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UBC Theses and Dissertations

Pyrazolyl based ligands in transition metal complexes Olson, Michael David 1989-12-31

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PYRAZOLYL BASED LIGANDS IN TRANSITION METAL COMPLEXES  by  MICHAEL DAVID OLSON B.SC,  UNIVERSITY OF B R I T I S H COLUMBIA, 1986  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE  REQUIREMENT FOR THE DEGREE OF MASTER OF SCIENCE  in  THE  FACULTY OF GRADUATE STUDIES DEPARTMENT OF CHEMISTRY  We accept t h i s t h e s i s as conforming to the required  THE  standard  UNIVERSITY OF' B R I T I S H COLUMBIA SEPTEMBER, 1989 6 MICHAEL DAVID OLSON, 1989  In  presenting  degree  at the  this  thesis  in  University of  partial  fulfilment  of  of  department  this thesis for or  by  his  or  scholarly purposes may be her  representatives.  permission.  Department The University of British Columbia Vancouver, Canada  for  an advanced  Library shall make it  agree that permission for extensive  It  publication of this thesis for financial gain shall not  DE-6 (2/88)  requirements  British Columbia, I agree that the  freely available for reference and study. I further copying  the  is  granted  by the  understood  that  head of copying  my or  be allowed without my written  il  Abstract  Several ligands  were  MeGapz'^ ,  uninegative/  synthesized H2BpZ2~/  -  multidentate  [eg.  H B P Z 3  Me2Bpz2~/  -  pyrazolyl  HBpz'^ ,  Me2GapZ2~/  2  pyrazolyl/  2  2  ligands  metal  X-ray was  and  of general  crystal  the  about  nickel field H B P Z 3 ,  ligand  The with  The  undergo  Furthermore  sterically 3-iPrmetal  isolated.  The  HBpz*3Nipz"3BH  complex,  arrangement  of  The e l e c t r o n i c s p e c t r a  were r e c o r d e d  of  a n d compared t o p r e d i c t e d  f i ta  of the four d , 8  tetrahedral,  complexes,  MeGapz'^),  coordinate  f i ta  ligand  HBpz*3NiL d , 8  (L =  octahedral,  model. p y r a z o l y l g a l l a t e l i g a n d s were  dimer  complexes,  oxidative these  [Rh(CO)2CI]2  LRh(CO)  Me2Gapz(0CH2CH2CH=CH2)]. to  were  octahedral  s i x coordinate  the  transition  HBpz*3ML,  near  HBpz*3NiCl,  rhodium  planar  a  MeGapz3,  with  mixed-ligand  formulae,  unsymmetrical  the  pz  (M = Co, N i ; p z * =  electronic spectra  The  HBpz"3,  field  reacted  the n i c k e l centre.  complex, model.  the  showing  n i c k e l complexes  transitions.  were  s t r u c t u r e o f one s u c h  determined  ligands  ;  2  HBpz*3MCl  complex,  4-Br-pyrazolyl) complexes  2  p z " = 3, 5 d i m e t h y l p y r a z o l y l ] . These  hindered  2  /  Me2Gapz"2~/  Me Gapz(OCH CH NH )Me Gapz(OCH CH CH=CH2)" 2  MeGapz3~  -  ,  based  These  additions  rhodium[I]  [L  to  =  give  the  square  Me Gapz(OCH CH NH ), 2  rhodium[I]  2  complexes  o f Mel, a l l y l b r o m i d e  complexes  reacted  appeared  2  2  appeared and I 2 .  to bind the  ill  s m a l l gas m o l e c u l e s , A  number  CO and  of heterobimetallic  metal-metal  bonds,  reaction  t h e molybdenum  of  transition  and  metal  GePh3Cl.  ethene.  were  halides,  prepared anion,  complexes, and  with  isolated  from  the  with  the  (R = Me,  Ph)  HBpz"3(CO)3M0  [CuPPb^Cl],*,,  SnF^Cl  direct  -  iv  Table of  Contents  Page Abstract  i i  Table of Contents  iv x  List  of Figures  List  of Tables  List  of Abbreviations  v i i i  xi  Acknowledgement  Chapter  I  xiii  P o l y p y r a z o l y l Based T r a n s i t i o n Metal  Complexes  1.1  General  1.2  General Techniques  Chapter  II  Ligands i n  Introduction  Mixed-Ligand  Metal  1 7  Complexes  2.1  Introduction  10  2.2  Experimental  13  2.2.1  Starting Materials  13  2.2.2  Syntheses  of Bidentate Ligands  a)  Preparation of K [ H B p z ] ~  14  b)  Preparation of Na [Me Bpz ]~.  15  c)  Preparation of Na [Me Ga(pz) ]~  +  2  2  +  2  2  and  +  2  2  Na [Me Ga(pz") ]"  15  +  2  2.2.3 a)  Syntheses  2  of Symmetrical  T r i d e n t a t e Ligands  P r e p a r a t i o n o f K [ H B p z ] " and K [ H B p z " 3 ] ~ +  +  3  16  V  b)  Preparation  o f N a [ M e G a p z 3 ] ~ and +  N a [MeGapz" ] ~  16  +  3  2.2.4  Syntheses o f Unsymmetrical  G a l l a t e Ligands  a)  Preparation  of Na [Me Gapz(OCH CH NH )]".  18  b)  Preparation  of Na [Me Gapz(OCH CH CH=CH )]~  19  c)  Preparation  of Na [Me Gapz"(OCH CH NH )]"  19  2.2.5 2.3  +  2  2  2  2  +  2  2  2  2  +  2  2  Syntheses o f Mixed-Ligand Metal  2  2  Complexes  C h a r a c t e r i z a t i o n o f M i x e d - L i g a n d Complexes  24  Mass S p e c t r o m e t r y  24  a)  Mass S p e c t r u m o f H B p z * 3 C o C l  25  b)  Mass S p e c t r u m o f HBpz*3Copz3BH  28  c)  Mass S p e c t r u m o f H B p z * 3 C o p z G a M e  2.3.1  2.3.2 a)  2  2  X-ray C r y s t a l l o g r a p h y The S o l i d  State Molecular  Structure of 33  3  b)  The S o l i d  State Molecular  Structure of  HBpz* Nipz"3BH  34  Electronic  35  3  2.3.3  Spectroscopy  a)  The T e t r a h e d a l  Approximation  b)  The O c t a h e d r a l  Approximation of  o f HBpz*3NiCl  HBpz*3Nipz" BH  2.4  Five Coordinate  42 44  R h o d i u m [ I ] Complexes o f U n s y m m e t r i c a l Pyrazolylgallate  3.1  N i c k e l [ I I ] Complexes  Conclusion  III  37  39  3  c)  30 32  HBpz* CoCl  Chapter  20  Introduction  Ligands 48  vl  3.2  Experimental  51  3.2.1  Preparation  o f M e G a p z (EA) Rh (CO)  52  3.2.2  Preparation  o f M e G a p z (but) Rh (CO)  53  3.2.3  Attempted  2  2  Preparation  o f M e G a p z " (EA)Rh(CO)  53  Reactions  54  2  3.2.4 a)  Oxidative A d d i t i o n Reactions  54  b)  A d d i t i o n Reactions  58  c)  Activation  59  d)  Reactions  3.3  Chapter  o f R h [ I ] Complexes  o f C a r b o n - H y d r o g e n Bonds o f M e G a p z (but) Rh (CO)  61  2  Conclusions  IV  61  H e t e r o b i m e t a l l i c Complexes Pyrazolylborate  Incorporating  Ligands  4.1  Introduction  64  4.2  Experimental  65 (MeCN) 3M0 (CO) 3  4.2.1  Preparation  of  65  4.2.2  Preparation  of K [(HBpz" )Mo(CO)3]"  66  4.2.3  Preparation  o f H e t e r o b i m e t a l l i c Complexes  66  a)  Preparation  of  b)  Attempted P r e p a r a t i o n  +  3  ( H B p z " ) (CO) 3M0CUPPI13 3  66  of  ( H B p z " ) (CO) 3M0CU ( P P h ) C H 3  2  2  67  2  c)  Preparation  of  (HBpz'^) (CO)3MoSnMe3  68  d)  Preparation  of  (HBpz" ) (CO) MoSnPh  3  68  e)  Preparation  of  (HBpz" ) (CO) MoGePh  3  69  f)  Attempted P r e p a r a t i o n  3  3  3  3  of  ( H B p z " ) (CO) M o N i ( P P h ) 3  3  3  2  70  vii  4.3  Discussion  70  4.4  Conclusion  74  Summary  75  Chapter V  References  78  Appendix 1  Crystal  Grower  2  Isotopic  3.a  X-ray S t r u c t u r a l  Data of HBpz* CoCl  84  3.b  X-ray S t r u c t u r a l  D a t a o f HBpz*3Copz3"BH..  87  Clusters  81 o f B,  Ga B r and C l 3  82  viii  L i s t o f Tables  Table  2.1.a  Page  A n a l y t i c a l Data o f HBpz* ML 3  (L = mono- and t r i s - c h e l a t i n g ligands) 2.1.b  22  A n a l y t i c a l Data o f HBpz* ML 3  (L = b i s - c h e l a t i n g ligands)  23  2.2  Mass S p e c t r a l Assignments o f HBpz* CoCl....  27  2.3  Mass S p e c t r a l Assignments of HBpz* Copz BH.  29  2.4  Mass S p e c t r a l Assignments o f  3  3  HBpz* Copz GaMe 3  2.5.a  2  3  31  2  UV/Vis S p e c t r o s c o p i c Data o f Solvated  HBpz* NiL 3  (L = mono- and t r i s - c h e l a t i n g l i g a n d s ) 2.5.a  UV/Vis S p e c t r o s c o p i c Data o f S o l v a t e d HBpz* NiL 3  2.6  36  (L = b i s - c h e l a t i n g ligands)  Calculated  36  and Observed E l e c t r o n i c  T r a n s i t i o n Energies of HBpz* NiCl  39  3  2.7  Calculated Transitions  2.8  Calculated Transitions  and Observed E l e c t r o n i c E n e r g i e s o f HBpz* Nipz" BH 3  3  41  and Observed E l e c t r o n i c Energies of HBpz* Nipz BH 3  2  2  43  ix  List  of Figures  Figure  Page  1.1  Pyrazole  1  1.2  Polypyrazolylborate Ligands  2  1.3  P o l y p y r a z o l y l g a l l a t e Ligands  9  2.1  T r i s - c h e l a t i n g Pyrazolylborate Ligand  11  2.2  HBpz*MCl  12  2.3  Preparation  of Poly(1-pyrazolyl)  Borate  Ligands 2.4  14  IR S p e c t r a and  o f HOCH CH NH , 2  2  Na [Me Gapz]~ +  2  3  N a M e G a p z (OCH CH CH=CH ) ] "  18  +  3  2  2  2  2.5  Mass S p e c t r u m o f H B p z * C o C l  2.6  Solid  26  3  State Molecular  Structure of  HBpz* CoCl  33  3  2.7  Solid  State Molecular  Structure of  HBpz* Nipz" BH 3  35  3  2.9  E l e c t r o n i c Spectrum o f H B p z * N i C l  39  2.10  E l e c t r o n i c Spectrum o f HBpz* Nipz" BH  2.11  UV/Vis Spectra  3  3  of HBpz* Nipz BH 3  2  3  2  in  B e n z e n e a n d THF a s S o l v e n t s 3.0  44  O x i d a t i v e A d d i t i o n o f Mel and Carbonyl I n s e r t i o n on M e G a p z ( O C H C H N M e 2 ) R h ( C O ) 2  3.1  41  2  2  49  T r i s - C h e l a t i n g Unsymmetric P y r a z o l y l g a l l a t e Ligand  50  X  3.2  IR S p e c t r a  o f [Rh(CO)2CI]2/  mixture a f t e r  the reaction  a 3 hour r e f l u x  and  M e G a p z (EA)Rh(CO)  50  2  3.3.a P r e p a r a t i o n  o f M e G a p z ( E A ) R h ( C O ) (Me) (I)  55  3.3.b  Preparation  o f M e G a p z (EA) Rh (CO) I  57  3.3.C  Preparation  of Me Gapz(EA)Rh(CO)(allyl)Br....  57  of Me Gapz(EA)Rh(n -allyl)Br  57  3.3.d P r e p a r a t i o n  2  2  2  2  3  2  3.3.e  M e G a p z (EA)Rh(CO)  3.3.f  M e G a p z (EA)Rh(CO) (ethene)  3.4  Reactions  4.0  3:3:1  2  58  2  59  2  o f Me Gapz(but)Rh(CO)  Structure  2  o f MeGapz (CO) MoCuPPh 3  3  3  71  xi List The  following  of Abbreviations  abbreviations  have  been  used  in  this  thesis.  A  Angstrom  amu  a t o m i c mass  B  Racah  B.M.  Bohr  but  but-3-enolate  °C  degree  unit  parameter Magneton  Celsius  calc.  calculated  cf  confer  cm~l  r e c i p r o c a l c e n t i m e t e r s (wave numbers)  Co.  company  CT.  charge t r a n s f e r  EA  ethanolamino  Fig.  figure  g  grams  gr  gerade  Hpz  pyrazole  i.e.  i d est  (Latin  (Latin  : compare)  band  : that  iPr  isopropyl  IR  infrared  L  pyrazolyl  M  t r a n s i t i o n metal  m/e  mass t o c h a r g e r a t i o  Me  methyl  based  is)  ligand  xii ml  millilitres  mmole  millimoles  nm  nanometers  No.  number  0^  octahedral  P  parent  Ph  phenyl  pz  pyrazolyl  pz"  3/5-dimethylpyrazolyl  pz*  3-isopropyl-4-bromo-pyrazolyl  t-bu  (peak)  tertiary  butyl  tetrahedral 10 Dg  crystal  THF  tetrahydofuran  tren  t r i e t h y l a m i n o amine  u  ungerade  U.B.C.  University  UV  ultraviolet  Vis  visible  Vol.  Volume  E  extinction  n  hapto  n  3  n  5  field  splitting  of B r i t i s h  (Greek,  haptein  pentahapto pi magnetic  $, #,@ A  /  Columbia  coefficient  trihapto  Ug  energy  moment  f o o t n o t e markers  : t o fasten)  xlll Acknowledgement  I Storr  would  like  t o express  f o r h i s guidance,  project  a  stimulating  t h a n k s t o my v e r y for their  help  2  wisdom years  particular  dedication  and of  thanks  wit  t o Dr. Alan  that  research.  I  made  this  extend  my  Gord and Jane  and t o l e r a n c e .  Peter  Borda  and t e c h n i c a l s t a f f  a t U.B.C.,  and  for  Steve  Rettig  their  to excellence.  Financial gratefully  sincere  g o o d ),£riends Tammy, M a r t i n ,  My t h a n k s t o t h e F a c u l t y in  my  support  f r o m U.B.C. T e a c h i n g A s s i s t a n t s h i p i s  acknowledged.  1 Chapter  I  P o l y p y r a z o l y l Based Ligands T r a n s i t i o n Metal  1.1  General  The  viability  then  the  their  Pyrazole  and  polypyrazolylborates  discovery  i n 1966  r e v i e w s ' 2/3/4  a n c  will  versatility  of these  react  with  the  j  ligand  Trofimenko . 1  ^he  numerous unique  ligands.  c e r t a i n compounds  forming multidentate,  (Fig.  containing  uninegative  H  In  S.  a  t h e r e i n have d e m o n s t r a t e d t h e  H 1.1  as  i s a f i v e membered h e t e r o c y c l i c compound  group elements,  Figure  by  1  referenced  characteristics  that  of  several  publications  1.1)  Complexes  Introduction  system began w i t h Since  in  main  ligands.  N 2  Pyrazole  p a r t i c u l a r the  general  = H,  alkyl,  0-2)  o r as  formula a r y l ) and  polypyrazolylborate  [R Bpz4_ ]~ n  can  n  (pz  ligands  = pyrazolyl; n =  f u n c t i o n as b i d e n t a t e  tridentate ligands  (n = 0,1)  (Fig.  are 0-2;  ligands 1.2).  of R  (n =  Figure  1.2  Polypyrazolylborate  Symmetrical  Ligands  Bidentate  N—N.  N—  N*  RoB 2 P 2  P2 2  Symmetrical  N — N* VS  D  Tridentate  Z  3 These  ligands  generally  form  b i s - l i g a n d complexes  with  f i r s t - r o w divalent t r a n s i t i o n metals^/^. The  tridentate  ligands  are uninegative  s i x electron  donors and bond t o t h e m e t a l t h r o u g h t h e t h r e e pairs  bidentate  donors t h a t metal  form  centre.  forced boron  on  A  ligands  four  electron  a s i x member r i n g on c o o r d i n a t i o n  with the  boat  and metal  are uninegative  shaped  the structure  pyrazolyl  must  by  be  (or planar)  conformation  the constraint  simultaneously  r i n g t o r e t a i n the resonance  that  both  coplanar  with  stabilization  is the each  energy  each p y r a z o l y l r i n g ^ . The  versatility  numerous  centre. terminal boron  steric  and  Substitutions group  atom  on  itself  stabilizing the  o f t h e l i g a n d system  substitutional possibilities  imparting  electronic  t h e boron  ring ' . 1  air-stable. position  nucleophilic Bulkier ring  the  provide about  means o f the  metal  7  c a n be  An example  by methyl  F o r example, (P "  F e  z  and t h e  is a  steric  s u b s t i t u t i o n on  (H2Bpz2)2  F e  is  3,5-dimethylpyrazolyl)  =  that  metal  altered  t h e methyl  center,  group  protecting  airis  i n the 3 i t  from  attack. substituents  can l e a d divalent  atom  about  I t i s suggested  covers  that  control  c a n be r e p l a c e d .  e f f e c t brought  pyrazolyl  comes t h r o u g h t h e  c a n be made on t h e p y r a z o l y l r i n g , t h e  s e n s i t i v e but (H2Bpz"2)2  the  lone  i n a tripodal fashion. The  in  nitrogen  at the 3 position of the pyrazolyl  t o the formation metals . 8  o f mono-ligand  F o r example  placing  complexes o f  a tertiary  butyl  4 group  i n the 3  position  chloride  7  Displacement complexes  leaves  of the halide  a sterically  from  these  mono  and e l e c t r o n i c a l l y  ligand  controlled  p o c k e t . I n c h a p t e r two o f t h i s work t h e p o c k e t o f one  s u c h mono l i g a n d sterically  been  ring  or  effect  ligands  varying  by  about  with  group.  i n t h e magnetic  complexes  by t h e l i g a n d  substitutions  the terminal  less  on  An  the  systems  pyrazolyl  example  of  of a  series  behaviour  this of  ( a t room t e m p e r a t u r e ) . 2  u  (B.M.)  B  [pzBpz3]2Fe  0.0  diamagnetic  [HBpZ3]2Fe  2.71  t e m p e r a t u r e dependent paramagnetism  [HBpz"3] Fe  5.03  paramagnetic  2  Iron[II]  i n a d^ o c t a h e d r a l  electrons  structure  by r e a c t i o n s  and a m i x e d - l i g a n d t r a n s i t i o n  e f f e c t s brought  demonstrated  i s seen  iron[II]  i s examined  i s developed.  Electronic have  complex  demanding  metal s e r i e s  free  t h e mono-ligand  H B ( 3 - t - b u - p y r a z o l y l ) 3 M C I (M = C o ) .  complex,  active  gives  would  in have  a  high  complex  spin  and would  structure.  a l l electrons  paired  A  have  four  low  spin  and t h e r e f o r e  be  diamagnetic. The of  substitutions  ligand by  magnetic  b e h a v i o u r o f t h e s e complexes on  i s a stronger  t h e magnetic  the pyrazolyl field  moments  ligand  ligand.  than  (u ) of t h e i r B  i s a result  The  [pzBpz3]~  i s [HBpz3]~ iron[II]  as seen  complexes.  5 The  fourth  toward  pyrazolyl  the  metal  (inductive  bonding  [pzBpz3]~ l i g a n d  all  the i r o n [ I I ]  the of  their  ligand  -  make t h e  Methyl  become a b e t t e r stronger  steric  by  ligand. magnetic  coordinate [HBpz3] makes  -  the the  A steric  iron  ligand,  the  [HBpz3]~  [HBpz'^]  thus  [HBpz'^]  for steric further factors  enhanced  sigma  interactions  ligand  a  where  odds  with  ring  donation of the ring  effect  would methyl  would  then  is  seen  [HBpz3]2Fe  in and  crowding of the methyl  greater  a  at  pyrazolyl  causes  the  high  weaker  with  of t h i s  conflict  reaction  of  divalent  donating a b i l i t y is  be  of  the  ligand  distance spin field  than  to the  complex.  This  ligand  than  reasons.  i s the  analogue)  at  forming  example  (borate  substituents  -  can  of  steric  ligand  centre  example  a m e t a l c e n t r e and t h u s a  moments  -  moments  reverse  that  complex.  the magnetic  substituted  The  3  of  electron  of  than i s  an  a  of  ligand  is  on  ligand  the p a i r i n g  field  effects  substitution  [HBpz" ]2Fe. I t i s l i k e l y groups  This  e f f e c t ) . The  the  [pzBpz3]~  donating a b i l i t y  above by  sigma d o n o r t o w a r d  field  comparing  sigma  density  and t h u s f o r m a low s p i n  seen  r i n g more b a s i c  (inductive  the  i s a stronger  as  and  of  electron  enough t o f o r c e  complexes.  effects  other.  groups  i s great  electrons  i r o n [II]  electronic each  enhanced  [HBpz3]~ l i g a n d  [HBpz'^]  contributes  orbitals  e f f e c t ) . This  the  The  ring  sometimes  the  [MeGapz'^]  transition  brought outweighed  of the methyl groups  of e l e c t r o n i c  about by  -  ligand  metals. by  the  the  and  The  methyl steric  on a t t e m p t e d c o m p l e x a t i o n .  6 Often the  ligand will  not  form t r i s - c h e l a t e d complexes  the  d i v a l e n t t r a n s i t i o n metals,  and  forms  a  dimer  rings bridge  between m e t a l  Analogues replacement 1.3).  The  of  of the  the 9  boron  atom  with  have  a  gallium  (2.01) make t h e  made  atom  gallate  pyrazolylgallate (Fig.  1.3)  that  behaviour i n that  either  a  facial  ligand has  i t may  or  system  coordinate  meridional  rhodium[I]  in  chapter  complexes are The ligands  anionic halides  also  tris  =  form  of  used  have  The  The  several the  a 1 2  have  rhodium[I]  forming  catalytic  complexes  reactivities  to  form  been  new  the  reacted  fourth  and  HBpz'^).  heterobimetallic  bonds.  incorporating  three.  MeGapz3, HBpz3,  complexes  metal-metal synthesis  their  may  to  of  are  these  described.  been  (L  to  and  chelating pyrazolylborate  have  [LMo(CO)3]~  ligands  that  has  manner .  complexes  described  of  demonstrated  square  These  ligands  IR measurements  have shown some p r o m i s e i n  activity.  (Fig.  (Allred-Rochow)  Furthermore these ligands planar  by  1  unique c o o r d i n a t i o n in  been  complexes* .  developed  centre  pyrazolyl  1 0  electronegativities  unsymmetrical  recently  fragments  atoms ' .  pyrazolylborates  in  ligand  substituted  sigma d o n o r s w h i c h i s e v i d e n c e d by  An  metal  where  (1.82) and. b^oron  analogous carbonyl  been  the  difference  of g a l l i u m better  complex  i n s t e a d the  with  with  pyrazolylgallate anionic These  with  describes  heterobimetallic  molybdenum a n i o n ,  molybdenum  transition-metal  compounds chapter  complex  direct the  complexes  [HBpz'^Mo(CO)3]~.  7 1.2  General  Techniques  Air (Vacuum out  sensitive materials  Atmospheres  i n the  d r y box The  appropriate a  refluxed  Methylene  (P2O5)  under  . The  sodium  Reactions  was  chloride  was  was  dried  solvents  THF  solvents  and  were  box  carried  with  an  under  hexane  benzophenone  were as  potassium  with  with  where  distillation  with  refluxed  dry  refluxing  using  refluxed  distilled  by  refluxed  a  atmosphere.  c o l l e c t e d by  metal,  Benzene  vacuum  routinely nitrogen  line  used  to  cooled  from r e a c t i o n Infrared  an  metal.  calcium  sulphate.  phosphorous  pentoxide  stored  in  the  dry  box  polystyrene KBr  solvent  fitted  dry  samples  solvent  trap  a Duo  and  Seal  Vacuum Pump  when f i t t e d  was  used  s p e c t r a were r e c o r d e d  to  with  remove  using  a Perkin  were c a l i b r a t e d u s i n g t h e standard.  solution cells blank  with  a  was  liquid  solvents  mixtures.  s p e c t r o m e t e r and  using  The  in  nitrogen. A  a  were  blanket.  Methylcyanide  handled  or under a n i t r o g e n  d r y i n g a g e n t and  with  indicator.  Corporation).  solvents  nitrogen  were  or  using  Infrared with  a  Nujol  1601  spectra  reference mulls  cm  Elmer - 1  where  cell  spread  598  band  of  recorded  containing  a  between  KBr  Borda of  the  windows. Microanalyses  were p e r f o r m e d by  U.B.C. M i c r o a n a l y t i c a l S e r v i c e s u s i n g Analyser.  Mr.  Peter  a Carlo Erba  Elemental  8 Mass Spectrometry Ionization  were  recorded  by  the  S e r v i c e s u s i n g a K r a t o s MS50 mass  o f compounds  X-ray this  spectra  was done by e l e c t r o n  s t u c t u r e s were  department  using  determined a  Rigaku  U.B.C.  Mass  spectrometer.  impact.  by D r . S . J . R e t t i g single  crystal  of  X-ray  diffractometer. UV/Vis spectrometer spectrometer.  s p e c t r a were and  recorded  near-infrared  with  spectra  a  Shimadzu with  a  UV-2100 Cary  14  9 F i g u r e 1.3  Polypyrazolylgallate  Ligands  Symmetrical Bidentate  Me Ga 2  /  /  Me Ga 2  \  N-N'  N-NP  Me Gapz 2  2  Me Gapz2 2  Symmetrical Tridentate  Me—G  MeGapzg  MeGapzg  Unsymmetrical Tridentate  Me G 2  Me Gi 2  10 Chapter  II  Mixed Ligand  2.1  Introduction  One is  of the  to  basic precepts  impart  reactive  steric  site  of  produce s e l e c t i v e The demonstrated sites  are  reactivity by  the  and  the and  electronic metal  ultimate  manifestation  to  the  us  by  reactive  very  nearly  to  particular  a  enzyme  perfect  organo-mass.  subtle  of  this  sites  on  in  their  ideal  steric  to  that  the  i t  may  principle  is  enzymes.  Mimicking  d i s c o v e r y o f new  and  is  nucleophilic in  selective  the  pockets  chemistry.  more i n t r i c a t e  i s p r o v i d i n g new  and  accomplished  changes  these  These  selectivity  and  conformational  of the goals of o r g a n o m e t a l l i c  pyrazolylborates  such  substrate. This  through  surrounding  The  properties  system  consistent reactivity.  and  one  i n designing a ligand  transition  conditions  is  Complexes  inroads  tris-chelating  into  this  type  of  chemistry. In t h e s e ring  ligand  systems t h e  i s t h e most s t e r i c a l l y  center  ( F i g . 2.1).  Ligands  bis-ligand  3 position  influential with  readily  form  complexes  metals.  However, when a b u l k y  H  or with  group such  on t h e  site Me  pyrazolyl  about t h e  in  this  divalent as t h e  metal  position transition  tertiary  11  Figure  2.1  butyl  group  complex  Tris-chelating Pyrazolylborate  is  will  h i n d e r a n c e by  in  the  form. the  position.  t e r t i a r y butyl  ligands  These  a bis-ligand  pocket In  are  + Co  2 +  an  has  around the to  is  an  what  1,2  pyrazolyl  created  examine  ligand  to  steric  he  a  metal  has  1 3  group  borotropic  2  .  called, i n the  r e s t r i c t e d , but  [HB(3-iPrpz)  metal  mono  due  isopropyl  sterically  of the  ligand  effort  —>  the  group around the  designed, placing  rearrangement  intermediate  active  by  only  this  complex w i t h a p e c u l i a r  3  the  has  ligands  2 HB(3-iPrpz) ~  This  position  Presumably  Trofimenko intermediate  3  Ligand  3  form  shift  1 4  .  (5-iPrpz)] Co 2  rings  suggests  sterically  that  controlled  centre. the  active  pocket  created  by  12 the  intermediate  pyrazolyl)  the  complex  with s t e r i c a l l y ligands metal  ligand  [HBpz*3]~  HBpz*3  MCI  (pz*  =  ( F i g . 2.2)  3-iPr-4Brwas  reacted  s m a l l e r p y r a z o l y l b o r a t e and p y r a z o l y l g a l l a t e  ( F i g . 1.2,  1.3)  t o produce  a series  of mixed-ligand  complexes.  Br  Figure  2.2  HBpz* MCl  In t h i s based  described. ligand each  chapter the syntheses  ligands,  complexes  (M = Co, N i )  3  and  the  syntheses  i n c l u d e s 4,  complexes  coordination  characterization Tables 2.1.a  of  the  the characterizations  The s e r i e s  metal  of the smaller  and  mode  studies.  a n d 2.1.b  are The  of these  metal  complexes i s  5 and 6 c o o r d i n a t e mixed-  given complete  A U V / V i s s t u d y was p e r f o r m e d series to further  mixed-ligand  representative  on p a g e s 22  pyrazolyl  and  as  complexes  examples  series  from  in  i s listed  the in  23..  on t h e m i x e d - l i g a n d  c h a r a c t e r i z e t h e c o m p l e x e s . The  nickel  transition  13 energies with  calculated  predicted  particular  2.2  the  recorded spectra  e n e r g i e s from  coordination  high  symmetry  were  models  compared for  each  (Hpz")  were  number.  Experimental  2.2.1  Starting  Materials  Pyrazole obtained without  (Hpz)  MeGaCl  further  1 6 2  and The  pyrazolyl)3  3,5-dimethylpyrazole  Napz  MCI  methods 1 7  were  supplied  to  prepare  Me3Ga ^, 1  . ligand  metal  (M = N i , C o ) were were  used  prepared  by  complexes, supplied reacting  c h l o r i d e with the borate l i g a n d  of the c o b a l t  as  purification.  bulky  complexes  metal  and  f r o m K and K L a b o r a t o r i e s and were u s e d  Literature  The  from  complex was  determined.  1 4  .  HB(3-iPr-4Br-  by  S.  Trofimenko.  an  excess  A crystal  of  the  structure  14  2.2.2  Syntheses of B i d e n t a t e  2.2.2a P r e p a r a t i o n  K BH " +  4  Liaands  of K + f H B P z 1 -  +  2 Hpz  > 102  This scheme. The  ligand extent  was  1 8  2  2  2  2  prepared  poly(1-pyrazolyl)  moisture-stable,  BH " 4  +  2  H  by  the  borates  are  on  ( F i g . 2.3.).  a l l air-stable  and  white s o l i d s .  -2H  2pzH  :  ~102°  X ~ieo-| P  z H  1~ * H  '  F i g u r e 2.3  Preparation  2  above  i n c o r p o r a t i o n i s dependent  the temperature of the r e a c t i o n as seen below The  +  +  °C  previously  of p y r a z o l e  K [H Bpz ]~  -220*  of Poly(1-pyrazolyl)  Borate Ligands  15  2,2.2b P r e p a r a t i o n  Me3B  of Na TMe2Bpz2l~ +  +  Na [Me Bpz]~  +  +  3  Napz  >  Hpz  >  6  Na [Me Bpz]~ +  3  Na [Me Bpz ]" +  2  2  +  MeH  T h i s compound had been p r e v i o u s l y prepared by t h e above scheme. Q u a n t i t i e s  r e q u i r e d were weighed  out and d i s s o l v e d  i n THF.  of Na TMe Ga (pz) 2"! ~ and  2.2.2c P r e p a r a t i o n  +  2  N a TMe Ga(PZ")ol~ +  6  2  NaH  +  Hpz  >  Napz  Me Ga  +  Napz  >  Na  +  Hpz  3  Na  +  [Me Gapz]" 3  To  ~—>  +  +  H  [Me Gapz]~ 3  Na [Me Gapz ]~ +  2  2  150 ml o f THF i n a round bottom  molar e q u i v a l e n t s  o f GaMe  3  2  flask  resulting  were  MeH  added  (1.510 g; 13.17 mmole) and Napz  (1.185 g; 13.17 mmole). The mixture was s t i r r e d The  +  overnight.  s o l u t i o n was made up t o a known volume  THF and s t o r e d under a n i t r o g e n  with  atmosphere.  A 25 ml a l i q u o t o f t h e s o l u t i o n o f Na [Me Gapz]~ (2.63 +  3  mmole) was mixed 2.63  mmole)  with  a 1:1 molar r a t i o  and r e f l u x e d under  a nitrogen  o f Hpz  (0.179 g;  atmosphere. The  16 reaction  proceeded  monitored at  3300  by  cm  with  the  evolution  the disappearance  up t o a known volume w i t h [Me2Gapz"2]~ was  The m i x t u r e  prepared  in a like  under  pyrazole  nitrogen.  On  (0.533 g; 5.55  completion  of the  was made up t o a known volume w i t h  2.2.3  Syntheses  of Symmetrical  +  3  +  +  4  manner.  then  3 Hpz  An  mmole) and reaction  made  aliquot amount  refluxed  the  mixture  THF.  Tridentate  2.2.3a P r e p a r a t i o n o f K r H B p z l ~  K BH "  was  was  stretch  stoichiometric  +  3,5-dimethyl  and  THF.  o f N a [ M e 3 G a p z " ] ~ was m i x e d w i t h a 1:1 of  methane  o f t h e p y r a z o l e N-H  i n t h e IR s p e c t r u m .  - 1  of  Ligands  and K r H B p z " l ~ +  7  3  >  K [HBpz ]~ +  +  3  3 H  2  180 °C  This were  ligand  previously  temperature  and t h e t r i s prepared  of reaction  r i n g s bonding  (3,5-dimethylpyrazolyl) analog by  the  determines  t o the boron  atom  above  t h e number  ( F i g . 2.3)  scheme. of  The  pyrazolyl  17 2.2.3b P r e p a r a t i o n Na  MeGaCl  added  for  3  one  solution  1 1  3  +  3 Napz  equivalent  t o a 3 molar  dissolved  and  +  rMeGapz" l"  +  2  A molar  of Na rMeGapz l~  >  Na [MeGapz ]" 3  o f MeGaCl2  equivalent  + 2 NaCl  +  (2.28 mmole)  o f Napz  i n THF, was  (1.85 g; 6.85  i n 30 ml o f THF. The r e a c t i o n m i x t u r e was week  under  a  nitrogen  atmosphere.  The  mmole) stirred  resulting  was made up t o a known volume by a d d i t i o n o f THF.  The  3,5-dimethylpyrazolyl  analog  was  prepared  in a  s i m i l a r manner by t h e r e a c t i o n o f t h r e e  molar e q u i v a l e n t s o f  Napz"  molar  (0.971  MeGaCl2  g;  mmole)  with  a  equivalent  (0.913 mmole). B o t h l i g a n d s were s t o r e d  under a n i t r o g e n The anions  2.74  alkali  of  as s o l u t i o n s  atmosphere. metal s a l t s  c a n be i s o l a t e d  (unlike the borate  of the poly (1-pyrazolyl)  as w h i t e  analogues).  solids  but are  gallate  hygroscopic  18 2.2.4  Syntheses o f Unsymmetrical  Gallate  Ligands  o f Na+ TMe Gapz ( O C H o C ^ N r ^ ) 1 "  2.2.4a P r e p a r a t i o n  N a [ M e G a p z ] " + HOCH CH NH +  3  2  2  2  —>  added  a  mmole).  a THF s o l u t i o n molar  +  2  2  equivalent  of the alcohol  of Na [Me Gapz]~ 3  o f ethanolamine  of  the  provided  reaction  was  a good  monitor  (Fig.2.4). volume  by  (0.311  cm  - 1  which  attributed  to  t h e O-H  i n t h e IR  grew d u r i n g a  Ga-0  f o r the reaction  spectrum  the course  stretch  and  p r o g r e s s as  well  The r e s u l t a n t m i x t u r e was t h e n made up t o a known addition  of  THF  and  stored  under  a  nitrogen  blanket.  {cm' ) 1  4000  Figure  2.4  was  g; 5.10  f o r 40 h o u r s u n t i l  a t 3480 - 1  2  (5.10 mmole)  +  d i s a p p e a r e d . A peak a t 570 c m  2  + MeH  The m i x t u r e was r e f l u x e d  stretch  2  Na [Me Gapz(OCH CH NH )]~  reflux  To  1  2  5  IR S p e c t r a o f H O C H C H N H Na [Me Gapz]" and N a M e G a p z ( O C H C H N H ) ~ +  2  2  2/  2  2  2  +  2  3  0  0  19 2.2.4b P r e p a r a t i o n  o f Na+FMe?Gapz(OCH?CH?CH=CH?)1 - 19  Na [Me Gapz]"  >  Na [Me Gapz(OCH CH CH=CH2)]"  reflux  + MeH  +  3  + HOCH CH CH=CH 2  2  To  a THF  a  molar  added mmoles)  and  2  +  2  solution of Na equivalent  the  [Me Gapz] ~  +  but-3-enol  was  refluxed  r e a c t i o n was c o m p l e t e when t h e O-H 3470  cm  i n t h e IR s p e c t r u m  then  made up t o a known  - 1  nitrogen  2  (5.10 nunoles)  3  of  mixture  2  (0.368  f o r 40  g;  Me Ga  +  3  hours.  The  stretch of the alcohol at  disappeared.  volume w i t h  THF  The s o l u t i o n and s t o r e d  was  under  a  of Na fMe Gapz"(OCH CH NH )1~ +  2  +  2  Napz"  >  N a [ M e G a p z ] " + HOCH CH NH 2  2  2  2  Na [Me Gapz"]~ +  3  > Na [Me Gapz"(OCH CH NH )]"  n  3  +  2  2  2  reflux  To  a THF  s o l u t i o n o f Me Ga  molar e q u i v a l e n t  3  o f Napz"  was  stirred  the  a d d i t i o n o f THF.  overnight  equivalent  O-H  band  2  (27.8 mmole)  was  added  a  mixture  a n d t h e n made up t o a known v o l u m e by  of ethanolamine  the  2  + MeH  (3.28 g; 27.8 mmole). T h i s  A 50 ml a l i q u o t o f t h i s  of  5.10  blanket.  2.2.4c P r e p a r a t i o n  loss  was  of  s o l u t i o n was r e a c t e d and the  refluxed alcohol  with  f o r 24 i n the  a molar  hours. IR  The  spectrum  20 signalled  the  t h e n made up  2.2.5  completion  of  the  reaction.  t o a known volume w i t h  Syntheses  of Mixed-Ligand  HBpz* MCl  +  3  mixture  Metal  Complexes  >  HBpz* ML  +  3  3  3  2  2  Me2Bpz2/  3  Me Gapz(OCH CH NH2),  Me Gapz , Me Gapz" / 2  NaCl  3-iPr-4Br-pyrazolyl)  pz* =  [L = H B p z , H B p z " , M e G a p z , M e G a p z " , H 2 B P Z 2 / 3  was  THF.  NaL  (M = N i , Co;  This  2  2  2  2  Me Gapz(OCH CH CH=CH )] 2  The of  a  general  THF  into  a  reaction  solution round  bottom  of  the  (HBpz* MCl)  dissolved  less  flask  bulky  solution  was  nitrogen  atmosphere.  in  stirred  2  and  THF  was  a  following  microanalysis 1)  The  reaction  mixture slowly 2)  The  was  p r o d u c t was The  minimum  ligand  stirring. chloride  added of  24  A  (NaL) molar  complex  dropwise. hours  solvent  aliquot  (THF)  The  under was  a  then  trap. were u s e d u n t i l  product  filtered  and  redissolved  benzene  t o promote c r y s t a l  chloride,  then  an  a satisfactory  obtained.  filtered.  reaction  bulky  metal  reaction  procedures  to place  begin  ligand  for The  was  sterically  removed u n d e r vacuum t o a c o l d The  2  procedure  of the  equivalent 3  2  was  i n b e n z e n e and  allowed  to  the  evaporate  growth. was 15  redissolved ml  of  i n 30  hexane  was  ml  methylene  added.  The  21 solvent 3)  was  The  4)  e v a p o r a t e d s l o w l y t o promote c r y s t a l  r e a c t i o n p r o d u c t was  The  reaction  appeared  d r i e d under  product  was  t o be q u i t e r o b u s t and  was be  line  and  at  on t h e  the  70  reaction  °C.  This  results  that  the f i r s t  6) The  grower i n one  vacuum l i n e . (or any tube  the  vacuum  growth  and  is  shown  line  by  to  appendix  grew  the  finger.  The  give  solvent,  flame  sealing  most  for future  1.  The  work  grower.  at  the  compound  into the  a  solvent  other  w o u l d be be  the  decanted  removed  at the next  into  by  tube.  nearest  sealed solute  into  was  chloride  constriction  making  The  attached to the  condensed  thus  would  vacuum  the  c o n c e n t r a t i o n of  solvent  crystals  the  e v a c u a t e d and m e t h y l e n e  attachment The  on  would  tried.  sealed  condensing  crystals  crystal could  be  finger.  If  this  same  freezing  the  constriction  and  removal  box.  Pertinent in  method t h a t  dried  seemed  s o l v e n t ) was  flame  environment.  collected  be  washings  placed i n a crystal  in  g r o w e r was  then  to the glove  under  sublimed.  o f t h e t u b e s and t h e a p p a r a t u s The  was  controlled  also  i t i s recommended  method  other suitable  The  that  then  method  r e a c t i o n p r o d u c t was  crystal placed  be  complexes  s u b l i m e d a t 220-250 °C  p r o d u c t . Three  compound w o u l d  satisfactory this  Most  °C.  e x t r a c t i o n w i t h 50:50 m e t h y l e n e c h l o r i d e / w a t e r  performed done  vacuum a t 70  sublimed.  vacuum, b u t t h e r e were i m p u r i t i e s 5) A s o l v e n t  growth.  data  Tables  of the mixed-ligand metal 2.1.a  and  gave s a t i s f a c t o r y  2.1.b  analysis  and  the  complexes i s purification  i s indicated.  22 Table  2.1.a A n a l y t i c a l D a t a o f HBpz*3ML ( L = mono- a n d t r i s - c h e l a t i n g  L  Metal  Color  Mass$  Purification  (amu)  C  H  N  Method*  red blue  671 670 671  32.26 32.20 32.48  3.76 3.81 3.83  12.54* 12.43 12.55  Ni Co  purple orange  848 847 84 8  38.26 38.54 38.50  4.16 4.17 4.18  19.83 20.02 20.18  5 5  Ni Co  purple orange  932 931 932  42.53 43.10 42.54  5.08 5.15 5.20  18.04 17.89 18.04  1 4  Ni Co  blue orange  921 920 921  36.53 36.94 36.39  4.05 4.07 4.16  18.26 18.50 18.05  1 2  1005  40.64 41.00  4.91 5.09  16.73  38.56 38.36  4.71 4.67  HBpz 3  HBpz"3  MeGapz3  MeGapz"3 Ni CH C1 CO 2  Microanalyses  Ni Co  CI  •1.0  ligands )  green  1004  2  orange  16.61  5  15.42 15.24  5  1005  # Numbers i n b o l d t y p e a r e e x p e c t e d v a l u e s . C o b a l t a n d n i c k e l a t o m i c w e i g h t s d i f f e r b y o n l y 0.22 g/mole t h e r e f o r e t h e i r expected microanalyses a r every n e a r l y i d e n t i c a l . $ E x p e c t e d mass was c a l c u l a t e d f r o m a v e r a g e m o l e c u l a r w e i g h t s ( n a t u r a l i s o t o p e a b u n d a n c e ) . The one mass u n i t d i f f e r e n c e o b s e r v e d i n t h e s p e c t r a i s due t o t h e most a b u n d a n t n i c k e l i s o t o p e a t mass 58 (68%) c f . c o b a l t a t mass 59 (100 % ) . * Refer  t o p a g e s 20-21.  23 Table  2.1.b  L  A n a l y t i c a l D a t a o f HBpz*3ML ( L = bis-chelating ligands )  Metal  Color  Mass$ (amu)  Microanalyses C  H  Purification N  Method  Ni Co  blue purple  780 781  36 .88 36 .83 37 .18  4 .26 4 .25 4 .22  17 . 9 2 * 17 .70 17 .75  5 5  Ni  red  810 794  38 .57 38 .89  4 .61 4 .57  17 .30 16 .98  1  purple  795  37 .20 37 .37  4 .49 4 .37  16 .41 15 .62  blue red  869 853 854  35 .95 36 .01 36 .28  4 .29 4 .20 4 .20  16 .13 16 .16 15 .45  3 5  M e G a p z " 2 * 0.5 C H C 1 Ni green purple Co  925 909 910  37 .87 38 .16 37 . 60  4 .79 4 .83 4 . 69  14 .48 14 .20 14 .88  3 5  Me2Gapz(EA) Ni Co  862 blue red  34 .84 34 .60 34 .96  4 .68 4 .26 4 .28  14 .63 14 .10 14 .10  3 3  Me Gapz"(EA) Ni Co  green purple  36 .44 34 .88 36 .61  4 .98 4 .99 4 .98  14 .17 13 .61 13 .93  3  782  H2BPZ2  Me2Bpz2  •0.5  CH C1 Co 2  2  Me2Gapz2  Ni Co 2  2  2  2  890 874 875  # Numbers i n b o l d t y p e a r e e x p e c t e d v a l u e s . C o b a l t a n d n i c k e l a t o m i c w e i g h t s d i f f e r b y o n l y 0.22 g/mole t h e r e f o r e t h e i r expected microanalyses are very n e a r l y i d e n t i c a l . $ E x p e c t e d mass was c a l c u l a t e d f r o m a v e r a g e m o l e c u l a r w e i g h t s ( n a t u r a l i s o t o p e a b u n d a n c e ) . The one mass u n i t d i f f e r e n c e o b s e r v e d i n t h e s p e c t r a i s due t o t h e most a b u n d a n t n i c k e l i s o t o p e a t mass 58 (68%) c f . c o b a l t a t mass 59 (100 % ) .  24 2.3  Characterization  2.3.1  weight  were  +  on  were the  fragments.  intense  mass  isotopic  fragments or  of  electron  observed. v  at  or  charge  ratio  This  peak  isotopes  because  (100%)]  where  (1.2%),  62  of  the  cobalt  easier to The in Figure  complexes  a  methyl  a large  number  from  64  in  the  any  most  given  probable  fragment.  of boron,  have  t o t h e most  gallium,  natural  These  bromine  isotopes.  The  combinations of  2. cobalt  has  has  and  lost  peak  o f t h e s e atoms and s e v e r a l  cobalt  parent methyl  refer  particular  one  which  of the  cases  terminal  easily  always  results  at l e a s t  nickel  (3.7%)  with  (m/e)  i n that  them a r e shown i n a p p e n d i x  examples  most  were u s e d t o i d e n t i f y  to  spectra  In  pure  were o b s e r v e d .  +  reported  a l l  the molecular  were a n a l y t i c a l l y  atom  numbers  isotopic patterns  The  confirm  Complexes  The  contained  chlorine,  to  impact.  gallium  [P-15]  patterns  pattern.  combination  by  boron  and p e a k s Isotopic  used  compound. A l l samples  ionized  [P]  groups group  s p e c t r o m e t r y was  of each  peaks  of  L i g a n d Complexes  Mass S p e c t r o m e t r y  Mass  and  of Mixed  complexes  only  five  [ 58  (1.1%)].  were  one  less  were  natural  (67.9%), The  selected isotope  as [58  60  (26.2%),  61  isotopic  patterns  of  complicated  and  therefore  reconcile. mass s p e c t r u m 2.5.  o f HBpz*3CoCl  i s given  as  an  example  25 2.3.1a Mass S p e c t r u m  HBpz 3 C 0 C I  The (m/e) at  671 m/e  Loss  to  have  317  the on  of  seen  stripped of  and 223  this  633  [Bpz*3Co]  and  +  [Hpz*] and  +  [i-Pr]  giving  +  This of  m/e +  of  [pz*B] .  188,  a t m/e  of  borate  There  +  and  number  o t h e r peaks  ligand  that  peak  and  most  of  likely  with  gave  the  parent the  a  ion  molecule  peak  at  m/e  the mixed-ligand  another  not  446  pz*  moiety  observed. Doubly  fragments  groups  giving  and  were  single  fragments  fragments  [Hpz*-Me]  would  charged  seen  at  m/e  a t m/e  m/e  are extensive  gallate of  +  a t m/e  404  a t m/e  bromides  and  [Hpz*B] 173,  592  and  were 553,  366. +  a t m/e  [pz]  +  a t m/e  199, 66  43.  Some f r a g m e n t s u n d e r  large  bromide  i m p o r t a n t f r a g m e n t s were t h e  at  peak  recombination  de-chlorinated  was  and  isopropyl  removed f r o m  Other  t h e most i n t e n s e  molecule  spectra  I t seemed  m/e  a  mass/charge  respectively.  Single  [Bpz*2Co]  the 445.  o f f but  ,  parent  from  i n the  the  of  at  715.  a t m/e  +  an  exchange  the  Hpz*  complexes.  species  was  a t m/e  +  [Bpz*2Co]  metal  seen  interesting  There  ligand  were  was  633.  3  633  peak  gave  [HBpz* CoBr]  gave  parent  ( F i g . 2 . 5 ) . L o s s o f HC1  corresponding chloride  o f HBpz*3CoCl  peaks  200  2  a r e shown i n t a b l e  to ring  rearrangement  complexes ^ in this  were due  which  region. 2.2.  opening  possibilities  accounted  for  the  Assignments  of  the  26 Mass S p e c t r u m o f  HBpz*3CoCl  27 T a b l e 2.2  Mass S p e c t r a l A s s i g n m e n t s m/e  Intensity  of HBpz* CoCl 3  Assignment  715  50  [HBpz* CoBr]  +  671  35  [HBpz* CoCl]  +  633  100  592  <5  589  10  [HBpz* Co(3-iPr-pz)Cl]  553  15  [Bpz* Co(3-iPr-pz)]  526  15  [Bpz* CoBr]  +  482  20  [Bpz* CoCl]  +  445  100  404  15  [HBpz*Co(4-Br-pz)]  366  15  [HBpz*Co ( 3 - i P r - p z ) ]  317  10  m = 633/  e = 2  223  10  m = 446;  e = 2  199  10  [Hpz*B]  188  10  [Hpz*]  173  5  [Hpz*  -  Me]  158  <5  [Hpz*  -  Me ]  132  5  [BrCCCHN]  119  5  [(3-iPrpz)B]  92  10  80  5  [pzCH ]  66  5  [Hpz]  55  5  [iPrC]  43  15  3  3  [Bpz* Co]  +  3  [HBpz* Co(4-Br-pz)]  +  2  2  2  2  2  [Bpz* Co]  +  2  +  +  3  [iPr]  +  +  +  +  2  [pzCCH ] 3  +  +  +  +  +  +  +  +  +  28 2.3.1b Mass S p e c t r u m  o f HBpz*3Copz BH  The  of  intensity 445  corresponding  a l l . Low  m/e  780  the  loss  to  (as s e e n  to  and of  s e e n a t m/e The  peaks  loss  pz  and  pz*  major  sturdier  bond  to  the  ligand.  Loss  of  pz  from  fragment  a t m/e  203.  There  ions  produced  417  to  and  observed  that  tables  similar  the  low  633  and  [HBpz*2Co] were  seen  pz*  for  not  +  seen  fragments  from the p a r e n t at corresponding to  parent  molecule  was  to  that  of  centre i n those  formed  the  [HBPZ3]  relatively +  at  a t m/e  m/e 348.  high  484/  the  starting  +  [BPZ3C0]  and  [Bpz2l•  intensity  [HBPZ3C0PZ2B]  +  T h i s same phenomenon  of the  displayed  the  [Bpz2Co]  HBpz*3Copz"3BH  A l l o f t h e o t h e r complexes  2.1.b  at  [HBpz*3]~  recombinations of  mass s p e c t r a  and  fragment  d i d the  gave  +  +  ligand  than  fragments  [HBPZ3C0PZ3B]  i n the  2.1.a  centre  of  +  [BPZ3C0]  [HBpz3]~  were  were  [(Bpz2)2^o]  the  [Bpz3Co]  s u g g e s t i n g t h e HBpz*3 l i g a n d cobalt  and  +  fragment  from  ligand  HBpz*3Copz3GaMe c o m p l e x e s . in  A  the  cobalt  [BPZ2C0] w i t h t h e  corresponding  was  and  peak o b s e r v e d was  indicated  a t m/e  a t m/e  a  580.  This  The  were  o f pz  271.  and  peaks  [HBpz*3Co]  respectively.  both  The  showed  i n t h e p r e v i o u s spectrum)  the  659  HBpz*3Copz3BH  848.  the  intensity  corresponding  m/e  spectrum  p a r e n t peak a t m/e  fragments at  mass  3  mass  compound,  spectra  and  listed more  HBpz*3CoCl/  f o r m e d t h e s t u r d i e r bond t o t h e  complexes.  T a b l e 2.3  Mass S p e c t r a l A s s i g n m e n t s o f HBpz*3Copz3BH  m/e  Intensity  Assignment  848  <5  [HBpz* Copz BH]  780  <5  [HBpz* Copz B]  +  659  <5  [Bpz* Copz BH]  +  580  <5  [Bpz* Copz ]  484  70  [HBpz Copz B]  +  417  65  [HBpz Copz B]  +  348  25  [(Bpz ) Co]  271  100  262  30  [MeCopz*H]  203  80  [Bpz Co]  188  25  [pz*]  173  85  [pz*-Me]  94  95  m = 188, e = 2  78  30  [HpzC]  68  45  [Hpz]  +  43  45  [iPr]  +  41  45  [NNCH]  3  3  3  2  2  3  2  +  2  3  3  3  2  2  +  2  [Bpz Co]  +  3  +  +  2  +  +  +  +  +  30 2.3.1c Mass S p e c t r u m  o f HBpz*3Cop_z2GaMe2  The p a r e n t peak o f HBpz*3Copz2GaMe2 was in  the  m/e  spectrum  854  parent  at  m/e  869.  The  major  corresponding to the loss molecule.  This  was  the  spectrum  HBpz*3Cop'Z2GaMe  pattern  as  dimethyl bis-chelating  that  seen  corresponding  [Copz*2  B H  spectra.  ]  in  to  respectively  +  These  peaks  was  has  2  mass  a  of  the peaks  fragments  were  of  absent  high in  the  similar  the  were  from t h e complexes  ligands.  spectrum  The  mass  fragmention the  starting  a t m/e  633  [Bpz*3Co] intensity  the  trace  observed at  o f a methyl group  compound, HBpz 3C0CI. I n p a r t i c u l a r 445  peak  observed i n a l l of  incorporating of  s e e n as a  mass  and and  +  in  both  spectrum  of  HBpz*3Copz3BH. The  introduction  of gallium  new  isotopic patterns that  The  fragment  assignments  Of p a r t i c u l a r molecular the gave  fragment,  attributed  There  m/e  251  complex  a t m/e  appears  weight  +  picked  seen  o f p z by  to give the ion t o be  gallium  i s consistent  up  fragments.  at  corresponding to a pz  moiety  i o n a t m/e  +  m/e  pz*  high  974  i n the  that  921.  which  was  fragment,  [HBpz*3Copz(pz*)GaMe] . +  dimerization  with  fragments.  2.4.  854,  [HBpz*3Copz3GaMe]  t o the replacement +  the  produced  were t h e r e c o m b i n a t i o n s a t  r e c o m b i n a t i o n was  [HBpz*3Copz2GaMe]  molecular  a r e made i n t a b l e  [HBpz*3Copz2GaMe]  the t r i s - c h e l a t e d Another  helped to i d e n t i f y  interest  w e i g h t s . The  i n t o t h e complexes  o f some o f t h e  F o r example  [Me2GapzGaMe] . +  small  t h e peak  at  31 Table  2.4  Mass S p e c t r a l  Assignments  o f HBpz*3Copz2GaMe2  m/e  Intensity  974  20  921  5  869  <5  [HBpz* Copz GaMe ]  854  45  [HBpz* Copz GaMe]  786  25  [Bpz* CopzGaMe]  715  5  680  15  664  100  633  25  620  5  586  20  [pz*2 P GaMe]  514  20  [HBpz* Copz]  466  30  [pz*Copz2GaMe]  445  30  [Copz* BH]  419  15  [HBpz*pz GaMe]  392  20  [pz*pz2Ga]  358  20  [BrCopz GaMe]  332  25  m = 664  251  10  [MeGapzGaMe ]  205  10  [Gapz ]  190  5  [Hpz*B]  188  5  [Hpz*]  Assignment  [HBpz* Copz pz*GaMe ] 3  2  [HBpz* Copz GaMe] 3  +  2  +  3  3  2  3  +  2  +  2  +  3  [Bpz* Copz Me] 3  +  2  [Bpz*2Copz GaMe ] 2  [Bpz* Copz GaMe] 2  +  2  +  2  [Bpz* Co]  +  3  [Bpz*(4-Br-pz)Copz2GaMe] C o  z  +  +  +  2  +  +  2  +  2  +  +  2  e = 2 +  2  +  2  +  +  continued  32 Table  2.4  continued  173  10  [Hpz*-Me]  151  10  [MeGapz]  99  15  [GaMe ]  94  10  m = 188  79/81  <5  78  2.3.2  +  +  2  [Br]  +  [Bpz]  5  e  +  69/71  15  [Ga]  68  20  [Hpz]  55  10  [iPrC]  43  10  [iPr]  41  15  [NNCH]  +  +  +  +  +  X-ray C r y s t a l l o g r a p h y  Several described four  +  crystal  techniques  i n the experimental  coordinate  benzene.  A  and  X-ray  the  growth  coordinate  starting  crystal  complexes  section of t h i s  compounds  suitable single  were  were  crystal  structure  initially  attempted chapter.  recrystallized  o f HBpz*3CoCl  was  gave  a viscous  The from  was  determined.  as  grown  The  five  material  that  c o u l d be d r i e d by h e a t i n g t o 70 °C u n d e r vacuum. T h e s e d r i e d compounds  were  not  organic  solvents  viscous  again.  hygroscopic  from Several  the of  glove the  but  would  rapidly  box  atmosphere  six  coordinate  pick  to  up  become  complexes  33 effloresced the  solvent  weakly  once was  bound.  was grown  the solvent intrinsic  A  from  suitable  2.3.2a The S o l i d  chelating length  by  State Molecular  three  94.4(3)°. Comparing  centre  b u t was  o f HBpz*3Nipz"3BH  growing  a p p a r a t u s and  S t r u c t u r e o f HBpz*3CoCl  i n HBpz* CoCl  ( F i g . 2.6) i s  3  pyrazolyl  nitrogens  and t h e a v e r a g e  these  of  2.207(3) A a n d a v e r a g e  it  i s clear  Figure  crystal  lattice  from  the  tris-  l i g a n d a n d one c h l o r i d e l i g a n d . The mean Co-N b o n d  i s 2.045(7) A  trigonal  single  Presumably  s t r u c t u r e was d e t e r m i n e d .  cobalt[II]  coordinated  removed.  to the crystal  CH2CI2 i n t h e c r y s t a l  the X-ray c r y s t a l  The  had been  that  pyramidal  2.6  Solid  data  with  N-Co-Cl  the three  the Co-Cl bond  nitrogens  s t r u c t u r e with  State Molecular  N-Co-N  angle form  bond bond  angle i s distance  o f 122.1(3)°, t h e base  of a  t h e c h l o r i d e a t t h e apex.  Structure of HBpz* CoCl 3  34 This  structure  along  then  has C 3  symmetry  V  with  the 3-fold  t h e C o - C l b o n d . The i s o p r o p y l g r o u p s a t t h e 3 p o s i t i o n  are  a r r a n g e d s u c h t h a t t h e two m e t h y l g r o u p s a r e b e n t  the  metal A  stereoscopic  2.3.2b The S o l i d  The  view o f t h e s t r u c t u r e , c r y s t a l l o g r a p h i c  lengths  three  have mean  In angle on has  the structure  3  The t h r e e  3 v  A  axes  symmetry  along  conformational  coordination ligand.  with  The  of  N-Ni-N b o n d nitrogens  lengths  from t h e metal c e n t r e A  stereoscopic  parameters  and  a p p e n d i x 3.b.  angles  from  the  o f 2.15(1) A and  o f 89.0(5)°.  the trans-nitrogens  nickel  are at a metal  at the o r i g i n .  mean  bonds l i e  The  molecule  t h e B-Ni-B a x i s . change h a s b e e n b r o u g h t  the  isopropyl  nitrogens  l i g a n d have mean N i -  and average  N-Ni bond  3  ( F i g . 2.7) i s  3  o f 1 7 9 . 4 ( 5 ) ° a n d so t h e s i x n i t r o g e n  Cartesian C  3  3  coordinating  a v e r a g e N-Ni-N b o n d a n g l e s  of HBPZ* NJPZ" BH  o f HBpz* Nipz" BH  o f 2.07(1) A The  ligand  3  Structure  t h e n i c k e l from t h e HBpz"  88.9(5)°.  HBpz*  State Molecular  a r e i n a p p e n d i x 3.a.  by s i x p y r a z o l y l n i t r o g e n s .  coordinating  of  and angles  n i c k e l [ I I ] centre  coordinated  bond  toward  centre.  parameters and bond l e n g t h s  N  axis  about  by t h e  tris(3,5-dimethylpyrazolyl)borate  methyl  groups  a r e now  pointing  away  (cf HBpz* CoCl). 3  view o f t h e s t r u c t u r e , c r y s t a l l o g r a p h i c  bond  lengths  and  angles  are  listed  in  35  Figure  2.3.3  2.7  Solid  Molecular  Structure  of  HBpz*3Nipz"3BH  E l e c t r o n i c Spectroscopy  The ligand spectra  e l e c t r o n i c t r a n s i t i o n s of  complexes from  (4,000 cm" and  State  1  were  the near  infrared to  t o 40,000 c m  s i x coordinate  36) . A l l s p e c t r a dissolved  investigated  - 1  ).  complexes were  done  i n benzene, a g a i n s t  The  by  solvated,  recording  series included 2.5.a  and  analytically  a benzene  mixed-  absorption  the u l t r a - v i o l e t  (Tables with  the  region  four,  five  2.5.b,  page  pure  reference.  samples  36 T a b l e 2.5.a  L  UV/Vis S p e c t r o s c o p i c Data o f H B p z * N i L & ( L = mono- a n d t r i s - c h e l a t i n g l i g a n d s ) 3  Dq (cm ) -1  CI  680  B (cm"" )® 1  Absorption Extinction  1030  1140  3  823  1090  3  720  1080  3  740  924  3  740  L  2  2  Me Gapz"  2  7  4  28  8  8  11  5  6  30  10  Peaks.(cm )* Coefficients(Lmol cm ) - 1  -1  -1  200  220  140  1  9  220  100  17  30  272  36000 31700 25700 15900 11200 6620  440  @  17  36000 32700 26500 16800 11400 6710  2  600  & *  130  36000 32300 27000 18200 11500 6540  2  Me Gapz  2  440  3  550 2  92  36000 32900 26700 17400 11700 6900 700 230 100 22 28 170  2  Me Bpz  100  UV/Vis S p e c t r o s c o p i c Data o f H B p z * N i L ( L = b i s chelate ligands ) Absorption Extinction  H Bpz  500  36000 24300 14900  1800  T a b l e 2.5.b  1  36000 26800 17200 10800  80 MeGapz"  1  36000 26500 17400 10900  330 MeGapz  - 1  36000 28900 18100 11400  100 HBpz"  (cm )* Coefficients(Lmol~ cm~ )  36000 20800 17900 12400 10900 6060  970 HBpz  Peaks  293  80  11  70  460  D i s s o l v e d i n benzene. E r r o r s i n a b s o r p t i o n peak p o s i t i o n s were d e t e r m i n e d by s u c c e s s i v e measurements a n d were o f t h e o r d e r o f 1-2%. N i c k e l f r e e i o n R a c a h p a r a m e t e r B ° = 1080 c m - 1  37 One assume  method  a  higher  present.  The  particular The  For be  symmetry  assumes are  arranged  example  the  six  octahedral  cause s p l i t t i n g  a  absorption the  of  field (B)  are  symmetry small  metal  d  ->  is a  have  or  d  field (10  assumed is  strengths not  a  (g) .  the  ligand  p a r i t y of  field  does  are  inversion  and  not  have  forbidden  and  transition ligand  orbitals. have  g  Octahedral  the  octahedral d  states are  expected.  the  and  parities  orbitals  that  Both Racah  between  The  d  the  made.  These  such The  are  g)  and  complex  of  are  inversion.  will  in  the  centre  coefficients  of  and  allowed  (g ->  arranged  an  B r o a d bands  shifts  each  forbidden).  even  to  only  strengths.  Dq)  for  transitions  disturb  tetrahedral  ligand  from  symmetry.  s i m i l a r symmetries  energy  arise  ligands  centre  t h e n does not the  (Laporte  #  point  symmetries  expected that  ligand f i e l d  (u)  extinction  complexes  with  t r a n s i t i o n s are  odd  so  the  21,22,23  be  method  higher  in  spectra.  calculated  elements t h a t  either  complexes way  can  to  actually  realistic  This  from the  splitting  parities  symmetry  is  is  equivalent  complexes  compounds  are  Electronic like  are  highest  symmetry.  reflect  comparisons of the  of  i n the  numbers i t w o u l d be  crystal  than  nickel[II]  ligands  observed i n these  peaks  parameter  the  deviations  series  coordination  of  coordinate (0^)  complex  of degenerate e l e c t r o n i c l e v e l s .  e x p e c t e d and In  the  spectra  interpreted in this  that  and  of  of  electronic spectra  a p p r o x i m a t i o n and  are  interpreting electronic  have b e e n w e l l  method  dipoles  of  an  field  However  inversion  38 centre  and  result  i s that  g symmetry  d i s t o r t s the the  forbiddeness  tetrahedral  complexes  coefficients  are  tetrahedral  complexes  comparison  of  is  of  than  2.5.b  shows t h i s t r e n d .  is  seen  in  the  darker  complexes  compared  coordinate  complexes.  2.3.3a The  Tetrahedal  orbitals.  d  Higher  extinction  complexes.  coefficients in  The  Tables  of  the  paler  four  colors  A  2.5.a  macroscopic e f f e c t of  the  The  transitions in  octahedral  colors  with  ->  d  e l e c t r o n i c t r a n s i t i o n s of  of  extinction  and  d  relaxed.  expected i n the  the  of the  this  coordinate of  the  six  Approximation of HBpz*3NiCl  A t e t r a h e d r a l l i g a n d f i e l d model i s used to p r e d i c t  the  allowed e l e c t r o n i c t r a n s i t i o n e n e r g i e s of HBpz*3NiCl. The  transitions for a d ,  t e t r a h e d r a l complex  8  >  3 _ T]  3  ->  3  •>  3  •>  1  •>  There transitions. calculated  are The fit  three  spin  observed from  T  A  v  1  2  v  2  Ti(P)  v  E(D) *T  2  2  3  spin (G)  and  peaks  are  Tanabe-Sugano  forbidden  spin  allowed  t e t r a h e d r a l l i g a n d environment  are:  two  spin  forbidden  compared  diagrams  (Fig. 2 . 9 ,  forbidden  Table  with  for 2.6).  a  a d  8  (nm)  Figure Table  2.9 E l e c t r o n i c 2.6  of HBpz*3NiCl  C a l c u l a t e d and Observed E l e c t r o n i c Energies of HBpz*3NiCl  Observed 6060  @  Spectrum  (cm )  C a l c u l a t e d (cm" )  - 1  10900  (440)  12400  (92)  17900  (100)  20800  (500)  36000  (970)  Charge t r a n s f e r  cm" . 1  v  5790  x  1  E(D)  12400  v 1  2  T (G) 2  v  20300  3  C.T. band  # Extinction  The Dq a n d B v a l u e s c a l c u l a t e d 1030  Assignment  1  (130)*  Transition  e  coefficients  are : D  = 680 cm" ; 1  q  B =  40 The  calculated  energies  fit  assignment  and  within  of  observed  3  near  %.  spin  The  allowed t r a n s i t i o n s  close  tetrahedral  fit  symmetry  supports to  the  the four  c o o r d i n a t e complex i n s o l u t i o n . The state  spin forbidden  to  the  singlet  bands at 17,900 cm A  descent  -1  of  t r a n s i t i o n s from the excited  states  ( A - > T ) and 3  2  symmetry  to  ground  assigned  10,870 cm  1  2  are  triplet  to  < A -> E).  -1  3  1  2  a t r i g o n a l pyramidal  geometry would cause s p l i t t i n g of the t r i p l e t  the  terms and  (C3 ) V  band  broadening.  2.3.3b The  The nearly  Octahedral Approximation of HBpz*3Nipz"3BH  c r y s t a l structure  octahedral  of HBpz*3Nipz"3BH showed a very  structure  model might be expected t o be The  3  so  an  octahedral  ligand  a good approximation.  expected t r a n s i t i o n s f o r a d^ o c t a h e d r a l  •>  A g 2  ->  •> ->  3  T g  3 T  3  transitions.  are The  three  spin  observed  l 2  lg  T  l g  are:  v  2  v  (P)  v  3  spin  ^gW  ->  There  field  (D)  allowed  and  peaks  are  spin  two  spin  compared  forbidden with  a  41  calculated  f i t from  octahedral O  ligand  Tanabe-Sugano  environment  diagrams  ( F i g . 2.10/  for  a  d  8  Table 2.7).  I  o " m  190  1000  2000 (nm)  Figure Table  2.10 E l e c t r o n i c 2.7  Spectrum o f HBpz*3Nipz"3BH  C a l c u l a t e d and Observed E l e c t r o n i c E n e r g i e s o f HBpz 3 N i p z B H  Transition  3  Observed  (cm" )  Calculated  10900  (8)  10900  V]_  17400  (8)  17000  v  2  26500  (28)  26500  v  3  36000  (330)  1  (cm ) - 1  Assignment  C.T.  The Dq and B v a l u e s c a l c u l a t e d are : Dq = 720 1090  1  B =  cm" . 1  The within  cm" ;  3  calculated %. The  octahedral solution.  close  symmetry  and  observed t r a n s i t i o n  f i t supports the to  the  six  energies f i t  assignment  coordinate  of  complex  near in  42 A  descent  triplet A the  state  o f symmetry w o u l d  a  splitting  of the  terms and t h e b r o a d e n i n g o f bands.  comparison  nickel  cause  of the c r y s t a l f i e l d  octahedral  when  complexed  from  strong  with  field  complexes  (Table  HBpz*3NiCl  ligand  splittings  the  t o weak  2.5.a)  ligands  field  (10 Dq) o f showed  were  ligand  that  ordered,  as  HBPZ3  >  HBpz"3 ~ MeGapz3 > MeGapz"3. A a  stronger  field  s t r o n g base t h a t  sterically  small  higher  pyrazolyl the  so  opposite  If electronic  analog.  ring and  so  at  approach  the  e f f e c t s were d o m i n a n t  then  boron  would a  effect.  make  The  Steric  field  the  and ring  field  ligand  would  5  around  strength  the  ligand  than  is  positions  more  field  make  reverse  basic  ligand,  conditions  [HB(3-iPr-4-Br-pz)3]~  determined the l i g a n d  3  the  stronger  i s observed.  just  the  either  t o the metal centre or  physically  of  However,  substitutions  electronic ligand,  i t can  t o be  r i n g more a c i d i c a n d so a weaker f i e l d  pyrazolyl effect)  that  electronegativity  gallium  Methyl  w o u l d be e x p e c t e d  would b i n d t i g h t l y  m e t a l more c l o s e l y . the  ligand  but  strength  imposed  by  the metal of t h i s  on  seen. the  (inductive again  the  i s n o t an the centre  series.  bulky has  43 Coordinate Nickel r i l l  2.3.3c F i v e  for  There  are c r y s t a l  high  spin  bipyramidal  field  configurations  2 2  models t h a t  nickel[II] (°3h) .  An  a n c  Complexes  complexes  *  square  attempt  was  have been  proposed  in  trigonal  pyramidal  2.8  (C4 ) V  made t o f i t t h e e l e c t r o n i c  s p e c t r u m o f HBpz*3Nipz2BH2 t o t h e s e m o d e l s  Table  both  (Table 2.8).  C a l c u l a t e d and Observed E l e c t r o n i c T r a n s i t i o n E n e r g i e s o f HBpz 3Nipz2BH2  Calculated  Observed (cm )  Calculated  (cm )  - 1  (cm )  - 1  D  Calculated (cm" )  - 1  3h  c  1  4v  Oh  6900  (170)  6900  6900  11700  (28)  13500  9320  11700  17400  (22)  14600  14100  17500  26700  (100)  22500  23200  27200  32500  (230)  26400  39300  36000  (700)  It  CT.  i s clear  spectrum  so  that  CT. CT,  CT,  neither  HBpz*3Nipz2BH2  model  possess  fits  the  neither  observed  of  these  symmetries. There complexes trigonal  a r e a few e x a m p l e s whose  electronic  bipyramidal  model  2 4  of five  coordinate  transition J25  #  energies  crystal  nickel[II] f i t the  structure  of  44  one  such complex, Me Gapz"(OCH2CH2NMe2)Nipz" GaMe2/ showed a 2  distorted  2  trigonal  structure  also  bipyramidal  showed  pyrazolylgallate coordinated  the  stucture. unsymmetrical  ligand,  in  a  crystal  tridentate  [Me Gapz"(OCH CH NMe2)]~ 2  meridonal  2  fashion,  2  which  i n s t r u m e n t a l i n the s t u c t u r a l symmetry. The used i n the m i x e d - l i g a n d  The  may  be  [HBpz*3]~ l i g a n d  complex s e r i e s w i l l o n l y  coordinate  i n a f a c i a l manner. The showed that  UV/Vis  an  spectra  a d d i t i o n a l band  is  not  seen  in  coordinate  complexes  extinction  coefficient  L m o l c m ) and - 1  - 1  »0  as  the  at  the  five  32,500  spectra  (cf. F i g . of t h i s  initially  400  F i g u r e 2.11  assigned  of  coordinate cm"" of  2.10 band  (as  1  and  the  a  shoulder)  four  Fig.  i s not  complexes  or  six  2.11).  The  large  (200-410  i t seemed the band c o u l d be  190  (n«)  «00  (nm)  UV/Vis S p e c t r a o f HBpz*3Nipz2BH2 i n Benzene and THF as S o l v e n t s a charge t r a n s f e r r e s u l t i n g  benzene  molecule.  However  spectra  of H B p z * N i p z B H 3  2  2  a  comparison  recorded  with  from a of  the  coordinated electronic  different  solvents  45 (benzene  and  THF)  showed o n l y  a slight  benzene m o l e c u l e had been c o o r d i n a t e d a  loss  band  of  at  a  charge  41,500  m o l e c u l e had In  could  The  ( F i g . 2.11)  - 1  there  i n bands.  should  If a  have  been  appearance of a  suggested  that  symmetry  a  THF  o f an  was  good.  octahedral  calculated  The  high  band  complex  (Table  a  2.8)  a t 32,500  f i t to  and cm  could  - 1  be  assigned  therefore  making  the  an  the f i t  t o a c h a r g e t r a n s f e r b u t t h e low b a n d a t 6090  not  new  coordinated.  reasonably  assigned  cm  anticipation  octahedral was  t r a n s f e r band.  shift  be cm"  1  0^  model  mixed  ligand  inappropriate.  2.4  Conclusion  The  syntheses  compounds  were  analytically The  and  refined  pure  mass  purifications to  give  of  good  the  yields  than  evidenced  spectral  any  of  by  the  corresponding  to  evidence  the  other  appearance the  ions  [MeGapz3M] , r e s p e c t i v e l y (M = +  Numerous c r y s t a l crystals  of  HBpz*3Nipz"3BH, produced.  of  products. showed  that  HBpz"3~ and MeGapz3~ l i g a n d s bound more t i g h t l y center  (60-90%)  only  ligands  of  intense  [HBpZ3M] , +  suitable  compounds, for  HBpz3~,  t o the metal  the  peaks  series at  as  masses  [HBpz'^M]" " 1  and  Ni,Co).  growth t e c h n i q u e s two  in  the  X-ray  were  attempted  HBpz*3CoCl  crystallography  but and were  46 The HBpz*3CoCl complex  a  at  the  four  state  the  s o l i d  and  starting  state  of  material,  structure  symmetry.  the  structure  ligands.  metal  with  the  of  The  formed  the three  the  chlorine  on  The the  four  by  atetrahedral  approximated  base ligand  f i e l d  gave  ligand  was  as  by  the  pocket  the an  The bipyramidal  of the  f i e l d  a  five  because  of  an  HBpz"3~  position  3  to  coordinate  and  the  of  the  t r i s a  [HBpz*3Ni]  by  rotation  pz*  showed  HBpz*3NiCl  two showed  the  ligand  evidenced  when of  coordinate  an  coordinate  +  of  ring. the  was  geometry  approximated  nor  with  HBpz3  of  the  complexes  >  HBpz"3  HBpz*3NiCl. of  was  the  ~  This active  [HBpz*3]~. fit  pyramidal symmetry  band  comparison  control  complexes  octahedral  geometry  octahedral of  steric  ligand  A  the  order  square  unassignable  of  complexed the  complex  symmetry.  strength  result  (03^) fit  the  the  also  imparted  energies  intermediate  to  was  that  of  structure  complex,  six  s p l i t t i n g  attempt  six  arrangement  octahedral  MeGapz"3  >  the  was  showed  symmetry.  by  crystal  in  complex  spectral  coordinate  Similarly  MeGapz3  in  electronic  of  the  that  coordination group  HBpz*3Nipz"3BH  of  The  change  isopropyl  a  of  octahedral  conformational complex  structure  structure  nearly  order  the  coordinating  pyramidal  crystal  chelating  the  of  apex.  The  very  that  coordinate  nitrogens  trigonal  s o l i d  structure  determined  was  pyrazolyl of  crystal  at  was  6900  neither (C4 ) V  also c m  -  1  .  a  trigonal  model.  The  unsuccessful Further  work  47 needs  to  be  done  to  elucidate  the  structures  of  these  complexes. The ligand  active  i n t h e complexes  characterization The  pocket created  series  ligands,  the  steric  Trofimenko's intermediate  [HBpz*3]MCl series  demonstrated  conformational coordination  of  by  of a substrate  of in  been  binding  substrate the  ligand.  p r o b e d by t h e  mixed-ligand  preferential  control changes  of  have  metal  complexes. of  some  ligands  and  complexes  on  48 Chapter  III  R h o d i u m [ I ] Complexes o f Pyrazolylgallate  3.1  are  a  complexes  that  activity.  These  an to  important a  have  step  Their Reactivity  complete  coordinate complex  a  coordination important  Rh(PPh3)3Cl, hydrogenation oxidative Another  show  electron  activity.  produces  The  a  six  complex,  must  cycle, A  for  square  look  perhaps  alkenes ^.  addition important  2  of  H2  a l s o take  planar,  place  a  four  rhodium[I]  providing  empty  another  reagent.  the  reactions. the  reductive  substrates,  activity  at  is  addition  regenerating  incoming  for catalytic  of  and  coordinate,  reaction,  complex.  catalysed is  species  reverse  of a c a t a l y t i c  to  catalytic  Oxidative  c o o r d i n a t i v e l y unsaturated,  When l o o k i n g  rhodium[I]  undergo o x i d a t i v e a d d i t i o n s . T h i s  catalytic  feature  successfully  to  sixteen  rhodium[III]  sites  important  are  complex  rhodium[I]  coordinate  reported  in catalytic  a  i s also  four  been  complex. of  of  complexes  rhodium[I]  elimination  is  number  expected to r e a d i l y  rhodium[III]  to  L i g a n d s and  Introduction  There  are  Unsymmetrical  most The and  rhodium[I]  i n a new  intermediate  steps  Wilkinson's known  for  catalytic ft  species i t  bonding catalytic  catalyst,  its steps of  in  an  catalytic include alkene.  reagent  is  49 RhH (CO) (PPh.3) 2/ The  catalytic  bonding  used  steps  i n the hydroformylation include  o f an a l k e n e  monoxide.  The  and a d d i t i o n  Monsanto  reagent,  catalyst  i n the synthesis  in  reaction  this  oxidative  of  o f E2,  addition  and i n s e r t i o n Rh(C0)2l2'  of acetic  acid  are the oxidative  2 8  ,  ^  s  u s e c  reaction  that  of  carbon-hydrogen  number  of  five  reported that  coordinate  in  Me Gapz(OC H N) 9  oxidative carbonyl  6  in  3 2  ,  addition  unsymmetric,  t  3.0  addition complexes  s  a  steps  important  o f R-H). A have  been  catalysis LRh(CO)  arose (L =  with  pyrazolyl-  reports  31  have  33  2  o f Mel and t h e subsequent  insertion  shown of a  (Fig. 3.0).  VCOt2063(CH CI )  v C O » 1 7 2 0 (CH^CI,)  2  O x i d a t i v e A d d i t i o n o f Mel and C a r b o n y l I n s e r t i o n on Me Gapz(OCH2CH NMe )Rh(CO) 2  that  Me2Gapz(OCH2CH2NMe2) ,  Me2Gapz(OCH (C5H4N) )  2  t  tridentate  i n t o t h e rhodium-methyl bond  VC0:1»55 (CH,Cl )  Figure  the  of formula  2  rhodium[I]  a  2  ligands  complexes  (ie. oxidative  TZ  i s the activation  show t h i s t y p e o f a c t i v i t y ^ / 3 0  Interest gallate  bonds  .  o f CH3I a n d  and i n s e r t i o n o f c a r b o n monoxide. A n o t h e r significance  *  important  addition  2 7  o f carbon  addition  has c a t a l y t i c  alkenes  2  2  50 This  activity  prompted  s i m i l a r rhodium[I] complexes  further  investigations  of  and t h e r e s u l t s a r e r e p o r t e d i n  t h i s chapter. The  unsymmetric,  are  derived  one  of the p y r a z o l y l  3.1).  Tris  lone p a i r s  pyrazolylgallate  from t h e [Me2Gapz2]~ l i g a n d  chelation  rings  can take  place  ligands  by replacement o f  with a b i f u n c t i o n a l  on t h e n i t r o g e n  donor atoms  through  of the p y r a z o l y l  moiety ( F i g the electron ring  and t h e  (X and Y) o f t h e b i f u n c t i o n a l moiety. The donor  atoms may be v a r i e d pyrazolyl  tridentate  and s u b s t i t u e n t s  ring providing  steric  may be added  and e l e c t r o n i c  t o the  c o n t r o l . The  carbon fragment o f t h e b i f u n c t i o n a l moiety may be v a r i e d and through  adroit  substitutions  can c o n t r o l  mode of t h e l i g a n d . These l i g a n d s to  coordinate  meridional  2 4  F i g u r e 3.1  i n either  The c o o r d i n a t i o n  may be important i n b i n d i n g  coordination  have been shown t o be able  t o t r a n s i t i o n metals  fashion .  the  a f a c i a l or  mode o f t h e l i g a n d  a s u b s t r a t e t o t h e metal  T r i s - C h e l a t i n g Unsymmetric Ligand  centre.  Pyrazolylgallate  51 A common c a t a l y t i c a  coordination  reattachment suggested that  site  i s the loss  f o r substrate  of a ligand to free  binding.  o f the l i g a n d t o complete  the use o f a m u l t i d e n t a t e  i f the displaced  ligand,  step  i t would  be  l i g a n d were  held  subsequent  the c a t a l y t i c  for a  on a  more  multidentate  expedient  a t t a c h m e n t . The u n s y m m e t r i c p y r a z o l y l g a l l a t e s l i g a n d s to  offer In  two  this this  chapter  was  c a r b o n c h a i n was  and  -CH=CH2  3.2  by  are  described.  varying  -CH2-CH2-.  and were  and  incorporating  unsubstituted,  the  (but)  preparations  ligands,  prepared  pyrazolyl. ring  the  complexes,  pyrazolylgallates were  re-  seemed  potential.  rhodium[I]  used  cycle  l i g a n d . The r e a s o n i n g i s an arm  nearby  The  only  reactivities the The  the  of  unsymmetric two  Y  ligands  group.  t h e X d o n o r was  The  oxygen and  The Y d o n o r g r o u p s were - N H 2  abbreviated  (EA)  f o r ethanolamino  and  f o r but-3-enolate.  Experimental  The  syntheses  Na [Me2Gapz(but)]~  are reported  +  were c a r r i e d purified  by  Microanalyses  out under the  methods  results  Na [Me2Gapz(EA)]~ +  i n chapter  a nitrogen  were a t t e m p t e d  gave s a t i s f a c t o r y  of  2. A l l r e a c t i o n s  atmosphere.  described  in  on a l l compounds  are reported.  and  Solvents  were  chapter  2.  and t h o s e  that  52 3.2.1 P r e p a r a t i o n o f Me?Gaoz(EA)Rh(CO)  Na [Me Gapz(EA)]" +  2  reflux  +  l/2[Rh(C0) Cl] 2  Me Gapz (EA)Rh(CO)  >  2  + CO + NaCl  2  Two molar e q u i v a l e n t s o f N a [ M e G a p z ( E A ) ] ~ +  2  in  THF were added  (0.198  g;  mixture hours.  0.510  was  t o a molar  mmole)  refluxed  The  equivalent  dissolved  under  disappearance  of  s t r e t c h e s a t 2070 and 1985 c m  -1  the  o f rhodium  i n 150 ml  a nitrogen  rhodium  -1  (THF) monitored  dimer  o f THF. The  atmosphere dimer  f o r 16 carbonyl  (THF) i n t h e IR spectrum and  the appearance o f the product monocarbonyl cm  (1.02 mmole)  the progress  stretch  at 1945  of the reaction ( F i g .  3.2). The mixture was made up t o a known volume w i t h THF and s t o r e d under n i t r o g e n .  2000  2000  2000  c a  [Rh(CO) Cl] 2  F i g u r e 3.2  2  3 hour r e f l u x  Me Gapz(EA)Rh(CO) 2  IR S p e c t r a o f [ R h ( C O ) C 1 ] t h e r e a c t i o n mixture a f t e r a 3 hour r e f l u x and Me Gapz(EA)Rh(CO) 2  2/  2  53 3.2.2  Preparation  of Me2Gapz(but)Rh(CO)  Na [Me Gapz(but)]" + 1/2 [ R h ( C O ) C l ]  >  +  2  2  Two  molar  mmole) i n THF dimer  (0.538  mixture  was  hours.  The  + CO + NaCl  equivalents  were added g; 1.38  of  (THF) was  under  the  a of  nitrogen the  -1  2  2  hours  carbonyl  -1  for  18  carbonyl  stretch  at  1995  r e a c t i o n . The and  cm  -1  mixture  s t o r e d under  a  2  Me Gapz" (EA) Rh (CO) 2  + CO + NaCl  2  r e a c t i o n was  c a r r i e d out  r e a c t i o n s . The under  of Me Gapz"(EA)Rh(CO)  a  i n a s i m i l a r fashion  r e a c t i o n mixture was  nitrogen  atmosphere.  The  (THF). The  s o l v e n t was  as  refluxed for rhodium  s t r e t c h e s i n the IR spectrum at 2070 and 1985  (THF) were r e p l a c e d by c a r b o n y l 2020 c m  dimer  The  (THF) i n the IR spectrum and  —X—> reflux  +  above  rhodium  atmosphere.  Attempted P r e p a r a t i o n  The  of  atmosphere  rhodium  monocarbonyl  N a [Me Gapz" (EA) ] ~ + 1/2 [ R h ( C O ) C l ]  18  equivalent  made up t o a known volume w i t h THF  3.2.3  the  2  monitored the p r o g r e s s of the  nitrogen  (2.77  +  t o a molar  disappearance  of  Na [Me Gapz(but)]~  miftole) d i s s o l v e d i n 150 ml of THF.  refluxed  appearance  2  2  s t r e t c h e s at 2070 and 1985 c m the  Me Gapz(but)Rh(CO)  reflux  dimer cm  -1  s t r e t c h e s at 2098, 2075 and s t r i p p e d o f f under vacuum  54 leaving and  a brown s o l i d .  the  mixture  evaporate  was  slowly  compound  solid  filtered.  to  analysed  This  promote  for  was  The  solvent  crystal  C7H7N202Rh,  i n CH2CI2  redissolved was  growth. as  the  allowed  The  to  isolated  probable  dimer  [Rh(CO) pz"] . 2  2  Microanalysis:  Calc. Found  3.2.4  C C  activation  Reactions  affected electron density  to by  the  the  11.03 10.80  carbon-hydrogen  attempted  bond  with  both  2  The  oxidation  metal  by  changes  ability  carbonyl  donating a b i l i t y about  and  were  were m o n i t o r e d  the  N N  Me Gapz(but)Rh(CO).  of the carbonyl region. bond  2.76 3.02  addition  reactions  2  H H  Complexes  addition,  M e G a p z ( E A ) R h ( C O ) and  back  Z  33.08 33.31  Reactions of Rhfll  Oxidative  [Rh(CO)2P "]2  i n the  o f t h e rhodium  antibonding state  of the  of  the  orbitals  the  ligands.  center,  IR  metal  The  weaker  spectrum centre to will and  be the  more  electron  the  carbonyl  stretch.  3.2.4a O x i d a t i v e A d d i t i o n R e a c t i o n s  An  e x c e s s o f Mel  was  added t o a s t i r r e d  Me2Gapz(EA)Rh(CO) and t h e m i x t u r e was  THF  refluxed  solution  f o r one  of  hour.  55 The  carbonyl  shifted C-0  stretching  from 1945 cm'  stretch  frequencies  i n the  (THF) t o 2030 cm"  1  o f t h e product  was  IR  (THF).  1  consistent  spectrum  The h i g h e r  with  a  higher  o x i d a t i o n s t a t e o f t h e rhodium c e n t r e . O x i d a t i v e a d d i t i o n o f Mel  to  the  coordinate  rhodium[I]  rhodium[III]  complex  would  produce  the s i x  adduct, Me2Gapz(EA)Rh(CO)(Me)I ( F i g  3 . 3 . a ) . The s o l v e n t was removed under vacuum l e a v i n g a dark red  solid.  mixture  This  solid  was f i l t e r e d .  was  r e d i s s o l v e d i n CH2CI2  The s o l v e n t was allowed  s l o w l y t o promote c r y s t a l  to  and t h e evaporate  growth. The i s o l a t e d compound was  u n i d e n t i f i a b l e by m i c r o a n a l y s i s . A  carbonyl  insertion  into  t h e newly  formed  rhodium-  methyl bond was a n t i c i p a t e d but t h e r e was no evidence  o f an  a c e t y l group i n t h e IR spectrum o f t h e p r o d u c t .  F i g u r e 3 . 3 . a P r e p a r a t i o n o f Me2Gapz(EA)Rh(CO)(Me)(I)  In a subsequent r e a c t i o n t h e mixture  was r e f l u x e d f o r  4 days. The c a r b o n y l s t r e t c h s h i f t e d from 2030 cm" 2060  cm"  leaving  1  a  (THF). dark  The  solvent  red s o l i d .  This  was  removed  solid  was  1  under  (THF) t o vacuum  redissolved i n  56 CH2CI2  and  solvent  the  left  mixture  a solid  filtered.  that  a n a l y s e d as  This  C C  compound  Me Gapz(EA)Rh(CO) which  clear. rhodium  rhodium[IV] of  a  rhodium[III]  measure w o u l d An  Me Gapz(EA)Rh(CO) carbonyl  stretch  (THF)  2095  oxidative  cm  - 1  redissolved was  allowed  that  of  I2  a  evaporate  way  i s not to  the  produced an  a  iodo  a salt  conductivity  possibility. to  a  THF  refluxed  solution  of  f o r 2 hours.  The  s h i f t e d from  shift  was  to  The  the  solvent solid.  The  1945  consistent  produce  the mixture slowly.  have  which  reddish-brown  and  bonded  have been  spectrum  (Fig. 3.3.b).  i n CH2CI2  unidentifiable.  as a  added  (THF) . The  leaving  to  may  the mixture IR  was  would  complex  was  addition  vacuum  iodide  to  The  i n t o the structure  second  complex  i n the  Me2Gapz(EA)Rh(CO)I2 under  I2  Mel2  of 2  cationic  and  2  to  the  The  of  addition  2  have e s t a b l i s h e d  excess  of  6.71 6.81  Me Gapz(EA)Rh(CO)(Me)I •  because  complex.  evaporation  CcjHis^C^T^Rh'  N N  incorporated  i s unlikely centre  2.89 2.97  net  give  t h e M e l 2 was  It  H H  the  to  2  in  17.24 17.62  was  slow  Me2Gapz(EA)Rh(CO)(Me)I2  Microanalysis:  Calc. Found  The  filtered. isolated  - 1  an  complex  was  This  with  cm  removed  solid  The  was  solvent  solid  was  57  »- : 1945 (THF)  r  co  Figure  3.3.b P r e p a r a t i o n  An e x c e s s of  M e G a p z (EA) Rh (CO) i n THF 2  carbonyl (THF)  stretch  to  oxidative the  of a l l y l  2065  addition  complex,  mixture  1  Figures  and s t i r r e d  was  bromide  from  When  the carbonyl  d i s a p p e a r e d . Presumably  the rx a l l y l  Me Gapz(EA)Rh(CO)(allyl)Br Me Gapz(EA)Rh(n -allyl)Br 2  3  2  The  with  - 1  an  3.3.C) t o p r o d u c e  f o r one h o u r ,  3.3.C 3.3.d  solution  1945 c m  consistent  (Fig.  2  2  f o r one h o u r .  shifted  Me Gapz(EA)Rh(CO)(allyl)Br.  was r e f l u x e d  IR s p e c t r u m  2  b r o m i d e was a d d e d t o a  (THF) w h i c h  of a l l y l  :  of Me Gapz(EA)Rh(CO)I  i n t h e IR s p e c t r u m cm"  CO 2095 (THF)  the reaction band  i n the  complex,  58 Me2Gapz(EA)Rh(n^-allyl)Br a  carbonyl  successfully  ligand  was  produced  ( F i g . 3.3.d).  through  Neither  loss  product  of was  isolated.  3.2.4b A d d i t i o n R e a c t i o n s  Carbon  bubbled  through  solution  o f M e 2 G a p z ( E A )fch(CO)  f o r one  carbonyl  stretch  which  monoxide  is  was  Figures  Ethene  consistent  was  suggesting (Fig.  hour.  The  (0°C)  THF  1945  cm""  with  the  ( F i g . 3.3.e).  dicarbonyl The  1  cm  - 1  species,  compound  was  not  isolated.  3.3.e  Me2Gapz(EA)Rh(CO)2  was b u b b l e d t h r o u g h a c o l d  Me2Gapz (EA)Rh(CO) stretch  cold  was r e p l a c e d by b a n d s a t 2075 a n d 2015  Me2Gapz(EA)Rh(CO)2 successfully  a  for  replaced the  3.3.f).  one  hour.  by  two  formation  of  This  The  bands isomers  compound  (0°C) THF s o l u t i o n o f  was  at  1945  cm"  2075  and  of  carbonyl  1  2005  t h e ethene  recrystallized  cm  - 1  adduct from  59  methylene c h l o r i d e and analysed as Me2Gapz(EA)Rh(CO)(ethene) • 0.5  CH C1 . 2  2  M i c r o a n a l y s i s : Me Gapz(EA)Rh(CO)(ethene)•0.5 CH Cl2 2  Calc. Found  C C  29.30 29.01  F i g u r e s 3.3.f  2  H H  4.70 4.61  N N  9.79 9.70  Me Gapz(EA)Rh(CO)(ethene) 2  3.2.4c A c t i v a t i o n o f Carbon-Hydrogen Bonds There are a few t r i p o d a l ligand systems reported t h a t activate  carbon-hydrogen  complex/  HBpz^Rh (CO)  2 /  photochemically hydrocarbons.  bonds **'30. reported  activates For  T^e  2  example/  by  Graham  aromatic when  a  pyrazolyl  and  benzene  et  based al./  saturated solution  HBpz*3Rh(CO)2 i s i r r a d i a t e d f o r 5 minutes with  of  a mercury  lamp there i s complete conversion to HBpz^RMCO) ( C 5 H 5 ) (H) . The success of HBpz^RhtCO)  2  activator  prompted the  as a carbon-hydrogen  investigation  of the  bond  unsymmetrical  60 tridentate LRh(CO) this  pyrazolylgallate 2  type  2  of  added  dicarbonyl  t o the HBpz'^Rh(CO) An of  attempt benzene  complex,  ice  a  solution  for  complexes,  made  with  appearance  tube.  The  tube  was  The  consistent  with  The  hours  lamp.  2  2  a  mercury  so  i t was  The  There  concluded  that  analogous  was  benzene  immersed  i n an  through  the  recorded  the  2030 c m  (benzene)  dicarbonyl  complex,  irradiated no  no  and  - 1  was was  five  monocarbonyl  in  spectra  the  solution  was  bubbled  IR  the  carbon-hydrogen  dissolved  monoxide  Me Gapz(EA)Rh(CO) . by  the 2  was  these  Graham.  activate  2  hour.  of  that  o f c a r b o n y l bands a t 2095 and  were  both  Me Gapz(EA)Rh(CO) .  carbon  2  LRh(C0) , 2  to  2  forming  complex r e p o r t e d by  2  was  one  2  carbonyl  adduct,  irradiation  and  2  Additionally,  2  i n an  spectrum  2  Me Gapz(EA)Rh(CO)  bath  that  2  behaviour.  readily  coordinate,  placed  carbonyl  (L = M e G a p z ( 0 C H C H N H ) , M e G a p z ( O C H C H C H = C H ) ) f o r  complexes  bond  rhodium[I]  change  for  in  activation  the  had  six IR  taken  place. The  five  (CO)(ethene) of  ethene  (Fig. 3.3.f), through  Me Gapz(EA)Rh(CO). 2  hydrogen  bond  coordinate  of  s e v e r a l h o u r s . No  In  ethene  was  Me Gapz(EA)Rh2  p r e p a r e d by b u b b l i n g a  a  cold  an  attempt  benzene  adduct,  this  a c t i v a t i o n was  benzene to  solution  solution  activate was  observed.  stream  a  of  carbon  irradiated  for  61 3.2.4d R e a c t i o n s o f M e G a p z ( b u t ) R h ( C O ) 2  The  reactivity  reaction  of  additions  additions  of carbonyl  dicarbonyl  o f Mel, I  3.3  Infrared  and a l l y l  2  and ethene  and ethene  adducts  a c t i v a t i o n b u t no r e a c t i v i t y reactions,  was  2  w i t h t h e same r e a g e n t s .  oxidative  The  Me Gapz(but)Rh(CO)  with relevant  evidence bromide,  ligands were  tested  suggested as w e l l  had taken  tested  by  as  place.  f o r C-H  bond  was o b s e r v e d . A s y n o p s i s o f t h e  IR s t r e t c h e s  i s shown i n f i g u r e  3.4  Conclusions  The  rhodium[I] monocarbonyl p y r a z o l y l g a l l a t e  appearred  t o take  reactions  b u t no f u r t h e r  The  versatility  substitutional on  part  the  i n oxidative activity  of these  possibilities.  unsymmetrical  demonstrated  by  2  after  2  oxidative  the  2  2  that  t h e donor  on  t h e former i s methyl  shown  addition  lies  that a  i n t h e numerous of substitutions ligands the  carbonyl  nitrogen  group  was  complex insertion  ( F i g . 3.0) where t h e complex  d i d n o t . The c o m p l e x e s d i f f e r  2  in  had  fact  and  observed.  The s u b t l e t y  o f Mel  Me Gapz(OCH CH NH )Rh(CO) 2  ligands  the  2  addition  was  pyrazolylgallate  Me Gapz(OCH CH NMe )Rh(CO) 2  additions  complexes  only  o f t h e b i f u n c t i o n a l moiety  substituted.  Figure  3.4  Reactions  o f Me2Gapz(but)Rh(CO)  64 Chapter Heterobimetallic  IV  Complexes I n c o r p o r a t i n g  Pyrazolylborate  Ligands  4.1 I n t r o d u c t i o n  It bonds  i s thought  t h e study  and t h e c o o p e r a t i v e  centers  in  particular In  halides Mo-Cu  higher  of  the  HBpz3,  order  have b e e n and  reactivity  carried  Mo-Sn 3 5  '  3 6  with  '  metal  .  This  been  present  +  3  [CuPPh Cl]4, 3  are discussed.  GePh Cl 3  lead  metal to  an  with  a  . metal-metal  bonds t h e  [LMo(C0)3]~  a variety  have  different  clusters,  anions,  of K [HBpz" Mo(CO)3]~  tetramer  3 4  metal-metal  will  (L  of t r a n s i t i o n  o u t . Complexes  bonds 3 7  between  t o form  molybdenum  HBpz'^)  of simple  complexes  reference to c a t a l y s i s  characterized  results  of  a continuing effort  reactions MeGapz3,  effects  heterobimetallic  understanding  the  that  with  direct  prepared chapter  towards  metal Mo-Rh,  and details  SnMe Cl, 3  and N i ( P P h 3 ) C l 2 2  =  fully the  SnPh Cl, 3  and t h e  65 4.2 E x p e r i m e n t a l  The  synthesis  described  in  of the tridentate  chapter  2.  The  [CuPPh3Cl]4  was  SnMe3Cl  was o b t a i n e d  from  3 8  Chemicals,  obtained  from  Alfa  SnPh Cl,  and N i ( P P h 3 ) C l  GePh Cl  3  3  Chemicals  +  tetramer  p r e p a r e d by a l i t e r a t u r e m e t h o d . Aldrich  K [HBpz"3]~, i s  ligand,  2  a n d were  used  without  were  2  further-  purification.  4.2.1  Preparation  Mo (CO)  +  6  o f (MeCN)3M0(CO)3  3 MeCN  (MeCN) 3 M 0 (CO) 3  >  +  3 CO  reflux  and  A  round  one  gram  bottom  flask  o f Mo(CO)g.  yellowish-green  color  atmosphere.  leaving  yellowish-green,  the  that  quality The  The  during  nitrogen  important  was  charged  colorless a  sixty  The s o l v e n t  t h e MeCN  with  hour  freshly  starting  pyrazolyl  complex  acetonitrile quantitative  material  dried  anion,  ligands yields  are  f o r the  of products.  under  a  under  vacuum, It  was  and d i s t i l l e d  as  inferior. found  preparation  [ (HBpz'^) (CO) 3M0] ~ easily  a  crystals.  (MeCN) 3M0 (CO) 3 , h a s b e e n  compound,  turned  reflux  was removed,  o f t h e p r o d u c t was o t h e r w i s e  preferred  solution  air-sensitive be  120 ml o f MeCN  removed  t o be a of the  39.40  allowing  #  T  h  e  almost  66 The stretches  4.2.2  IR  spectrum  a t 1912  and  +  +  3  1773  (MeCN)3M0(CO) 3  cm  showed  (THF) .  - 1  4 1  (MeCN)3M0(CO)3  >  K [(HBpz" )(CO)3M0]~ +  3  reflux  A molar dissolved  overnight was  i n 50  ml  and  and  1720  reaction. w i t h THF  4.2.3  carbonyl  (THF)  1  a  THF  reaction from  dark  a  1773  cm  then  the  made  a nitrogen  up  to  equivalent  green  the  infrared  to  1885,1760  a  of  known  the  volume  Complexes  3  of the tetramer,  over night  t o d a r k brown was  green  atmosphere.  +  scirred  of  stirred  completion  [CuPPh3Cl]4  o f THF,  s o l u t i o n of K [(HBpz"3)(CO)3M0]~ was  mmole),  solution  (THF)  - 1  0.482 mmole) d i s s o l v e d i n 50 ml  mixture  3.63  THF  in  (HBpz"3)(CO)3MoCuPPh  of  g;  green t o dark  stretches  of Heterobimetallic  molar  to  light  signalling  s t o r e d under  (1.22  -  added  from  and  s o l u t i o n was  4.2.3a P r e p a r a t i o n  to  1912  + 3 MeCN  mmole). The m i x t u r e was  The  Preparation  (0.174 g;  3.63  change  cm"  A quarter  was  a color  from  and  THF,  g;  shifted  The  +  of  (1.10  observed.  spectrum  of K [ H B p z " 3 ]  equivalent  (MeCN)3M0(CO)3  carbonyl  o f K + H H B p z " 3) Mo (CO) 31 ~  Preparation  K [HBpz" ]"  of  (1.93  and  a  o b s e r v e d . The  was  added  mmole). color  The  change  solvent  was  67 removed  under  to  o f hexane was  evaporate  o b t a i n e d by  1885  leaving  slowly.  added  carbonyl  and  1780 cm  stretches  Calc. Found  A molar  to  mmoles). removed  C C  a  equal  mixture allowed  samples  were  IR s p e c t r u m  Preparation  of  of Cul  of Ph PCH2PPh 2  solution  vacuum  4.85  finally  were s e e n  at  10.47  10.50  (HBpz"3) (CO) 3 M 0 C U ( P P h o )  (0.168  g;  (0.336  2  0.880  g;  stirred  overnight.  a green  of  hexane  allowed  to  evaporate  slowly.  and No  the  The  solid.  portion  added  0.880  (0.880  solid  f i l t e r e d . An  analytically  was was  equal  mixture pure  a  were  solvent  This  solvent  and  mmoles)  +  i n C H 2 C I 2 and t h e m i x t u r e was was  mmoles)  K [(HBpz"3)(CO)3M0]~  of  leaving  N N  4.64  redissolved  were o b t a i n e d .  was  (HBpz'^)(CO)3MoCuPPh3 H H  m i x t u r e was  under  solid  benzene.  i n the  54.13  THF  The  This  f i l t e r e d . An  solvent  pure  from  53.85  equivalent  equivalent  added  solid.  (Nujol).  - 1  Attempted  the  Analytically  Microanalysis:  molar  and  recrystallization  The  4.2.3b  a brown  i n C H 2 C I 2 and t h e m i x t u r e was  redissolved portion  vacuum  was  samples  68 4.2.3c P r e p a r a t i o n  A molar dissolved  of  (HBpz"3)(CO)3MoSnMe  equivalent  o f SnMe3Cl  (0.332 g; 1.67 mmole),  i n 50 ml o f THF, was a d d e d t o a THF s o l u t i o n o f  K [(HBpz'^)(CO)3M0]~  (1.67 mmole).  +  The m i x t u r e  overnight  and a c o l o r  change f r o m  observed.  The s o l v e n t  was  removed  This  solid  yellowish-brown and  solid.  dark  and  the solvent  mixture  green  under  was  stirred  t o brown  vacuum  was  leaving  a  was r e d i s s o l v e d i n CH2CI2  t h e m i x t u r e was f i l t e r e d . An e q u a l  added  3  was  p o r t i o n o f h e x a n e was allowed  to  evaporate  slowly.  Microanalysis: Calcd. Found  4.2.3d P r e p a r a t i o n  A molar dissolved  C C  equivalent  13.11 13.30  N N  4.88 5.03  o f SnPt^Cl  (0.643 g; 1.67 mmole),  i n 50 m l o f THF, was a d d e d t o a THF s o l u t i o n o f  overnight  and a c o l o r  observed.  The s o l v e n t  the  H H  3  +  mixture  39.35 39.44  o f (HBpz"3)(CO) MoSnPh3  K [(HBpz"3)(CO)3M0]~  yellow  (HBpz'^)(CO)3MoSnMe3  solid.  This  filtered.  (1.67 mmole). change f r o m was  solid  removed  The m i x t u r e dark  green  under  was  stirred  t o yellow  vacuum  was  leaving  a  was r e d i s s o l v e d i n CH2CI2 a n d t h e  An e q u a l  portion  s o l v e n t m i x t u r e was a l l o w e d  o f hexane was a d d e d a n d  t o evaporate  slowly.  69 The  carbonyl  1955 a n d 1865 c m  stretches  Calcd. Found  dissolved K  +  C C  Preparation  A molar  (HBpz'^) (CO)3MoSnPh3  52.22 51.85  H H  4.59 4.49  3  ml  of GePh Cl 3  o f THF,  [ (HBpz"3) (CO)3M0]~  was  (0.298 mmole).  and a c o l o r  change f r o m  observed.  The  was  solid.  mixture and  was  solvent This  filtered.  the solvent The  solid An  m i x t u r e was  carbonyl  2000 a n d 1915 c m  - 1  stretches  green  under  portion  C C  mmole),  solution of was  stirred  t o orange  vacuum  leaving  i n CH2CI2  allowed t o evaporate  was an  and t h e  o f hexane was  added  slowly.  i n t h e IR s p e c t r u m were s e e n a t  (THF).  Microanalysis: Calcd. Found  0.298  The m i x t u r e  redissolved  equal  3  (0.101 g;  dark  removed was  10.15 9.95  a d d e d t o a THF  overnight  orange  N N  o f (HBPZ" )(CO)3MoGePh  equivalent  i n 50  were s e e n a t  (Nujol).  - 1  Microanalysis:  4.2.3e  i n t h e IR s p e c t r u m  (HBpz'^)(CO)3MoGePh3  55.36 55.24  H H  4.78 5.00  N N  10.76 11.00  70 4.2.3f A t t e m p t e d  Preparation of  (HBpz"3)(CO) MoNi(PPh )0 3  A  molar  mmole), of  3  equivalent  dissolved  i n 50  of  ml  was  solid  3  o v e r n i g h t w i t h no  removed  under  was  filtered.  equal  mixture  isolated  p r o d u c t was  The  a  dark  CH2CI2  and  1910  of  hexane  allowed not  cm  to  The  g;  c h a n g e . The green the was  i n the  by  IR  0.298  solution  mixture  was  solvent  solid.  This  mixture  was  added  evaporate  identifiable  carbonyl stretches  1995,1935 and  4.3  was  mmole).  leaving in  (0.195  2  a d d e d t o a THF  color  portion  solvent  2  apparent  vacuum  redissolved An  was  (0.298  +  stirred  3  THF,  K [ ( H B p z " ) (CO) Mo]" 3  Ni(PPh ) C1  and  the  slowly.  The  microanalysis.  spectrum  were s e e n  at  (THF).  - 1  Discussion  The  reactions  [ (HBpz" ) ( C O ) M o ] ~ 3  with  3  successful  of  the  transition  metal  organometallic halides  synthesis  of  several  new  anion,  led to  the  heterobimetallic  complexes. The  reaction  a  brown  gave  of  3  3  was  not o b t a i n e d but  of  the  structure 3  3  A  crystal  with  that structure  [CuPPh Cl] 3  analysed of  this  i n f e r e n c e s were made by t h e  of  (MeGapz )(CO) MoCuPPh 3  3  compound  (HBpz" )(CO) MoCuPPh . 3  [(HBpz" )(CO) Mo]"  an 3  has  analogous been  compound.  made  and  an  4  as  complex  examination  The X-ray  compound crystal  71 structure showed  that  geometry fold  has  arrangement  The  3  had  t h e molybdenum  along  essentially  determined ^.  t h e molecule  about  axis  been  the  a  centre  nearly  ( F i g . 4.0.) . symmetric  capped  linear  The  about  with  structure  octahedral  (3:3:1)  an a p p r o x i m a t e Ga**Mo—Cu  three  this  crystal  axis.  CO  atomic  ligands  The  3-  were  solution  IR  s p e c t r u m o f t h e Cu complex showed two c a r b o n y l b a n d s a t 1898 and  1798  symmetry  cm  X-ray  t h e Cu  distances Mo-C-0  which  v  were  consistent  with  a  were  bond  interactions  data  centre  suggested  and t h e c a r b o n y l  2.259(6),  angles  there  2.274(7)  were  near  were  V  interactions  carbons  ( t h e Cu-C  a n d 2.419(6) A ) . The mean linear  which  were o f t h e s e m i - b r i d g i n g t y p e .  implied  r Ph  4.0  i  p  Ph  3:3:1 S t r u c t u r e o f  (MeGapz )(CO) MoCuPPh 3  the  The i n t e r a c t i o n  Me  Figure  C3  (a a n d e m o d e s ) . The  between  (CH2Cl2)'  - 1  3  3  72 between t h e bond  Cu  and  (2.5041(8)  Mo  A)  moieties  and  c o n s i s t e d of  some t y p e  of  a  direct  semi-bridging  Cu-Mo  carbonyl  interaction. The carbonyl  IR  spectra  stretches  similarity  of  at  the  ( H B p z " ) (CO) 3M0CUPPI13  of  1885  and  spectra  of  (HBpz'^) (CO) 3M0CUPPI13  suggested  structures,  a  with  that  was  equivalent, The  yellow  compound structure  made by  the  the  structure the  Mo  An  atomic  symmetrically  C-0  showed  and  possibility  carbonyl  ligands.  as  significantly intermolecular  crystal  X-ray  octahedral C3  inferences  (3:3:1) axis  with  solid  1.139(3)  that  hydrogen from of  gave  3  the  bands  different  splitting  SnPh Cl  but  the  one from  ligands  state  IR  spectrum and  terminal  1.141(3)  the  the  arranged  This  mode  would  i n the  thus  of  this  1875  A).  two  the  cm  carbonyls.  carbonyl  other  symmetry e  1900  The  X-ray  groups due  was  to  have  explaining  - 1  terminal  The  solid  of  about  along  CO  and  bonding. C3  existed  A  crystal  geometry  expected range f o r  of  a  were  structure  the  (1990,  were w i t h i n t h e  departure  structure  (HBpz"3)(CO)3MoSnPh3.  w h i c h were c o n s i s t e n t w i t h  showed  similar  3  three  structure  of  (MeGapz3> (CO)3MoSnPh3 ^. The  i t . The  (1.154(4),  caused  (MeGapz3) (CO) 3M0CUPPI13  determined  arrangement  carbonyls  a  The  octahedral  approximate  about  bond l e n g t h s  about  of  showed a c a p p e d  Ga**Mo—Sn  (Nujol)),  not  complex,  centre.  complex  was  two  (THF) .  - 1  capped  analysed  examination  analogous  cm  [ (HBpz"3) ( C O ^ M o ] " w i t h  that  crystal  1780  the  3:3:1  semi-bridging  r e a c t i o n of  showed  3  weak  brought  state the  and  three  73 bands  that  were  seen  i n t h e IR spectrum.  between t h e Mo and Sn m o i e t i e s Mo-Sn bond The two  of a d i r e c t  (2.8579(3) A ) .  carbonyl  s t r e t c h e s a t 1955 and 1865 c m  bands  i n t h e IR s p e c t r a  the c a r b o n y l  ligands.  A  The  -1  3:3:1  capped  indicated a C 3  octahedral  structure  V  compound  The Ga analog  symmetry carbonyl  with  three  l i g a n d s was surmised.  r e a c t i o n of [(HBpz"3) (CO)3M0]~ with  yellowish-brown  showed  (THF). The two  band p o s i t i o n s suggested t e r m i n a l  equivalent terminal carbonyl  SnMe3-  consisted solely  s o l u t i o n IR spectrum o f (HBpz'^) (CO) 3 M o S n P h 3  carbonyl and  The i n t e r a c t i o n  that  of t h i s  analysed  as  SnMe Cl gave a 3  (HBpz'^)(CO)3M0-  complex was made but an X-ray  crystal  s t r u c t u r e has not been determined. The s o l u t i o n IR  spectra  o f t h e two complexes were s i m i l a r  terminal  carbonyls.  This  suggested  and showed  structures  three  similar  to  (MeGapz )(CO) MoSnPh3. 3  The orange  3  r e a c t i o n of [ (HBpz"3) ( C O ^ M o ]  compound t h a t  solution stretches  IR spectrum  of t h i s  as  3  (HBpz'^)(CO)3MoGePh3.  compound  showed two  carbonyl  symmetry  and t h e  c a r b o n y l band p o s i t i o n s suggested t e r m i n a l c a r b o n y l  ligands.  i n t h e IR s p e c t r a  3:3:1  capped  octahedral  terminal carbonyl  -1  (THF) .  The  carbonyl  A  and 1915 c m  with G e P h C l gave an  The two  bands  a t 2000  analysed  -  indicated a C 3  structure  V  with  l i g a n d s was surmised.  three  equivalent  74 4.4  Conclusion  Several the have  pyrazolyl been  have  been  new  based  capped  molybdenum  synthesised. made  [(MeGapz3)(CO)3M0]~ structures  heterobimetallic  by  comparing  a r e known.  octahedral  anion,  Inferences  analogs, The  complexes  for  their  which  the  and  ligands  with  the  crystal  t o be a l l  centred  molybdenum. The Mo-Cu complex h a d s e m i - b r i d g i n g of the carbonyl  with  appeared  (3:3:1)  -  structures  spectra  structures  structures  [ (HBpz"3) ( C O ^ M o ]  about IR  incorporating  about  interactions  t h e two m e t a l s where t h e Mo-Sn  Mo-Ge c o m p l e x e s showed o n l y t e r m i n a l  carbonyl  ligands.  75  Chapter V Summary  The has  versatility  been  demonstrated  presented In  i n this  chapter  complex  an  ligand  with  less  mixed-ligand  metal  microanalysis,  mass  electronic  the  three  ligand  systems  different  studies  thesis.  incorporating  compounds  by  2 the r e a c t i v e pocket  pyrazolylborate  that  of the p y r a z o l y l based  intermediate,  was  probed  sterically  by p r e p a r i n g  a  hindered s e r i e s of  sterically  hindered  complexes  were  characterised  X-ray  crystallography  spectrometry,  spectroscopy.  the ligands  of a t r a n s i t i o n metal  The mass  [HBpz^] , -  ligands.  spectrometry  [HBpz'^]  -  and  [MeGapz3]~  formed  hindered  [ H B p z * 3 ] ~ l i g a n d . The e l e c t r o n i c s p e c t r o s c o p y bulk  of the substrate  determined the strength crystal  structure  HBpz*3CoCl  showed  transition  energies  the  nickel  predicted The  analog,  HBpz*3Nipz"3BH two  a  coordinate  trigonal  derived  from  HBpz*3NiCl  structure showed  tris-chelating  of  a near  pyrazolyl  study  ligands  centre.  starting  The  compound,  stucture.  The  the e l e c t r o n i c spectrum o f  compared  the  sterically  tridentate  pyramidal  transitions for a tetrahedral  crystal  d i d the  of bonding t o the metal  of the four  and  showed  bonds t o n i c k e l a n d c o b a l t  the s t e r i c  by  study  stronger  showed  than  These  six  ligand  with  field  coordinate  octahedral ligands.  favorably  model.  complex,  arrangement  The c r y s t a l  the  of the  structure  76 also  showed  brought  a  about  transition  by  nickel  the  predicted  derived  complex,  The  transitions  and  intermediate  of  no  on  the  I2  was  ligand was  addition  Mel  the  of  and  allyl  ligand  species  observed.  the  and  many  nitrogen  donor  by  substitutional many  differs was  f o r C-H  subtlety  oxidative  bond of  also  carbon  activation  substitutions effect  the  on  oxidative  Me Gapz(OCH CH NH2)Rh(CO) 2  2  The  methyl  compounds  and  subsequent  latter  from the  possibilities more  complexes,  ethene  comparing  complexes,  group  more  studies.  rhodium[I]  their  2  i n s e r t i o n and  not  numerous  provide  with  The  demonstrated to  field  was  The  of  with  bromide. These complexes  reactions  systems  The  favorably  study.  will  Me2Gapz(0CH CH2NMe2)Rh(CO).  provide  spectrum  coordinate  c o m p l e x e s were t e s t e d  activity  carbonyl  electronic  octahedral  planar  ligand  ligand.  Me2Gapz(but)Rh(CO) underwent  addition  reactivity  and  bulky  substrate  compared  further  square  o f Mel,  m o n o x i d e . The but  five  the  l i g a n d metal complexes f o r f u t u r e  Me2Gapz(EA)Rh(CO) and  underwent  a  an  possibilities  The  additions  in  from the  for  the  needs  substitutional  of  HBpz*3Nipz"3BH  stucture  determined  change  complexation  energies  the  model.  conformational  2  underwent  former only  substituted.  on  the  to  be  ligand tested  in  for  that  Again  system  a  the will  catalytic  activity. In synthesized moieties  the with was  fourth  chapter  several  d i r e c t metal-metal the  molybdenum  new  compounds  b o n d s . One  anion,  of  the  were metal  [HBpz"3(CO)3M0]~,  77 incorporating Reaction with  with  Mo-Cu,  surmised known  the  by  tridentate  transition Mo-Sn  and  octahedrons  the  complexes Ph)  (3:3:1)  carbonyl  of  about  3  terminal  involve  p y r a z o l y l based  bonds.  IR  had  ligands.  structures  with  be  metals  studies  metals  and  The  interactions  3  transition  of  capped  centre.  semi-bridging  Future  were  complexes to  molybdenum  both  complexes  while  and HBpz" (CO)3MoSnR  carbonyls.  other  The  seemed  between  ligand.  produced  spectra  the  complex ligaijds  3  halides  structures  HBpz" (CO) MoGePh3  had only  certainly  Mo-Ge  The  HBpz"3(CO)3MoCuPPh3 of  metal  comparisons  structures.  pyrazolylborate  3  the  (R = Me, will  most  substituted  78 References  1  S. T r o f i m e n k o ,  A c c t s . Chem. R e s . 4., 17  (1971).  2  S. T r o f i m e n k o ,  Chem. Rev. 22, 497  3  A. S h a v e r ,  4  S. T r o f i m e n k o ,  I n o r g . 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W.B.  81 Appendix 1 Crystal  Grower  c  82  Appendix Isotopic 11  Clusters  2 o f B, Ga B r and CI 68  22  7 9  BA  71  37  10 201  261  Br3B2  182  Br2Bs  Br  Ga  CI  B  171  Br 2 B  00  Br B  m/e  Isotopic  Clusters  331  267  Br B  250  Br BCI  4  400  o f B, Ga Br and C l  Br B  3  321  •iHllllil.i  •HHlll.i  Br4GaB  Br,GaB  m/e  3  2*0  JliuL Br2GaB  161  Jli_ BrGaB  85 Bond  lengths  standard  in parentheses  Length(A)  Bond  Br( 1 )-C(2) Br(2)-C(5) Co - C l Co -N(2) Co - N U ) N O )-N(2) NO)-C(l) N( 1 ) - B N(2)-C(3) N(3)-N(4) N(3)-C(4)  1.874(10) 1.876(7) 2.207(3) 2.057(9) 2.039(6) 1.385(11) 1.358(12) 1.514(13) 1 . 3 0 9 ( 13) 1 .383(8) 1 .332(8)  N(3)-B N(4)-C(6) C( 1 ) - C ( 2 ) C(2)-C(3) C(3)-C(7) C(4)-C(5) C(5)-C(6) C(6)-C(9) C(7)-C(8) C(9)-C(10) C(9)-C(11)  angles  standard Bonds -Co -Co -Co  N(2)-Co N(2)-Co N(4)-Co  -N(2) -N(4) -N(4)' -N(4)  -NU)'  -N(4)'  N(2)-N(1] - C O ) N(2)-N(1]i - B CO ) - N ( l ]• -B CO -N(2]l-NO) Co -N(2]l-C(3) N( 1)-N(2l>-C(3) N(4)-N(3 >-C(4) N(4)-N(3 l-B C(4)-N(3 l-B Co -W(4 |-N(3) Co - N ( 4 ]l-C(6) N(3)-N(4'•-C(6) NO ) - C ( 1 )-C(2)  BrO ) - C ( 2 ) - C ( 1) BrO  deviations  estimated  Bond  Bond  Cl Cl Cl  (A) w i t h  )-C(2)-C(3)  (deg) w i t h  deviations  Length(A) 1 .540(8) 1 .347(9) 1.352(15) 1 . 3 9 7 ( 13) 1.52(2) 1 .360(10) 1 .381(1 1) 1.510(10) 1.513(11) 1 .544 ( 1 4 ) 1.525(15)  estimated  in parentheses  Angle(deg)  Bonds  Angle(deg)  122.7(3) 121.8(2) 121.8(2) 94.1(2) 94.1(2) 94.9(3)  CO  N(2)-C(3)-C(2) N(2)-C(3)-C(7) C(2)-C(3)-C(7)  106.8(9) 108.9(9) 122.8(9) 128.3(9) 108.3(6)  107.5(9)  Br(2)-C(5)-C(6)  126.5(6) 126.3(5) 107.2(6)  121.9(7) 130.6(9) 109.3(6) 142.3(7) 108.4(8) 109.3(5) 120.5(6) 130.2(6) 110.6(4) 142.8(5) 106.5(6) 108.4(9) 125.9(7) 127.3(8)  )-C(2)-C(3)  N(3)-CU)-C(5) Br(2)-C(5)-CU) C(4)-C(5)-C(6) N(4)-C(6)-C(5) N(4)-C(6)-C(9) C(5)-C(6)-C(9) C(3)-C(7)-C(8) C(3)-C(7)-C(8)' C(8)-C(7)-C(8)' C(6)-C(9)-CO0) C(6)-C(9)-C(11) C(10)-C(9)-COD NO)-B -N(3) N(1)-B -N(3)' N(3)-B -N(3)*  108.7(6) 122.7(7) 126.6(7) 111.6(6) 111.6(6) 110.900) 109.8(8) 112.7(8) 110.9(8) 110.2(5) 110.2(5) 109.2(7)  86  Final positional and  isotropic  ( f r a c t i o n a l x 10*; Br, Co, CI x 10 ) s  thermal parameters (U x 10  3  A ) 2  with e s t i m a t e d standard d e v i a t i o n s i n parentheses Atom  X  y  z  U eg  Br(D  0  56130(10)  Br(2)  32108( 5)  -2959( 9)  -27(10)  57  33034  45  Co  0  1747(13)  2422503)  30  CI  0  -1 1245(23)  35014(18)  43  N( 1 )  0  2622( 7)  1 794 ( 5)  32  N(2)  0  2056( 8)  2583( 6)  37  N(3)  861 ( 4)  1070( 5)  927( 4)  33  N(4)  1031 ( 4)  196( 5)  1 546( 4)  36  CO )  0  3858( 9)  1 927 ( 7)  33  C(2)  0  4065( 8)  2774( 7)  26  C(3)  0  291 2 ( 8)  31 69( 7)  32  C(4)  1 535 (5)  1 046 ( 7)  355( 5)  35  C(5)  2138( 5)  148( 7)  581 ( 5)  35  C(6)  1821 ( 5)  -365( 7)  1328( 5)  37  2621(10)  4115( 8)  44  C(7)  0  C(8)  855( 7)  1926( 8)  4375( 5)  59  C(9)  2249( 6)  -1374( 8)  1857( 6)  61  COO)  1 623 ( 8)  -2522( 8)  1852( 7)  78  COD  2455( 7)  -964(11)  2765( 7)  76  0  1889( 9)  975( 7)  29  B  87  68  Empirical  Formula  C(33)H(47)B(2)Br(3)N(12)Ni(l)  Formula  Weight  931.85  Crystal  System  Orthorhombic  Lattice  Parameters:  Space  a b « c -  Group  20.65 (1) angstroms 29.158 (3) angstroms 13.306 (2) angstroms  V -  8011 (4)  Pbca  (#61)  angstroms**3  Z value  8  Dcalc  1.55 g/cm**3  F000  3776  mu(Mo K - a l p h a )  34.90 cm**-l  Di f f T a c t o m e t e r  Rigaku AFC6  Radiation  Mo K-alpha (lambda- 0.71069) Graphite-monochromated  Temperature  21 degrees Cent.  2-theta(max)  50.0 degrees  No. O b s e r v a t i o n s  (I>2.00(sig(I)))  1976  No. V a r i a b l e s  460  Residuals:  0.054; 0.048  R; Rw  Goodness o f F i t I n d i c a t o r  1.37  Maximum S h i f t  0.09  i n Final  Cycle  L a r g e s t Peak i n F i n a l D i f f . Map  0.50  e/angstrom**3  Intramolecular  Distances  I n v o l v i n g t h e Nonhydrogen Atoms  atom  atom  distance  atom  atom  distance  Br(l)  C(2)  1.89(1)  N(9)  N(10)  1.37(2)  Br(2)  C(5)  1.90(1)  N(9)  B(2)  1.49(2)  Br(3)  C(6 )  1.86(1)  N(10)  C(15)  1.33(2)  Ni  N(12)  2.05(1)  N(ll)  C(16)  1.34(2).  Ni  N(8)  2.07(1)  N(ll)  N(12)  1.36(1)  Ni  N(10)  2.08(1)  N(ll)  B(2)  1.54(2)  Ni  N(4)  2.13(1);  N(12)  C(18)  1.34(2)  Ni  N(2)  2.15(1 )  C(l)  C(2)  1.35(2)  Ni  N(6)  2.16(1)  C(2)  C(3)  1.39(2)  N(2)  1.35(1)  C(3)  C(19)  1.52(2)  N(l )  C(l)  1.35(1)  C(4)  C(5)  1.35(2)  N(l )  B(l  1.53(2)  C(5)  C(6)  1.35(2)  N(2 )  C(3)  1.34(2)  C(6)  C(22)  1.51(2)  N(3)  C(4 )  1.32(1 )  C(7)  C(8)  1.37(2)  N( 3)  N( 4 )  1.37(1)  C(8)  C(9)  1.39(2)  N(3)  B(l  1.54(2)  C(9)  C(25)  1.55(2)  N(4)  C(6)  1.38(2)  C(10)  C(ll)  1.33(2)  N(5)  C(7)  1.34(1)  C(10)  C(28)  1.51(2)  N(5)  N(6)  1.38(1)  C(ll)  C(12)  1.41(2)  N(5)  B(l)  1.51(2)  C(12)  C(29)  1.52(2)  N(6)  C(9)  1.32(2)  C(13)  C(14)  1.34(2)  N(7)  C(10)  1.35(2)  C(13)  C(30)  1.49(2)  NO)  N(8)  1.37(1)  C(14)  C(15)  1.42(2)  N(7)  B(2)  1.53(2)  C(15)  C(31)  1.50(2)  N(8)  C(12)  1.30(2)  C(16)  C(17)  1.35(2)  N(9)  C(13)  1.36(2)  C(16)  C(32)  1.52(2)  N(l  )  .  )  )  v  D i s t a n c e s a r e i n angstroms. Estimated standard d e v i a t i o n s i n the l e a s t s i g n i f i c a n t f i g u r e a r e g i v e n i n p a r e n t h e s e s .  I n t r a m o l e c u l a r D i s t a n c e s I n v o l v i n g t h e Nonhydrogen Atoms atom  atom  distance  C(17)  C(18)  1 .38(2)  C(18)  C(33)  1 .51(2)  C(19)  C(21)  1-52(2)  C(19)  C(20)  1 .54(2)  C(22)  C(23)  1 .50(2)  C(22)  C(24)  1 .56(2)  C(25)  C(26)  1 .51(2)  C(25)  C(27)  1 .53(2)  atom  atom  9 0  distance  D i s t a n c e s are i n angstroms. Estimated standard d e v i a t i o n s i n the l e a s t s i g n i f i c a n t f i g u r e a r e g i v e n i n p a r e n t h e s e s .  Intramolecular  Bond A n g l e s  I n v o l v i n g t h e N o n h y d r o g e n Atomt,  atom  atom  atom  angle  atom  atom  atom  N(12)  Ni  N(8)  88.3(5)  C(6)  N( 4 )  Ni  140(1)  N{12)  Ni  N(10)  89.7(5)  C(7)  N(5)  N(6)  108(1)  N(12)  Ni  N(4)  89.8(5)  C(7)  N(5)  B(l)  130(1)  N(12)  Ni  N(2)  91.6(5)  N(6)  N(5)  B(l)  122(1)  N(12)  Ni  N(6)  179.2(4)  C(9)  N(6)  N(5)  107(1)  N(8)  Ni  N(10)  88.7(5)  C(9)  N(6)  Ni  140(1)  N(6)  Ni  N(4)  91.8(5)  N(5)  N(6)  Ni  113(1)  N(8)  Ni  N(2)  179.7(7)  C(10)  N(7)  N(8)  109(1)  N(8)  Ni  N(6)  91.1(5)  C(10)  N(7)  B(2)  134(1)  N(10 )  Ni  N(4)  179.3(5)  N(8)  N(7)  B(2)  117(1)  N(10)  Ni  N(2)  91.0(5)  C(12)  N(8)  N(7)  107(1  N(10)  Ni  N(6)  90.8(5)  C(12)  N(8)  Ni  136(1)  N<4 )  Ni  N(2)  88.4(5)  N'.7 )  N(8)  Ni  117(1  N(4 )  Ni  N(6)  89.7(4)  C(13)  N(9)  N(10)  107(1)  N(2)  Ni  N(6)  88.9(5)  C(13)  N(9  )  B(2)  134(2)  N(2)  N(l )  C(l )  111(1)  N(10)  N(9)  B(2)  119(1  N(2)  N(l)  B(l)  123(1)  C(15)  N(10)  N(9)  110(1)  C(l)  N(l )  B(l)  127(1)  C(15)  N(10)  Ni  135(1  C(3)  N(2)  N(l)  107(1)  N(9)  N(10)  Ni  115(1)  C(3)  N(2)  Ni  141(1)  C(16)  N(ll)  N(12)  110(1)  M(l)  N(2)  Ni  112.8(8)  C(16)  N(ll)  B(2)  132(2)  C(4)  N(3)  H(4)  111(1)  N(12)  N(ll)  B(2)  117(1)  C(4)  N(3)  B(l)  129(1)  C(18)  M(12)  N(ll)  105(1)  M(4)  N(3)  B(l)  120(1)  C(18)  M(12)  Ni  137(1)  M(3)  N<4)  C(6)  105(1)  N(ll)  N(12)  Ni  117(1)  N(3)  N(4)  Ni  115(1)  C(2)  C(l)  N(l)  107(1)  angle  )  )  )  )  Angles are i n degrees. Estimated standard d e v i a t i o n s i n the l e a s t s i g n i f i c a n t f i g u r e a r e given i n parentheses.  Intramolecular  Bond A n g l e s  atom  atom  atom  C(l)  C(2)  C(3)  C(l)  C(2)  C(3)  Involving  the Nonhydrogen  Atoms  atom  atom  atom  107(1)  C(ll)  C(12)  C(29)  126(2)  Br(l)  125(1)  C(14)  C(13)  N(9)  109(2)  C(2)  Br(l)  128(1)  C(14)  C(13)  C(30)  130(2)  N(2)  C(3)  C(2)  109(1)  N(9)  C(13)  C(30)  121(2)  N(2)  C(3)  C(19)  121(1)  C(13)  C(14 )  C(15)  107(1)  C(2)  C(3)  C(19)  130(1)  N(10)  C(15)  C(14)  106(2)  N(3)  C(4)  C(5)  108(1)  N(10)  C(15)  C(31)  125(2)  C(6)  C(5)  C(4)  106(1)  C(14)  C(15)  C(31)  129(2)  C(6)  C(5)  Br(2)  129(1)  N(ll)  C(16)  C(17)  109(2)  C(4)  'C(S)  Br(2)  123(1)  N(ll)  C(16)  C(32)  123(2)  C(5)  C(6)  N(4)  108(1)  C(17)  C(16)  C(32)  129(2)  C(5)  C(6)  C(22)  129(1)  C(16)  C(17)  C(18)  105(1)  N(4)  C(6)  C(22)  122(1)  N(12)  C(18)  C(17)  111(2)  N(5)  C(7)  C(8)  109(1)  N(12)  C(18 )  C(33)  122(2)  C(7)  C(8)  C(9)  105(1)  C(17)  C(18 )  C(33)  128(2)  C(7)  C(8)  Br(3)  124(1)  C(3)  C(19)  C(21)  113(2)  C(9)  C(8)  Br(3)  131(1)  C(3)  C(19)  C(20)  112(2)  N(6)  C(9 )  C(8)  110(1)  C(21)  C(19)  C(20)  107(1)  N(6)  C(9)  C(25)  124(2)  C(23)  C(22)  C(6)  113(1)  C(8)  C(9)  C(25)  126(1)  C(23)  C(22)  C(24)  108(1)  C(ll)  C(10)  H(7)  108(1)  C(6)  C(22)  C(24)  111(1)  C(ll)  C(10)  C(26)  131(1)  C(26)  C(25)  C(27)  111(1)  H(7)  C(10)  C(28)  121(1)  C(26)  C(25)  C(9)  113(1)  C(10)  C(ll)  C(12)  106(1)  C(27)  C(25)  C(9)  110(1)  M(8)  C(12)  C(ll)  109(1)  W(5)  B(l)  N(l)  110(1)  N(8)  C(12)  C(29)  125(1)  H(5)  B(l)  N(3)  110(1)  angle  angle  Angles a r e i n degrees. Estimated standard d e v i a t i o n s i n the l e a s t s i g n i f i c a n t f i g u r e are given i n parentheses.  Intramolecular  Bond A n g l e s I n v o l v i n g t h e Nonhydrogen Atoms  atom  atom  atom  angle  N(l)  B(l)  N(3)  109(1)  N(9)  B(2)  N(7)  111(1)  N(9)  B(2)  N(ll)  110(1)  N(7)  B(2)  N(1D  110(1)  atom  atom  atom  9 3 angle  0  Angles are i n degrees. Estimated standard d e v i a t i o n s i n the l e a s t s i g n i f i c a n t f i g u r e are given i n parentheses.  

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