p y r i d i n e same s o l v e n t .  ml  a l i q u o t of t h i s  +  2  was  s o l u t i o n was  Na Me Gapz~ (12.96 mmol) l i g a n d s o l u t i o n i n THF  mmol) i n the  3  mmol) d i s s o l v e d i n ~50  f o r ~4  in a volumetric  5  species.  to t h a t  MeH  described  starting material.  s o l u t i o n were then used i n  140  5.2.6  Preparation  2NaVa  o f L Re(CO)., a o  + [Re(C0).Cl] 4  T  H  F  ^  c o  >  2L Re(CO), + 2C0 + 2NaCl a o  ^  A 40.0 ml a l i q u o t o f the l i g a n d s o l u t i o n Na L~ (0.64 mmol) was added a +  slowly  to [ R e ( C 0 ) C l ] 4  2  (0.216 g, 0.324 mmol) d i s s o l v e d i n -30 ml THF. The  r e a c t i o n mixture turned was  cloudy  almost immediately.  r e f l u x e d f o r -24 h during which time the c l o u d i n e s s  yellow  coloration intensified.  The s o l u t i o n was c o o l e d  temperature, and the s o l v e n t removed was  The r e a c t i o n mixture  e x t r a c t e d with  under vacuum.  benzene and f i l t e r e d .  to room  The r e s u l t i n g  Evaporation  s o l v e n t c o n t a i n i n g the e x t r a c t s a f f o r d e d pale y e l l o w of the d e s i r e d rhenium t r i c a r b o n y l complex  i n c r e a s e d and the  o f the benzene crystalline  i n -80% y i e l d .  in Table 5.2.7  P h y s i c a l data  periods  f o r t h i s complex are given  X I I , p. 161.  Preparation  of L Mn(CO)., a  NaV  a  o  + Mn(C0) Br c  o  T  H  F  A  >  L Mn(C0), + 2C0 + NaBr a  To a s t i r r e d THF s o l u t i o n of Mn(C0)gBr a 30 ml a l i q u o t of the Na L~ a +  solvent.  needles  T h i s compound  i s s t a b l e to o x i d a t i o n but s o l u t i o n s d e t e r i o r a t e a f t e r prolonged even under an i n e r t atmosphere.  residue  (0.421 g, 1.53 mmol) was added  (1.53 mmol) l i g a n d s o l u t i o n i n the same  The r e a c t i o n mixture immediately turned  The mixture was r e f l u x e d o v e r n i g h t ,  a cloudy  orange c o l o r .  a f t e r which the s o l v e n t was removed i n  vacuo, and the r e s u l t i n g orange r e s i d u e e x t r a c t e d with  benzene.  141  Evaporation  o f the benzene from the f i l t r a t e  Trituration  o f the s t i c k y orange o i l e v e n t u a l l y y i e l d e d an a i r - s e n s i t i v e  orange powder as the product are l i s t e d 5.2.8  i n -75% y i e l d .  r e s u l t e d i n an orange o i l .  P h y s i c a l data  f o r the complex  i n Table X I I , p. 161.  Preparation of L N i ( N O ) a  NaV  Ni(N0)I  + Ni(N0)I  a  T  H  F  L N i ( N O ) + Nal a  >  (0.33 g, 1.5 mol) was d i s s o l v e d i n -50 ml THF.  A solution of  N a L ~ (1.5 mmol) i n the same s o l v e n t was added to the s t i r r e d a +  the n i t r o s y l . The with  The r e s u l t i n g  dark blue  s o l u t i o n was s t i r r e d  overnight.  s o l v e n t was removed under vacuum, and the dark blue r e s i d u e e x t r a c t e d benzene.  The benzene f i l t r a t e  t r a t e d and, upon e v a p o r a t i o n product  were r e c o v e r e d  5.2.9  c o n t a i n i n g the e x t r a c t s was concen-  o f the s o l v e n t , f l a k y blue c r y s t a l s o f the  i n -60% y i e l d .  f o r t h i s complex are c o l l e c t e d  Analytical  and s p e c t r o s c o p i c  data  i n Table X I I , p. 161.  P r e p a r a t i o n o f L Re(CO)^  2Na L" + [ R e f C O L C l L q +  T  H  F  A  >  2L R e ( C 0 h + 2C0 + 2NaCl ^  Two molar e q u i v a l e n t s of Na L^ were added to [ R e ( C 0 ) C l ] 2 +  4  0.27  solution of  mmol) d i s s o l v e d i n -30 ml THF, and the r e s u l t i n g  refluxed overnight. mixture  under vacuum.  The s o l v e n t was then  s o l u t i o n was  removed from the r e a c t i o n  The r e s i d u e was e x t r a c t e d with benzene.  t i o n o f s o l v e n t from the f i l t e r e d  (0.18 g,  extract resulted in a yellow  Evaporacake.  142  Recrystallization  of the y e l l o w cake from CH^C^/hexane  (1:1)  s t a b l e y e l l o w c r y s t a l s o f the d e s i r e d product i n ~80% y i e l d . physical 5.2.10  data f o r t h i s complex are summarized i n Table XVI,  Selected p.  174.  P r e p a r a t i o n of L M n ( C O ) ,  NaV  + Mn(C0),Br b  q  An equimolar (0.19  afforded  g, 0.68  T  H  F  >  L Mn(C0)-> + 2C0 q 3  A  amount of Na L~ l i g a n d q +  mmol) d i s s o l v e d  i n THF,  i n the same s o l v e n t .  r e a c t i o n mixture o v e r n i g h t , the s o l v e n t was solution  i n vacuo.  extracting  was  Work-up of the r e s u l t i n g  s o l v e n t , gave orange  + NaBr  added to Mn(C0),-Br o After refluxing  removed from the cloudy  c r y s t a l s of the product i n ~80%  yield.  in color  exposure  benzene),  S o l u t i o n s of the complex ( i n acetone or  d e t e r i o r a t e with time. Table XVI, 5.2.11  p.  on  data f o r t h i s compound are presented i n  174.  Attempted  A 1:1  Physical  orange  r e s i d u e , u s i n g benzene as the  T h i s complex i s s t a b l e under i n e r t c o n d i t i o n s but darkens to a i r .  the  p r e p a r a t i o n of L^Ni(NO)  r e a c t i o n of Ni(N0)I and Na L~ l i g a n d +  both a t room and r e f l u x temperatures.  i n THF was  carried  In both r e a c t i o n s , the  out  reaction  mixture turned blue/green and a f t e r work-up, blue/green s o l i d s were obtained. final  The  solution  blue/green s o l i d  i n the n i t r o s y l  of e i t h e r the r e a c t i o n mixture or the  showed no n o t i c e a b l e evidence of a b s o r p t i o n bands  s t r e t c h i n g frequency r e g i o n of the spectrum.  and mass s p e c t r a l expected  i r spectrum  data o f the s o l i d  The  i s o l a t e d were c o n s i s t e n t with  *H  nmr  those  f o r an o c t a h e d r a l Ni ( I I ) complex f o r m u l a t e d as [Me,,GapzO-  (CgH6N)]2Ni.  However, repeated attempts  at obtaining a n a l y t i c a l l y  pure  143  samples, or i s o l a t i n g  s u i t a b l e c r y s t a l s f o r X-ray  structural  d e t e r m i n a t i o n , were u n s u c c e s s f u l . 5.2.12  P r e p a r a t i o n of Mo(MeCN) (r) -C H )(C0) Br 3  2  Mo(C0)  Excess  6  + C H Br 3  allyl  M  e  C  3  2  M o ( M e C N ) ( r i - C H ) ( C 0 ) B r + 4C0  >  N  5  5  3  2  6  2  (2.04 g, 7.70 mmol) i n  The c o o l e d y e l l o w s o l u t i o n was l e f t t o  stand i n an i n e r t atmosphere f o r another c r y s t a l l i n e p r e c i p i t a t e had formed.  2 days, at which stage a y e l l o w  The y e l l o w s o l i d was then  collected  d r i e d i n vacuo to give a i r - s e n s i t i v e y e l l o w c r y s t a l s of the product i n  ~80% y i e l d . frequency  T h i s compound  e x h i b i t s two strong bands i n the CO  r e g i o n o f the i r spectrum ( v C Q :  i s recommended use  5  bromide was r e f l u x e d with M o ( C 0 )  ~60 ml a c e t o n i t r i l e f o r 2 days.  and  3  t h a t t h i s compound  be prepared  s i n c e i t decomposes r e a d i l y on A l t e r n a t i v e l y , the compound  o x i d a t i v e a d d i t i o n of a l l y l from M o ( C 0 ) 5.2.13  6  as c i t e d  CH C1 ). 2  2  [It  p r i o r to f u r t h e r  standing.]  can be prepared  v i a a two-step  bromide to the l a b i l e  process-  (MeCN) Mo(C0) 3  3  generated  [184].  L Mo(C0) (T] -C H ) 3  a  2  Na L~ + Mo(MeCN) (ri -C H )(CO) Br 3  2  -1  immediately  i n the l i t e r a t u r e by Hayter  P r e p a r a t i o n of  +  1945, 1860 c m  stretching  3  5  3  T  H  5  >  F  2  l _ M o ( C 0 ) ( r i - C H ) + 2MeCN + NaBr 3  a  Equimolar  2  3  5  amounts o f the l i g a n d Na L~ and Mo(MeCN) (r) -C H )(C0) Br +  3  2  3  5  2  144  were reacted reagents, stirred  i n THF.  An  immediate c l o u d i n e s s  indicating precipitation  overnight  r e s i d u e was  followed  extracted  by  with  crystals  d e s i r e d product  under i n e r t physical 5.2.14  conditions  data  are  the  The  was  r e a c t i o n mixture  filtered.  The  Evaporation  resulting  of  the  s o l u t i o n c o n t a i n i n g the e x t r a c t s a f f o r d e d  but  i n ~70%  yield.  This  XII,  p.  orange  compound i s s t a b l e  s o l u t i o n s d e t e r i o r a t e with  c o l l e c t e d i n Table  Preparation  observed upon mixing  removal under vacuum.  benzene and  from the  of the  of NaBr s a l t .  solvent  benzene s o l v e n t  was  time.  Pertinent  161.  of L M o ( C 0 ) ( T i - C H ) 3  2  q  3  5  3 The  -C3H5) was  compound LqMo(C0) (r) 2  t o that described from t h i s  i n s e c t i o n 5.2.13.  Work-up of the  identical  residue r e s u l t i n g  r e a c t i o n , u s i n g hexane as the e x t r a c t i n g s o l v e n t , a f f o r d e d  red-orange c r y s t a l s of the  product  spectrosocpic  complex are  5.2.15  prepared by a procedure  data  f o r the  Preparation  i n ~70% y i e l d . listed  Analytical  i n Table  XVI,  shiny  and  p.  174.  of L Rh(CO) a  2 N a V + [Rh(C0%Cl] a <L <L  T  H  F  9  Two (0.30  molar e q u i v a l e n t s  g, 0.77  (V^Q:  2068, 1989  juncture,  of the  three  cm" new  at 2085, 2025 and  1  until THF)  bands had  1970  cm" , 1  the  was  2L  a  Rh(CO) + 2C0  + 2NaCl  l i g a n d Na L~ were added t o +  mmol) d i s s o l v e d i n ~40  r e f l u x e d under n i t r o g e n  >  A  ml  THF.  The  disappearance  i n d i c a t e d by  2  r e a c t i o n mixture  of the  [Rh(C0) Cl] 2  i r measurements.  appeared i n the V ^ Q region respectively.  [Rh(C0) Cl]  The  At  of the  r e a c t i o n mixture  2  was dimer  2  this  spectrum was  145  c o o l e d , and the s o l v e n t  removed i n vacuo.  The  hexane f o l l o w e d by e x t r a c t i o n with benzene. s o l v e n t from the f i l t r a t e of the product  E v a p o r a t i o n of the benzene  i n ~60% y i e l d .  The  compound i s moderately  Physical  orange  crystals  stable  data are summarized  but  i n Table X I I ,  161.  5.2.16  P r e p a r a t i o n of L Rh(CQ) q  P r e p a r a t i o n of the compound L Rh(CO) was s i m i l a r t o the one 2020, and 1965  cm"  described 1  i n THF  mixture p r i o r t o s o l v e n t crystals *H  washed w i t h  c o n t a i n i n g the e x t r a c t s a f f o r d e d  s o l u t i o n s decompose with time. p.  r e s i d u e was  nmr  5.2.17  i n s e c t i o n 5.2.15.  New  by a procedure  V Q bands at 2080, C  were i n d i c a t e d by i r sampling of the  removal  i n vacuo.  of the product were i s o l a t e d  data are c o l l e c t e d  accomplished  A f t e r work-up, y e l l o w - o r a n g e  i n ~65% y i e l d .  i n Table XVI,  reaction  p.  Analytical,  i r and  174.  R e a c t i o n of L Rh(CO) with Mel d  CH C1 L Rh(CO) + Mel > L Rh (Me) (I)CO a a excess of methyl i o d i d e i n C H C 1 was added dropwise t o a ?  c  A slight stirred  ?  C  2  solution  of L Rh(CO) (0.30 a  g, 0.70  2  mmol) i n the same s o l v e n t .  A f t e r s t i r r i n g the  r e a c t i o n mixture at room temperature  the i n i t i a l  s o l u t i o n had turned deep red-orange.  orange  of the s o l u t i o n  at t h i s  stage revealed the presence  ~2060 cm"•''and the complete  disappearance of the  a t t r i b u t a b l e t o the U R h ( C O ) s t a r t i n g m a t e r i a l . vacuo,  extraction  of the  f o r about 18 h, The  i r spectrum  of a new  band at  band at 1970  cm" ',  Removal  1  of the s o l v e n t i n  residue i n benzene, f o l l o w e d by r e c r y s t a l l i z a t i o n  146  from CH 2 C1 » 2  yield.  a f f o r d e d red c r y s t a l s  of the product  T h i s compound c r y s t a l l i z e d  a f t e r several  i n almost  quantitative  as a benzene s o l v a t e which  remained  days of pumping under vacuum.  A n a l . C a l c d . For [ M e G a p z » 0 ( C H N ) C H N M e ] R h ( M e ) ( I ) C 0 ' 0 . 5 C H : 2  34.31, H, 4.13;  vCQ:  N, 8.89.  2060 cm" ;  5  Found:  v^:  IR(Nujol)  1  3  2  2  g  C, 33.93, H, 4.06;  H  l  2055 cm" . 1  IR(CH2C12)  N, 8.55.  NMR  (270 MHz,  CDC1 3 ):  xCHCl^ = 2.73  ppm,  (-CH ); 3.71t  ( p z - H ) ; 2.43d ( p z - H ) ; 2.98d ( p z - H ) ; 9.25s (Rh-Me). 4  2  ^HCCH  ~ ^  =  2  Z  10.34s, 10.12s (-GaMe ); 8.85s, 7.63s (-NMe ); 2  ^  ^  o r  P  Z  r o t o n s  ')  5  Positive  Ion Fast Atom Bombardment Mass  Spectrometry  (FABMS) i n t h i o g l y c e r o l  (P  ion) i o n s i g n a l s were observed  +  = parent  6.15s  2  3  C,  6  matrix:  [P+H] , [ P - H ] , +  at 591,  +  589 and  and  [P-Me]  +  575 mass  69 units,  (based  5.2.18  on  Ga)  respectively.  R e a c t i o n of L Rh(C0) with q  Mel  CH?C1? L R h ( C 0 ) + Mel  >  q  To a s o l u t i o n  of L R h ( C 0 ) (0.40  added one molar e q u i v a l e n t of Mel stirred  f o r about  presence 1700  of two  cm" , 1  1-1/2  new  mmol) i n -35  i n the same s o l v e n t .  bands i n the v ^ r e g i o n no t r a c e  starting material.  The  solution.  orange s o l i d  dark  q  h, at which stage i r evidence  r e s p e c t i v e l y with  The  g, 0.91  q  L Rh(C0Me)I  s o l v e n t was  benzene t o give small dark  ml C H 2 C 1  2  The mixture indicated  of the spectrum  was was  the  at -2070 and  of the v ^ b a n d due t o the L Rh(C0) q  then allowed t o evaporate from  obtained was  orange c r y s t a l s  the  washed i n hexane f o l l o w e d by  i n low y i e l d  (-35%).  147  A n a l . C a l c d . f o r [Me Gapz'0(C HgN)]Rh(C0Me)I: 2  7.20.  Found:  cm" .  IR(Nujol) v „ :  1  C, 3 3 . 0 0 , H, 3.04; N, 6 . 9 0 . 1710 c m " . 1  2.73 ppm, 1 0 . 0 8 s , 9.89s pz-H  +  +  2  2  and P - 2 M e - I  +  2070, 1700  2  (-GaMe ); 7.58s (-COMe); 3.71t  (P  +  T CHC1  (pz-H ); 4  2.29d  ' r i n g p r o t o n resonances.  obscured by the q u i n o l y l  P-Me , P-Me-C0 , P - M e - I  IR(CH C1 ) v ^ ;  NMR (270 MHz, CDC1,):  H  l  5  3  (pz-H );  C, 3 2 . 9 0 ; H, 3.08; N,  g  MS: P ,  = parent i o n ) i o n s i g n a l s were  +  observed. 5.2.19  R e a c t i o n of L*Rh(C0) (L* = L ,  L ) with  fl  L*Rh(C0) + I  To a C H C 1 2  dihalogen I  2  C  H  2  q  C  l  2  2  >  I  g  L*RhI (C0) 2  s o l u t i o n of L Rh(C0) was added a s l i g h t excess of the  2  i n the same s o l v e n t .  An immediate c o l o r change from orange  t o red was observed on m i x i n g the r e a g e n t s .  A f t e r s t i r r i n g the mixture  f o r a few h o u r s , an i r spectrum i n d i c a t e d complete d i s a p p e a r a n c e of the V^Q band of the rhodium(I) monocarbonyl s t a r t i n g m a t e r i a l , and the appearance of a new L ). Q  band at ~2090 cm  -1  (L  = L ), and ~2085 cm  -1  * (L =  The s i n g l e V^Q band p e r s i s t e d i n s o l u t i o n a f t e r s t i r r i n g the  r e a c t i o n mixture overnight.  A l t h o u g h the i r s p e c t r a of the  m i x t u r e s suggested the presence of s i x - c o o r d i n a t e Rh ( I I I ) species  reaction  monocarbonyl  i n s o l u t i o n , a n a l y t i c a l l y pure compounds of the expected *  d i i o d i d e s , L R h I ( C 0 ) , c o u l d not be i s o l a t e d from the black s o l i d m a t e r i a l 2  o b t a i n e d a f t e r removal of  solvent.  148  5.3  Results  5.3.1  and  Discussion  [Me GaO(C H N)CH NMe ] 2  5  A general  3  2  2  r e a c t i o n of Group 13  hydrogen-containing ligands  (B, A l , Ga,  i s the e l i m i n a t i o n  compound s t r u c t u r a l l y c h a r a c t e r i z e d [Me NCH CH 0GaMe ] 2  2  2  2  was  2  In) a l k y l s toward of a l k a n e s .  product  of the  t r i m e t h y l g a l l i u m with N,N-dimethylethanolamine [185]. exception  of H NCH CH 0GaMe , the 2  2  2  molecules c o n t a i n i n g monomer u n i t s structural distorted  2  structure  gallium  gallium  reaction  of  With the  notable  of monomeric  atoms [186],  systems have been shown by  analyses t o d i m e r i z e v i a four-membered bipyramidal  as  of which c o n s i s t s  t e t r a h e d r a l l y coordinated  of s i m i l a r dimethyl  F o r example, a  by X-ray c r y s t a l l o g r a p h y  i s o l a t e d as the  active  [-Ga-0-]  X-ray  rings giving a  2  arrangement about each f i v e - c o o r d i n a t e  gallium  atom  [173,185]. The  reaction  of 2-(dimethylaminomethyl )-3-hydroxypyridine with  t r i m e t h y l g a l l i u m y i e l d e d the structure  ( f i g u r e 40)  which d i s p l a y the  compound [Me Ga'0(C H N)CH NMe ], the c r y s t a l 2  of which c o n s i s t s  gallium  5  Ga-N  bond length  gallium length  systems  gallium  considerably  dimeric  ( f i g u r e 41,  species.  see  of the  It i s i n t e r e s t i n g t o compare reported  the  f o r s i m i l a r dimethyl-  p. 158).  The  Ga-N  bond  [Me Ga*0(C H N)CH NMe ] complex i s 2  of the  5  [Me  3  2  2  dimer [Me GaOCH CH NMe ]  l o n g e r than 2.056A and  independent molecules  arrangements  geometry expected f o r a  a l s o Table XI,  present  s h o r t e r than t h a t  2.471A) [185], but  2  atoms i n d i s t o r t e d t e t r a h e d r a l  i n t h i s complex t o those  of 2.135A i n the  2  of d i s c r e t e monomeric molecules  r a t h e r than a d i s t o r t e d t r i g o n a l bipyramidal five-coordinate  3  GaOCH CH  2  2  2.072A reported NH  2  2  2  (Ga-N  f o r the  ] monomeric s p e c i e s  =  two [186].  Figure 40.  M o l e c u l a r s t r u c t u r e of [ M e G a - 0 ( C H N ) C H N M e ] 2  5  s h o r t e r Ga-N bond l e n g t h of 2.135A i n the present  The  3  2  [Me Ga»0(C H N)CH 2  NMe ] complex compared with the 2.471A above i s s u g g e s t i v e  actions  In the [Me GaOCH CH NMe ] 2  2  2  l e d t o bond l e n g t h e n i n g .  2  complex, severe  The monomeric nature  [Me GaO(CgH N)CH NMe ] compound i s probably 2  3  straints  2  2  i n the plane  coplanar.  2  2  steric  inter-  of the present  r e l a t e d t o the s t e r i c  con-  Since the  are c o n s t r a i n e d t o l i e approximately  In o r d e r t o minimize a n g u l a r s t r a i n , the che-  r i n g adopts a steep and s l i g h t l y  the NMe  3  of the p y r i d i n e r i n g , f o u r atoms of the six-membered c h e l a t e  must be roughly late  steric  imposed by the u n s a t u r a t i o n of the p y r i d i n e r i n g .  p y r i d i n e s u b s t i t u e n t atoms 0 and C(6)  5  of l e s s  2  interactions.  2  and GaMe  2  t w i s t e d boat  groups are n e a r l y e c l i p s e d .  conformation  The p a r t i a l  i n which  staggering  about the Ga-N bond which would be r e q u i r e d f o r d i m e r i z a t i o n most results  i n t o o high a degree of r i n g s t r a i n .  related  compound [Me GaOCH CH NH ] [ 1 8 6 ] , 2  hydrogen bonding present monomer u n i t s .  2  2  2  likely  It i s noteworthy that i n the  an e x t e n s i v e  i n the compound prevented  network of N-H«««0  d i m e r i z a t i o n of the  N  O ,Ga  [Me ^GaOCH^CH ^NH ^]  [Me Ga.0(C H N)CH NMe ] 2  Figure 41  5  3  2  Comparison of the Ga-N bond lengths  2  Ga  0  ^GaOCH^NMe,,]  in the dimethylgall  2  ium compounds,  151  The  mass spectrum of the compound [Me GaO(CgH N)CH NMe ] 2  i t s highest as  a very  mass peaks, a moderately strong  strong P-Me  +  s i g n a l , confirming  compound i n the gas phase.  3  2  d i s p l a y e d as  2  parent i o n ( P ) s i g n a l as w e l l +  the monomeric nature of the  The most i n t e n s e  s i g n a l s were those  corre-  sponding t o l o s s of the 'CH NMe ' moiety from the monomer s p e c i e s . 2  mass s p e c t r a l data f o r t h i s  Table IX.  +  2  The  compound are c o l l e c t e d i n Table IX below.  Mass S p e c t r a l Data of  [Me GaO(C H N)CH NMe ] 2  5  3  2  2  * m/e  Assignment  250  [Me Ga'0(C H N)CH NMe ]  235  [MeGa*0(C H N)CH NMe ]  192  [Me Ga*0(C H N)]  177  [MeGa*0(C H N)]  151  [0(C H N)CH NMe ]  109  [H0(C H N)CH ]  2  5  2  5  68°C.  Based on  The  1  H  3  2  19.3  2  85.3  +  2  100.0  +  3  14.5  +  2  3  [Me Ga]  2  3  3  5  5.0  +  2  58.5  +  3  15.2  +  2  80  At  3  5  5  99  *  5  Intensity +  C  5 6 H  N +  8  69  Ga  58  [-CH NMe ]  44  [NMe ]  '  2  35.2  +  2  43.2  +  2  18.6  +  2  69 Ga.  nmr s p e c t r a  i n CgDg s o l u t i o n , and of the complex Me Ga0(CgH N)CH NMe 2  3  2  s o l u t i o n , are shown i n f i g u r e s 42 and 43, r e s p e c t i v e l y . spectrum of Me GaO(CgH N)CH NMe 2  H0(Cr H N)CH NMe  of the hydroxy s t a r t i n g m a t e r i a l ,  3  planar structure f o r this  2  2  species  )  2  3  2  2  i n CgDg The H A  nmr  complex i s c o n s i s t e n t with an o v e r a l l i n s o l u t i o n , with the two methyl  groups  b  154  on g a l l i u m , and the two methyl methylene  protons l y i n g above and below t h i s p l a n e ; t h i s  singlets 5.3.2  groups on n i t r o g e n , as well  f o r the -GaMe , -NMe 2  [Me GaO(C H N)] 2  The  g  6  and -CH -  2  groupings.  2  ' [Me Ga0(C HgN)]' which has been shown t o be 2  g  The mass spectrum of t h i s  prominent s i g n a l s due t o the parent i o n P ,  P-Me  +  being the most i n t e n s e i n the spectrum  "Ws  T a b l e X.  *  At  leads t o sharp  2  monomeric i n the gas phase.  *  two  r e a c t i o n of 8 - h y d r o x y q u i n o l i n e with t r i methyl gal l i u m a f f o r d e d the  c o o r d i n a t i o n compound  +  as the  Spectral  Data  of  +  compound d i s p l a y e d  and P-2Me , the +  latter  (see Table X below).  '[Me GaO(C H N)]' 2  g  m/e  Assignment  243  [Me GaO(C H N)]  228  [MeGaO(C H N)]  213  [GaO(C H N)]  145  [H0(C H N)]  115  [Me GaO]  2  g  g  g  g  6  Intensity +  6  +  6  5.9  +  6.2  +  2  [Me Ga]  84  [MeGa]  69  Ga  100.0 28.0  +  6  6  99  12.0  2.3  +  2  50.7  +  50.7  +  180°C  Based  on  The H X  69  Ga.  nmr s p e c t r a  of the hydroxy s t a r t i n g m a t e r i a l  H0(C HgN), and g  the q u i n o l i n o l a t o complex Me Ga0(C HgN) i n CgDg s o l u t i o n s are shown i n 2  f i g u r e s 44 and 45,  respectively.  g  The H A  nmr spectrum of the q u i n o l i n o l a t o  155  156  157  complex i s i n accord solution. and  In t h i s  with  an o v e r a l l  p l a n a r s t r u c t u r e f o r the complex i n  s t r u c t u r e , the two methyl  below the plane,  hence a sharp s i n g l e t  groups on g a l l i u m l i e above  i s observed f o r the 'GaMe ' 2  protons. The  X-ray c r y s t a l  f i g u r e 46.  2  This structure  v i a the formation planar  s t r u c t u r e of the [Me GaO(CgHgN)]  2  complex i s shown i n  revealed the d i m e r i z a t i o n of the monomer u n i t s  of a four-membered  [-Ga-0-]  2  r i n g t o form a nearly  ( t o w i t h i n 0.053(5)A) cent rosy mmetric molecule c o n s i s t i n g of a  system of seven fused  rings.  The c o o r d i n a t i o n  geometry about each  atom i n the above r i n g system i s d i s t o r t e d t r i g o n a l bipyramidal due  t o the s t e r i c  system.  requirements  The Ga-N bond length  complex i s s h o r t e r than those  F i g u r e 46.  imposed by the e x i s t e n c e of 2.211A f o r the present reported  Molecular  gallium  primarily  of the fused  ring  quinolinolato  f o r the r e l a t e d [MeoGaOCH-CrLNMe?]?  s t r u c t u r e of [Me GaO(C H N)] .  158  (Ga-N  = 2.471A) [185],  (see T a b l e  2  XI below).  the  present  and  [Me Ga»0(C H N)]  2  5  the present  9  4  2  5  Thus s t e r i c  [Me GaO(C H N)]  2  for  and [ M e G a O ( C H N ) ]  6  2  4  2  (Ga-N = 2.276A) [173] dimers  i n t e r a c t i o n s are l i k e l y l e s s severe i n  complex compared with  complexes above.  the [Me GaOCH CH NMe ] 2  q u i n o l i n o l a t o compound i s , however, longer  g a l l i u m complex, G a C l [ 0 C H N ] 1 0  reported e a r l i e r  Table XI.  g  by Dymock and P a l e n i k  2  than t h a t  bipyramidal,  2  2  reported five-  (Ga-N = 2.109A), 2.105A)  [187].  Comparison o f Ga-N and Ga-0 Bond Lengths i n Four and F i v e Gallium  2  The Ga-N bond l e n g t h o f 2.211A o f  the f i r s t c r y s t a l l o g r a p h i c example o f a t r i g o n a l  coordinate  2  Coordinate  Compounds.  Gallium  Bond D i s t a n c e s  (A)  Coordination Compound  Number  [Me NCH CH OGaMe ] 2  2  2  2  [Me NCH CH 0GaH ] 2  2  2  2  2  2  [Me Ga«0CH (C H N)] 2  2  5  4  [Me Ga«0(C H N)] 2  g  6  2  [MeN(CH CH 0) GaH] 2  2  2  2  2  Me Ga«0(C H N)CH NMe 2  5  3  Me GaOCrLCrLNH ?  2  ?  2  Ga-N  Ga-0  Reference  5  2.471  2,078,1.913  185  5  2.279  2.053,1.911  185  5  2.276  1.939-2.086  173  5  2.211  1.937  T h i s work  5  2.193  1.843-2.019  188  4  2.135  1.897  T h i s work  4  2.056,2.072  1.917  186  159  5.3.3  L M(C0) a  The  first  (M = Mn,  3  Re)  of t h i s c l a s s of unsymmetric t r i d e n t a t e l i g a n d s , Me Gapz(02  CHgCH^NRg)" (R = H or Me), or m e r i d i o n a l  has  been shown to be capable  c o o r d i n a t i o n i n t r a n s i t i o n metal complexes [ 4 3 ] .  in a l l octahedral  t r a n s i t i o n metal  c o o r d i n a t i o n of the unsymmetrical to  be e x c l u s i v e l y f a c i a l  tricarbonyl (L~), a  of e i t h e r f a c i a l However,  t r i c a r b o n y l compounds s t u d i e d thus f a r , p y r a z o l y l g a l l a t e l i g a n d has  [173,174].  The  been found  present manganese and  rhenium  compounds, i n c o r p o r a t i n g the l i g a n d Me2GapzO(CgH N)CH2NMe2 3  therefore represent  the f i r s t  complexes i n which both f a c and mer  and  the only examples of such  isomers c o - e x i s t i n s o l u t i o n .  Evidence f o r the presence of both isomers i n s o l u t i o n i s based s o l e l y ir  and  *H  nmr  data,  s i n c e p e r s i s t e n t attempts at i s o l a t i n g  s u i t a b l e f o r X-ray c r y s t a l  s t r u c t u r e determination  on  crystals  were u n s u c c e s s f u l .  I n f r a r e d measurements i n cyclohexane showed s i x bands ( f o u r s t r o n g , two  weak) i n the  spectra obtained  r e g i o n of the spectrum.  tricarbonyl  to the f a c isomer, while  to the mer  isomer.  strong  bands while  to  s t r o n g and  two  vCQ Re  values o b t a i n e d  s t r o n g and  Thus, f o r octahedral  two  strong  weak bands  transition  weak  f o r a mer  arrangement one  bands [51,80].  metal  donates more e l e c t r o n d e n s i t y to the CO of the  hence i m p l i e s a s t r o n g e r  values 'M-CO' bond  due  would expect  A comparison of  f o r both compounds (Table X I I , p. 161),  r e s u l t s i n a lowering and  one  Three  the  complexes, a fac arrangement of the t r i d e n t a t e l i g a n d would  give t h r e e see one  example of  f o r both complexes i s shown i n f i g u r e 47.  bands were a s s i g n e d were a s s i g n e d  A typical  indicates that  l i g a n d s than does Mn. to i n c r e a s e d M-CO  [189].  the  This  backbonding,  160  1933  2400  F i g u r e 47.  I r spectrum  Mn(C0)  1800  2000  i n the v  region of  C Q  i n cyclohexane s o l u t i o n .  3  [Me Gapz»0(C H N)CH NMe ]  A  r e p r e s e n t a t i v e example, the H  nmr  A  [Me Gapz»0(C H N)CH NMe ]Re(C0) 2  5  3  2  In the spectrum two NMe  2  and the CH  with a mer  2  2  3  2  2  isomer.  s p e c t r a o f the complexes.  spectrum of the rhenium  As a  complex  i n CgDg s o l u t i o n i s shown i n f i g u r e 48.  groups appeared  ( f i g u r e 49B,  5  isomers i n s o l u t i o n i s  s e t s o f s i g n a l s were d i s p l a y e d .  methylene  structure  3  nmr  2  A f a c isomer; B mer  F u r t h e r support f o r the proposed f a c and mer p r o v i d e d by the room temperature H  (cm")  1600  p.  In one s e t the GaMe , 2  as sharp s i n g l e t s c o n s i s t e n t  163), and a second s e t c o n s i s t i n g of  Table X I I .  P h y s i c a l Data f o r the Complexes L MT (where L fl  ANALYSIS  v  CALCD/F0UND M  T  Re  (co)  3  •0.17C H 6  Mn  (co)  v  ( c m  "  »  C  H  N  33.95  3.49  9.32  2  Me Gapz'0(C H N)CH NMe ) 2  5  3  2  2  *H nmr  1 )  , 6 12 (CH CT ) C  H  2  2  A 2035.1920,1900  b  6  (CO), o  Mo  C0' N0  fl  34.08  3.98  9.44  B 2022,2015,1910  42.05  4.41  12.26  A 2040,1943,1915  a  B 2030,2020,1933  42.47  4.56 12.32  42.30  4.90  1950,1805  42.06  4.97  (1925,1825)  c  GaMe  NMe  10.53s  8.21s  9.83s  7.68s  10.25s  8.39s  10.65s  7.58s  10.05s  7.24s  10.31s 10.27s  CH  2  H  4  H  5  H  3  4.19t  3.29d  2.41d  6.40s  3.96t  3.08d  2.21d  6.73br  3.54t  3.00d  2.51d  7.41s  6.00s  3.36t  2.85d  2.12d  7.43s  5.95s  3.56t  2.85d  2.30d  8.57d,8.67H  (J * 9.0 Hz)  10.09s  7.36 b r  H  $  6.68 br Hy Nl  NO •0.75CgH  Rh  6  CO •0.33C H 6  A = fac a  C  5.27 15.06  44.86  5.79 14.51  40.23  5.17  40.32  5.07 11.52  1770 (THF) (1775)  11.73  c  b  b  10.39s  7.63s  6.16s  4.13t  3.35d  2.66d  10.20s  8.35s  6.38s  3.98t  2.68d  2.33d  10.27s  8.40s  6.41s  4.01t  2.76d  2.38d  (1970)  s = singlet  Isomer; B = mer Isomer  (CD ) C0; x(CH ) C0  = 7.89 ppm; J  H  CgD,;  * 2.84 ppm; J  H C C  3  b  1 4  45.17  2  3  2  xCgH,  CDC1 ; 3  xCHC?  3  =2.73  ppm; J  C  C  H  * 2.0 Hz f o r pz p r o t o n s .  L | " 2.0 HZ  H C C L )  f o r pz p r o t o n s .  2.0 f"o r pz " " Hz "  protons.  A  d = doublet t = triplet q = quartet br = broad  F i g u r e 48.  80 MHz H ]  A  nmr spectrum o f [ M e G a p z 0 ( C H N ) C H N M e ] R e ( C 0 )  fac isomer; B  2  mer isomer.  5  3  2  2  3  in C D g  6  solution.  163  164  two  s i n g l e t s each of the  'GaMe ' and 2  'NMe ' m o i e t i e s s u g g e s t i n g 2  i n e q u i v a l e n c e of the methyl groups on g a l l i u m and a facially clearly isomer two both  coordinated ligand  d e f i n e d AB  ( f i g u r e 49A,  p a t t e r n expected  i s somewhat p u z z l i n g however.  s e t s f o r each p r o t o n , adding the f a c and mer  isomers  p. 163).  The  pz proton  f u r t h e r credence  Mass s p e c t r a l  resonances  2  2  data o b t a i n e d f o r both  3  isomers  (M = Mn, the Mn  Re)  These  related  results,  complexes  complexes.  and Re complexes  XIV)  pounds.  For example, w h i l e the Re s p e c i e s d i s p l a y e d s i g n a l s  (Tables  r e v e a l e d some i n t e r e s t i n g d i f f e r e n c e s between the two  to the parent, P , +  f o r the Mn  P-Me , and +  P-2Me-2H  s p e c i e s was  r e l u c t a n c e to l o s e the CO  +  as  in solution f o r  XIII and  observed  appeared  f o r the c o - e x i s t e n c e of  r e s u l t s from  of both  the p r e s e n t [ M e G a p z 0 ( C H N ) C H N M e ] M ( C 0 ) 3  absence of the  of the complexes i n s o l u t i o n .  [173,174], s t r o n g l y support the presence 5  The  for  f o r the methylene group of the f a c  the i r data d i s c u s s e d above, t o g e t h e r with  2  n i t r o g e n as expected  com-  corresponding  i o n s , the h i g h e s t mass fragment  a t t r i b u t a b l e to the P-3C0  +  ion.  The  l i g a n d s e x h i b i t e d by the Re s p e c i e s i s  r e f l e c t i v e of the c o m p a r a t i v e l y  s t r o n g e r 'M-CO' bonds i n t h i s complex  i n the valence i s o e l e c t r o n i c Mn  compound.  than  165  Table XIII.  *  At  Mass S p e c t r a l  Data o f  [Me Gapz0(C H N)CH NMe ]Mn(C0) 2  5  Assignment  m/e  3  2  2  Intensity  372  [Me Gapz* 0 ( C H N ) C H N M e M n ] 2  12.7  342  [Gapz'0(C H N)CH NMe Mn]  27.2  340  [Gapz-0(C H N)CNMe Mn]  319  [(Me Gapz)  272  [Ga«0(C H N)CNMe Mn  251  [(Me Gapz)  235  [MeGaO(C H N)CH NMe ]  192  [Me Ga»0(C H N)]  177  [MeGa*0(C H N)]  151  [0(C H N)CH NMe ]  2  5  5  5  69  Ga  58  [-CH NMe ]  +  15.1  +  +  39.1 60.9 73.6  +  3  2  15.0  +  2  +  21.4 24.2  +  2  26.2  +  2  Ga.  - H]  2  3  3  [Me Ga]  69  2  5  5  100.0  +  - Me - pz + H ]  2  3  99  Based on  - Me + 2 H ]  +  46.0  +  2  2  2  +  2  3  2  5  120°C.  2  3  2  5  2  3  5  2  3  2  +  20.0  166  T a b l e XIV.  •  f  Mass S p e c t r a l  2  5  3  2  Intensity  588  [Me Gapz«0(C H N)CH NMe Re(C0) ]  573  [MeGapz«0(C H N)CH NMe Re(C0) ]  556  [Gapz'0(C H N)CNMe Re(C0) ]  528  [Gapz«0(C H N)CNMe Re(C0) ]  500  [Gapz-0(C H N)CNMe Re(CO)]  472  [Gapz«0(C H N)CNMe Re]  319  [(Me Gapz)  2  - Me + 2 H ]  251  C(Me Gapz)  2  - Me - pz + H ]  235  [MeGa-0(C H N)CH NMe ]  192  [Me Ga«0(C H N)]  177  [MeGa»0(C H N)]  151  [0(C H N)CH NMe ]  2  5  5  5  2  2  2  69  Ga  58  [-CH NMe ]  187 Re.  2  10.9  24.8  +  +  24.9 94.8 100.0  +  3  16.5  +  2  16.8  42.2  +  +  40.7  +  8.4  46.5  +  2  i 0 /  2  +  10.2  10.6  +  2  3  +  +  +  28.0  +  2  ad  2  2  2  [Me Ga]  3  3  2  3  3  3  2  2  5  5  2  2  3  5  69 Ga  3  3  5  o y  2  3  5  5  3  3  5  99  Based on  2  Assignment  m/e  ' A t 120°C. *  Data o f [Me Gapz0(C H N)CH NMe ]Re(C0)  2  +  38.0  167  5.3.4  L Ni(NO) a I n f r a r e d measurements o f the L Ni(NO) complex i n s o l u t i o n a  the presence o f a c o o r d i n a t e d NO group CH C1 ) c l e a r l y 2  2  cm" ) t y p i c a l  i n the n i t r o s y l  o f metal  1  nitrosyl  (  V N Q  :  1770 cm"  THF; 1775 cm"  1  s t r e t c h i n g frequency r e g i o n complexes [190].  indicated  The  1  (~1500-2000  value observed  f o r t h i s complex i s i n d i c a t i v e o f a c o n s i d e r a b l y weakened N-0 bond i n comparison  to t h a t o f f r e e NO which  absorbs i n the range 1840-1833 c m  -1  [189,191]. The solution  room temperature H nmr spectrum o f t h i s compound i n CDCl-j A  i s interesting  'GaMe ', 'NMe ' and CH 2  2  2  i n t h a t i t d i s p l a y s sharp s i n g l e t s f o r t h e groups  respectively  s u g g e s t i v e o f a square p l a n a r arrangement  ( f i g u r e 50).  about the Ni c e n t e r with a  pseudo-meridionally coordinated organogallate l i g a n d . u n l i k e l i h o o d o f such an arrangement s t u d i e s which  This i s  However, t h e  f o r t h i s complex i n l i g h t o f p r e v i o u s  have shown t h a t square p l a n a r {MNO} ^ ( i . e . , 1  on the metal M, when the n i t r o s y l  10 d e l e c t r o n s  l i g a n d i s f o r m a l l y c o n s i d e r e d to be  bound as N 0 ) , complexes should have an M-N-0 bond angle o f 120° [192,193] +  ( c o n t r a r y t o the l i n e a r M-N-0 grouping suggested by the observed i r r e s u l t s ) ; l e d us to suspect t h a t a f l u x i o n a l  process was probably  r e s p o n s i b l e f o r the observed room temperature H nmr spectrum. A  closely  related  [Me Ga(3,5-Me pz)(0CH CH NMe )]Ni(NO) has been shown to be 2  2  2  2  2  s t e r e o c h e m i c a l ^ n o n - r i g i d a t room temperature a tetrahedral  in solution  conformation about the Ni c e n t e r i n the s o l i d  A v a r i a b l e temperature H nmr i n both dg-acetone X  indeed reveal experiment  The  a fluxional  and to possess s t a t e [194].  and toluene-dg d i d  process to be o p e r a t i v e i n s o l u t i o n .  the sharp -GaMe  signal  was monitored.  In t h i s  As the s o l u t i o n was  169  c o o l e d , marked broadening (the  lowest temperature  the o r i g i n a l  signal  of the -GaMe  attainable),  and observe  these lower temperatures,  2  signal  was observed.  i t was s t i l l  A t -85°C  not p o s s i b l e to c o l l a p s e  new s i g n a l s i n t h i s  region.  the t e t r a h e d r a l conformation  e s t a b l i s h e d due t o a slowing down o f the f l u x i o n a l  Evidently, at  was becoming  process.  U n f o r t u n a t e l y , i n s t r u m e n t a l l i m i t a t i o n s p r e c l u d e d the attainment o f temperatures  low enough to observe  splitting  o f the s i g n a l s .  The i r r e s u l t , t o g e t h e r with i r data r e p o r t e d f o r some {MNO} complexes  (see T a b l e XV below),  as well as the H A  10  nmr r e s u l t s d i s c u s s e d  above, l e d to the c o n c l u s i o n o f a f a c i a l l y  c o o r d i n a t e d L , l i g a n d i n the a p r e s e n t L Ni(NO) complex with the c o o r d i n a t i o n geometry about Ni being a tetrahedral.  T a b l e XV.  Comparison o f v  Values  i n Selected Four-coordinate  {MNO}  10  Complexes.  Reference  Compound [Me Gapz«0(C H N)CH NMe ]Ni(NO)  1775  (CH C1 )  [Me Ga(3,5-Me pz)(0CH CH NMe )]Ni(N0)  1770  (C H  1 2  )  194  [MeGa(3,5-Me pz) ]Ni(N0)  1785  (C H  1 2  )  194  [MeGapz ]Ni(N0)  1786  (C H  1 2  )  194  [Me Ga(3,5-Me pz)»0CH (C H N)]Ni(N0)  1783  (C H  1 2  )  173  (n-C H )Ni(N0)  1833  2  5  2  3  2  2  2  2  2  2  2  3  3  2  2  5  2  5  5  [Ni(CH C(CH PPh ) )N0] BF4 +  3  2  2  3  4  1750  2  g  6  g  g  2  T h i s work  196 (Nujol)  195  170  P o s s i b l e mechanisms f o r the proposed f l u x i o n a l figure  51.  Two  intermediate inversion  p o s s i b i l i t i e s may  (A) i s formed by breaking  a t the pyramidal  A second a l t e r n a t i v e inversion  be e n v i s a g e d .  process  are shown i n  F i r s t , a trigonal  planar  the Ni-N(amino) bond, f o l l o w e d by  oxygen and r e f o r m a t i o n of the Ni-N(amino) bond.  i s v i a a square-planar  a t the Ni c e n t e r through  intermediate  the plane.  (B) with  Figure 51.  Proposed mechanisms f o r the f l u x i o n a l  process observed f o r  [Me GapzO(C H N)CH NMe ]Ni(NO) i n CDC1 2  A = trigonal  5  3  2  2  p l a n a r ; B = square  3  planar.  solution.  172  5.3.5  L M(CO)o (M = M n ,  9  _~  Both of their  these t r i c a r b o n y l  respective  tridentate  Re)  ligand  ir  spectra,  (see F i g u r e  complexes  indicative  gave t h r e e of a f a c i a l  Ir  spectrum i n the v  cyclohexane  bands  arrangement of  in  the  52).  2006"  F i g u r e 52.  strong  C Q  solution.  ieoo  region of  (  CM-  1  [Me Gapz'0(C HgN)]Mn(C0) 2  g  3  in  173  As evident from Table XVI,  p. 174,  the  values f o r the Re species are  consistently lower than those of the Mn complex, again a r e f l e c t i o n of the  * stronger 'M-CO'  dit-Tt  backbonding component in the Re species compared t o  the valence-isoelectronic Mn compound. Further confirmation of a f a c i a l tridentate organogallate ligand i n these L M(C0)o compounds is provided by the *H nmr results. A typical q o spectrum is shown f o r the [Me2Gapz*0(CgHgN)]Re(C0)2 species in figure 53. Of significance in the spectrum is the gallium alkyl where two sharp singlets were observed f o r the  region (~9-ll  x),  'GaMe2' moiety as expected  f o r inequivalent methyl groups on gallium in a f a c i a l arrangement of the ligand.  A meridionally coordinated ligand, on the other hand, would lead  to equivalent Ga-Me groups, and therefore a singlet in this region of the spectrum. The mass spectral data f o r both the Mn and Re species are l i s t e d i n Tables XVII, p. 176 and XVIII, p. 177, respectively.  In both compounds,  the most intense signals were those attributable t o the [MeGa0(CgHgN)] ion fragment.  While the mass spectrum of the Re species displayed  + prominent parent  +  (P ), and P-Me  ion signals, the strongest signals  observed f o r the Mn species were those corresponding fragment.  +  This observation lends further support  to the P-3C0 ion +  f o r a stronger 'M-CO'  it-backbonding component in the Re compound than in the Mn analog as expected when comparing valence isoelectronic f i r s t and t h i r d row t r a n s i t i o n metal carbonyl  compounds in the same group.  Table XVI.  P h y s i c a l Data f o r the Complexes L MT (where L q  ANALYSIS  v  CALCD/F0UND M  T  (co)  Re  3  co  • Me Gapz'0(C HgN))  q  2  g  *H nmr  (cnfl)  C  H  N  36.36  2.69  7.07  2025,1927,1901  36.21  2.93  7.06  2030,1925,1900  (Nujol?  GaMe a  2  10.33s  (CC1 )  H  4  H  5  H  3  4.05t  3.19d  2.23d  3.86t  3.13d  2.14d  3.85t  3.16d  1.66d  '^"^V  9.48s  4  (2025,1915,1895)  (co)  Mn  3  (co)  Mo  2  45.37  3.34  9.34  2040,1950,1920  46.05  3.55  8.86  2035,1948,1915  45.27  3.97  8.34  1955,1863  46.03  3.91  8.33  1950,1858  a  10.35s  (THF)  9.46s a  10.28s  (CC1 )  9.46s  4  8.41d,8.31dH. (J = 9 . 0 Hz) 7.06 br  H  $  6.50 br Hy  Rh  CO  •33C H 6  a  CgD ; 6  43.62  3.64  8.98  43.22  3.63  9.34  a  9.80s  (1968)  6  "tCgHg = 2.84 ppm; J  s = singlet,  d = doublet,  H  C  C  H  = 2.0 Hz f o r pz p r o t o n s .  t = t r i p l e t , b r = b r o a d , dd • d o u b l e t o f  doublets.  3.84t  2.69d  2.28d  175  176  XVII.  At  f  Mass S p e c t r a l  Data o f [Me Gapz-0(CgH N)]Mn(C0) 3 2  6  m/e  Assignment  419  [Gapz-0(C H N)Mn(C0) ]  378  [MeGapz'0(C H N)Mn(C0) ]  365  [Me Gapz-0(C H N)Mn]  335  [Gapz*0(C H N)Mn]  319  [(Me Gapz)  2  - Me]  251  [(Me Gapz)  2  - Me - p z H ]  243  [Me Ga«0(C H N)]  228  [MeGa-0(C H N)]  213  [Ga-0(C H N)]  199  [0-(C H N)Mn]  151  [pzHMn(C0)]  9  6  9  9  2  9  84  [MeGa]  69  Ga  2  180°C. 69  Ga.  6  6  [Me Ga]  +  6  +  +  +  +  +  +  0.4  2.4  +  +  +  22.4  +  6  6  g  g  2  6  2  g  0.1  +  3  2  99  Based on  6  9  2  Intensity  5.4  +  +  7.9 6.5 100.0 0.1 18.3 3.0 13.8 1.8 64.5  177  T a b l e XVIII.  Mass S p e c t r a l  Data o f  m/e  1  *  [Me Gapz'0(C H N)]Re(C0) 2  9  6  Assignment  Intensity  581  [Me Gapz»0(C H N)Re(CO) ]  566  [MeGapz'0(C H N)Re(C0) ]  553  [Me Gapz.0(C H N)Re(C0) ]  510  [MeGapz'0(C H N)Re(C0)]  497  [Me Gapz.0(C H N)Re]  482  [MeGapz'0(C H N)Re]  467  [Gapz'0(C H N)Re]  331  [0-(C H N)Re]  228  [MeGa*0(C H N)]  213  [Ga'0(C H N)]  2  9  9  2  2  g  9  9  [Me Ga]  78  C  69  Ga  2  A t 80°C. 69 Ga  o y  and  187 Re.  i 0 /  H  +  +  6  6  6  +  6  6  +  +  +  +  +  +  9.5 5.8 33.5 12.3 6.9 3.4  +  6  9  6 6  6  g  9  2  17.3 48.4  +  3  6  g  +  3  6  9  99  Based on  6  +  100.0 14.5 3.5 2.4 25.1  178  5.3.6  L*Mo(C0) (n -C H ) 3  *  L )  &  5  Q  3 LMO(C0) (T] -C Hg) compounds  The their  (L* = l ,  3  2  2  d i s p l a y e d two s t r o n g  3  i r s p e c t r a , s i m i l a r t o those r e p o r t e d  for related  vCQ  bands i n  molybdenum  3 dicarbonyl  'TI -CgHg' complexes  (see Table  XIX below), and t h i s i s  i n d i c a t i v e o f a cis-arrangement of the CO l i g a n d s about the Mo atom. 3 Table  XIX.  Comparison o f  i n some LMO(C0) (T) - ^ 5 )  values  2  v  C0  ( c m  "  1 )  i  n  C  complexes.  Reference  6 12 H  [Me GapzO(C H N)CH NMe J  1950,1805  T h i s work  [Me Gapz*0(C H N)]  1955,1863  T h i s work  [Me GapzOCH (C H N)]  1942,1855  173  [Me Gapz*(0CH CH NMe )]  1934,1848  197  [MeGapz3]  1948,  [HBpz ]  1958,1874  2  5  2  3  2  9  2  6  2  2  2  5  2  4  2  2  3  E(T)-C H )] 5  Interpreted  34  1860  53  *1970,1963,1903,1889  5  as i n d i c a t i v e  198  o f the presence o f two d i f f e r e n t  species i n  solution.  * The  higher  suggestive due  vCQ  values  observed when L  = L  Q  (see Table  XVI, p. 174) i s  o f weaker backbonding to the a n c i l l a r y l i g a n d  to c o m p e t i t i v e  i n t h i s complex  backbonding to the Tt-system of the p y r i d y l  ring  i n the  179  L"  ligand.  The  i r data  recorded f o r the  present  complexes, t o g e t h e r with  3 r e s u l t s from  r e l a t e d molybdenum di carbonyl  above, i n a d d i t i o n  t o the  A  H  nmr  'TI - ^ H g  complexes  1  tabulated  r e s u l t s d i s c u s s e d below, provide  strong  evidence f o r f a c i a l l y c o o r d i n a t e d t r i d e n t a t e o r g a n o g a l l a t e l i g a n d s i n * 3 present L MO(C0) (T) -C Hg) complexes. 1 * 3 The s o l u t i o n H nmr s p e c t r a of the L MO(C0) (TI -C Hg) complexes 2  the  3  2  3  3 typified  by the  spectrum of [Me Gapz*0(C HgN)]Mo(C0) (T) ^ H g ) 2  CgDg s o l u t i o n  ( f i g u r e 54),  inequivalent,  thereby p r o v i d i n g  unsymmetric t r i d e n t a t e conformation groups on  of the  gallium  g  clearly  show the  ligand  unsymmetric t r i d e n t a t e  '-GaMe ' grouping.  and  Positional  2  methyl  groups on  gallium  more s u p p o r t i v e evidence f o r a  organogallate  equivalent  complex i n  2  isomerism cannot be  A  mer  render the  hence a s i n g l e t would be ruled  methyl  observed f o r out  be  facial  i n these complexes. l i g a n d would  to  i n the  the  above  3 complexes, s i n c e  substitution  of the T) -CgHg group f o r a CO  in  the  * * L Mo(CO), (L = L , L ) p r e c u r s o r could p o t e n t i a l l y occur at any one of o a q three p o s i t i o n s . It i s c l e a r , however, from the nmr spectrum, t h a t  3  substitution  of the  Substitution  of t h i s  than one  of Ga-Me s i g n a l s  that  set  substitution  sterically, related  'TI - ^ H g  group occurs e x c l u s i v e l y  1  group i n more than one i n the  o p p o s i t e the  a position  one  position.  p o s i t i o n would lead  spectra.  t o more  M o l e c u l a r models  " p y r a z o l y l " moiety  confirmed by  at  indicate  i s most f a v o r e d  X-ray s t r u c t u r a l  determination f o r  complex [ M e G a ( 3 , 5 - M e p z ( 0 C H C H N H ) ] M o ( C 0 ) ( T i - C H ) [ 9 8 ] .  It i s  3  2  noteworthy, however, that  2  i n the  2  2  related  2  2  4  the  7  [Me Ga(3,5-Me pz)(0CH CH NH )]?  ?  ?  ?  ?  C D, s o l u t i o n . C  181  M o ( C 0 ) ( n - C H ) C199], and  [Me Ga(3,5-Me pz)(0CH CH SEt)]Mo(C0) (Ti -C H )  3  2  7  3  7  2  2  2  2  2  7  7  3 [200], the  T)  moiety o c c u p i e s a p o s i t i o n o p p o s i t e the amino n i t r o g e n  -ZJH-J  and the a l k y l  s u l f u r donor atoms, r e s p e c t i v e l y .  3  p r e f e r e n c e of the TI -C-,H-, l i g a n d was  This  positional  r a t i o n a l i z e d using s t r u c t u r a l  trans  3  e f f e c t arguments i . e . , an TI -C^H-, group occupying a p o s i t i o n t r a n s to the pyrazolyl alkyl  n i t r o g e n would  r e s u l t i n c l o s e c o n t a c t s with the amino group or  s u l f i d o group i n the l a t t e r complexes.  In the *H nmr  spectrum o f  3  the l_ Mo(C0) (T) -C Hg) complex i n CDCI3, even though a  2  3  were observed f o r the GaMe on g a l l i u m , the methyl  2  moiety  groups of the NMe  2  to r a t i o n a l i z e .  sharp  moiety  seemingly  T h i s unusual behaviour i s  The presence of only two  bands i n CH C1 2  A p p a r e n t l y some s o r t of c o n f i g u r a t i o n a l  i n v o l v i n g the amino p y r i d y l  groups  remained  cyclohexane f o r t h i s s p e c i e s i n d i c a t e s the presence of only one fac, in solution.  singlets  i n d i c a t i n g i n e q u i v a l e n t methyl  e q u i v a l e n t d i s p l a y i n g only one sharp s i n g l e t . difficult  two  2  or  isomer,  change  moiety of the l i g a n d L~must be o p e r a t i v e t o a  e x p l a i n the nmr  result.  The two a n t i  protons (H^) f o r the C^H^  appeared as two  d o u b l e t s , w h i l e the syn protons (H<0  group  collapsed into a  broad u n r e s o l v e d s i n g l e t r a t h e r than the expected d o u b l e t o f d o u b l e t s f o r a syn proton c o u p l e d to two d i f f e r e n t p r o t o n s , the a n t i unique proton (Hy). triplet an  3  (H ) and the A  The unique proton (ti^) appeared as a broad u n r e s o l v e d  r a t h e r than the more c o m p l i c a t e d t r i p l e t of t r i p l e t s expected f o r  'TI -COH,-' group  i n an unsymmetrical  environment.  182  L J q  L*Rh(CO) ( L * = L , .  5.3.7  a  The and  uninegative, e l e c t r o n i c a l l y  t r i d e n t a t e c y c l o p e n t a d i e n y l , CgHjI,  the analogous s i x - e l e c t r o n donor l i g a n d HB(3,5-Me pz) , are known t o 2  r e a c t with  [Rh(C0) Cl] 2  Me pz) ]Rh(C0) 2  3  2  2  to give the ( r i - C H ) R h ( C 0 ) 5  5  [202,203] complexes r e s p e c t i v e l y .  3  [201], and [HB(3,5-  2  However the  i n t r o d u c t i o n of the s i m i l a r HBpz^ and MeGapz^ l i g a n d systems l e d t o the di n u c l e a r rhodium s p e c i e s [ H B p z ] R h ( p . - C 0 ) 3  C0)  [101].  3  Recently,  2  2  3  attempts a t i s o l a t i n g  [102], and [ M e G a p z ] R h ( u.3  rhodium d i c a r b o n y l  2  2  complexes  i n c o r p o r a t i n g the u n i n e g a t i v e , unsymmetrical, t r i d e n t a t e [Me Gapz2  ( 0 C H C H N R ) ] " (R = H, Me), and the [ M e G a p z ' 0 C H ( C H N ) ] ~ l i g a n d systems 2  2  2  2  2  5  4  r e s u l t e d i n the i s o l a t i o n o f s t a b l e , f o u r - c o o r d i n a t e , square-planar Rh(I) monocarbonyl complexes.  In the complexes, s t r u c t u r a l l y c h a r a c t e r i z e d by  X-ray c r y s t a l l o g r a p h y as [Me Gapz(0CH CH NH )]Rh(C0) [175], and [Me Gapz«2  2  2  2  2  0 C H ( C H N ) ] R h ( C 0 ) [176], the c o o r d i n a t i o n mode o f the t r i d e n t a t e 2  5  4  o r g a n o g a l l a t e l i g a n d s about the Rh(I)  c e n t e r was u n e q u i v o c a l l y  demonstrated to be m e r i d i o n a l . The  r e a c t i o n o f the s t e r i c a l l y more bulky L~ and L~ l i g a n d s with a q [ R h ( C 0 ) C l ] d i m e r i c s p e c i e s a f f o r d e d orange to dark orange c r y s t a l s o f 2  Rh(I)  2  monocarbonyl compounds v i a t r a n s i e n t d i c a r b o n y l  e v i d e n t from i r m o n i t o r i n g  o f the r e a c t i o n mixture  ic  species L Rh(C0)  2  as  d u r i n g the course o f  * the r e a c t i o n s .  A proposed sequence f o r the formation  complexes i s shown i n f i g u r e 55.  The  complexes compare q u i t e well with  those  carbonyl  complexes  (Table XX).  o f the L Rh(C0)  values o b t a i n e d  f o r the present  r e p o r t e d f o r r e l a t e d Rh(I)  mono-  183  [RhCCO)^!],  2Na*L*  L  A  V : CQ  (A)  2 0 6 8 , 1 9 8 9 (cm"')  L (B) P  T H F , I reflux  2085,2025(cm- )(A) ,  O  Rh-  i  2080,2020 N  N  P 0  Rh  CO v  1970 (cm~ )(A) 1  •  co • 1 9 6 8  F i g u r e 55.  Proposed r e a c t i o n  (B)  (B)  sequence f o r the formation of L Rh(CO)  ( L * = L , Lq) complexes. g  (Note: For c l a r i t y , shown).  only the donor s i t e s o f the l i g a n d s are  184  T a b l e XX.  Comparison o f  values i n some LRh(CO) complexes.  _i v  C0^  ^ '  c m  1  n C H  2  C 1  2  Reference  [Me Gapz*0(C H N)CH NMe ]  1970  T h i s work  [Me Gapz«0(C H N)]  1968  T h i s work  2  5  2  9  3  2  2  6  [Me Gapz(OCH CH NR )]  1957 (R = Me)  175  1955 (R = H)  175  [Me Gapz'0CH (C H N)]  1962  176  [Me(Cl)Gapz«0CH (C H N)]  1968  176  2  2  2  2  2  2  5  4  2  The h i g h e r v C Q  5  4  value observed f o r [Me Gapz'0(C HgN)]Rh(C0) (1968 cm" ), i n 1  2  g  comparison to those observed f o r [Me Gapz(0CH CH NR )]Rh(C0) (1957 cm" , 1  2  = Me; 1955 cm" , ring  i n the [Me Gapz*0(C HgN)]~ l i g a n d . 2  2  2  r e s u l t from the n - a c i d i t y  R = H), may well  1  2  g  The s l i g h t l y  1  2  5  3  2  2  of the poor e l e c t r o n - d o n a t i n g a b i l i t y  of the p y r i d y l  higher v C Q  recorded f o r [ M e G a p z » 0 ( C H N ) C H N M e ] R h ( C 0 ) (1970 cm" )  R  value  may be r e f l e c t i v e  of the [ M e G a p z » 0 ( C g H N ) C H N M e ] " 2  3  2  2  ligand. The  nmr spectrum of the L Rh(C0) complex i n CgDg s o l u t i o n  f i g u r e 56 c l e a r l y  q  e s t a b l i s h e d the presence of a square p l a n a r Rh(I)  species i n solution -GaMe  2  ligand  shown i n  f o r t h i s complex.  The sharp s i n g l e t observed f o r the  group i s c o n s i s t e n t with a m e r i d i o n a l l y c o o r d i n a t e d i n the complex.  organogallate  S i m i l a r l y , with the L Rh(C0) compound, sharp a  s i n g l e t s were d i s p l a y e d f o r the '-GaMe ', '-NMe ' and '-CH -' m o i e t i e s i n 2  2  2  185  conformity Rh(I)  with a mer c o n f i g u r a t i o n  monocarbonyl The  of the l i g a n d i n t h i s  compound.  mass spectrum of the L Rh(CO) s p e c i e s a  showed t r a c e  (<0.5%) a t t r i b u t a b l e t o the P-3Me and P-2Me-C0 +  i o n was not observed and the most intense assigned  square-planar  t o the C^H^N* i o n fragments.  the LqRh(CO) s p e c i e s  displayed  +  ions.  signals  The parent ( P ) +  s i g n a l i n the spectrum was  In c o n t r a s t , the mass spectrum of  prominent s i g n a l s due t o the parent ( P ) +  i o n , i n a d d i t i o n t o s i g n a l s c o r r e s p o n d i n g t o the P-Me , P-C0 , and +  P-Me-C0  +  ions.  The mass s p e c t r a l data f o r the [ M e G a p z 0 ( C H N ) ] R h ( C 0 ) 2  complex are compiled that  +  i n Table XXI on p. 187.  s i g n a l s were d i s p l a y e d  presence of GaRh  +  ions.  g  6  I t i s i n t e r e s t i n g t o note  at ~172 i n the mass spectrum, s u g g e s t i n g the  187  Table XXI.  "'"Mass S p e c t r a l  Data of [Me Gapz'0(C H N)]Rh(CO) 9  m/e  f  *  fi  Intensity  Assignment  441  [Me Gapz'0(C H N)Rh(C0)]  426  [MeGapz'0(C H N)Rh(C0)]  413  [Me Gapz-0(C H N)Rh]  398  [MeGapz.0(C H N)Rh]  383  [Gapz'0(C H N)Rh]  316  [Ga'0(C H N)Rh]  228  [MeGa'0(C H N)]  213  [Ga.0(C H N)]  199  [pzHRh(C0)]  172  [GaRh]  145  [H0(C H N)]  115  [Me Ga«0]  103  Rh  2  Q  9  2  Ga  +  6  6  +  +  +  +  +  +  +  16.0 28.9 22.2 100.0 5.7 16.0  +  +  68.0 34.3 10.6 11.0  +  6  +  +  8.3 2.5 12.4  +  H  6  6  g  g  6  6  9  69  Ga.  9  g  6 6  6  6  2  C  69  Q  g  78  A t 120°C. Based on  q  +  92.4 69.9  188  R e a c t i v i t y o f L*Rh(C0) (L* = L , L )  5.3.8  H  a  i)  Mel:  With  r e a c t i o n o f L q Rh(C0) with  The  methyl  i o d i d e r e s u l t e d i n the i s o l a t i o n  o f a f i v e - c o o r d i n a t e Rh(III) a c e t y l complex  [Me GapzO(C HgN)]Rh(COMe)I, 2  9  presumably v i a a s i x - c o o r d i n a t e Rh(III) o x i d a t i v e a d d i t i o n band o f the Rh(I) monocarbonyl  Thus, the cm  -1  slowly  disappeared  upon a d d i t i o n o f Mel,  by two new bands a t 2070 and 1700 cm" Attempts a t i s o l a t i n g the s p e c i e s 2070 cm"  1  failed,  LqRhfCOMen  (  v  :  1  7  1  0  c m _ 1  c o  >  which i n t e n s i f i e d with  responsible  f o r the  replaced  time.  band a t  A proposed r e a c t i o n  o f the Rh(III) a c e t y l s p e c i e s t h a t the  i s shown i n  band a t 2070 cm" , 1  observed i n  the r e a c t i o n i n the above sequence, i s probably  presence o f a l a b i l e  s i x - c o o r d i n a t e Rh(III) product.  v i a t h i s mode [204,205].  d  haiides  Rh(I) and I r ( I )  This six-coordinate Rh(III)  subsequently undergoes a methyl m i g r a t i o n  due t o the  Thus, a l k y l o  are g e n e r a l l y known to o x i d a t i v e l y add to square-planar centers  a t 1968  and was g r a d u a l l y  N u j o l ) were o b t a i n e d .  I t i s postulated  s o l u t i o n during  s t a r t i n g material  and i n s t e a d c r y s t a l s of the Rh(III) a c e t y l complex  sequence f o r the formation f i g u r e 57.  1  intermediate.  intermediate  r e a c t i o n t o form the  f i v e - c o o r d i n a t e R h ( I I I ) complex L Rh(C0Me)I, c o n t a i n i n g a terminal q  group.  The s o l u t i o n i r spectrum o f the Rh(III) a c e t y l product i s o l a t e d i s  interesting  i n t h a t i t shows two bands a t ~2070 cm"  C H C 1 , but i n Nujol 2  2  cm" . 1  acetyl  m u l l , only one strong v C Q  This observation  1  and 1700 cm"  1  in  band was observed a t ~1710  r e v e a l s the presence o f both the s i x - c o o r d i n a t e  R h ( I I I ) , and the f i v e - c o o r d i n a t e R h ( I I I ) a c e t y l s p e c i e s  in solution.  A  190  s i m i l a r o b s e r v a t i o n has been  r e p o r t e d f o r the compound [Ru(ri -COMe)I(CO)-  2 (PMe^L a-alkyl  an TI - a c y l  complex  which e x i s t s  isomer, [ R u ( C O ) ( M e ) I ( P M e ) ] , 2  The  solution  nmr  3  2  i n e q u i l i b r i u m with i t s carbonyl  in solution [206].  spectrum of the p r e s e n t L Rh(C0Me)I complex q  ( f i g u r e 58) i s c o n s i s t e n t with a square pyramidal  about the Rh c e n t e r , s i n c e such a non-planar arrangement methyl for  the  groups on g a l l i u m 'GaMe ' moiety 2  arrangement.  The  inequivalent.  n i c e l y with those r e p o r t e d [17,176,207];  o f the COMe s i g n a l for similar  rhodium a c e t y l  2  2  are c o l l e c t e d parent, P , +  2  +  +  the mass spectrum of t h i s compound, but no P-C0  t r a n s i t i o n metal groups.  compounds  carbonyl  been  related  complex  S i g n a l s c o r r e s p o n d i n g to the  +  from the l a t t e r  singlets  with the above  Q  P-Me , P-Me-I , P-2Me-I , and P-Me-C0  Signals arising  sharp  data f o r the [Me Gapz*0(C HgN)]Rh(COMe)I  i n T a b l e XXII, p. 192.  render the  [175].  2  The mass s p e c t r a l  would  proposed has  f o r the c l o s e l y  [Me Gapz(0CH CH NMe )]Rh(C0Me)I complex 2  arrangement  (7.58x, CDCl-j) compares  and the square pyramidal arrangement  e s t a b l i s h e d by X-ray c r y s t a l l o g r a p h y  o  The presence of two  i n the spectrum i s i n agreement  position  i n CDCU  +  +  ions were observed i n  s i g n a l s were o b s e r v e d .  i o n are u s u a l l y c h a r a c t e r i s t i c  compounds c o n t a i n i n g t e r m i n a l l y bound  of CO  191  192  T a b l e XXII.  +  Mass S p e c t r a l  Data o f [Me Gapz*0(C H N)]Rh(C0Me)I 2  m/e  g  6  Assignment  Intensity  583  [Me Gapz»0(C H N)Rh(C0Me)I]  568  [MeGapz•0(C H N ) R h ( C O M e ) I ]  553  [Gapz«0(C H N)Rh(C0Me)I]  540  [MeGapz'0(C H N)RhMeI]  525  [Gapz'0(C H N)RhMeI]  510  [Gapz'0(C H N)RhI]  456  Cpz0(C H N)RhMeI]  441  [Me Gapz»0(C H N)Rh(C0)]  426  [MeGapz*0(C H N)Rh(C0)]  413  [Me Gapz«0(C H N)Rh]  398  [MeGapz»0(C H N)Rh]  383  [Gapz»0(C H N)Rh  316  [Ga«0(C H N)Rh]  288  [{0(C H N)} ]  247  [0(C H N)Rh]  228  [MeGa»0(C H N)]  213  [Ga»0(C H N)]  199  [pzHRh(C0)]  142  [Mel]  2  9  6  g  9  g  g  g  g  6  g  g  g  g  g  g  6  6  6  +  6  6  g  g  +  8.0 14.3 12.1 100.0 4.9 14.7  6.7  +  6  6  +  +  +  +  +  8.0  +  2  6  +  8.5  +  6  2  0.9  4.9  +  6  g  15.2  9.8  +  6  2  1.3  4.5  +  6  6  g  g  +  6  +  +  +  +  77.2 38.4 9.8 21.9  193  Table XXIII.  +  Mass S p e c t r a l  Data o f [Me Gapz»0(C H N)]Rh(C0Me)I (Cont'd) 2  *  m/e  Q  6  Assignment  127  I  115  [Me Ga*0]  103  Rh  Intensity  8.0  +  4.5  +  2  11.6  +  84  [MeGa]  78  C H  69  Ga  58  Me C0  g  31.7  +  22.3  + 6  55.8  +  72.3  +  2  51 t *  A t 150°C. Based on  69 Ga.  In c o n t r a s t to the mode o f r e a c t i v i t y  d i s c u s s e d above f o r the L^Rh-  (C0) complex, the r e a c t i o n of the L Rh(C0) monocarbonyl complex with Mel a  a  proceeds d i r e c t l y  to the f o r m a t i o n o f what i s thought t o be a s i x -  c o o r d i n a t e R h ( I I I ) o x i d a t i v e t r a n s - a d d i t i o n product L Rh(Me)(I)C0. a interestingly, methyl  such s i x - c o o r d i n a t e a d d i t i o n products c o n t a i n i n g  rhodium carbonyl  (ri-C Me )Rh(C0) 5  acetyl  a-bonded  groups have not been observed e i t h e r as i n t e r m e d i a t e s or as the net  r e a c t i o n products i n the analogous r e a c t i o n o f the r e l a t e d dienyl  Quite  5  2  cyclopenta-  compounds with Mel. For example, r e a c t i o n o f  with Mel proceeds d i r e c t l y t o the  complex a t 50°C [208].  (ri-C Me )Rh(C0)(COMe)I 5  5  Thus, the d i a g n o s t i c t e r m i n a l  v  r n  band a t  194  2060 cm" , observed d u r i n g the r e a c t i o n of L Rh(CO) w i t h M e l , p r o v i d e d a s t r o n g e v i d e n c e f o r the presence of a s i x - c o o r d i n a t e Rh(111) s p e c i e s i n solution. The o n l y c r y s t a l l i n e p r o d u c t i s o l a t e d from the r e a c t i o n of L Rh(CO) a w i t h Mel was i d e n t i f i e d as the s i x - c o o r d i n a t e t r a n s - a d d i t i o n  Rh(III)  d e r i v a t i v e , s i n c e o n l y a s i n g l e band was observed i n the c a r b o n y l s t r e t c h i n g frequency r e g i o n , and no band was seen i n the a c e t y l frequency r e g i o n s of the spectrum ( Nujol).  V C Q  :  2060 c m , C H C 1 ; 2055 c m , - 1  - 1  2  2  These i r r e s u l t s are c o n s i s t e n t w i t h a s i x - c o o r d i n a t e  s p e c i e s f o r m u l a t e d as  stretching  Rh(III)  [Me Gapz'0(C H N)CH NMe ]Rh(Me)(I)CO. 2  5  3  2  2  The room temperature H nmr data f o r the p r e s e n t  L,Rh(Me)(I)C0  X  a  compound d i s p l a y i n g two sharp s i n g l e t s f o r the 'GaMe ' and  'NMe '  2  groupings were c o n s i s t e n t w i t h a f a c i a l  2  c o o r d i n a t i o n of the  organogallate  l i g a n d . A sharp s i n g l e t was observed f o r the Rh-Me resonance a t ~9.3x; s i g n a l s a t t r i b u t a b l e t o a -COMe resonance were not observed i n the spectrum. A mass s p e c t r a l  study of the L . R M M e H D C O complex under  electron  a  impact (EI) c o n d i t i o n s d i d not g i v e a spectrum of any worth p r o b a b l y due to thermal l a b i l i t y or n o n - v o l a t i l i t y of the compound.  However, w i t h the  F a s t Atom Bombardment (FAB) t e c h n i q u e , s i g n a l s c o r r e s p o n d i n g to the [ P - M e ] , [P+H] +  +  and [ P - H ]  +  i o n s were o b s e r v e d .  The [P+H]  and [ P - H ]  +  +  ions  are g e n e r a l l y c h a r a c t e r i s t i c f o r m o l e c u l e s i o n i z e d by the FAB t e c h n i q u e [209].  The presence of s i g n a l s c o r r e s p o n d i n g to the [ P + H ] , and [ P - H ] +  +  195  ions  i n the mass spectrum i s an i n d i r e c t  weight  of t h i s  by elemental  compound at ~590,  analyses  however, t h a t the  data  FAB  technique  (ri-C H )RhC0DSi ( C H ) ( M e O ) 5  2  highly  intractable,  3  oily,  crystals  ii)  g  labile,  compound t h a t i s  and m o i s t u r e - s e n s i t i v e .  c o r r e c t s t r u c t u r e of the present  of the  With  L )  [Me Gapz*0(C H N)CH NMe ]Rh(Me)(I)C0 2  5  3  2  f o r X-ray c r y s t a l  2  structure  determination  I : 2  of m o l e c u l a r  r e s u l t e d i n the  q  a t t r i b u t a b l e t o the  iodine to a CH C1 2  2  solution  immediate disappearance  a p p r o p r i a t e Rh(I)  of L Rh(CO) (L  of the  monocarbonyl  s t a r t i n g material  -1  with  *  V ^ Q band at 2090 cm  concomitant appearance of a new  =  band  -1  cm  complex  i s c u r r e n t l y i n progress,  Addition L ,  It i s noteworthy  rhodium s p e c i e s ,  an o r g a n o m e t a l l i c  thermally  compound have been submitted which  of the s i l y l  the  supported  r e c e n t l y used s u c c e s s f u l l y t o  [210],  3  In o r d e r t o e s t a b l i s h unequivocally,  was  molecular  the f o r m u l a t i o n i s f u r t h e r  (see s e c t i o n 5.2.17, p. 146).  determine the m o l e c u l a r weight 5  and  c o n f i r m a t i o n of the  (L  = L ) , or 2085 f l  * (L  = Lq).  The  new  bands suggest  a weakly-bound CO  l i g a n d t o the  Rh o  metal  c e n t e r i n the p r o d u c t s .  Oxidation  of the  rhodium c e n t e r  (Rh(I)(d  •*• R h ( I I I ) ( d ^ ) ) would l e a d t o weaker backbonding c o n t r i b u t i o n from metal,  a strengthening  of the C-0  bond and  value.  Based on t h i s  observation,  Rh(III)  d i i o d i d e s p e c i e s L R h I ( C 0 ) had  consequently  )  the  an i n c r e a s e d V ^ Q  i t does appear t h a t a s i x - c o o r d i n a t e  * 2  samples of the product  c o u l d not  be  formed, although  isolated.  The  analytically  V ^ Q values  pure  of the  * present sane  L R h I ( C 0 ) s p e c i e s are 2  related Rh(III)  i n good agreement with  d i i o d i d e s (see Table XXIV below).  those  reported f o r  196  Comparison o f v r n  T a b l e XXIV.  values  L  v  i n L R h I ( C 0 ) complexes. ?  c o  (cm  - 1  ) in CH^Cl  Reference  2  [Me Gapz'0(C H N)CH NMe ]  2090  T h i s work  [Me Gapz«0(C H N)]  2085  T h i s work  2090  175  [Me Gapz'0CH (C H N)]  2095  176  [HB(3,5-Me pz) ]  2090  203  [HBpz ] 3  2112  102  CBpz ]  2100  102  [(n-C H )]  2065 (Nujol)  211  [(n-C Me )]  2035  212  2  5  2  g  3  2  2  6  [Me Gapz(0CH CH NR )] 2  2  2  2  2  2  5  2  (R = H, Me)  4  3  4  5  5  5  5  I t i s i n t e r e s t i n g , however, t h a t the borate-containing  species  values  are c o n s i s t e n t l y higher  f o r the analogous c y c l o p e n t a d i e n y l - c o n t a i n i n g This  i s r a t h e r unusual  f o r the p y r a z o l y l g a l l a t e / -  rhodium d i i o d i d e  s i n c e they oppose the t r e n d  f o r complexes i n c o r p o r a t i n g  these l i g a n d s  than the values  [34,53].  previously  reported  species. established  That i s , p y r a z o l y l -  g a l l a t e t r i d e n t a t e l i g a n d s , and the r e l a t e d i s o e l e c t r o n i c t r i d e n t a t e pyrazolylborate  a n i o n s , are g e n e r a l l y  stronger  compared to the t r i d e n t a t e c y c l o p e n t a d i e n y l v„  n  values  i n analogous t r a n s i t i o n metal  net e l e c t r o n  donors  l i g a n d and g i v e r i s e  carbonyl  complexes.  to lower  197  5.4  Summary  The  coordination  (CgHgN)]  2  compounds [Me GaO(C H N)CH NMe ], and 2  have been i s o l a t e d and The  3  2  by  l a t t e r compound i s dimeric  with  gallium  atom assuming a d i s t o r t e d t r i g o n a l bipyramidal prevented d i m e r i z a t i o n  of the  Facial  of the  2  5  [Me Gapz»0(CgH N)]~ 2  6  [ M e G a p z ' 0 ( C H N ) C H N M e ] " (L~)  successful  5  isolation  3  2  of the  which e x i s t i n both f a c and complexes r e p r e s e n t  the  L,M(C0)o  a  transition  metal  (M = Mn,  mer  center,  arrangement suggested by  ligands  and  the  f a c and  although  the  coordination  i n the  monocarbonyl  only  mer  addition  Re)  (L~)  l i g a n d has The  been  versatility  been demonstrated by octahedral  the  complexes  operative  The  t r a n s i t i o n metal  in solution.  The  to possess a  latter  carbonyl  isomers, i n c o r p o r a t i n g  stereochemical  the  tetrahedral  n o n r i g i d i t y of  the  the  square-planar  room temperature *H  nmr  spectral  has  triden-  four-coordinate  to e x p l a i n  data.  a l s o been demonstrated f o r the L", and a f o u r - c o o r d i n a t e s q u a r e - p l a n a r Rh(I)  f o r m a t i o n of the •k ic s p e c i e s , L Rh(CO) (L = L  f a c i l e oxidative  2  tetrahedrally  conformations i n s o l u t i o n .  complex L Ni(NO) i s b e l i e v e d a  complex i n s o l u t i o n must be  Meridional  2  o  t a t e l i g a n d , have been shown to c o - e x i s t nitrosyl  3  complexes.  l i g a n d has  2  first  complexes i n which both the  nickel  Steric  atoms.  coordination  2  each  '[Me GaO(C H N)CH NMe ]'  demonstrated f o r a v a r i e t y of t r a n s i t i o n metal of the  X-ray  geometry.  compound, which c o n s i s t s of monomeric u n i t s c o n t a i n i n g gallium  2  structurally characterized  structure  coordinated  [Me Ga»0-  2  crystal  constraints  analyses.  5  , L ). These compounds undergo a q r e a c t i o n with m o l e c u l a r i o d i n e to give R h ( I I I )  L~ q  198  * di i o d i d e L RhI (C0) s p e c i e s . 2  However, with methyl  undergoes f a c i l e o x i d a t i v e a d d i t i o n , f o l l o w e d  iodide,  L Rh(C0) q  by methyl m i g r a t i o n  to give  a f i v e - c o o r d i n a t e Rh(III) a c e t y l  s p e c i e s L Rh(C0Me)I.  L Rh(C0) o x i d a t i v e l y adds methyl  i o d i d e to give what i s thought to be a  q  six-coordinate reaction  q  Rh(III) t r a n s - a d d i t i o n  product.  In c o n t r a s t ,  s p e c i e s L Rh(Me)(I)C0 as the net a  199  CHAPTER VI  CONCLUSION AND  The  MeGapZg" and  o t h e r hand they  versatility reactivity  has  or a r y l The  l i g a n d s can,  on the  one  display s i g n i f i c a n t l y  hand, s u c c e s s f u l l y  3  anions towards  (L = MeGapz ), 3  the  MeGapz Mo(C0)  anion,  3  3  3  requirement  [MeGapz ]Mo(C0) H, and 3  3  haiides  This  group 14  the  and  ( i i ) a v a r i e t y of t r a n s i t i o n (iii)  on  metal  ( S i , Ge,  Sn)  = Na ,  Et^N ,  (L = MeGapz^).  successful i s o l a t i o n  HAsPh ) s a l t s ,  behaviour.  work by e x p l o r i n g  (i) alkyl  (L = MeGapz^ or HBpz-j) and halide species  more i m p o r t a n t l y ,  different  been demonstrated i n the present  species  species  alkyl  can  of the LMo(C0)  protonating halide  3  b e h a v i o u r of the ri-C^Hg l i g a n d system but,  mimic the the  HBpz  PERSPECTIVES  of the M MeGapz Mo(C0) +  3  of a s t r o n g  the d i s s o c i a t i o n  (M  acid to f u l l y  of the Mo-H  the t r a n s f o r m a t i o n  3  of the  +  +  +  protonate  bond i n the  the  hydride  '[MeGapz ]Mo(C0) Me 3  1  3  2 a-methyl  complex t o the q u a s i - s i x - c o o r d i n a t e  taken t o g e t h e r centre the  suggests a s t r o n g p r e f e r e n c e  i n complexes c o n t a i n i n g the MeGapz  [MeGapz ]Mo(C0) R 3  3  species  compounds t o the LMO(C0) (T) 2  or Ph)  has  and  -COR)  the  3  [MeGapz ]Mo(C0)2 (TI -COMe) 3  f o r s i x - c o o r d i n a t i o n by the ligand.  The  transformation  r e l a t e d [HBpz ]Mo(C0) R 3  complexes  never been d u p l i c a t e d i n the  (L = MeGapz  chemistry  3  3  of the  (R = Me,  or HBpz ; 3  analogous  R =  Mo of Ph) Me  200  (TI-C H )MO(C0) R 5  5  or ( t ) - C M e ) M o ( C 0 ) R  3  5  5  complexes.  3  However, the  lack of  2 success  r e l a t e d t o the its  analogous  been noted  (t)-C H )Mo(C0) Et 5  5  been encountered the  3  study  3  i s probably  and  decomposition  instability,  accompanied by the  p r e v i o u s l y by McCleverty compound [213].  by C u r t i s et a l . who  formation  and W i l k i n s o n f o r the  Similar difficulty  provided  and  3  In f a c t , the pronounced  in purification,  e t h y l e n e has  i n the present  of the a - e t h y l [MeGapz ]Mo(C0) Et p r e c u r s o r  instability  tendency t o decompose.  difficulty of  an rj -COEt product  i n forming  structural  may  have  information f o r  [ H B p z ] M o ( C 0 ) ( i i - C 0 R ) (R = Me, Ph) compounds [65] with no data f o r 2 the c o r r e s p o n d i n g TI -COEt d e r i v a t i v e . In any event, m e c h a n i s t i c s t u d i e s 2 as w e l l as thermodynamic data f o r these LMO(C0) (T) -COR) (L = MeGapz o r 2  3  2  2  HBpz ; R = a l k y l  3  or a r y l ) complexes should p r o v i d e some c l u e s as t o the  3  2 factors  governing  seven-coordinate useful metal  insights  the s t a b i l i t y  of the above TI - a c y l  LMo(C0) R p r e c u r s o r s .  Such i n f o r m a t i o n may  3  i n t o the p o s s i b i l i t y  h y d r i d e t o a c o o r d i n a t e d CO  compounds over  the  provide  of promoting hydride m i g r a t i o n from a  group i n the same metal  t o form  an  2 TI -formyl but the One  complex.  reverse  The  above  r e a c t i o n has  observed  r e a c t i o n i s well e s t a b l i s h e d [96].  of the primary  o b j e c t i v e s of t h i s work was  route t o h e t e r o b i metal l i e  t o develop  a synthetic  complexes i n c o r p o r a t i n g the t r i d e n t a t e  gal l a t e / b o r a t e l i g a n d s i n which d i r e c t to  never been d i r e c t l y  metal-metal  pyrazolyl  bonds are f e a t u r e d  provide  insights  i n t o the s t r u c t u r a l , s p e c t r o s c o p i c and  bonding  properties  of these  compounds.  been  The  3:3:1  T h i s o b j e c t i v e has  s t r u c t u r e demonstrated f o r the  SnPho) complexes  represents the f i r s t  and  largely  [MeGapz ]Mo(C0) X 3  the  3  fulfilled.  (X = CuPPh  only known examples  and  3  or  of t h i s  201  geometry f o r LMo(C0) X  (L = r ) - C H , HBpz  3  5  donor l i g a n d ) type complexes.  5  3  or MeGapz ; X = two 3  It appears from t h i s study, t h a t the  structure  i s most favoured by a s u b s t i t u e n t  ancillary  l i g a n d with  low  and  a single substituent  yet  small  accord  in size,  with the  energy vacant that  orbitals  axial  position.  theoretical predictions As  p a t t e r n which i n c l u d e of a p p r o p r i a t e  i s both a good a donor and  occupying the  Hoffmann et a l . [214].  The  by the  H B p z M o ( C 0 ) B r [ 6 0 ] , and 3  d e r i v a t i v e discussed properties (M  (M  1  or Sn)  1  The  similarity  e l e c t r o n d e f i c i e n t t r a n s i t i o n metals i n high  The  general  reported in this  compounds. pyrazolyl  gallate/borate  of these compounds. (Mo^Mo) dimer has CH N , P ( 0 M e ) 2  reactivity  of the  i n d i c a t e d the f o r m a t i o n well  2  catalytic  3  be that the  In f a c t the  potential  CO  'SnMe Cl' 2  spectroscopic  of the tendency of  Mo-M  1  highly  o x i d a t i o n s t a t e s t o behave  heterobimetal 1 i c compounds Preliminary  of u n i d e n t i f i e d mixture  r e l a t e d homobi metal l i e as u n r e a c t i v e  by C u r t i s et a l . [ 3 8 ] .  of these heterobimetal l i e  e s p e c i a l l y f o r complexes of the  studies  of  s t e r i c bulk of the t r i d e n t a t e  l i g a n d i s an i n h i b i t i n g f a c t o r i n the  been reported  and  is  (Lewis a c i d s ) .  chemical  It may  This  'bromo' d e r i v a t i v e  in  i n t h i s t h e s i s needs f u r t h e r i n v e s t i g a t i o n . regard,  halide  compounds t o those of the  is a reflection  in  and  structure.  f l u x i o n a l b e h a v i o u r of the  = Z r or Hf)  complexes  l i k e main group elements  above f a c t o r s are  s t r u c t u r e by C u r t i s  i n Chapter IV.  of the Mo-M  = S i , Ge  1  a l s o the  3  an  a good n donor,  noted by the former authors, an a x i a l  adoption of a 3:4  3:3:1  symmetry,  of Kubacek et a l . [141],  (even though a good it donor), d e s t a b i l i z e s the 3:3:1 borne out  electron  type LMM'  reactivity  [HBpz ] Mo (C0) 3  2  toward a c e t y l e n e s , Further  studies  2  4  Ph CN , 2  2  i n t o the  complexes i s needed  (where L = MeGapz , or HBpz ;  202  M = T i - H f o r V-Ta; and M  1  this  = Ru, Rh, I r , Pd o r P t ) .  r e g a r d , i s to ensure t h a t the i n i t i a l  the c a t a l y t i c  complex  One obvious problem i n remains i n t a c t  during  cycle.  In Chapter V, the l i g a n d L~ gave the dimer [ M e G a O ( C H N ) ] , and the 2  f a c L M(CO) (M = Mn or Re) complexes. q o 0  the monomer Me GaO(C H N)CH NMe 2  5  3  2  2  9  6  2  In c o n t r a s t , the L l i g a n d a a  yielded  and both the f a c and mer isomers o f  L M(CO).j (M = Mn or Re) complexes. a o  The l a t t e r o c t a h e d r a l  tricarbonyl  complexes are the only examples o f such complexes i n c o r p o r a t i n g the unsymmetric is  tridentate ligand  difficult  i n both the f a c and mer c o n f o r m a t i o n s .  to r a t i o n a l i z e the d i f f e r e n c e i n r e a c t i v i t y  It  toward Mel  observed f o r the L Rh(CO) and L Rh(CO) complexes. I t i s probable, a q however, t h a t the Rh-Me bond i s s t r o n g e r i n the L Rh(Me)(I)CO s p e c i e s a compared  to the LqRh(Me)(I)CO s p e c i e s , hence methyl m i g r a t i o n i s  d i s c o u r a g e d i n the former compound.  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Inorg.  214  APPENDIX I  STEREO DIAGRAMS, BOND LENGTHS AND BOND ANGLES OF SOME OF THE PREPARED DERIVATIVES  Me GaO(C H N)CH NMe 2  5  3  2  2  Intra-annular standard  torsion  deviations  Atoms N(2)-Ga Ga  -0  -0  in  angles  (cleg)  parentheses Value(deg)  -C(2)  41.7(3)  -C(2)-C(1)  -49.5(5)  C(6)-C(1)-C(2)-0  -5.0(7)  C(2)-C(1)-C(6)-N(2)  64.9(6)  Ga 0  -N(2)-C(6)-C(1) -Ga  -N(2)-C(6)  -56.1(5) 9.8(3)  215  Me GaO(C H N)CH NMe , cont'd 2  Bond  5  lengths  standard  Bond Ga -0 Ga - N ( 2 ) Ga - C ( 7 ) Ga - C ( 8 ) 0 -C(2) N(1)-C(1) N(1)-C(5) N(2)-C(6)  -Ga -K(2) -C(7) -Ga -Ga -C(8) -C(7) -Ga -Ga -C(8) -Ga -C(8) -0 -C(2) C(1 )- N ( 1 ) - C ( 5 ) -N(2) -C(6) Ga Ga -N(2) -C(9) -N(2) -C(10) Ga C(6) -N(2) -C(9)  2  (A) w i t h  deviations  estimated  in  parentheses  cor r.  Bond  1.892(3) 2.127(4) 1.950(5) 1.939(6) 1.328(5) 1.325(7) 1.324(13) 1.492(6)  1.897 2.135 1 .956 1 .947 1 .332 1 .329 1 .327 1 .496  N(2)-C(9) N(2)-C(10) C(1)-C(2) C(1)-C(6) C(2)-C(3) C(3)-C(4) C(4)-C(5)  angles  standard  0 0 0 N(2) N(2) C(7) Ga  2  uncorr.  Bond  Bonds  3  (deg)  deviations  with  estimated  in  parentheses  Angle(deg) 95. 110. 108. 107. 107. 124.  116.  116. 107. 112. 111. 109.  24(15) 3(2) 3(2) 3(2) 4(2) 3(3) 8(3) 5(7) 6(3) 4(3) 1(3) 8(4)  Bonds C(6) C(9) NO) NO) C(2) O 0 C(1) C(2) C(3) NO) N(2)  -N(2) - C O O ) -N(2) - C O O ) - C ( 1 )- C ( 2 ) - C O )-C(6) - C O ) -C(6) -C(2) - C O ) -C(2) -C(3) -C(2) -C(3) -C(3) -C(4) -C(4) -C(5) -C(5) -C(4) -C(6) - C O )  r .  uncorr.  cor  1 .477(6) 1.480(6) 1.415(6) 1.496(7) 1.389(6) 1.423(14) 1.353(15)  1 .481 1 .480 1 1 1 1 1  .420 .503  .393 .427 .358  Angle(deg) 107 . 8 ( 4 ) 107 . 7 ( 4 ) 124 . 2 ( 5 ) 1 17 . 2 ( 6 ) 1 16 . 6 ( 5 ) 120 . 3 ( 4 ) 122 . 2 ( 5 ) 1 17 . 4 ( 5 ) 1 17 . 8 ( 7 ) 1 16 . 2 ( 1 2 ) 125 . 7 ( 1 3 ) 1 1 3. 0 ( 4 )  216  [Me GaO(C H N)] 2  Bond l e n g t h s  9  6  (A) w i t h  2  estimated  standard d e v i a t i o n s i n parentheses* Bond Ga -0 Ga -N Ga -C(10) Ga -C(11) Ga -0' 0 -C<8) N -C(1) N -C(9) C(1)-C(2)  Length(A) 1.937(3) 2.211(3) 1 .948(6) 1.945(5) 2.297(3) 1 .336(5) 1.319(5) 1 .362(5) 1 .397(7)  * P r i m e d atoms r e l a t e d by i n v e r s i o n  Bond C(2)-C(3) C(3)-C(4) C(4)-C(5) C(4)-C(9) C(5)-C(6) C(6)-C(7) C(7)-C(8) C(8)-C(9)  through  Length(A) 1.356(7) 1.411(6) 1.400(6) 1.419(5) 1.367(7) 1.403(6) 1.369(5) 1.415(5)  the centre a t  (1/2,1/2,1/2).  217  [Me GaO(C H N)] , cont'd 2  Bond  angles  standard  Bonds 0 -Ga 0 -Ga 0 -Ga 0 -Ga N -Ga N -Ga N -Ga C( 1 0 ) - G a C( 1 0 ) - G a C(11)-Ga Ga -0 Ga -0 C(8)-0 Ga -N Ga -N C( 1 ) - N  g  6  2  (deg) with  deviations  estimated  in  parentheses  Angle(deg)  -N -C(10) -C<11) -0' -C(10) -C(11) -0'  78.37(11) 114.0(2) 113.6(2) 71.29(12) 100.1(2) 98.2(2) 149.65(11) 131.5(3). 92.9(2) 93.2(2) 118.9(2) 108.71(12) 132.3(2) 132.0(3) 109.1(2) 118.9(4)  -c(11)  -0' -0" -C(8) -Ga' -Ga' -CO ) -C(9) -C(9)  Bond  lengths  estimated  Bond  standard  0. 0. 0. 0. 0. 0.  Bond  angles  estimated  Bonds N -CO )-HO ) C(2) - C O ) - H O ) C O )-C(2) -H(2) C(3) -C(2) -H(2) C(2) -C(3) -H(3) C(4) -C(3) -H(3) C(4) -C(5) -H(5) C(6) -C(5) -H(5) C(5) -C(6) -H(6) C(7) -C(6) -H(6) C(6) -C(7) -H(7) C(8) -C(7) -H(7)  N CO) C(2) C(3) C(3) C(5) C(4) C(5) C(6) 0 0 C(7) N N C(4)  involving  Length(A)  C O ) -H( 1 ) C(2) -H(2) C(3) -H(3) C(5) -H(5) C(6) -H(6) C(7) -H(7)  Bonds  81(5)  89(7) 89(5) 88(5) 91 ( 6 ) 92(5)  involving standard  Angle(deg) 115(3) 123(3) 112(5) 128(5) 122(3) 117(3) 122(4) 117(4) 118(4) 120(4) 116(4) 123(4)  Angle(deg)  -C(1)-C(2) -C(2)-C(3) -C(3)-C(4) -C(4)-C(5) -C(4)-C(9) -C(4)-C(9) -C(5)-C(6) -C(6)-C(7) -C(7)-C(8) -C(8)-C(7) -C(8)-C(9) -C(8)-C(9) -C(9)-C(4) -C(9)-C(8) -C(9)-C(8)  hydrogen  atoms  deviations  in  122.4(5) 119.6(4) 120.7(4) 125.5(4) 115.9(4) 118.5(4) 119.7(4) 121.7(4) 120.6(4) 124.4(4) 117.2(3) 118.3(4) 122.6(3)  116.3(3) 121.1(3)  (A) w i t h  parentheses  Bond  Length(A)  C(10)-H(10a) C( 1 0 ) - H ( 1 0 b ) C( 1 0 ) - H ( 1 0 c ) C O 1 )-H( 1 l a ) C O 1 )-H( l i b ) C( 1 1 ) - H ( 1 I c )  hydrogen deviations  atoms in  0 .76(11) 0 .92(7) 0 .65(6) 0 .97(7) 0 .77(8) 1. 0 0 ( 1 2 )  (deg)  with  parentheses  Bonds Ga -COO)-H(lOa) Ga -C(IO)-HOOb) Ga -COO)-H(lOc) H O 0 a ) - C ( 10)-H(10b) HOOa)-C(lO)-HOOc) H(lOb)-COO)-HOOc) Ga - C O D - H O la) Ga - C O D - H O i b ) Ga - C O 1)-H(1 i c ) H( 1 1 a ) - C ( 1 1 ) - H O l b ) H(11a)-C(11)-H(11c) H(11b)-C(11)-H(11c)  Angle(deg) 113(7) 105(4) 97(4) 104(8) 109(8) 128(6) 117(4) 108(7) 122(6) 106(7) 86(6) 116(9)  218  [MeGapz ]Mo(C0) Rh(PPh ) 3  3  3  219  [ M e G a p z ] M o ( C 0 ) R h ( P P h ) , cont'd 3  Bond  lengths  standard  Bond  3  3  (A) w i t h  deviations  in  Length(A)  2  estimated parentheses  Bond  Length(A)  (MeGapzj)Mo(CO) Rh(PPh ) 3  Rh Rh Rh Rh Rh Rh Mo Mo Mo Mo Mo Mo Ga Ga Ga Ga P(l P(1 P(i P(2 P(2 P(2 0(1 0(2 0(3 N(1 N(1 N(2 N(3 N(3 N(4 N(5 N(5 N(6 C(5 C<6 C(B C(9  -Mo -P(1 ) -P(2) -C(1) -C(2) -C(3) -N(1) -N(3) -N(5) -C(1 ) -C(2) -C(3) -N(2) -N(4) -N(6) -C(4) -C(14) -C(20) -C(26) -C(32) -COB) -C(44) -C( 1 ) -C(2) -C(3) -N(2) -C(5) -C(7) -N(4) -C(8) -C(10) -N(6) -C(11) -C(13) -C(6) -C(7) -C(9) -C(10)  2.6066(5) 2.2491(13) 2.2B36(12) 2.845(5) 2.334(5) 2.079(5) 2.249(4) 2.273(4) 2.247(4) 1 .982(5) 1.971(6) 2.034(5) 1.915(4) 1.924(4) 1.927(4) 1.931(5) 1.640(5) 1.634(5) 1.639(5) 1.637(5) 1.636(5) 1.848(5) 1.154(6) 1.175(6) 1.190(5) 1.367(5) 1.327(6) 1.344(6) 1.364(5) 1.328(6) 1.337(6) 1.369(5) 1.326(6) 1.344(6) 1.376(7) 1.355(B) 1.383(7) 1.347(7)  .  3  C( 1 1 C ( 12) C ( 14 C ( 14 C(15 C ( 16 C ( 17 C ( 16 C(20 C(20 C(21 C(22 C(23 C(24 C(26 C(26 C(27 C(28 C(29 C (30 C(32 C(32 C(33 C(34 C(35 C(36 C(38 C(38 C(39 C(40 C (4 1 C(42 C(44 C(44 C(45 C(46 C(47 C(48  2  -C(12) -C(13) -C(15) -C(19) -C(16) -C(17) -C(18) -C(19) -C(21 ) -C(25) -C(22) -C(23) -C(24) -C(25) -C(27) -C(31) -C(28) -C(29) -C(30) -C(31 ) -C(33) -C(37) -C(34) -C(35) -C(36) -C(37) -C(39) -C(43) -C(40) -C(41) -C(42) -C(43) -C(45) -C(49) -C(46) -C(47) -C(4B) -C(49)  1 . 363(7 ) 1 . 357(7 ) 1 .383(7) 1.374(7) 1.411(6) 1.355(9) 1.377(9) 1 .396(6) 1 . 383(7) 1.366(7) 1 .397 (6) 1.346(10) 1 .364 ( 1 1 ) 1.3BB(9) 1 .377(7) 1.393(7 ) 1 .399(8) 1 . 344 ( 9 ) 1.368(9) 1.380(8) 1.361(7) 1.400(7) 1.385(7) 1.353(9) 1.376(9) 1.376(B) 1.366(7) 1.396(7) 1.385(7) 1.369(8) 1.369(9) 1.382(8) 1.383(7) 1.383(7) 1.387(7) 1.365(9) 1.364(8) 1.390(6)  220  [MeGapz ]Mo(C0) Rh(PPh3)2, cont'd 3  Bond angles (deg)  3  with estimated  standard d e v i a t i o n s in parentheses Bonds  Angle(deg)  Bonds  (MeGapZj)Mo(CO)jRh(PPh ) 3  -Rh Mo -P Mo -Rh -P -Rh Mo -c -Rh Mo -c -Rh Mo -c -P P ( 1 ) -Rh -c P( 1 ) - R h -c P(1 ) -Rh -C P ( 1 )- R h P(2) -Rh -c P(2) -Rh -c P(2) -Rh -c C O ) -Rh -c C ( 1 )- R h -c C(2) -Rh -c Rh -Mo -N Rh -Mo -N Rh -Mo -N Rh -Mo -c Rh -Mo -c Rh -Mo -c N( 1 )- M o -N N( 1 ) - M o -N N( 1 )- M o -c N( 1 )- M o -c N ( 1 ) -Mo -c N ( 3 ) -Mo -N N ( 3 ) -Mo -c N ( 3 ) -Mo -c N ( 3 ) -Mo -c N ( 5 ) -Mo -c N ( 5 ) -Mo -c N ( 5 ) -Mo -c C(1 ) -Mo -c C(1 ) -Mo -c C ( 2 ) -Mo -c N(2) -Ga -N N(2) -Ga -N N(2) -Ga -c N(4) -Ga -N N(4 ) -Ga -c N(6) -Ga -c Rh - P ( 1 ) -c Rh - P ( 1 ) -c  1 ) 2) 1) 2) 3) 2) 1 ) 2) 3) 1 ) 2) 3) 2) 3) 3) 1 ) 3) 5) 1 ) 2) 3) 3) 5) 1 ) 2) 3) 5) 1 ) 2) 3) 1 ) 2) 3) 2) 3) 3) 4 ) 6) 4 ) 6) 4 ) 4 ) 14) 20)  135 . 8 0 ( 4 ) 12B . 7 0 ( 4 ) 42 . 3 5 ( 0) 46 . 6 1 ( 3) 49 .91 ( 4) 95 . 2 7 ( 5 ) 172 . 1 7 ( 2 ) 110 . 9 7 ( 4 ) 110 . 9 0 ( 4 ) 87 . 6 4 ( 1 ) 130 . 2 0 ( 3 ) 116 . 6 4 ( 4 ) 61 . 9 ( 2 73 . 8 ( 2 93 . 1 ( 2 1 11. 6 4 ( 1 ) 128 . 3 B ( 0 ) 142 , 5 0 ( 0 ) 75 . 2 7 ( 4) 59 • 4 0 ( 4 ) 51 . 4 5 ( 3 ) 86 . 9 2 ( 4 ) 85 . 6 9 ( 4) 172 . 9 ( 2 96 . 1 ( 2 68 . 2 ( 2 63 • 7 4 ( 4 ) 69 . 7 ( 2 169 . 7 ( 2 63 . 3 ( 2 67.8(2 66 . 7 ( 2 166 . 0 ( 2 86 . 1 ( 2 97 . 5 ( 2 106 . 5 ( 2 103 . 0 ( 2 100 . 5 ( 2 116 . 3 ( 2 9B . 0 ( 2 116 . 5 ( 2 119 . 4 ( 2 114 . 8 ( 2 1 18. 9 ( 2  2  Ga -N(6)-N(5) Ga -N(6)-C(13) N(5)-N(6)-C(13) Rh -C(l)-Mo Rh -C(1)-0(1) Mo -C(1)-0(1) Rh -C(2)-Mo Rh -C(2)-0(2) Mo -C(2)-0(2) Rh -C(3)-Mo Rh -C(3)-0(3) Mo -C(3)-0(3) N( 1 ) - C ( 5 ) - C ( 6 ) C(5)-C(6)-C(7) N(2)-C(7)-C(6) N(3)-C(8)-C(9) C(8)-C(9)-C(10) N(4)-C(10)-C(9) N(5)-C(11)-C(12) C( 1 1 ) - C ( 1 2 ) - C ( 1 3 ) N(6)-C(13)-C(12) P(1)-C(14)-C(15) P( 1 ) - C ( 1 4 ) - C ( 1 9 ) C(15)-C(14)-C(19) C(14)-C(15)-C(16) C(15)-C(16)-C(17) C(16)-C(17)-C(1B) C(17)-C(1B)-C(19) C(14)-C(19)-C(IB) P( 1 ) - C ( 2 0 ) - C ( 2 1 ) P(1 ) - C ( 2 0 ) - C ( 2 5 ) C(21)-C(20)-C(25) C(20)-C(21)-C(22) C(21)-C(22)-C(23) C(22)-C(23)-C(24) C(23)-C(24)-C(25) C(20)-C(25)-C(24) P(1)-C(26)-C(27) P(1)-C(26)-C(31) C(27)-C(26)-C(31) C(26)-C(27)-C(26) C(27)-C(2B)-C(29) C(2B)-C(29)-C(30) C(29)-C(30)-C(31 )  cont i nued•••  Angle(deg)  1 2 0 . 5(3 1 3 0 . 8(3 1 0 B . B(4 6 2 . 37( 122. 5(4 1 7 3 . 9(5 7 4 . 0(2 1 1 7 . 9(4 167. 4(4 78. 6(2 1 2 8 . 1(4 153. 2(4 110. 6(5 105. 5(5 108. 8(5 110. 6(5 1 0 5 . 1(5 109. 3(5 111. 4(4 104. 4(4 109. 5(4 115. 7(4 125.3(4 1 I B .8(5 120. 5(5 120. 0(6 1 1 9 .7 ( 6 120. 7(6 120. 2(5 117. 7(4 122. 9(4 119. 2(5 119. 8(6 1 2 0 . 3(7 120. 0(6 1 2 0 . 5(7 1 2 0 . 0(6 125. 4(4 1 1 7 . 3(4 1 1 7 . 3(5 121 . 1 ( 6 1 2 0 . 8(6 1 1 9 . 0(6 121 . 4 ( 6  221  [MeGapz ]Mo(C0) Rh(PPh ) , 3  3  113. 5(2) 1 0 6 . 5(2) 1 0 3 . 3(2) 9 7 . 5(2) 112. 6(2) 1 2 6 . 2(2)  Rh  - P O ) - C(26) C O O - P O ) -C(20) C(14) - P O ) -C(26) C(20) -P( l) -C(26) Rh - P(2)- C ( 3 2 ) Rh - P(2)- C O B ) Rh - P(2)- C(44 ) C(32) -P(2) - C O B ) C ( 3 2 ) - P ( 2 ) -C(44 ) C O B ) - P ( 2 ) -C(44 ) Mo -N O )-N O ) Mo - N( 1 ) -C(5) N(2)- N O ) -C O ) Ga -N(2)- N O ) Ga -N(2)- C O ) N O ) -N(2)- C O ) Mo "N(3)- N ( 4 ) Mo -N(3)-C O ) N ( 4 ) - N(3)-C O ) Ga -N ( 4 ) - N O ) Ga -N(4>- C O O ) N(3)-N ( 4 ) - C O O ) Mo -N ( 5 ) - N ( 6 ) Mo -N ( 5 ) - C O D N(6)- N(5)- C O D  107. 101 . 104 . 102. 125. 128. 106. 120. 130. 108. 126. 127. 106. 118. 132. 109. 125. 128. 105.  41(15)  1(2) 5(2) 9(2) 6(3) 1(3)  3(4 ) 4(3) 6(4) 9(4)  5(3) 5(3) 0(4)  9(3) 0(3) 1 (4) 3(3) 7(3) 9(4)  Intra-annular standard  3  C(26) - C O D - C O O ) P ( 2 ) - C ( 3 2 ) - C(33) P(2)-C ( 3 2 ) - C(37) C(33) - C ( 3 2 ) - C ( 3 7 ) C ( 3 2 ) -C(33) - C ( 3 4 ) C(33) - C ( 3 4 ) - C ( 3 5 ) C(34) -C(35) -C(36) C(35) - C ( 3 6 ) - C ( 3 7 ) C(32) -C(37) -C(36) P(2)-C ( 3 8 ) - C ( 3 9 ) P(2)-C ( 3 8 ) - C ( 4 3 ) C(39) - C O B ) -C(43) C O S ) -C(39) -C(40) C(39) -C(40) -C(41) C(40) -C(41) -C(42) C(41 ) - C ( 4 2 ) - C ( 4 3 ) C O B ) -C(43) -C(42) P(2)-C ( 4 4 ) - C ( 4 5 ) P(2)-C ( 4 4 ) - C(49) C(45) -C(44) -C(49) C(44) -C(45) -C(46) C(45) -C(46) -C(47) C(46) -C(47) -C(48) C(47) -C(48) -C(49) C(44) -C(49) - C U B )  torsion  deviations  cont'd  2  in  angles (deg) parentheses  Atoms  Value(deg)  (MeGapz,)Mo(CO),Rh(PPh ) 3  2  5(4) 9(5) 3(4) 4(4) 8(5) 3(4)  - N O ) -N(2) N O ) -Mo Mo - N O ) - N O ) -Ga -NO) -NO ) N(4) -Ga N(2) -Ga -N(4 ) - N O ) MO - N O ) -N(4 ) -Ga - N O ) -N(4 ) N O ) -Mo  -38. -3. 52. -47. -3. 43.  -NO )- N O ) N ( 5 ) -Mo Mo - N O ) - N O ) -Ga -NO) -NO ) N(6) -Ga -N(6) -N(5) N(2) -Ga MO - N ( 5 ) - N ( 6 ) -Ga -N(5) -N(6) N O ) -Mo  45. 4(4) - 3 . 9(5) -48. 6(4) 52. 1 (4) - 2 . 2(5) -41 . 7 ( 4 )  N(5) MO N(6) N(4) Mo NO)  -MO -NO) -Ga -Ga -N(5) -Mo  -NO) -N(4) -N(4) -N(6) -N(6) -N(5)  -N(4) -Ga -NO) -N(5) -Ga -N(6)  -42. -3. 55. -52. -2. 45.  7(4) 8(5) 4(4) 8(4) 2(5) 7(4)  1 2 0 . 4(5) 1 2 0 . 0(4) 121 . 5(4 ) 1 1 8 . 5(5) 1 2 0 . 3(5) 120. 7(6) 1 2 0 . 3(5) 120. 0(6) 1 2 0 . 2(6) 1 2 2 . 5(4 )  1 19.6(4 ) 1 1 7 . B(4 ) 120. 7(5) 1 2 0 . 6(5)  1 19.6(5)  120. 4(6) 1 2 0 . 7(5) 1 1 8 . 2(4) 122. 2(4) 1 19.5(5) 1 2 0 . 0(5) 1 2 0 . 0(5) 1 2 0 . 1(5) 1 2 0 . 2(6) 1 2 0 . 2(5)  222  [MeGapz ]Mo(C0) Cii(PPh ) 3  3  3  223  [MeGapz,]Mo(CO),Cu(PPM  224  [MeGapz ]Mo(C0) Cu(PPh ), cont'd 3  Bond  lengths  standard  Bond  3  3  (A) w i t h  deviations  estimated  in  Length(A)  parentheses  Bond  Length(A)  (MeGapzj)Mo(CO) Cu(PPhj) 3  Mo Mo Mo Mo Mo Mo Mo Mo' Mo' Mo' Mo' Mo' Mo' Mo' Ga Ga Ga Ga Ga' Ga' Ga' Ga" Cu Cu Cu Cu Cu' Cu' Cu' Cu' P P P P' P' P'  -Cu -N( 1 ) -NO) -N(5) -C(1 ) -C(2) -C(3) -Cu'  -N(1')  -N(3') -N(5')  -C(1' )  -C(2') -C(3') -NO) -N(4)  -N(6)  -C(4) -N(2') -N(4')  -N(6')  -C(4') -P -C( 1 ) -C(2) -C(3) -P' -C(1') -C(2') -C(3') -C(14) -C(20) -C(26) -C(14') -C(20') -C(26')  2.5041(B) 2.254(5) 2.257(4) 2.246(4) 1.966(7) 1.958(7) 1.971(7) 2.5216(8) 2.253(5) 2.273(5) 2.257(5) 1.958(7) 1.970(7) 1.980(7) 1.922(5) 1.929(5) 1.917(5) 1.943(6) 1.924(5) 1.926(5) 1.92B(5) 1.935(6) 2.193(2) 2.259(6) 2.274(7) 2.419(6) 2.199(2) 2.410(6) 2.322(6) 2.234(6) 1.819(6) 1.826(6) 1.633(6)  1.811(6)  0(2) - C ( 2 ) 0(3) - C ( 3 )  1.812(6) 1.817(6) 1.160(7) 1.174(7) 1.159(6)  0(2')-C(2' ) 0(3')-C(3') N(1 )- N O ) N(1 )- C ( 5 ) N(2) -C(7) N(3) -N(4) N(3) -C(B) N(4 ) - C ( 1 0 )  1.164(7) 1.155(6) 1.373(6) 1.332(7) 1.347(7) 1.367(6) 1.345(7) 1.347(7)  0(1 )- C ( 1 ) 0( 1 ') - c ( r )  1.169(6)  N 3' ) - N ( 4 ' ) N 3' ) - C ( 8 ' ) N 4' ) - C ( 1 0 ' ) N 5' ) - N ( 6 ' ) N 5' ) - C ( 1 1 ' ) N 6' ) - C ( 1 3 ' ) C 5 ) - C(6) C 6 ) - C(7) C 8 ) - C(9) C 9 ) - C(10) C 11 )- C ( 1 2 ) C 12) - C ( 1 3 ) C 14) - C ( 1 5 ) C 14 ) - C ( 1 9 ) C 15) - C ( 1 6 ) C 16) - C ( 1 7 ) C 17) - C ( 1 8 )  c 18) - C ( 1 9 ) c 20) - C ( 2 1 ) c 20) - C ( 2 5 ) c 21 ) - C ( 2 2 ) c 22) - C ( 2 3 ) c 23) - C ( 2 4 ) c 24) - C ( 2 5 ) c 26) - C ( 2 7 ) c 26) - C O D c 27) - C ( 2 8 ) c 28) - C ( 2 9 ) c 29) - C O O ) c 30) - C O D c< 5 ' ) - C ( 6 ' ) c< 6 ' ) - C ( 7 ' ) ci 8 ' ) - C O ' ) c( 9 ' ) - C O O ' ) c 11 ') - C ( 1 2 ' ) c< 1 2 ' ) - C ( 1 3 ' ) c< 1 4 ' ) - C ( 1 5 ' ) c< 1 4 ' ) - C ( l 9 ' )  C( 15* ) - C ( 1 6 ' ) c< 16' ) - C ( 1 7 ' ) c< 1 7 ' ) - C O B ' ) c< 1 6 ' ) - C ( 1 9 ' ) c 20' ) - C ( 2 T ) c 20' ) - C ( 2 5 ' ) c 21 ' ) - C ( 2 2 ' ) c 22' ) - C ( 2 3 ' ) c 23' ) - C ( 2 4 ' ) c 24 ' ) - C ( 2 5 ' )  continued  /.  1 . 3 5 8( 6 ) 1 . 3 2 3( 7 ) 1 . 3 4 8( 7 ) 1 . 3 6 6( 6 ) 1 . 3 3 6( 7 ) 1 . 3 3 9( 7 ) 1 . 3 7 5( 9 ) 1 . 3 6 6( 9 ) 1 . 3 6 7 B) 1 .361 8) 1 . 3 8 5 B) 1.353 8) 1.383 7) 1 . 3 7 2 7) 1.379 8) 1 . 3 7 8 9) 1.361 8) 1 . 3 7 6 B) 1 . 3 7 8 7) 1.378 7) 1 . 3 7 5 B) 1 . 3 7 4 9) 1 . 3 B 3 9) 1 . 3 8 3 9) 1 . 3 8 3 8) 1 . 3 6 5 8) 1 .371 9) 1 .371 10) 1 . 3 4 1 10) 1 . 3 7 8 9) 1 .361 8) 1 . 3 7 5 8) 1 . 3 9 5 8) 1.347 8) 1 . 3 6 6 9) 1 . 3 4 6 9) 1 . 3 8 B B) 1 . 3 7 4 7) 1.381 8) 1 . 3 7 5 B) 1 . 3 5 9 6) 1 . 3 8 6 6) 1 . 3 7 4 B) 1 . 3 6 4 8) 1 . 3 9 2 8) 1 . 3 5 4 9) 1 . 3 6 1 10) 1 . 3 9 1 9)  225  [ M e G a p z ] M o ( C 0 ) C u ( P P h ) , cont'd 3  N(5)-N(6) N(5)-C(11) N(6)-C(13) N(1')-N(2') N(1' )-C(5') N(2')-C(7')  3  1.371(6) 1 . 334 ( 7 ) 1 .343(7 ) 1.364(6) 1 .323(7 ) 1.316(7) Bond  angles  standard  Bonds  3  C(26')-C(27') C(26')-C(3D C(27')-C(2B') C(2B*)-C(29") C(29')-C(30') C(30')-C(31')  (deg) with  deviations  in  Angle(deg)  1.365(7) 1 .385(B) 1.384(8) 1.358(8) 1.365(9) 1 . 364 (6 )  estimated parentheses  Bonds  Angle(deg)  (MeGapz j ) M o ( C O ) C u ( P P h j ) 3  -Mo Cu -Mo Cu -Mo Cu -Mo Cu -Mo Cu -Mo Cu N( 1 )- M o N( 1 )- M o N O ) -Mo N O ) -Mo N O ) -Mo N ( 3 ) -Mo N ( 3 ) -Mo N ( 3 ) -Mo N ( 3 ) -Mo N ( 5 ) -Mo N ( 5 ) -Mo N ( 5 ) -Mo C O ) -Mo C O ) -Mo C ( 2 ) -Mo Cu' -Mo' Cu' -Mo' Cu' -Mo' C u ' -Mo* Cu* - M o ' Cu' -Mo' N O ' )-Mo' N O ' )-Mo' N O ' )-M0' N O ' )-M0' N O ' )-Mo' N ( 3 ' )-Mo' N(3' )-M0' N ( 3 ' )-Mo' N ( 3 ' )-Mo' N ( 5 ' )-Mo' N ( 5 ' )-Mo' N ( 5 ' )-Mo' C O ' )-Mo' C O ' )-Mo' C(2' )-M0' N(2) -Ga  -NO ) -N(3) -N(5) -CO ) -C(2) -C(3) -N(3) -N(5) -CO ) -C(2) -C(3) -N(5) -CO ) -C(2) -C(3) -CO ) -C(2) -C(3) -C(2) -C(3) -C(3) -NO" ) -N(3') -N(5*) -CO ') -C(2*) -C(3') -N(3') -N(5') -CO * ) -C(2*) -C(3' ) -N(5' ) -CO ') -C(2') -C(3*) -CO ') -C(2') -C(3') -C(2') -C(3') -C(3*) -N(4)  130. 5 2 0 131 . 4 6 ( 123. 5 5 0 59. 3(2 59. 8(2 6 4 . 1 (2 8 4 . 1(2 86. 4(2 170. 0(2 86. 6(2 86. 7(2] 65. 3(2 87. 0(2 168. 5(2 90. 2(2 86. 4(2 85. 4(2 172. 1(2 99. 4(3 97. 6(3 98. 3(3 1 2 5 . 14( 126. 36(1 132. 66(1 63. 7(2 60. 6(2 56. 0(2 84. 5(2 65. 2(2 171 . 1 ( 2 6 9 . 1 (2 87. 2(2 65. 0(2 90. 4(2 170. 8(2 86. 8(2 6 7 . 1 (2 88. 0(2 169. 3(2 9 5 . 1 (2 99. 8(2 99. 4(2 100. 2(2  2) 2) 2)  1 ) 2) 3)  continued  N(5)-N(6)-C(13) Mo' - N O ' ) - N ( 2 ' ) Mo' - N O ' ) - C ( 5 ' ) N(2')-N(1')-C(5') Ga' -N(2')-N(1') Ga' -N(2')-C(7') N O ' )-N(2' )-C(7' ) Mo' -N(3')-N(4') Mo' -N(3')-C(8') N(4')-N(3')-C(8') Ga' -N(4')-N(3*) Ga' -N(4*)-CO0') N(3' )-N(4' ) - C O 0 ' ) Mo' -N(5')-N(6*) Mo* - N ( 5 * ) - C ( 1 1 *) N(6*)-N(5*)-C(11*) Ga' -N(6')-N(5') Ga' -N(6')-C(13') N(5')-N(6')-C(13') Mo -C(D-Cu Mo -C(I)-OO) Cu -CO)-O(I) Mo -C(2)-Cu Mo -C(2)-0(2) Cu -C(2)-0(2) Mo -C(3)-Cu Mo -C(3)-0(3) Cu -C(3)-0(3) NO )-C(5)-C(6) C(5)-C(6)-C(7) N(2)-C(7)-C(6) N(3)-C(8)-C(9) C(6)-C(9)-CO0) N(4)-C(10)-C(9) N(5)-C(11)-C(12) CO 1 )-C02)-C03) N(6)-C(13)-C(12) P -C(14)-C05) P -C(14)-C(19) C(15)-C(14)-C09) C( 1 4 ) - C ( 1 5 ) - C ( 1 6 ) C ( 1 5 ) - C ( 1 6 ) - C ( 17) C06)-C07)-C(18) /.  10B. 5 ( 5 ) 126. 4(3) 128. 3(4) 105. 3(5) 120. 0(4) 130. 7(4) 109. 3(5) 126. 0(4) 127. 4(4) 106. 5(5) 120. 1 (4) 131 . 3 ( 5 ) 108. 3(5) 127. 0(4) 127. 6(4) 105. 4(5) 119. 2(4) 132. 0(5) 108. 7(5) 72. 3(2) 170. 6(5) 116. 9(4) 7 2 . 1 (2) 170. 6(6) 117. 2(5) 68. 7(2) 172. 6(6) 118. 6(5) 111. 8(6) 104. 4(6) 109. 4(6) 110. 9(6) 104. 9 ( 5 ) 109. 8(5) 111. 7(6) 103. 7(5) 110. 5(5) 119. 2(5) 121 . 9 ( 4 ) 118. 9(6) 119. 1 (6) 121 . 1 ( 6 ) 119. 7(6)  226  [MeGapz ]Mo(C0) Cu(PPh ), 3  -N(6) N(2)-Ga N(2)-Ga -C(4) -N(6) N(4 )-Ga -C(4) N(4 )-Ga N(6)-Ga -C(4) N(2' ) - G a * - N ( 4 ' ) N(2' )-Ga' - N ( 6 ' ) N(2')-Ga * - C ( 4 ' ) N(4')-Ga' - N ( 6 ' ) N(4')-Ga* - C ( 4 ' ) N(6')-Ga' -C(4') Mo -Cu -P Mo -Cu -CO ) Mo -Cu -C(2) Mo -Cu -C(3) P -Cu -C( 1 ) P -Cu -C(2) P -Cu -C(3) C(1 ) - C u -C(2) C( 1 H C u - C ( 3 ) C(2)-Cu -C(3) Mo' - C u * - P ' Mo' - C u ' - C O ' ) Mo' - C u ' - C ( 2 ' ) Mo' - C u ' - C ( 3 ' ) P' -Cu' -CO ') P' -Cu' -C(2*) P' -Cu' -C(3') C( 1 ' ) - C u ' - C ( 2 ' ) C( 1 ' ) - C u ' - C ( 3 * ) C(2')-Cu' -C(3') Cu -P -C04) Cu -P -C(20) Cu -P -C(26) C(14)-P -C(20) C(14)-P -C(26) C(20)-P -C(26) Cu' - P ' - C O 4' ) Cu* - P ' -C(20') Cu' -P* -C(26') C(14')-P* -C(20') C(14*)-P' -C(26') C(20')-P' -C(26*) Mo - N O )-N(2) Mo - N O )-C(5) N(2)-NO )-C(5) Ga -N(2)-NO ) Ga -N(2)-C(7) N(1 ) - N ( 2 ) - C ( 7 ) Mo - N ( 3 ) - N ( 4 ) Mo - N ( 3 ) - C ( B ) N(4)-N(3) -C(6) Ga -N(4)-N(3) Ga -N(4)-COO) N(3)-N(4) -COO) Mo -N(5) -N(6) Mo -N(5)- c o n N(6)-N(5) - C O D Ga -N(6) -N(5) Ga -N(6)- C 0 3 )  101 . 7 ( 2 ) 116. 7(3) 100. 3(2) 115. 7(3) 119. 1 ( 3 ) 100. 0(2) 101 . 3 ( 2 ) 117. 1(3) 99. 7(2) 116. 4 ( 3 ) 1 1 9 . 1(3) 177. 0 2 ( 6 ) 48. 4(2) 4 6 . 1(2) 47. 2(2) 132. 7(2) 129. 0(2) 134. 7(2) 82. 6(2) 78. 6(2) 7B. 5(2) 175. 17(6) 4 6 . 72(15) 47. 8(2) 48. 8(2) 128. 8(2) 132. 0(2) 135. 2(2) 75. 5(2) 80. B(2) 82. 8(2) 113. 0(2) 114. 9(2) 113. 3(2) 102. 7(2) 107. 3(3) 104. 7(3) 119. 1 ( 2 ) 111. 3(2) 111. 1 (2) 104. 3(3) 104. 6(3) 105.5(3) 125.9(3) 128. 3(4) 105. 7(5) 119. 7 ( 4 ) 131 . 5 ( 5 ) 108. 7(5) 125. 9(3) 127. 8(4) 106. 2(4) 119. 5 ( 3 ) 132. 2(4) 106. 2(5) 127. 1(3) 127. 2(4) 105. 6(4) 118. 6(3) 1 3 2 . 9(4)  3  3  cont'd  C(17)-C(18)-C(19) C(14)-C(19)-C(18) P -C(20)-C(21) P -C(20)-C(25) C(21 ) - C ( 2 0 ) - C ( 2 5 ) C(20)-C(21)-C(22) C(21 ) - C ( 2 2 ) - C ( 2 3 ) C(22)-C(23)-C(24) C(23)-C(24)-C(25) C(20)-C(25)-C(24) P -C(26)-C(27) P -C(26)-C(3D C(27)-C(26)-C(3D C(26)-C(27)-C(26) C(27)-C(26)-C(29) C(28)-C(29)-C(30) C(29)-C(30)-C(31 ) C(26)-C(31)-C(30) Mo' - C O ' )-Cu* Mo' - C O ' ) - 0 O ' ) Cu' - C O * ) - 0 O ' ) Mo' -C(2')-Cu* Mo' -C(2')-0(2*) Cu* - C ( 2 ' ) - 0 ( 2 ' ) Mo* - C ( 3 * ) - C u * Mo' -C(3*)-0(3*) Cu* - C ( 3 ' ) - 0 ( 3 * ) N( 1 * ) - C ( 5 ' ) - C ( 6 * ) C(5*)-C(6')-C(7*) N(2')-C(7*)-C(6') N(3')-C(B')-C(9' ) C(6' )-C(9' ) - C O 0 ' ) N(4' ) - C O 0 ' )-C(9' ) N(5')-C(11')-C(12') C O T )-C( 12' )-C(l3' ) N(6')-C(l3')-C(12*) P* -C(14*)-C(15') P' -C(14')-C(19') C(15' ) - C d 4 ' ) - C ( l 9 ' ) C(14')-C(15')-C(l6') C(15' )-C(16' ) - C 0 7 * ) C(16*)-C(17*)-C(l6* ) C(17* ) - C O B * )-C(l9' )  C(14* )-C(19')-C(l6') P' -C(20* ) - C ( 2 T ) P' -C(20*)-C(25*) C(21 * ) - C ( 2 0 ' ) - C ( 2 5 * ) C(20')-C(2l')-C(22*) C(21')-C(22')-C(23*) C(22*)-C(23')-C(24*) C(23*)-C(24*)-C(25') C(20*)-C(25*)-C(24') P' -C(26*)-C(27*) P* -C(26')-C(3l ') C(27')-C(26')-C(3l ') C(26')-C(27')-C(28' ) C(27')-C(28*)-C(29') C(2B')-C(29')-C(30') C(29")-C(30*)-C(31*) C(26")-C(3l')-C(30')  119. 4 121 . 8 123. 6 116. 7 119. 6 120. 6 119. B 120. 0 120. 0 119. 9 1 16. 5 123. 3  6 6  118. 2  6 6 7 7 7 6 2 5  120. 120. 118. 122. 119. 69. 171 .  6 7 2 3 9 6 5 118. 4 71 . 4 170. 7 117. 6 73. 2 169. 6 117. 1 112. 3 103. 5 109. 7 111. 0 103. 6 110. 2 111. 4 104 . 7 109. 8 119. 4 121 . 7 11B. 9 120. 3 119. 7 120. 7 119. 7 120. 7 119. 0 122. 1 1 I B .9 121 . 3 118. 4 122. 0 119. 5 119. 8 123. 8 117. 8 1 IB4 . 120. 4 120. 5 120. 0 120. 3 120. 3  4 5 6 6 6 6 6 6  5 5  4 2 5 5 2 5 4 5 5 6 6 5 6 6 6 6 5 5 5 6 6 6 6 6 5  5  6 6 6 7 7 6  5 5 5 5  6 6 6 6  227  [MeGapz ]Mo(CO) Cu(PPh ), cont'd 3  3  Intra-annular standard  3  torsion  deviations  in  angles  (deg)  parentheses  Atoms  Value(deg)  (MeGapzj)Mo(CO) Cu(PPh,) 3  - N( 1 ) -N ( 2 ) N ( 3 ) -Mo Mo - N ( 1 )N ( 2 > - Ga -N ( 2 ) - N(1 ) N(4 ) -Ga N(2) -Ga -N ( 4 ) - N ( 3 ) Mo - N ( 3 ) - N ( 4 ) - Ga -N ( 3 ) - N ( 4 ) N(1 )- M o  42. 9(4) 2. 6 ( 5 ) - 5 3 . 3(4) 47. 5(4) 7. 9(6) -49.1(4)  N(5) Mo N(6) N(2) Mo N( 1  -Mo -N(1 ) -N ( 2 ) - N ( 1 ) - N ( 2 ) ~ Ga -Ga - N ( 2 ) - N( 1 ) -Ga -N ( 6 ) - N ( 5 ) - N ( 5 ) - N ( 6 ) - Ga -Mo -N ( 5 ) - N ( 6 ) )  -42. 2. 49. -53. 5. 38.  7(4) 6(5) 6(4) 9(4) 4(5) 4(4)  N(5) Mo N(6) N(4) Mo N(3)  -Mo -N ( 3 ) - N ( 4 ) - N ( 5 ) - N ( 6 ) - Ga -Ga -N(4 ) -N ( 3 ) -Ga -N ( 6 ) - N ( 5 ) - N ( 3 ) - N(4 ) -Ga -Mo -N ( 5 ) - N(6)  37. 5. -56. 48. 7. -46.  7(4) 4(5) 6(4) 9(4) 9(6) 0(4)  N(3' Mo' N(4' N(2' Mo' N O '  )-Mo' -N( 1 -N(3') -N(4' )-Ga' -N(2' )-Ga' -N(4' - N ( T )-N(2' )-Mo' - N ( 3 '  *) - N ( 2 ' ) )-Ga' )-N(1') )-N(3' ) )-Ga' )-N(4')  41 . 0 ( 4 ) 5. 3(6) -53.6(4) 48. 3(4) 3. 8 ( 6 ) - 4 6 . 3(4)  N(5' Mo' N(6' N(2' Mo' N O '  )-Mo' -N(5*) )-Ga' )-Ga' -N(1') )-Mo'  -N(1 ' -N(6' -N(2' -N(6' -N(2* -N(5*  )-N(2') )-Ga' )-N(1') )-N(5') )-Ga' )-N(6')  -44 . 4(4) 1 .7(6) 48. 5(4) -51 . 3 ( 4 ) 3. 8(6) 41 . 4 ( 4 )  N ( 5 ' )-Mo' Mo' - N ( 5 ' ) N(6' )-Ga' N(4 ' ) - G a ' Mo' - N ( 3 ' ) N(3')-Mo'  -N(3* -N(6' -N(4* -N(6' -N(4' -N(5'  )-N(4') )-Ga' )-N(3') )-N(5' ) )-Ga' )-N(6')  39. 3(4) 1 .7(6) - 5 5 . 1 (4) 51. 0 ( 4 ) 5. 3(6) - 4 3 . 5(4)  228  [MeGapz,]Mo(CO),SnPh  Bond  lengths  standard  (A) with  deviations  Bond  Length(A)  Sn -Mo Sn -C(14) Sn -C(20) Sn -C(26) Mo -NO ) Mo -N(3) Mo -N(5) Mo -C( 1 ) Mo -C(2) Mo -C(3) -N(2) Ga Ga -N(4) Ga -N(6) Ga -C(4) 0( 1 )- C ( 1 ) 0(2) - C ( 2 ) 0(3) - C ( 3 ) N O ) -N(2) N( 1 )- C ( 5 ) N(2) - C ( 7 ) N(3) -N(4) N(3) - C ( B ) N(4) - C ( 1 0 ) N(5) -N(6) N ( 5 ) -C(11)  2.B579(3) 2.157(3) 2.166(3) 2.151(3) 2.244(2) 2.239(2) 2.244(2) 1.967(3) 2.000(3) 1.994(3) 1.923(3) 1.920(3) 1.931(3) 1.943(4) 1.154(4) 1.139(3) 1.14K3) 1 . 367 (3) 1 . 327(4 ) 1 .343(4 ) 1.364(3) 1 .331(4) 1 .343(4 ) 1 .356(3) 1.344(4)  estimated  in parentheses Bond N(6)-C(13) C(5)-C(6) C(6)-C(7) C(B)-C(9) C(9)-C(10) C( 1 1 )-C(12) C( 1 2 ) - C ( 1 3 ) C(14)-C(15) C( 14)-C(19) C( 1 5 ) - C ( 1 6 ) C( 1 6 ) - C ( 1 7 ) C( 1 7 ) - C ( I B ) C( 18)-C(19) C(20)-C(21) C(20)-C(25) C(21)-C(22) C(22)-C(23) C(23)-C(24) C(24)-C(25) C(26)-C(27) C(26)-C(31 ) C(27)-C(2B) C(2B)-C(29) C(29)-C(30) C(30)-C(31)  LengthU)  1 .346(4) 1 . 377( 5) 1 . 370(6) 1 . 360(5) 1 .356(5) 1 .380(5) 1 .362(6) 1.364(5) 1 .365(4) 1 .386(5) 1 .362(6) 1 .379(6) l .382(5) 1 .372(5) 1 .380(5) 1.364(5) 1.386(6) 1 .351(6) 1.390(5) 1.380(5) 1.388(4) 1 . 376(5) 1 .384(5) 1 .372(5) 1 .386(5)  229  [MeGapZo]Mo(CO)oSnPho, cont'd  Bond a n g l e s standard  Bonds  Mo -Sn -C(14 ) Mo -Sn -C(20) Mo -Sn -C(26) C( 1 4 ) - S n -C(20) C( 1 4 ) - S n - C ( 2 6 ) C(20)-Sn -C(26) Sn -Mo -N( 1 ) Sn -Mo -N(3) Sn -Mo -N(5) Sn -Mo -C( 1 ) Sn -Mo -C(2) Sn -Mo -C(3) N(1)-Mo -N(3 ) N(1)-Mo -N(5) N(1)-Mo -C( 1 ) N(1)-Mo -C(2) N(1)-Mo -C(3) N(3)-Mo -N(5) N(3)-Mo -C( 1 ) N(3)-Mo -C(2) N(3)-Mo -C(3) N(5)-Mo -C( 1 ) N(5)-Mo -C(2) N(5)-Mo -C(3) C(1)-Mo -C(2) C(1)-Mo -C(3) C(2)-Mo -C(3) N(2)-Ga -N(4 ) N(2)-Ga -N(6) N(2)-Ga -C(4) N(4)-Ga -N(6) N(4)-Ga -C(4) N(6)-Ga -C(4 ) Mo -N(1) -N(2) Mo -N(1) -C(5) N ( 2 ) - N ( 1 ) -C( 5) Ga - N ( 2 ) -N( 1 ) Ga -N(2)-C(7) N(1)-N(2) -C(7) Mo - N ( 3 ) -N( 4 ) Mo -N(3) -C(8) N(4)-N(3) -C(8) Ga -N(4) -N(3) Ga -N(4) -C(10)  (deg) w i t h  deviations  Angle(deg)  112. 50( 8) 113. 69( B) 113. 00( 8) 105. 57( 1 1 ) 1 0 6 .01 ( 1 1 ) 105. 38( 1 1 ) 129. 32( 6) 127. 95( 6) 126. 83( 7) 6 7 . 22( 9) 6 7 . 57( 6) 67. 82( B) 8 5 . 61 ( 9 ) 8 6 . 02( 9) 1 6 3 .4 6 ( 1 1 ) 8 2 . 7 2 ( 10) 8 3 . 3 8 ( 10) 8 6 . 42( 9) 8 2 . 32( 10) 1 64 .4 7 ( 1 0 ) 8 2 . 7 2 ( 10) 81 . 9 8 ( 1 1 ) 8 2 . 5 9 ( 10) 1 6 5 .3 5 ( 10) 1 0 6 .8 4 ( 1 2 ) 1 0 6 . 1 5 ( 12) 1 0 5 . 9 7 ( 12) 9 9 . 99( 1 1 ) 99. 47{ 1 1 ) 117. 9(2 100. 00( 1 1 ) 117. 8(2 118. 1(2 125. 0(2 128. 4(2 106. 5(2 120. 7(2 1 3 0 .6 ( 2 108. 6(3 125. 0(2 128. 3(2 1 0 6 .7 ( 2 120. 8 ( 2 131. 0(2  in  estimated parentheses  Bonds  N(3)- N(4)-C(10) Mo -N ( 5 ) - N ( 6 ) Mo -N ( 5 ) - C ( 1 1 ) N(6)- N(5)-C(11 ) Ga -N ( 6 ) - N ( 5 ) Ga -N ( 6 ) - C ( 1 3 ) N(5)- N(6)-C(13) Mo -C(1)-0(1) Mo -C ( 2 ) - 0 ( 2 ) Mo -C ( 3 ) - 0 ( 3 ) N( 1 ) -C ( 5 ) - C ( 6 ) C(5)- C(6)-C(7) N(2)- C(7)-C(6) N(3)- C(B)-C(9) C(8)- C(9)-C(10) N(4)- C(10)-C(9) N(5)- C(11)-C(12) C( 1 1 -) C ( 1 2 ) - C ( 1 3 ) N ( 6 ) - C( 1 3 ) - C ( 1 2 ) Sn -C(14)-C(15) Sn -C ( 1 4 ) - C ( 1 9 ) C( 15) - C ( 1 4 ) - C ( 1 9 ) C( 1 4 ) - C ( 1 5 ) - C ( 1 6 ) C( 1 5 ) - C ( 1 6 ) - C ( 1 7 ) C( 1 6 )- C ( 1 7 ) - C ( 1 B ) C( 1 7 ) - C ( 1 8 ) - C ( 1 9 ) C(14) - C ( 1 9 ) - C ( 1 8 ) Sn -C ( 2 0 ) - C ( 2 1 ) Sn -C ( 2 0 ) - C ( 2 5 ) C(21 ) - C ( 2 0 ) - C ( 2 5 ) C(20) - C ( 2 1 ) - C ( 2 2 ) C(21 ) - C ( 2 2 ) - C ( 2 3 ) C(22) - C ( 2 3 ) - C ( 2 4 ) C(23) - C ( 2 4 ) - C ( 2 5 ) C(20) - C ( 2 5 ) - C ( 2 4 ) Sn -C ( 2 6 ) - C ( 2 7 ) Sn -C(26)-C(31 ) C(27) -C(26)-C(31) C(26) - C ( 2 7 ) - C ( 2 8 ) C(27) - C ( 2 8 ) - C ( 2 9 ) C(28) -C(29)-C(30) C(29) -C(30)-C(31) C(26) - C ( 3 1 ) - C ( 3 0 )  Angle(deg)  107. 125. 127. 106. 120. 130. 106.  9 4 9 6 5 7 9 169. 7 172. 1 172. 7 111. 1 104. 6 109. 2 110. 9 104. 2 110. 3 110. 3 104. 9 109. 4 12 1. 9 120. 2 117. 8 120. 9 120. 5 119. 6 120. 0 121. 1 122. 7 119. 6 117. 6 122. 2 119. 0 1 1 9 .7 120. 8 120. 7 123. 0 1 2 0 .1 116. 9 122. 2 120. 2 118. 7 1 2 0 .6 121 . 4  3  2 2 2 2 2 3 3 3 3 3 3 3 3 3 3 3 3 3 2 2 3 3 4 3 3 3 2 2 3 4 4 3  4 4 2 2 3 3  3 3 3 3  230  APPENDIX II  THEORETICAL  INTENSITY PATTERNS  FOR  MASS SPECTROMETRY ANALYSIS  Ga  138  140  Mo  2  92  142  95  B6  97  9B  100  Ga-Mo  Ga  69  94  71  161  163 164 165 166 167 168 169  171  

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