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The chemistry of group VIB organometallic nitrosyl complexes Hames, Barry Wayne 1981

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THE C H E M I S T R Y OF GROUP V I B ORGANOMETALLIC N I T R O S Y L COMPLEXES  by  B A R R Y WAYNE HAMES B.Sc.  ( H o n o u r s ) , The U n i v e r s i t y  o f Regina,  A THESIS SUBMITTED I N P A R T I A L FULFILLMENT THE R E Q U I R E M E N T S  FOR THE DEGREE  1976  OF  OF  DOCTOR OF P H I L O S O P H Y  in THE F A C U L T Y OF GRADUATE S T U D I E S (Department  We  accept  this  o f Chemistry) .  thesis  required  as conforming standard  THE U N I V E R S I T Y OF B R I T I S H April, (^cT)  to the  COLUMBIA  1981  B a r r y Wayne Hames,  1981  In p r e s e n t i n g  this thesis i n partial  f u l f i l m e n t o f the  requirements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make it  f r e e l y a v a i l a b l e f o r reference  and study.  I further  agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head o f my department o r by h i s o r her r e p r e s e n t a t i v e s . understood t h a t  copying or p u b l i c a t i o n of t h i s t h e s i s  f o r f i n a n c i a l gain  s h a l l n o t be allowed without my  permission.  Department o f  Chemistry  The U n i v e r s i t y o f B r i t i s h 2075 Wesbrook P l a c e Vancouver, Canada V6T 1W5 Date  Itis  May 22, 1981  Columbia  written  ABSTRACT The r e a c t i o n of chromocene with n i t r o g e n monoxide i n a v a r i e t y of o r g a n i c s o l v e n t s leads to the formation of CpCr(NO) (n  1 - C  2  5 5) H  a  CpCr(NO) (N0 ) and 2  s  t  n  major product, as w e l l as  e  [CpCr(NO) ]  2  2  a  s  2  minor p r o d u c t s .  Their  formation i n these c o n v e r s i o n s can be r a t i o n a l i z e d of  the r e a c t i v e i n t e r m e d i a t e CpCr(NO)^•.  i n terms  The r e a c t i o n of  p h o t o c h e m i c a l l y generated molybdenocene with n i t r o g e n monoxide t o produce CpMo (NO) (n -C,-H ) i s a l s o d e s c r i b e d . 1  2  5  Sodium dihydridobis(2-methoxyethoxy)aluminate,  I,  undergoes m e t a t h e t i c a l r e a c t i o n s i n benzene with a v a r i e t y of n i t r o s y l h a l i d e complexes. (X = N0 ,  of CpCr(NO) X 2  I, n - C H , or BF^), CpMn(CO) (NO)I,  N0 ,  3  Thus treatment  1  2  5  CpCo(NO)I, and  5  [CpMo(NO) T^]  w i t h I i n 1:1 s t o i c h i o m e t r i e s  2  a f f o r d s the r e s p e c t i v e d i m e r i c compounds [CpCr (NO) 1 > 2  [CpMn (CO) (NO) ] / [CpCo(NO)] / and 2  2  [CpMo (NO) I] . 2  2  These  l a t t e r c o n v e r s i o n s probably proceed v i a t h e r m a l l y u n s t a b l e h y d r i d o complexes. the r e a c t i o n  The chromium dimer a l s o r e s u l t s  [CpCr(NO) (CO)]PF 2  from  with the aluminum reagent  g  and r e a c t s f u r t h e r with I t o produce i n low y i e l d s a mixture of C p C r ( N O ) 2  2  (NH )(OH). 2  2  2  2  2  Cp Cr (NO) ~  2  2  2  2  i s converted  by  (NO) (NH ) . 4  2  2  Reduction of [ C p C r ( N O ) ] 2  produces  2  In a s i m i l a r manner, Fe(NO)^Cl  2  I to F e  (NH ), C p C r ( N O ) ( N H ) , and  2  with BH^  and w i t h LiEt^BH  the same t h r e e b i m e t a l l i c products as when I serves  as the reducing agent,  and  i n comparably low  yields.  - iii  -  However, w i t h LiEt^BH as r e d u c t a n t the complexes CpCr(NO) Et 2  and C p C r ( N O ) ( E t N B E t ) are a l s o formed, r e f l e c t i n g 2  2  3  unpre-  2  cedented modes o f r e a c t i v i t y o f the h y d r i d o b o r a t e . c r y s t a l l o g r a p h i c a n a l y s i s o f the new complex has been performed.  An  x-ray  Cp Cr (NO)^(EtNBEt ) 2  2  2  The most c h e m i c a l l y i n t e r e s t i n g  f e a t u r e o f the m o l e c u l a r s t r u c t u r e i s the n o v e l E t N B E t  ligand  2  which i s c o o r d i n a t e d v i a N i n a symmetrical  f a s h i o n t o the  two  around N i s t h a t  Cr atoms.  The c o o r d i n a t i o n environment  of a d i s t o r t e d t e t r a h e d r o n , but the N-B  d i s t a n c e o f 1.459(5) &  suggests some degree o f m u l t i p l e bonding between these atoms.  two  Such an i n f e r e n c e i s c o n s i s t e n t w i t h the s t a b i l i t y  of  the complex and i t s s p e c t r o s c o p i c p r o p e r t i e s . The p r e p a r a t i o n and c h a r a c t e r i z a t i o n o f s e v e r a l o r g a n o m e t a l l i c h y d r i d o n i t r o s y l complexes, i . e . CpMo(NO) H 2  and  [Cp M M (NO) H ] X ~  (M  +  2  X = BF  1  2  4  and/or PF )  4  g  ][  = M  = Mo,  2  are d e s c r i b e d ^  W;  1^ = Mo,  M  2  The monometallic  =  W:  hydride  i s prepared by r e d u c t i o n o f CpMo(NO) Cl w i t h I, w h i l e the 2  homonuclear b i m e t a l l i c c a t i o n s are formed upon r e a c t i o n of CpM(NO) H 2  (M = Mo,  W) w i t h 0.5  e q u i v a l e n t s of a h y d r i d e  a b s t r a c t i o n agent such as P h C X  or C^H^BF^ i n C H C 1 .  +  3  2  2  The h e t e r o n u c l e a r c a t i o n can be prepared by the r e a c t i o n o f CpMo(NO) Cl w i t h AgBF 2  may  4  to produce  CpMo(NO) BF ~, which +  2  4  then be r e a c t e d w i t h CpW(NO) H t o y i e l d the c a t i o n .  Attempts  2  to deprotonate these c a t i o n s w i t h a v a r i e t y o f bases  r e s u l t i n cleavage o f the metal-metal hydride and a monometallic (where L i s the base used).  bond t o y i e l d the "•  c a t i o n o f the type CpM(NO) (L) 2  - iv-  The  f a i l u r e o f t h e attempted  deprotonations l e d to  an e x a m i n a t i o n o f t h e L e w i s b a s e p r o p e r t i e s and o f t h e L e w i s a c i d p r o p e r t i e s  C r ( C O ) , W(CO) , (MeCp)Mn(CO) , H g C l , line  2  (i.e.ZnCl ), 2  and h a r d  Specifically,  +  2  5  2  o f CpW(N0)2 .  t h e i n t e r a c t i o n o f CpW(NO) H w i t h a v a r i e t y 5  o f CpW(NO) H  2  of soft ( i . e .  and C d C l ) , 2  border-  ( i . e . H , A l C l ^ , and BEt^) +  acids i s observed s p e c t r o s c o p i c a l l y .  The o b s e r v e d  Lewis  Lewis  b a s e c h a r a c t e r i s t i c s o f CpW(NO) H a r e d i s c u s s e d i n l i g h t o f 2  t h e s e r e s u l t s , a n d when c o m b i n e d w i t h t h e L e w i s a c i d of  CpW(NO) , i t i s p o s s i b l e  route.  to r a t i o n a l i z e the f a i l u r e to  +  2  prepare t h e dimers  properties  [CpM(NO) J 2  2  (M = Mo, W) v i a t h e d e s i r e d  -  v -  ACKNOWLEDGEMENTS  I the  chemistry  advice thank of  wish  the faculty  department  fortheir  throughout Professors  this  The  t o thank  this  study.  F. Aubke  expert  In p a r t i c u l a r ,  proofreading  suggestions  I wish t o  who  read  for its  o f D.T. M a r t i n  of  a s s i s t a n c e and  and E.E. B u r n e l l  t h e s i s and o f f e r e d  diligent  and t e c h n i c a l s t a f f  portions  improvement.  i s also  greatly  appreciated. I and  David  provided  am  especially  T. M a r t i n a pleasant  meetings'  after  encouragement; and  Randy  Sciences is  work  been  were  f o r work.  a constant  excellence 'committee  o f s o l a c e and  D r . Howard  Financial assistance Research  to  Kolthammer  T h e many  source  acknowledge  W.S.  Council  from  E. Morton  the Natural  o f Canada  (1976-80)  acknowledged.  Finally,  without  atmosphere  and E n g i n e e r i n g  Legzdins.for  t o Dr. Brian  whose w i t and d e d i c a t i o n  I especially  J . Mikula.  gratefully  indebted  I wish  t o e x p r e s s my  h i s guidance,  which  possible.  the completion  support, of this  gratitude  t o Dr.  and c o n s t a n t t h e s i s would  Peter  enthusiasm, n o t have  - v i-  TABLE: OF  CONTENTS  Page ABSTRACT  . • . ... . .. .... . ........ .... ... .:  ACKNOWLEDGEMENTS TABLE OF CONTENTS LIST OF TABLES LZST  Of  •  FIGURES"  . . . ... ,  ...  . ..............  ..  ..  . ... . ... ..  •  .....  v  ix ...  .  x  .  xi  INTRODUCTION  1  I:. The B a s i s o f t h e Problem I I . The R e a c t i o n o f NO w i t h Complexes  .  1  Transition-metal 4  I I I . The Bonding and R e a c t i v i t y o f T r a n s i t i o n m e t a l C o o r d i n a t e d N i t r o g e n Monoxide ... CHAPTER IT  i i  vi  ..............  ABBREVIATIONS AND COMMON NAMES" CHAPTER, I  ..  5  SOME REACTIONS OF NITROGEN MONOXIDE WITH ELECTRON-DEFICIENT METALLOCENES  11  Experimental  12  R e s u l t s and D i s c u s s i o n Reactions Cp Cr Reactions Cp Mo  21  . . . . . . . v  o f N i t r o g e n Monoxide w i t h 21  2  o f N i t r o g e n Monoxide w i t h 28  2  R e a c t i o n o f N i t r o g e n Monoxide w i t h Cp V  30  Summary and C o n c l u s i o n s  30  2  CHAPTER I I I REACTIONS OF SODIUM DIHYDRIDOBIS— (2—METHOXYETHOXY) ALUMINATE WITH' SOME CATIONIC AND NEUTRAL NITROSYL COMPLEXES Experimental  ............ . . . . ...........  R e s u l t s and D i s c u s s i o n .  ...  ................  31 33 41  -  v i i-  Page  Reactions- o f Sodium D i h y d r i d o b i s C2-methoxy^t'lldxy^aluminate .. . . ............ (a. I. W i t h . M o n o m e r i c C h r o m i u m N i t r o s y l Complexes . . ..... .,....................................... (b)  W i t h . Some. M o n o m e r i c Complexes-  CHAPTER  W i t h . [CpMo ( N O ) X ]  (dI  Wi.th. { C p C r (NO\  (el  With Fe(NO) Cl  IV  2  V  }  (X =  I, CI) Complexes  42 44  ....  46 52  3  REACTIONS' OF B I S [ (.n, — C Y C L O P E N T A D I E N Y L ) . — DINITROSYLCHROMIUM] WITH L I T H I U M T R I E T H Y L BOROHYDRIDE AND WITH BORANE  57  Experimental  58  5  Results  CHAPTER  2  41  Iodonitrosyl  . . . . . . . . . . . . . . . . . ......... . ..........  (c)  41  .........  and D i s c u s s i o n  The  Reaction  of LiEt^BH  The  Reaction  o f BH^  61 with  with  [CpCr(NO) ] 2  [CpCr(NO) ] 2  2  61 77  2  A, STUDY OF T H E L E W I S B A S E P R O P E R T I E S OF CYCLOPENTADIENYLTUNGSTENDINITROSYL H Y D R I D E AND T H E L E W I S A C I D P R O P E R T I E S OF THE CYCLOPENTADIENYLTUNGSTENDINTTROSYL CATION  79  Experimental  83  Results  and D i s c u s s i o n  .  The P r e p a r a t i o n and C h a r a c t e r i z a t i o n o f CpMo (NO) H . . ... . ..... . . .. . 2  109  109  The P r e p a r a t i o n _ a n d Characterization of [Cp W (NO) H] X (X = B F , P F )  111  The P r e p a r a t i o n and C h a r a c t e r i z a t i o n , o f I C p M Q (NO 1 H] P F ., .... . . . . . . . ... ... . . ...  124  2  2  2  4  4  2  4  6  6  The P r e p a r a t i o n and C h a r a c t e r i z a t i o n o f [Cp M o W ( N O I H ] B F 2  4  4  125  - viii -  Page Attempted Deprotonations of [Cp M (NO) H] (M = Mo, W)  131  Summary of the P r o p e r t i e s of [Cp„M,M„(NO) .H] (M, = M_ = Mo, W; M, = Mo, :,_ M = W) . 7 7.  134  Attempted S y n t h e s i s o f [Cp Cr (NO)  136  2  2  2  2  H] ...  2  The I n t e r a c t i o n of CpW(NO)'„H With Lewis Acids 7 (a) The I n t e r a c t i o n o f CpW(NO) H With M(CO) (M = C r , W) and With (MeCpjMn(CO) 7.  138  ?  2  142  (b) The I n t e r a c t i o n o f CpW(NO),H With MCI, (M = Zn, Cd, Hg)  7  (c) The Reaction of CpW(NO) H With H  148 +  2  152  (d) The Reaction of CpW(NO) H With A l C l g  153  (e) Summary and C o n c l u s i o n s  154  2  EPILOGUE  158  REFERENCES AND NOTES  15 9  - ix -  LIST OF TABLES Table I  Page Low-Resolution Mass S p e c t r a l Data f o r CpCr ( N O ) C n - C H ) and CpCr(NO) (N0 )  15  Low-Resolution Mass S p e c t r a l Data f o r C p C r (NO) (NH )X (X = NH or OH) Complexes .  48  H i g h - R e s o l u t i o n Mass S p e c t r a l Data f o r F e (N0) ( N H ) ••  55  1  2  IT  2  III  2  2  IV  5  2  4  2  VII  2  2  2  S e l e c t e d Bond D i s t a n c e s and Bond Angles (deg) f o r C p C r (NO) (EtNBEt ) 2  3  NMR  2  3  Data f o r C p C r ( N O ) ( E t N B E t ) 2  2  3  2  i n CDC1  3  ..  74  C h a r a c t e r i s t i c N i t r o s y l A b s o r p t i o n s of CpM(NO) H (M = Mo, W) D e r i v a t i v e s  123  Low-Resolution Mass S p e c t r a l Data f o r CpCr(NO) (0 SC H -pCH )  139  C h a r a c t e r i s t i c N i t r o s y l A b s o r p t i o n s of CpW(.N0) H Adducts  144  2  IX  72  2  2  VIII  68  2  H i g h - R e s o l u t i o n Mass S p e c t r a l Data f o r Cp Cr (NO) (EtNBEt ) 2  VI  2  2  2  V  5  9  3  6  4  3  -  x  -  LIST OF FIGURES Figure 1  Page S t e r e o s c o p i c view of the contents c e l l o f C p C r (NO) (EtNBEt ) 2  2  65  2  2  3  2  66  The H NMR Spectrum of [Cp W (NO) .H] BF. i n CD N0 S o l u t i o n ...  116  The hydride r e g i o n of the *H NMR a [CpJVI„ (NO) .H] PF mixture (Mo:W i n CD N0 ...  129  X  ?  3  4  3  A p e r s p e c t i v e view of the molecular s t r u c t u r e of C p C r ( N O ) ( E t N B E t ) i n c l u d i n g the atom numbering scheme 2  3  2  of a u n i t  2  3  2  spectrum of r a t i o 1.5:1)  - x i-  ABBREVIATIONS AND COMMON NAMES  R  Angstrom  Anal. Calcd  analysis calculated  atm  atmosphere(s)  br  broad  °C  degrees C e l s i u s  cm  centimetre(s)  cm  wave numbers i n r e c i p r o c a l  Cp  pentahapto-cyclopentadienyl  d  doublet  dec  decomposes  deg  plane  DMF  N,N-dimethylformamide  e  electron(s)  eq  equation(s)  Et  ethyl  eV  electron volts  f  stretching  g  gram(s)  h  hour(s)  Harpoon Base  ..  centimetres  angle  force  constant  2,2,6,6,-tetramethylpiperidine  HMPA  hexamethylphosphoramide  Hz  Hertz,  hv  irradiation  I  Nuclear  I  NaAlH (OCH CH OCH )  "IR  infrared  J  homonuclear magnetic resonance c o u p l i n g constant  Spin  2  J  m  c y c l e s p e r second  2  i n u n i t s o f h/2-rr 2  3  2  heteronuclear magnetic resonance c o u p l i n g c o n s t a n t , where x i s t h e number o f bonds s e p a r a t i n g t h e s p i n - c o u p l e d n u c l e i and y s p e c i f i e s the coupled n u c l e i multiplet  -  moles  M  *  per  x i i -  litre  metastable  M  i o n (s) ,  millidynes  mdyn  methyl  Me  minute(s)  min  millilitre(s)  mL  millimole(s)  mmol  melting  mp  nuclear  NMR  magnetic  parts  PPm Proton  Sponge  .  abund  per m i l l i o n  N,N,N',N -tetramethyl-1,8-naphthalenediamine 1  alkyl  R  or  relative  aryl abundance  s  singlet  sh  shoulder  st  strong  t-Bu  tertiary-butyl  THF  tetrahydrofuran  Torr  millimetres  w  weak  S  NMR  v  o f mercury  chemical  "5  shift  pressure  i n parts  per million  monohapto infrared  stretching  approximately a  resonance  phenyl  Ph  1  ratio  pentahapto-methylcyclopentadienyl  (MeCp)  rel  point  mass-to-charge  m/z  -n  -.-..''i  percent  frequency  - xiii  -  A s e r i e s of judgements, r e v i s e d without c e a s i n g , goes t o make the i n c o n t e s t a b l e p r o g r e s s of s c i e n c e . P i e r r e Emile Duclaux  (1840-1904)  - 1 -  CHAPTER 1 INTRODUCTION I.  The B a s i s o f the Problem The  focused  a n t i c i p a t e d shortage o f f u t u r e o i l s u p p l i e s has  i n t e r n a t i o n a l a t t e n t i o n on c o a l as a p o t e n t i a l  source o f energy and as a raw m a t e r i a l f o r i n d u s t r y .  The  c u r r e n t emphasis on the u t i l i z a t i o n o f c o a l c e n t r e s on i t s conversion ical for  i n t o o i l , gas, and feedstocks  industries ' . 1  2  f o r the petrochem-  A p r i n c i p a l method o f l i q u e f y i n g c o a l  these purposes i s F i s c h e r - T r o p s c h  s y n t h e s i s , which i s 1  p r e s e n t l y employed i n the SASOL p l a n t s i n South A f r i c a t o produce waxes, o i l s , motor f u e l , and chemicals.  The essen-  tial  steps i n t h i s method  are :  (1)  combustion o f c o a l i n the presence o f oxygen and steam  2  to generate a gas composed mostly o f carbon monoxide and  hydrogen  ( i . e . raw s y n t h e s i s g a s ) , the p r i n c i p a l  exothermic r e a c t i o n being C + H0 2  (2)  •  CO + H  2  p u r i f i c a t i o n o f the gas t o remove u n d e s i r a b l e  impurities  (including p o t e n t i a l c a t a l y s t poisons). (3)  adjustment o f the CO:H  2  r a t i o t o s u i t the p a r t i c u l a r  s y n t h e s i s r e q u i r e d by u s i n g the Water Gas S h i f t Reaction: H 0 + CO 2  — •  H  2  + C0  2  -  f o l l o w e d by removal of C 0  2 -  2  f o r most  subsequent  reactions. (4)  r e a c t i o n of CO w i t h H  2  using appropriate c a t a l y s t s to  promote the f o r m a t i o n o f the d e s i r e d p r o d u c t s . 3  The exhaust gases i n c o a l combustion  (step 1). a l s o  c o n t a i n s i g n i f i c a n t amounts of n i t r o g e n o x i d e s ( p r i m a r i l y NO and a l e s s e r amount of N0 ) o r i g i n a t i n g from 2  n i t r o g e n and/or from the c o a l i t s e l f .  atmospheric  The removal of these  oxides from the e f f l u e n t gases i s of paramount environmental importance  s i n c e they are i n v o l v e d i n the f o r m a t i o n o f both  photochemical smog and a c i d r a i n .  In p r i n c i p l e ,  this  removal can be e f f e c t e d e i t h e r by d i r e c t decomposition of the o x i d e s i n t o n i t r o g e n and oxygen o r by r e d u c t i o n of the NO  s p e c i e s t o N~ w i t h v a r i o u s r e d u c i n g agents'*' . 5  X  Hence,  Zt  p r e v i o u s e f f o r t s t o remove n i t r o g e n monoxide e f f i c i e n t l y from both s t a t i o n a r y and mobile exhaust stream  effluents  have i n c l u d e d : CI)  attempts t o decompose NO d i r e c t l y i n t o N  2  and 0  2  Ca thermodynamically f a v o u r a b l e but k i n e t i c a l l y unfavourable p r o c e s s ) by employing c a t a l y s t s o r oxide c a t a l y s t s ' - . 4  5  reduced m e t a l l i c However, the m e t a l l i c  c a t a l y s t s are d e a c t i v a t e d r a p i d l y by the 0  2  released  from the decomposed NO, and the oxide c a t a l y s t s which are s t a b l e i n o x i d a t i v e r e a c t i o n c o n d i t i o n s d i s p l a y low a c t i v i t i e s f o r NO decomposition. C2).  s t u d i e s of the homogeneous c a t a l y t i c o x y g e n - t r a n s f e r process:  -  3  2N0 + CO  -  •  C0  + N 0  2  2  a r e a c t i o n which i s c a t a l y z e d , a l b e i t slowly, by i o n i c rhodium and i r i d i u m complexes [Rh(CO) C1 ]~, 2  such as  [Rh(NO) (  p P n  2  3)2^ ' +  and [ I r ( N O ) ( P P h ) ] , as w e l l as some +  2  2  3  2  p l a t i n u m - and p a l l a d i u m - c o n t a i n i n g compounds . 6  (3)  complete c o n v e r s i o n o f NO i n t o N  and C 0  2  composite c a t a l y s t s such as C o - L a 0 - P t 2  by u s i n g  2  supported on  3  a c t i v e carbon, i r r e s p e c t i v e of the c o e x i s t e n c e o f 0  ? 2  «  T h i s p r o c e s s i n v o l v e s a high-temperature, c a t a l y t i c g a s - s o l i d r e a c t i o n a t atmospheric p r e s s u r e which r e q u i r e s no a d d i t i o n a l gaseous r e d u c i n g agents but does consume the a c t i v e carbon. (4)  Exxon's Denox p r o c e s s ( p r e s e n t l y i n use),.which e f f e c t s the,overall'gas-phase NO + NH  3  i n the combustion  reaction  + l/40  *  2  N  2  + 3/2H 0 2  zone, a p p a r e n t l y v i a a complex  r a d i c a l c h a i n mechanism . 8  free-  The above r e a c t i o n i s i n  competition with NH  3  + 5/40  •  2  NO + 3/2H 0 2  but w i t h i n a narrow temperature range these r e a c t i o n s can be balanced t o permit e f f i c i e n t net r e d u c t i o n o f NO w i t h l i t t l e r e s i d u a l NH  3  l e f t over i n the f l u e gases.  While these and r e l a t e d p r o c e s s e s have been s u c c e s s f u l i n removing n i t r o g e n monoxide from exhaust gases t o v a r y i n g degrees, the emphasis  of most of the work has been  to accomplish the c o n v e r s i o n o f NO i n t o l e s s noxious produ c t s , p r i n c i p a l l y N„.  However, the N~ thus produced i s  -  4  -  q u i t e n o n r e a c t i v e , and n i t r o g e n f i x a t i o n  (another area of  c u r r e n t i n t e n s e r e s e a r c h e f f o r t ) must be e f f e c t e d i n order 9  to convert i t i n t o important  n i t r o g e n - c o n t a i n i n g chemicals  such as f e r t i l i z e r s , e x p l o s i v e s , p l a s t i c s , e t c .  Thus an  a l t e r n a t i v e approach t o t h i s problem which m e r i t s g a t i o n i s the d i r e c t t r a n s f o r m a t i o n of NO compounds.  into useful  At the o u t s e t of t h i s r e s e a r c h , one of t h e ;  o b j e c t i v e s -was  to. study the- f e a s i b i l i t y of c a r r y i n g out  these trans-formations Cl)  investi-  by:  t r a p p i n g the n i t r o g e n monoxide on e l e c t r o n - r i c h tion-metal centres  (such as those present i n organo-  m e t a l l i c compounds) t o form n i t r o s y l complexes, (2)  transi-  and  examining and e x p l o i t i n g the r e a c t i v i t y of the c o o r d i n ated n i t r o s y l l i g a n d  (which can r e a s o n a b l y be  to be d i f f e r e n t from t h a t d i s p l a y e d by NO  expected  i n the  gas  phase) t o a t t a i n the d e s i r e d o b j e c t i v e . II.  The  Reaction of NO w i t h T r a n s i t i o n - m e t a l Complexes Ample precedents  i n d i c a t e t h a t the f i r s t t r a p p i n g of NO ible  1 0  .  e x i s t i n the chemical l i t e r a t u r e to step of the proposed study  ( i . e . the  on t r a n s i t i o n - m e t a l c e n t r e s ) i s indeed  Although  poss-  a systematic study of t h i s mode of r e a c t i o n  has not been conducted,  i t i s nevertheless well established  t h a t n i t r o g e n monoxide can r e a c t w i t h a p p r o p r i a t e t r a n s i t i o n metal complexes to e f f e c t : (1)  simple adduct f o r m a t i o n , Cr(NR ) 2  3  + NO  e.g. •  Cr(NO)(NR ) 2  3  - 5 -  Co(chelatel  2  + NO  »  Co (NO) (chelate)  (where c h e l a t e = dithiocarbamate, dimethylglyoxime o r S c h i f f  2  dithiolate,  base).  T h i s type o f behaviour occurs when the r e a c t a n t possesses e i t h e r a 15- o r 1 7 - e l e c t r o n the metal c e n t r e .  complex  configuration at  The i s o l a t e d adducts then  satisfy  the i n e r t gas c o n f i g u r a t i o n . (2)  s u b s t i t u t i o n whereby each NO group r e p l a c e s capable o f f o r m a l l y donating  ligands  3 electrons t o the metal,  e.g. Cr(CO)  g  + 4N0 (hv i n pentane)  [CpV(.CO) (CN) ] " + 2N0  •  3  [CpCr (CO) 3 ]  2  + 2N0  •  — •  Cr(NO)  CpV (CO) (NO)  2CpCr (CO) (NO) 2  (a Cr-Cr s i n g l e bond being  2  4  + 6C0  + 2CO + CN~  + 2C0  cleaved)  However, r e a c t i o n o f NO with a c o o r d i n a t i v e l y  unsatur-  ated complex o f t e n r e s u l t s i n a redox r e a c t i o n w i t h concomitant d i s p r o p o r t i o n a t i o n o f the n i t r o g e n monoxide (3)  1 0  .  r e d u c t i v e n i t r o s y l a t i o n , e.g. rCpCrCl ] 2  MoClg The  N 2  ° >  ( i n CH C1 ) 2  2  CpCr(NO) Cl 2  N  ° »  Mo (NO) C1 2  2  o x i d i z e d product i n these t r a n s f o r m a t i o n s  i s prob-  a b l y C1N0. III.  The Bonding and R e a c t i v i t y o f T r a n s i t i o n - m e t a l  nated N i t r o g e n  Coordi-  Monoxide  Once i n c o r p o r a t e d  i n t o the metal's c o o r d i n a t i o n  sphere i n t h i s manner, the bound NO group can engage i n one  -  6  -  of three p r i n c i p a l bonding modes , namely; (1)  i t can f u n c t i o n as a 3 - e l e c t r o n donor N0 )  (i.e. formally  to the metal c e n t r e when i n v o l v e d i n a t e r m i n a l ,  +  l i n e a r M-NO  grouping.  Such l i n k a g e s e x i s t i n the  m a j o r i t y of n i t r o s y l complexes  great  (e.g. Cr(NO) (NR,,)^  and CpCr (NO) C1 s p e c i f i e d p r e v i o u s l y ) . 2  (2)  i t can f u n c t i o n as a 1 - e l e c t r o n donor N0~)  ( i . e . formally  to the metal c e n t r e when i n v o l v e d i n a t e r m i n a l ,  bent M-N-0 12 0 ° /  l i n k a g e , the bond angle being  S e v e r a l of the Co CNO) ( c h e l a t e )  2  approximately  compounds have,  been shown to c o n t a i n bent Co-N-0 g r o u p s . 1 0  (3)  i t can b r i d g e two  or more metal atoms, a feature, w e l l  e x e m p l i f i e d by the s o l i d - s t a t e s t r u c t u r e of Cp^Mn^(NO) , i . e .  1 1  4  -MnCp Molecular  o r b i t a l c a l c u l a t i o n s are c u s t o m a r i l y  to p r o v i d e  required  an adequate d e s c r i p t i o n of the m e t a l - n i t r o s y l  bonding i n such compounds. (A)  Terminal,  l i n e a r M-NO  While the M-NO  bonds  bonding d e s c r i p t i o n s i n cases  (2) above are o v e r s i m p l i f i c a t i o n s , they are  coordinated  For i n s t a n c e , a t e r m i n a l , l i n e a r  grouping can be represented  and  nevertheless  u s e f u l guides f o r p r e d i c t i n g the r e a c t i v i t y of a nitrosyl ligand.  (1)  by the resonance h y b r i d  M-N-0  -  7 -  F> M=N=0  M-NEG Ca} Consequently, i n accord  (b)  w i t h Pearson's c r i t e r i o n t h a t  "hard  a c i d s p r e f e r t o a s s o c i a t e w i t h hard bases, and s o f t a c i d s p r e f e r t o a s s o c i a t e w i t h s o f t b a s e s " , i t would be expected 1 2  t h a t t e r m i n a l , l i n e a r n i t r o s y l l i g a n d s would undergo by hard a c i d s and  ( i . e . e l e c t r o p h i l e s ) a t the n i t r o s y l 0 atom  a t t a c k by hard bases  N atom.  attack  ( i . e . nucleophiles)  a t the n i t r o s y l  Furthermore, s i n c e c o o r d i n a t i o n by N 0 t o metals +  i s d i r e c t l y analogous t o m e t a l - c a r b o n y l bonding w i t h i t s synergic c o u p l i n g _of o and TT bonding components , i t 13  would also: be a n t i c i p a t e d t h a t g r a d a t i o n s  i n the l i g a n d  r e a c t i v i t y would occur as the n e t e l e c t r o n d e n s i t y on the n i t r o s y l ligand  ( i n f l u e n c e d by both M-HSIO cr bonding and M->NO  TT bonding) v a r i e d .  Indeed, the a n t i c i p a t e d r e a c t i v i t y i s  known f o r a number o f c o o r d i n a t i o n compounds , e.g. 6  [ I r C l (NO) ( P P h ) ] 3  and  3  ,  2  + OEt  0 I r C l g C^-OEt 1 C.PPh )  — •  3  2  i t has been proposed * t h a t those metal n i t r o s y l 11  compounds having v mdyn A  - 1  N  Q  > 1886 cm  Cor, b e t t e r , f  N  Q  > 13.8  ) w i l l be s u s c e p t i b l e t o a t t a c k a t the N atom by  nucleophiles  such as;.OH~, 0R~, NH , N H , NH OH, and N "~. 3  2  4  2  3  I t i s o f obvious i n t e r e s t t o determine whether a s i m i l a r c r i t e r i o n can be e s t a b l i s h e d f o r the NO l i g a n d r e a c t i v i t i e s of o r g a n o m e t a l l i c  n i t r o s y l compounds.  I t f o l l o w s t h a t s p e c i e s having p a r t i c u l a r l y - l o w values  of v  N  Q  would be l i a b l e t o a t t a c k by e l e c t r o p h i l e s ,  e i t h e r a t the N o r 0 atom.  Lewis a c i d s such as EX- CE = B  - 8 -  or A l , X = a h a l i d e o r pseudohali.de).  would be expected t o  form i s o n i t r o s y l l i n k a g e s w i t h a p p r o p r i a t e o r g a n o m e t a l l i c nitrosyls via M-NO + E X interactions.  • M-N=0-^EX  3  3  Some precedent  f o r t h i s type o f behavior i s  known, w i t h a c i d i c C p L n complexes  (Ln = a l a n t h a n i d e metal),  3  having been shown t o p r e f e r e n t i a l l y form i s o n i t r o s y l l i n k a g e s w i t h CpM(CO) (NO) (M = Cr, Mo, or W). compounds . 15  2  However,  the g e n e r a l i t y and f a c t o r s i n f l u e n c i n g such acid-base  inter-  a c t i o n s s t i l l remain t o be a s c e r t a i n e d . Of course, e l e c t r o p h i l i c a t t a c k c o u l d a l s o occur d i r e c t l y a t the n i t r o s y l N atom, i . e . + [M-N=0] A  M-N=0  •  (where A - = H , a c a r b o c a t i o n , e t c . ) +  +  i f t h e r e i s s u f f i c i e n t e l e c t r o n d e n s i t y on the NO l i g a n d . However, i n t h i s case, the s o f t t r a n s i t i o n metal and the oxygen atom w i l l probably be competing c e n t r e s o f r e a c t i v i t y . Hence, i n i n v e s t i g a t i o n s o f M-NO r e a c t i o n s w i t h e l e c t r o p h i l e s , p a r t i c u l a r a t t e n t i o n should be g i v e n t o determining the f a c t o r s which i n f l u e n c e the r e g i o s e l e c t i v i t y o f these t r a n s formations.  The p r e s e n t l y known examples of e l e c t r o p h i l i c 2+  a t t a c k a t N (e.g. the r e a c t i o n o f [ C o ( d i a r s ) ( N O ) ]  with  2  HBr)  can be r a t i o n a l i z e d i n terms o f p r i o r bending  M-NO bond angle, i . e . [Co ( d i a r s )  (NO) ]  of the  6  2+  (18e~, l i n e a r Co-N-O)  —  •  [Co ( d i a r s ) B r (NO)]  +  2  C20e~, l i n e a r Co-N-O)  •  -  -*•  -  H+  [Co C d i a r s ) B r CN0I3 +  [Co Cdiars) B r CN-H) ]  2+  2  2  C18e (B)  9  , bent Co-N-Ol  Terminal, bent M-NO  bonds and b r i d g i n g NO  linkages  In a s i m i l a r manner, the Lewis s t r u c t u r e s of t e r m i n a l , bent M-N-0  l i n k a g e s and d o u b l y - b r i d g i n g n i t r o s y l groups, i . e . -N*  0:  •ff-  and  \  M  M suggest  M  t h a t the N atom i n the former should undergo e l e c t r o -  p h i l i c a t t a c k whereas the N atom i n the l a t t e r should s u s c e p t i b l e to n u c l e o p h i l i c a t t a c k .  be  The oxygen atoms i n  both cases are again s i t e s of hard Lewis b a s i c i t y and  should  thus form s t a b l e c o o r d i n a t e c o v a l e n t bonds w i t h hard Lewis a c i d s such as the t r i v a l e n t compounds of the l i g h t e r group 3A elements. A 0:  N ^  + A  M 0:  'N^  I  k  M oII  M  M  M"  "M  II  + A  + B  where A = a Lewis a c i d and B  0:  •N  + A  M  ^M  Celectrophilel  = a Lewis base C n u c l e o p h i l e )  Some of these e x p e c t a t i o n s concerning the r e a c t i v i t y of a  - 10. -  c o o r d i n a t e d n i t r o s y l l i g a n d have been r e a l i z e d d u r i n g ious s t u d i e s .  However, t h i s e a r l i e r work was  6  almost NO  prev-  concerned  e x c l u s i v e l y w i t h c o o r d i n a t i o n compounds i n which the  l i g a n d s are attached t o t r a n s i t i o n metals i n p o s i t i v e  formal o x i d a t i o n s t a t e s .  An aim of t h i s r e s e a r c h was  to  a s c e r t a i n the g e n e r a l v a l i d i t y of the e x p e c t a t i o n s o u t l i n e d above by i n v e s t i g a t i n g the r e a c t i v i t y of c o o r d i n a t e d  NO  groups i n a v a r i e t y of o r g a n o m e t a l l i c n i t r o s y l compounds. U n f o r t u n a t e l y , no o r g a n o m e t a l l i c compounds c o n t a i n i n g a t e r m i n a l , bent M-NO  l i n k a g e are p r e s e n t l y known, but s e v e r a l  complexes c o n t a i n i n g d o u b l y - b r i d g i n g n i t r o s y l l i g a n d s [CpCr CN0). 3 , 2  2  [CpCo(N0)] , and 2  (e.g.  [CpFeCNOl] ) are a v a i l a b l e t o 2  t e s t the v a l i d i t y of the l a t t e r two r e a c t i o n s . In t h i s c o n t e x t , Chapter I I d e s c r i b e s the r e a c t i o n s of s e v e r a l n e u t r a l o r g a n o m e t a l l i c compounds w i t h f r e e NO produce o r g a n o m e t a l l i c n i t r o s y l complexes.  Chapter  p r e s e n t s r e a c t i o n s of the n u c l e o p h i l i c hydride  to  TTI  source.  N a [ A 1 H ( O C H C H O C H ) 1 w i t h t r a n s i t i o n - m e t a l n i t r o s y l com2  2  2  3  2  pounds c o n t a i n i n g a v a r i e t y of other f u n c t i o n a l groups (especially halides). (NO) ] 2  2  In Chapter IV the r e a c t i o n s of  w i t h the extremely  w i t h the Lewis a c i d BH^  [CpCr-  n u c l e o p h i l i c hydride L i E t ^ B H  and  are compared t o i t s r e a c t i o n w i t h  Na [AlH^lOCH^C^OCH^ ] . In the f i n a l chapter, attempts t o 2  prepare  the analogous complexes  described.  [CpM(NO) ]  T h i s chapter concludes  2  2  (M = Mo,  Wl  are  w i t h a study of the Lewis  base p r o p e r t i e s of CpW(NO) H and the Lewis a c i d p r o p e r t i e s 2  of CpW(N0) . +  9  C H A P T E R  rr  SOME REACTIONS OF NITROGEN MONOXIDE WITH ELECTRON-DEFICIENT METALLOCENES There was  no g e n e r a l p r e p a r a t i v e route t o t r a n s i t i o n  metal n i t r o s y l compounds b e f o r e 1970. then e x i s t i n g methods produced  A l s o , many of the  the d e s i r e d products i n low  y i e l d s and/or w i t h much expenditure of e f f o r t . more g e n e r a l l y u s e f u l procedures the treatment  of a n i o n i c  with n i t r o s y l c h l o r i d e ,  1 6  have been r e p o r t e d i n v o l v i n g  or n e u t r a l  Z  c a r b o n y l complexes  1 7  e.g.  (Ph_P) _N[W(CO) _Br] + CINO 5  —•  W(C0) . (NO) Br  2  + CINO  2  CD  4  O  Fe (CO) (NO)  Recently,  •  C2)  Fe(NO) Cl 3  Another p o t e n t i a l l y g e n e r a l method f o r the s y n t h e s i s of v these n i t r o s y l complexes i s the r e a c t i o n of n i t r o g e n monoxide w i t h e l e c t r o n - d e f i c i e n t or c o o r d i n a t i v e l y unsaturated o r g a n o m e t a l l i c compounds.  The  l a t t e r c l a s s i f i c a t i o n of  r e a c t a n t s encompasses those s p e c i e s i n which the metal a t t a i n s c o o r d i n a t i v e u n s a t u r a t i o n d u r i n g t h e r m o l y s i s or photolysis.  Some r e a c t i o n s of t h i s type have been i n d i v i d -  u a l l y r e p o r t e d p r e v i o u s l y , e.g. 1 0  CrlN(SiMe ) J  + NO  Cp Mn + NO  f  Cr(CO)  h V  3  2  2  6  + NO  3  —•  Cr (NO) IN (SiMe )^] 3  Cp Mn (NO) ( n - C H ) 1  2  2  » ,CrCN0)  3  4  5  5  3  C3) C4) C5)  - 12 -  but a s y s t e m a t i c study of these t r a n s f o r m a t i o n s has not been carried  out. T h i s chapter d e s c r i b e s r e a c t i o n s between n i t r o g e n  monoxide and a v a r i e t y of cyclopentadienylchromium The chromium systems were chosen  as a convenient  complexes.  starting  p o i n t because s e v e r a l of the cyclopentadienylchromium  nitro-  s y l s one might l o g i c a l l y expect as products have been c h a r acterized p r e v i o u s l y NO  1 6 - 1 8  .  A l s o , i n the context of u t i l i z i n g  formed d u r i n g the p r o d u c t i o n of raw  Chapter  s y n t h e s i s gas  (see  I ) , chromocene has the added advantage of being  u n r e a c t i v e w i t h e i t h e r CO or H  under ambient c o n d i t i o n s .  2  The r e a c t i o n s of NO w i t h Cp MoH 2  2  and Cp V are a l s o d i s c u s s e d . 2  Experimental A l l chemicals used were of reagent grade or compara b l e p u r i t y and were e i t h e r purchased  from  commercial  s u p p l i e r s or prepared a c c o r d i n g t o p u b l i s h e d procedures. T h e i r p u r i t y was  a s c e r t a i n e d by elemental a n a l y s e s and/or  melting point determinations.  A l l m e l t i n g p o i n t s are  u n c o r r e c t e d and were taken i n c a p i l l a r i e s under p r e p u r i f i e d n i t r o g e n u s i n g a Gallenkamp M e l t i n g P o i n t Apparatus. N i t r o g e n monoxide was  f u r t h e r p u r i f i e d by p a s s i n g i t through o  a column of a c t i v a t e d s i l i c a g e l maintained a t -78 mass spectrum peak a t m/z  C.  A  of the e f f l u e n t gas e x h i b i t e d o n l y a sharp  =30  a s s i g n a b l e t o NO ; +  a t t r i b u t a b l e t o i o n s such as N 02  i t d i d not e x h i b i t peaks or N0  2  .  A l l solvents  were d r i e d a c c o r d i n g t o standard p r o c e d u r e s , 1 9  and t h o r o u g h l y deaerated p r i o r t o use.  distilled,  A l l manipulations,  - 13 -  u n l e s s otherwise  s t a t e d , were performed on the bench u s i n g  c o n v e n t i o n a l techniques s e n s i t i v e compounds  20  f o r the m a n i p u l a t i o n  of a i r -  o r i n a Vacuum Atmospheres C o r p o r a t i o n  D r i - L a b model HE-43-2 d r y box f i l l e d w i t h p r e p u r i f i e d  nitro-  gen. I n f r a r e d s p e c t r a were recorded on P e r k i n Elmer 457, 710A, o r 598 spectrophotometers and c a l i b r a t e d w i t h the 1601 cm ^ a b s o r p t i o n band of a p o l y s t y r e n e f i l m .  Proton  magnetic resonance s p e c t r a were recorded on a V a r i a n A s s o c i ates T-60 spectrometer  u s i n g t e t r a m e t h y l s i l a n e as an i n t e r -  n a l standard o r on Bruker WP-80, WH-400 or V a r i a n A s s o c i ates XL-100 spectrometers A l l H chemical 1  Me^Si.  w i t h r e f e r e n c e t o the s o l v e n t used.  s h i f t s are r e p o r t e d i n ppm downfield  Carbon-13 NMR  s p e c t r a were recorded on a V a r i a n  A s s o c i a t e s CFT-20 spectrometer used, but the  1 3  C  from  chemical  s h i f t s are r e p o r t e d i n ppm down-  f i e l d from Me^Si.  The  WP-80 spectrometer  w i t h r e f e r e n c e t o the s o l v e n t used, and  the chemical BF «OEt . 3  2  s p e c t r a were recorded on a Bruker  s h i f t s are r e p o r t e d i n ppm downfield  Dr. S.O. Chan, Mrs. M.M.  and Ms. M.A. spectra.  X 1  B  w i t h r e f e r e n c e t o the s o l v e n t  from  Tracey, Mr. J.K. Chow,  Heldman a s s i s t e d i n o b t a i n i n g the v a r i o u s NMR  The l o w - r e s o l u t i o n mass s p e c t r a were obtained a t  7 0 eV on an A t l a s CH4B spectrometer  and the h i g h - r e s o l u t i o n  mass s p e c t r a l data were a c q u i r e d on an A s s o c i a t e d I n d u s t r i e s MS902 spectrometer  Electrical  u s i n g the d i r e c t - i n s e r t i o n  method w i t h the a s s i s t a n c e o f Mr. J.W.  Nip and Mr. G. Gunn.  Elemental .analyses were performed by Mr. P. Borda.  The ...  - 14 -  x-ray s t r u c t u r a l d e t e r m i n a t i o n was  c a r r i e d out by Dr.  R.G.  Ball. R e a c t i o n o f N i t r o g e n Monoxide w i t h Chromocene. (a)  In hexanes.  monoxide was Cp Cr  A slow stream of p r e p u r i f i e d  passed over a r a p i d l y s t i r r e d , red s o l u t i o n of  (0.91 g, 5.0 mmol) i n hexanes  2:1  2  Immediately  formed.  The n i t r o g e n monoxide  was maintained over the r e a c t i o n mixture f o r 15  min t o ensure complete r e a c t i o n . was  a t Q?Cv  (150. mL)  the s o l u t i o n developed a dark brown c o l o u r a t i o n  and a brown p r e c i p i t a t e was atmosphere  nitrogen  reduced t o ~15 mL  The volume of the s o l v e n t  i n vacuo and the r e a c t i o n mixture  was  then t r a n s f e r r e d to the top of a 2 x 15 cm column of alumina (Woelm n e u t r a l , a c t i v i t y grade I V ) . w i t h hexanes developed two bands. brown i n c o l o u r , was  collected  E l u t i o n of the column  The f i r s t band, golden  and the s o l v e n t was  from the e l u a t e i n vacuo t o o b t a i n CpCr (NO) (TI  1  2  dark brown  V  N Q  1785,  (.s, 5H) .  as a  -CgH ) 5  solid.  Anal. Calcd f o r C N, 11.56.  removed  Found: 1686  H CrN O : 1 0  2  2  C, 49.75; H, 4.31;  cm" . 1  ^ C l ! ! } NMR 1  (in a i r ) 64-5°C.  1 ( )  *H NMR  (CDCl ): 3  (CDC1 ): 3  C, 49.59; H, N, 11.20. 6 6.01  IR  4.16; (CH C1 ): 2  (s, 5H),  5 113.89 (s) , 101.41  2  4.99  (s) .  Mp  I t s mass spectrum i s summarized i n Table I.  E l u t i o n of the second band from the column w i t h hexanes produced a p u r p l e s o l u t i o n which c o n t a i n e d [CpCr(.NO) l , 2  2  i d e n t i f i e d by i t s i n f r a r e d  d i m e r i c product was  spectrum . 22  This  i s o l a t e d as a r e d - v i o l e t s o l i d by t a k i n g  the e l u a t e t o dryness i n vacuo, and i t s i d e n t i t y was  con-  - 15 -  Table I .  Low-Re s o l u t i o n M a s s Sp e c t r a l  Cn. -c H ) and CpCr (NO) V ( N O 1 1  5  a  0  5  C p C r (NO) irt/z  D a t a f o r C p C r (NO)  r  Rel  0  Assignment  abund  242  13  182  100  CC H ). Cr ( N O ) 5  5  2  CC H l Cr 5  5  +  2  177  8  (C H )Cr (NO)  147  7  ( C H ) C r CNO}  117  36  65  5  52  31  5  5  5  5  5  Cr  + 2  +  5  CC H )Cr C H  + 2  +  5  + 5  +  CpCr CNOJ. ( N 0 ) 2  m/z  Rel  2  abund  Assignment  223  18  (.C H )Cr (NO) ( N 0 )  193  7  C C H ) C r (NO) CN0 )  177  49  ( C H ) C r (NO)  163  39  ( C H ) C r (N0 )  147  5  133  100  117  12  105  29  65  3  52  27  5  5  5  2  5  5  2  5  5  5  5  5  5  H  Cr  +  H r >  5  4 5 5  +  5  (C H )Cr  C H  +  5  (C H )CrO  C  + 2  2  ( C H ) C r (NO)  C  r  +  '  + 5  +  The a s s i g n m e n t s i n v o l v e t h e m o s t a b u n d a n t n a t u r a l l y occurring  isotopes  i n each  fragment.  +  2  +  0  - 16 -  firmed by; i t s c h a r a c t e r i s t i c mass spectrum A t h i r d band was w i t h dichloromethane  then e l u t e d from the alumina column  as e l u a n t , thereby producing a green  s o l u t i o n which a f t e r a d d i t i o n of hexanes and slow removal of s o l v e n t i n vacuo,  a f f o r d e d green, m i c r o c r y s t a l l i n e CpCr-  (N0) (N0 ) . 2  2  A n a l . C a l c d f o r C,_H -CrN 0 , : [  o  J  DO  18.83. v  N  Q  air)  Found:  1825,  1719  1  *H NMR  N,  4  C, 27.21; H, 2.15; cm" .  C, 26.92; H, 2.26;  /  N, 18.76.  (CDClg) :  (CH C1 1:  IR  6 5.78  2  2  ( s ) . Mp ( i n  86-7°C. F i n a l l y , e l u t i o n of the column w i t h t e t r a h y d r o f u r a n  produced  an orange-brown s o l u t i o n which was  under reduced p r e s s u r e .  Proton NMR  and mass spectroscopy [ ^Q  i n d i c a t e d t h a t the remaining brown s o l i d 1660  cm ^] was  an aggregated  taken to dryness  species.  (CH C1 ):*  V  2  For i n s t a n c e , i t s  mass spectrum a t 200°C e x h i b i t e d the h i g h e s t m/z 466 which c o u l d be assigned t o the  1640-  2  (Cj-H^)  C r  2  peak a t  3 ( °) g N  +  i° n  U n f o r t u n a t e l y , t h i s s o l i d c o u l d not be rendered pure by chromatography, s u b l i m a t i o n or r e c r y s t a l l i z a t i o n . (b)  In benzene or t e t r a h y d r o f u r a n . These r e a c t i o n s were  performed  i n a manner s i m i l a r t o t h a t d e s c r i b e d i n p a r t  (a)  except t h a t the benzene r e a c t i o n mixture was maintained a t ~6°C and the r e a c t i o n time was conversions.  extended  t o 3 0 min  f o r both  In both cases, the f i n a l r e a c t i o n mixture  c o n s i s t e d of a v e r y dark s o l u t i o n w i t h no p r e c i p i t a t e being present. but  S e p a r a t i o n of the products was  [CpCr (NO) „] „ was  e f f e c t e d as i n (a),  not d e t e c t e d i n e i t h e r  solvent.  - 17  -  In a l l three solvents-, the y i e l d s of the products  were somewhat v a r i a b l e , appearing  the r a t e of i n t r o d u c t i o n of NO  nitrosyl  to depend both on  and on the r e a c t i o n time.  T y p i c a l y i e l d s are t a b u l a t e d below. Yield  (%)  CpCr(NO) 2  C n "C H )  Solvent  [CpCr (NO) ]  1  5  5  2  CpCr (NO)  2  (N0 )  2  2  hexanes  35  6  4  benzene  25  0  10  tetrahydrofuran  13  0  10  Reaction  of N i t r o g e n Monoxide w i t h CpCr (NO) _ (n -C Hi-) .  A-  1  —-•—-• 2-  5—5  r  slow stream of p r e p u r i f i e d n i t r o g e n monoxide was  passed over  a s t i r r e d , brown s o l u t i o n of C p C r ( N O ) ( n —C^H^) (0.018 g, 1  2  0.10  mmol) i n hexanes (2 5 mL)  at ambient temperature f o r 1 h,  d u r i n g which time a dark brown p r e c i p i t a t e was formed.  The  i n vacuo and (~5 mL)  s o l v e n t was  gradually  removed from the r e a c t i o n mixture  the r e s i d u e was  of dichloromethane.  r e d i s s o l v e d i n a s m a l l amount An  i n f r a r e d spectrum of  the  dichloromethane s o l u t i o n r e v e a l e d t h a t ~3 5% of the organom e t a l l i c r e a c t a n t had been consumed and  t h a t the o n l y  n i t r o s y l - c o n t a i n i n g complex present was  CpCr(NO) (N0 ).  Treatment of a hexanes s o l u t i o n of  2  other  2  [CpCr(N0) ] 2  2  w i t h n i t r o g e n monoxide i n an i d e n t i c a l manner r e s u l t e d i n the formation  of the n i t r i t e s p e c i e s i n low  yields.  Reaction of N i t r o s y l C h l o r i d e w i t h Chromocene.  To a s t i r r e d  - 18  CO.27 g, 1.5 mmolI i n dichloromethane  s o l u t i o n of C p C r 2  mL)  a t 0°C was  added an excess of C I N O  dichloromethane.  Immediately  green c o l o u r a t i o n , s o l u t i o n was  dissolved  23  in  the s o l u t i o n developed a b l u e -  but no p r e c i p i t a t e was  formed.  s t i r r e d f o r 3 0 min w h i l e i t was  s l o w l y warm t o room temperature. at reduced p r e s s u r e t o ~15 mL  I t was  and was  onto a 2 x 7 cm F l o r i s i l column.  The  permitted to  then c o n c e n t r a t e d  transferred  by s y r i n g e  E l u t i o n of the column w i t h  dichloromethane developed a green band which was  collected.  The o l i v e - g r e e n e l u a t e c o n t a i n e d o n l y C p C r ( N O ) C l , 2  by i t s c h a r a c t e r i s t i c i n f r a r e d and H NMR 1  Photonitrosylation Cp MoH 2  21 2  of Cp MoH . 2  C50  identified  spectra . 1 6  A s t i r r e d y e l l o w s o l u t i o n of  2  (0.43 g, 1.9 mmol) i n hexanes  (200 mL)  was  irradi-  ated f o r 0.5 h i n a p h o t o r e a c t o r u s i n g a medium-pressure mercury  lamp  (Hanovia L-4 50W)  housed  immersion w e l l , w i t h p r e p u r i f i e d  i n a water-cooled Pyrex  n i t r o g e n monoxide bubbled  through the s o l u t i o n d u r i n g the i r r a d i a t i o n .  N i t r o g e n was  then passed through the s o l u t i o n t o remove any unreacted  NO,  and the l i g h t brown s o l u t i o n and f l o c c u l e n t brown p r e c i p i t a t e were t r a n s f e r r e d  as a s l u r r y t o another f l a s k where the  v o l a t i l e s were removed from the r e a c t i o n mixture i n vacuo. An IR spectrum of the r e s u l t i n g brown r e s i d u e i n C H C 1 2  s o l u t i o n r e v e a l e d two and 1650  cm  strong n i t r o s y l absorptions at  The s o l u t i o n was  a 3 x 7 cm column of alumina IV).  transferred  (Wbelm n e u t r a l ,  E l u t i o n of the column w i t h C H C 1  orange-brown band, which was  2  2  2  1737  t o the top of activity  grade  developed a s i n g l e  c o l l e c t e d and the s o l v e n t  - 19 -  removed under reduced onto a water-cooled 0.07  pressure.  Sublimation o f t h e r e s i d u e  probe a t 45°C and 0.005 T o r r y i e l d e d  g (13% y i e l d ) o f orange-brown CpMo(NO) (n -C,-H,-) , mp 1  24  2  77-8°C.  IR CCH C1 ) : 2  2  v  1737 , 1650 'cm" ; "• :E." NMR. l  1  N  Q  (CDC 1 ^) :  <5 6.18 Cs, 5H) , 5.40 (s, 5H). A mass spectrum o f t h e s o l i d was  a l s o i d e n t i c a l t o t h a t o f an a u t h e n t i c sample o f t h e  compound.  U n f o r t u n a t e l y , s a t i s f a c t o r y a n a l y t i c a l data c o u l d  not be o b t a i n e d . H,  Anal. Calcd f o r C H MoN O : 10  3.52: N, 9.79. Found:  1Q  2  2  C, 41.98;  C, 44.35; H, 4.14; N, 9.14.  Photolysis of Cp WH 2  under comparable c o n d i t i o n s  21 2  y i e l d e d a yellow-brown s o l i d  (v  (CH C1 ):  N Q  2  2  1640, 1555 c m ) -1  which d e f i e d a l l attempts t o p u r i f y i t . Reaction o f Cp MoH 2  w i t h NO.  2  N i t r o g e n monoxide was passed  over a s o l u t i o n c o n t a i n i n g Cp MoH 2  2  (0.23  g, 1.0 mmol) i n  hexanes (4 0 mL) f o r 3 0 min a t room temperature d u r i n g which, time t h e s o l u t i o n s l o w l y darkened. removed under reduced solved i n CH C1 . 2  The s o l v e n t was then  p r e s s u r e and the brown r e s i d u e d i s -  An IR spectrum r e v e a l e d two weak, broad  2  n i t r o s y l a b s o r p t i o n s a t 1820 and 1590 cm Reaction o f C p M o C l  2  green THF s o l u t i o n  .(75 mL) c o n t a i n i n g 1.63 g (5.5 mmol) o f  2  Cp MoCl 2  2 5 2  w i t h Na/Hg i n an NO Atmosphere.  A  was t r a n s f e r r e d t o a f l a s k c o n t a i n i n g -2.5 equiv-  a l e n t s o f a 2% Na amalgam, and the v i g o r o u s l y s t i r r e d r e a c t i o n mixture  was immediately  of p r e p u r i f i e d n i t r o g e n monoxide. a p e r i o d o f approximately  p l a c e d under an atmosphere A gray s o l i d  formed  over  10 minutes t o produce an opaque  - 20. -  suspension.  A f t e r 30 min the f l a s k was purged w i t h N , and 2  the supernatant was c a r e f u l l y removed by s y r i n g e and taken to dryness  i n vacuo.  An IR spectrum of a N u j o l m u l l o f the  gray r e s i d u e r e v e a l e d no a b s o r p t i o n s a t t r i b u t a b l e t o coordi n a t e d NO, so the r e a c t i o n product was not i n v e s t i g a t e d further. Reaction o f C p  v 2  w i t h N i t r o g e n Monoxide.  n i t r o g e n monoxide was s l o w l y passed solution  Prepurified  over a p u r p l e benzene  (125 mL) c o n t a i n i n g 0.84 g (0.46 mmol) o f C p V  2 1  2  .  Reaction was immediate and y i e l d e d a b l a c k s o l u t i o n and precipitate.  The mixture was s t i r r e d f o r 1 h t o ensure  complete r e a c t i o n and was then f i l t e r e d through porosity f r i t t e .  An IR spectrum of the f i l t r a t e r e v e a l e d  n i t r o s y l a b s o r p t i o n s a t 1675 and 1565 cm was c o n c e n t r a t e d under reduced approximately  a medium  .  The f i l t r a t e  p r e s s u r e t o a volume of  10 mL, and the s o l u t i o n was t r a n s f e r r e d t o the  top of a 5 x 9 cm column o f F l o r i s i l . e l u a n t an orange band developed but would not e l u t e f u r t h e r .  With benzene as  a t the top o f the column,  With CH^Cl,, as e l u a n t , the  band smeared; THF e l u t e d the band c l e a n l y .  Solvent removal  from the THF e l u a t e a f f o r d e d 0.2 g of an orange-brown s o l i d . IR  (CH C1 ):  cm \  2  2  *H NMR  v  N  Q  1776 (w), 1673 (st) , 1618 (w), 1566  (st)  and mass s p e c t r a of the product, as w e l l as  elemental a n a l y s e s , v a r i e d from r e a c t i o n t o r e a c t i o n , although the IR spectrum was q u i t e r e p r o d u c i b l e .  Numerous  attempts a t chromatography on a v a r i e t y o f supports and recrystallization  from a v a r i e t y of s o l v e n t mixtures  - 21 -  ( i n v a r i a b l y g i v i n g powders1, as w e l l as attempted tion  sublima-  (the s o l i d i s q u i t e n o n - v o l a t i l e ) f a i l e d t o y i e l d a  pure product. R e s u l t s and D i s c u s s i o n Reactions of N i t r o g e n Monoxide w i t h Cp^Cr. D e s p i t e the f a c t t h a t chromocene r e q u i r e s an addi-'" t i o n a l two e l e c t r o n s f o r the c e n t r a l metal t o achieve a noble gas c o n f i g u r a t i o n , chromocene appears t o be a f a i r l y non-reactive complex . 26  H, 2  C  H 2  Thus, no r e a c t i o n i s observed  with  4 ' PhC=CPh, or HC=CH under the c o n d i t i o n s i n v e s t i -  gated .  With carbon monoxide r e a c t i o n i s incomplete; a  2 6  product i s observable but i s u n s t a b l e a t standard temperat u r e and p r e s s u r e , i . e . C p C r + CO 2  ,  Cp Cr(CO)  (6)  2  F u r t h e r r e a c t i o n w i t h CO can occur, but t h i s process r e q u i r e s both h i g h temperatures  and h i g h p r e s s u r e s of CO t o b r i n g  about the displacement of a c y c l o p e n t a d i e n y l r i n g  C  P  C r 2  +  C  0  ^  i  C  0  '  [C Cr(CO) ] P  3  2 7  : (7)  2  In sharp c o n t r a s t , when a hexanes s o l u t i o n of C p C r 2  at 0°C i s exposed t o an atmosphere of p r e p u r i f i e d NO, the o r g a n o m e t a l l i c r e a c t a n t i s r a p i d l y consumed C p C r + excess NO — h e x a n e s 2  fc  C  p  CpCr(NO) (N0 ) 2  2  C  r  (  N  0  )  i n the r e a c t i o n .  (_ i_c n  ^ +  H  + [CpCr(NO) ] 2  2  (8)  [A p r i n c i p a l product i n t h i s r e a c t i o n i s a red-brown c l u s t e r  - 22  -  compound whose exact f o r m u l a t i o n has yet to be determined.] Indeed, the ease w i t h which n i t r o g e n monoxide r e a c t s w i t h chromocene resembles i t s ready r e a c t i v i t y w i t h manganocene and n i c k e l o c e n e  a t room temperature and  2 9  pressure, i . e .  C p N i + NO  •  CpNi (NO)  Cp Mn + NO  •  Cp Mn (NO) (n -C H )  2  2  (9) (10)  1  2  2  The major i s o l a b l e product  3  5  5  of the r e a c t i o n w i t h chromocene  i s C p C r ( N O ) ( n C ^ H ^ ) which can be obtained  i n ~35%  1_  2  T h i s complex has been prepared  3 0  2  31  i n y i e l d s of 16 and  20%  or CpCr(NO) Br  respectively.  1  Even when  i s employed i n such  metatheses, the d e s i r e d complex can o n l y be o b t a i n e d yield and  3 2  .  Hence, r e a c t i o n 8 r e p r e s e n t s  with  2  (n -C^H^)^Al  the g e n t l e a l k y l a t i n g agent  yield.  p r e v i o u s l y by the m e t a t h e t i c a l  r e a c t i o n s of CpCr (NO) C1 w i t h C g H ^ T l Cj-Hj-Na  28  the most  i n 17%  convenient  h i g h e s t - y i e l d p r e p a r a t i v e route to the b i s ( c y c l o p e n t a —  dienyl) species. C p C r ( N O ) ( n - C ^ H ^ ) i s a dark-brown, v o l a t i l e , a i r 1  2  s e n s i t i v e s o l i d t h a t i s known  30  to be  stereochemically  n o n r i g i d i n s o l u t i o n a t room temperature.  I t s formation  in  r e a c t i o n 8 can be viewed as r e s u l t i n g from the s e q u e n t i a l a d d i t i o n of NO  groups to chromocene, a process  i n which,  c o o r d i n a t i o n of even the f i r s t n i t r o s y l l i g a n d as a t h r e e e l e c t r o n donor to the e l e c t r o n - d e f i c i e n t chromium atom r e q u i r e s a change i n the bonding mode of one  of the c y c l o -  p e n t a d i e n y l r i n g s i f the i n e r t gas  i s to  satisfied.  The  formalism  be  C p C r ( N O ) ( n C ^ H ^ ) so formed can then 1_  2  react  23 -  f u r t h e r w i t h excess NO t o g i v e the n i t r i t e complex, i . e . CpCr (NO) ( n - C H ) + excess NO 1  2  5  5  •  CpCr (NO) ( N 0 ) (.11) 2  but performing t h i s r e a c t i o n s e p a r a t e l y r e v e a l s t h a t conversion  2  this  proceeds r a t h e r slowly under the experimental  c o n d i t i o n s employed. Since C p C r ( N O ) ( N 0 )  has been mentioned o n l y i n  i n the l i t e r a t u r e ,  i t s physical properties merit  2  2  passing  2 8  delineation. solid  C p C r ( N O ) ^ ( N 0 ) i s an o l i v e - g r e e n , diamagnetic 2  (mp 86-7°C) which can be handled i n a i r f o r s h o r t  p e r i o d s o f time without n o t i c e a b l e decomposition o c c u r r i n g . I t i s f r e e l y s o l u b l e i n common o r g a n i c  solvents  (except  p a r a f f i n hydrocarbons) t o g i v e a i r - s e n s i t i v e , green s o l u t i o n s , and i t sublimes a t 40°C  (5 x 10 ^ Torr) with  con-  comitant decomposition. The H NMR spectrum of the complex 1  i n CDClg e x h i b i t s a sharp resonance a t 6 5.78 c h a r a c t e r i s t i c of a pentahapto c y c l o p e n t a d i e n y l trum o f CpCr (NO) 2 ( N 0 ) 2  ring.  The i n f r a r e d spec-  i n CH^C^, which shows two strong  bands a t 1825 and 1719 cm  a t t r i b u t a b l e to terminal  nitro-  s y l groups, i s a l s o c o n s i s t e n t with the compound having the molecular  structure  - 24  I t s mass spectrum  -  (summarized i n Table. I) e x h i b i t s the  parent i o n and the expected  fragmentation  p a t t e r n , namely  the s e q u e n t i a l l o s s of l i g a n d s from the metal I n t e r e s t i n g l y , the base peak i s due s i m i l a r oxo-ions  to the  centre.  (C^H^)CrO  ion;  +  have been p r e v i o u s l y d e t e c t e d i n the mass  s p e c t r a of other o r g a n o m e t a l l i c n i t r o s y l  compounds . 33  Based on the slow r a t e at which CpCr (NO) ^ (n. —C,-H,-). 1  r e a c t s w i t h NO  to produce C p C r ( N O ) ( N 0 ) , i t i s apparent 2  2  t h a t t h i s i s not the major route by which the n i t r i t e com- . plex i s formed.  I t s formation can, however, be  rationalized  v i a the r a d i c a l i n t e r m e d i a t e CpCr(NO) « and indeed the  iso-  2  l a t i o n of  [CpCr (NO) ] 2  2  from r e a c t i o n 8 i s c o n s i s t e n t with,  the formation of such a t r a n s i e n t s p e c i e s .  Relevant  to t h i s  p o s s i b i l i t y i s the o b s e r v a t i o n t h a t when, a hexanes s o l u t i o n of CpCr (CO) (NO) ;  l  2  the presence  i s subjected to u l t r a v i o l e t i r r a d i a t i o n i n  of n i t r o g e n monoxide, the o r g a n o m e t a l l i c r e a c t —  ant i s g r a d u a l l y converted  to a mixture  of  [CpCr ( N O ) ] 2  CpCr(NO) (N0 ) as the o n l y n i t r o s y l - c o n t a i n i n g 2  2  and  products , 3 2  2  i.e. CpCr(CO) (NO) + excess NO  • hexanes  2  [CpCr (NO) 1 2  Analogously, (THF)  2  + CpCr (NO) (N0 )  when the photogenerated  i s r e a c t e d w i t h NO  2  2  (12)  s p e c i e s CpCr (CO) (NO)-  i n the absence of l i g h t , the same  products are again i s o l a t e d , i . e . 3 2  CpCr(CO)(NO)(THF) + excess NO  THF —  »  - 25  [CpCr CN01 ] 2  The  formation  of CpCr (NO)  r e a c t i o n s 12 and ted  2  2  -  + CpCrCNO) (N0 ). 2  (.13)  2  (.N0) as- the p r i n c i p a l product  in  2  13 can be r a t i o n a l i z e d i n the manner d e p i c -  below. CpCr (CO)  2  (NO)  + NO  ^  _  2 C 0  eq. 12 CpCr (NO) •  C14)  2  eq. 13 CpCr (CO) (NO) (THF) followed  + NO -""""-THF ,  -CO  by 1/2 [CpCr CNO) ] 2  CpCr(NO)  2  NO  (15)  CpCr(NO) (N0 ) 2  Initially labile  the incoming n i t r o g e n monoxide c o u l d r e p l a c e  (or d i s s o c i a t e d ) l i g a n d s capable of donating  e l e c t r o n s each to the metal t o form the s p e c i e s , CpCr(NO) '• to  [CpCr (NO) 12  nitrite.  o  r  2  The  two  two  seventeen—electron  T h i s e n t i t y c o u l d then e i t h e r dimer-  2  ize  2  r e a c t f u r t h e r with NO  to produce the  l a t t e r complex c o u l d a l s o r e s u l t , i n p a r t ,  from the r e a c t i o n of the dimer w i t h n i t r o g e n monoxide. f o l l o w i n g experimental  The  f a c t s are i n accord w i t h t h i s r a -  tional : CD NO,  [CpCr (NO) ] 2  i s 2  indeed  converted  to CpCr (NO)  2  (N0 ). by 2  but o n l y s l o w l y a t ambient temperature i n s o l v e n t s such.  as t e t r a h y d r o f u r a n  or hexanes.  The  r a t e of the. r e a c t i o n i n  - 26 -  hexanes can be enhanced s i g n i f i c a n t l y by i r r a d i a t i o n o f the r e a c t i o n m i x t u r e , an i n c r e a s e t h a t probably r e f l e c t s the 3 2  e f f e c t of the p h o t o d i s s o c i a t i o n of the dimer, i . e .  —i^L_>  [CpCr (NO) ]2 2  2CpCr(NO) -  (16)  2  [Since the completion of t h i s work other photochemical t i o n s i n v o l v i n g [CpCr ( N O ) ] 2  2  have been r e p o r t e d , i . e .  Mn (CO) + CpCr(N0) Cl 2 10 2 0  i n  o  c  hv, CO heptane  CpCr (CO) (NO) 2  [ C  and  P  C r ( N O )  ]  heptane »  M  n(CO) Cl + 5 c  + [CpCr (NO) J 2  ( > 17  2  CpCr (CO) (NO)  (18)  2  the authors a l s o r a t i o n a l i z e t h e i r r e s u l t s as i n v o l v i n g  the r a d i c a l (2)  2 2  reac-  CpCr(NO) • .] 3k  2  The p h o t o n i t r o s y l a t i o n o f CpCr(CO) (NO) i n e i t h e r CHC1 2  or CC1  4  r e s u l t s i n complete d e c a r b o n y l a t i o n  and  formation  of a homogeneous yellow-brown s o l u t i o n c o n t a i n i n g (N0) C1 . 3 5  2  This transformation  CpCr—  can a l s o be understood i n  terms o f the r e a c t i v e intermediate  CpCr(NO) * which, once 2  formed, c o u l d a b s t r a c t halogen from the s o l v e n t t o g i v e the f i n a l product.  Such h a l o g e n - a b s t r a c t i o n  known f o r a v a r i e t y of o r g a n o m e t a l l i c (3)  r e a c t i o n s are w e l l  carbonyl  radicals . 36  The i s o l a t i o n o f a n i t r i t e - c o n t a i n i n g s p e c i e s  from  r e a c t i o n s i n v o l v i n g t r a n s i t i o n - m e t a l complexes and n i t r o g e n monoxide has s e v e r a l precedents i n the l i t e r a t u r e Generally,  '  3 7  .  such complexes a r e b e l i e v e d t o arise, from the.  oxidation of a coordinated monoxide.  1 0  n i t r o s y l l i g a n d by n i t r o g e n  A s i m i l a r mechanism, i . e .  3  - 27  CpCr CNO) - •+•• NO  •+  2  -  0 N CpCr-N50  C19)  0 o  N CpCr-N=0 N 0  +  2NO  CpCr (NO)  N  (N0  2  i n v o l v i n g e l e c t r o p h i l i c a t t a c k of f r e e NO group may  w e l l be o p e r a t i v e  in this  2  2  CpCr(NO)2*•  [CpCr(NO) ] 2  +  N  (2  2°  on the bound  0)  NO  system.  Thus i t i s q u i t e l i k e l y t h a t the C p C r ( N O ) ( N 0 ) and  ) 2  formation  of both  r e a c t i o n 8 occurs v i a  i n 2  Based on the r e l a t i v e r a t e s of the  various  r e a c t i o n s under comparable c o n d i t i o n s , i t appears t h a t p r o d u c t i o n of CpCr(NO) " can occur without the involvement of 2  CpCr(NO)2 dl ~C^H^) as an i n t e r m e d i a t e , 1  C p C r + NO 2  • CpCr(NO) ( n * - C H ) 5  -C H 5  5  N  °  i.e.  » CpCr (NO)  2  t n . -C H 5  -  C  5  H  5  .  CpCr(NO) (N0 ) 2  +NO -  +exeess NO  2  2  +exce.ss NO 1/2[CpCr(NO) ] 2  The  observation  i s obtained  5  -fexcess- NO  5  {CpCr(NO)}  CpCr(NO)  }  1  2  t h a t a comparable d i s t r i b u t i o n of products  when the r e a c t i o n i s c a r r i e d out a t -78°C i n  hexanes argues a g a i n s t  initial  formation  of some ' a c t i v a t e d '  form of CpCr(NO)2(n C^H^) which subsequently e i t h e r l o s e s 1_  Ci-H,.' or l o s e s i t s excess energy v i a c o l l i s i o n s w i t h molecules.  The  f a c t t h a t the dimer i s not d e t e c t e d  same r e a c t i o n i s performed i n t e t r a h y d r o f u r a n  other when the  or benzene but  - 28 -  improved y i e l d s of CpCr (NO) (NO,,) are obtained 2  probably  r e f l e c t s a longer l i f e t i m e f o r CpCr(NO) " i n these s o l v e n t s , 2  a l o n g e v i t y t h a t i n c r e a s e s the l i k e l i h o o d o f i t s r e a c t i o n with NO as d e p i c t e d i n equations 19 and 20. In c o n t r a s t t o i t s behavior towards NO, chromocene r e a c t s o n l y s l o w l y with CINO i n C H C l 2  a t 0°C t o y i e l d  2  C p C r ( N O ) C l as the o n l y n i t r o s y l - c o n t a i n i n g product. 2  Infra-  red m o n i t o r i n g of the r e a c t i o n f a i l s t o d e t e c t any of the products from r e a c t i o n 8 as i n t e r m e d i a t e s even though some r e a c t i o n s of CINO can be u n d e r s t o o d  i n terms of the e q u i -  16  l i b r i u m shown below: 2C1NO  *  2NO + C l  2  Reactions o f N i t r o g e n Monoxide with Cp Mo. 2  While chromocene i s s t a b l e and r e a d i l y n e i t h e r molybdenocene nor tungstenocene stable to allow t h e i r i s o l a t i o n . generated routes . 3 8  prepared,  are s u f f i c i e n t l y  They can, however, be  as h i g h l y r e a c t i v e s p e c i e s by a v a r i e t y of Thus r e d u c t i o n of Cp^MG^  (M = Mo, W) with  sodium amalgam produces Cp M as a t r a n s i e n t s p e c i e s , as 2  does the i r r a d i a t i o n o f s o l u t i o n s o f Cp MH . 2  The photochemical s o l u t i o n Cp MoH 2  2  g e n e r a t i o n of Cp Mo from a hexanes 2  while b u b b l i n g NO through the s o l u t i o n  2  leads t o the formation of CpMo (NO) (n -C,-H,-) i n low y i e l d 1  2  as the s o l e n i t r o s y l - c o n t a i n i n g product, i . e . Cp M0H 2  2  + NO  h  ^  » C Mo(NO) (n -C H ) + { ( C ^ M o ) ^ 1  a  n  e  s  P  2  5  5  (22)  -  29 -  While an a n a l y t i c a l l y pure product c o u l d not be i s o l a t e d , the IR, H NMR, and mass s p e c t r a o f the product a r e i n d i s 1  t i n g u i s h a b l e from those o f CpMo (NOJ 2 Ox -C^H,.) prepared by 1  metathesis o f CpMo(NO) Cl w i t h e i t h e r C H T 1 or ( n - C H ) ~ 1  2  Al . 2h  5  5  5  3  The r e a c t i o n of CP2M0H2 w i t h NO i n the absence o f  i r r a d i a t i o n i s found t o l e a d s l o w l y t o a d i f f e r e n t , tified  5  uniden-  n i t r o s y l s p e c i e s which has thus f a r d e f i e d a l l  purification  attempts.  CpMo (NO) 2 ( n -C,-H,-) i s an orange-brown, v o l a t i l e 1  s o l i d which d i s s o l v e s r e a d i l y i n common o r g a n i c s o l v e n t s t o yield  air-sensitive solutions.  I t s H NMR spectrum :  con-  s i s t s of two sharp s i n g l e t s {6 6.18 (s, 5H) , 5.40 (s,  5H)  i n CDCl^} r e v e a l i n g t h a t , l i k e i t s Cr analogue, CpMoCNO)^— (n C^H^) i s s t e r e o c h e m i c a l l y n o n r i g i d i n s o l u t i o n a t room 1_  temperature. The r e a c t i o n of NO w i t h CP2M0 (generated by the r e d u c t i o n of CP2M0CI2 w i t h sodium amalgam) under an atmosphere of n i t r o g e n monoxide f a i l s n i t r o s y l - c o n t a i n i n g products.  t o y i e l d any o r g a n o m e t a l l i c  Any CpMo (NO) ^ (Tl -Cj-H,-) formed 1  i n t h i s r e a c t i o n must subsequently decompose under the cond i t i o n s of the experiment. The r e a c t i o n o f CP2W, generated by p h o t o l y s i s of CP2WH2, w i t h a n i t r o g e n monoxide atmosphere y i e l d s a n i t r o s y l - c o n t a i n i n g product  (v  N 0  (CH C1 ): 2  2  1640, 1555 c m ) -1  which has- d e f i e d a l l attempts- t o i s o l a t e , i t ; i t i s n o t , however, CpW(NO) ( n ^ - C ^ ) " 2  2  cm ^) as might  Cv  N 0  (CH^C^) :  1710, 1628  have been expected b y analogy w i t h t h e Mo  reaction. Reaction of N i t r o g e n Monoxide w i t h  Cp^V.  The r e a c t i o n of NO w i t h a s o l u t i o n of Cp V occurs 2  very r a p i d l y t o y i e l d , a f t e r p a r t i a l p u r i f i c a t i o n , orange-brown n i t r o s y l - c o n t a i n i n g product 1675,  1565  cm ^ ) .  (V  N 0  an  (CI^C^)  :  I t has not, however, been obtained i n  s u f f i c i e n t l y pure form to a l l o w i t s i d e n t i f i c a t i o n . Summary and C o n c l u s i o n s Although some success i n p r e p a r i n g n i t r o s y l - c o n t a i n ing products from the r e a c t i o n of NO w i t h e l e c t r o n - d e f i c i e n t metallocenes has been achieved, i t i s r a t h e r l i m i t e d . compounds prepared are i s o l a t e d o n l y i n r e l a t i v e l y  The  low  y i e l d s , and c o n s i d e r a b l e d i f f i c u l t y i n attempting t o p u r i f y the n i t r o s y l products formed i s encountered.  This  appears  to be a r e s u l t of the r e a c t i v i t y of the C^-H,.* r e l e a s e d i n the course of the r e a c t i o n , r e s u l t i n g i n the formation of o r g a n i c by-product w i t h unfavourable p h y s i c a l p r o p e r t i e s . Even when the n i t r o s y l complexes formed can be chromatographed,  pure products are o f t e n not o b t a i n e d .  It therefore  appears t h a t t h i s method of p r e p a r i n g o r g a n o m e t a l l i c n i t r o s y l complexes i s not as convenient as was  anticipated.  It  i s c l e a r , n e v e r t h e l e s s , t h a t s e l e c t i v e r e a c t i o n of organom e t a l l i c complexes w i t h NO a realistic  objective.  i n the presence of CO and  is  CHAPTER  REACTIONS  OF  WITH  CATIONIC  SOME  SODIUM  Research currently metal ates  being  hydride in  and  addition  cluster  with  aim  the  s t r u c t u r a l ,  the  hydride  received  and  continue  complexes, remain  many  methods  are  was  g e n e r a l  3  begun  .  of  an  anionic  reagents  such  of  the  or  9  .  In  synthesized  c a t a l y s t s  4  .  0  Thus  c h a r a c t e r i s t i c s in  receive,  capable  that  most  as  of  of  organo-  Indeed, had 4 1  .  useful  been  N a B H .  3  9  .  A  only  there  when are  hydrides, for  the  few  preparing  replacement  employing  factor  in  isolated  methods  by  analogous  the  While  involves  halide,  carbonyl  existence  transition-metal  complexes  such  LiAlH.  to  CpRe(CO)(NO)H  hydrido  ligand, as  hydride  was  3  organometallic  unknown.  synthesizing One  transition-metal  though  v i r t u a l l y  n i t r o s y l  for 9  even  hydro-  .  attention  n i t r o s y l  work  9  intermedi-  o l e f i n s  significance  the  have  this  3  as  been  chemical  is  Covalent  including of  have  to  hydrides  organometallic  reactions  paramount  chemistry  contrast  reactions,  and  chemistry  pace.  heterogeneous  a n a l y t i c a l ,  transition-metal  hydride  implicated  complexes  modelling  COMPLEXES  vigorous  been  c a t a l y t i c  have  metal  a  have  hydride  ligand  p r i n c i p l e ,  at  hydroformylation  of  NITROSYL  transition  complexes  genation  In  NEUTRAL  conducted  homogeneous  the  DIHYDRIDOBIS(2-METHOXYETHOXY)ALUMINATE AND  in  III  which  hydride poten-  - 32  t i a l l y can complicate i s the occurrence c o o r d i n a t e d NO i n t e r - and  -  the p r e p a r a t i o n of n i t r o s y l  of simultaneous  chemical  cated redox changes at the n i t r o g e n .  by  leads to  both  compli-  In the context of  3 9  i n a t e d NO  a t t a c k on a  of the r e a c t a n t , which can proceed  i n t r a - m o l e c u l a r mechanisms and  the o v e r a l l  hydrides  o b j e c t i v e of studying the r e a c t i v i t y of coordf-  i n o r g a n o m e t a l l i c environments, i t i s of  interest  to determine what reagents r e a c t w i t h the n i t r o s y l u n i t the presence of other p o t e n t i a l  in  s i t e s of r e a c t i v i t y .  Instances where the n i t r o s y l l i g a n d  reacts concurrently with  other l i g a n d s c o u l d perhaps prove to be an a s s e t r a t h e r than a complication. In r e c e n t years a g r e a t v a r i e t y  of new  and organoboron h y d r i d e s have been prepared, u t i l i t y as agents f o r the s e l e c t i v e functional  groups i n v e s t i g a t e d . 4 2  r e a c t i v i t y of one  organoaluminum  and  their  r e d u c t i o n of o r g a n i c In t h i s chapter  the  such reducing agent, sodium bis(2-methoxy-  ethoxy)aluminumdihydride  ( I ) , towards a v a r i e t y  t i o n — m e t a l n i t r o s y l complexes i s r e p o r t e d .  of  transi-  [In Chapter V  the s u c c e s s f u l p r e p a r a t i o n of s e v e r a l o r g a n o m e t a l l i c  nitrosyl  h y d r i d e s i s d i s c u s s e d i n the context of an attempted  syn-  thesis of  of  [CpM(.NO) ] 2  I i n aromatic  2  CM = Mo,  W).]  The  hydrocarbons and e t h e r s combined w i t h a  reducing s t r e n g t h comparable to l i t h i u m and d i i s o b u t y l  extreme s o l u b i l i t y  aluminum  hydride  aluminum hydride make t h i s a i r - s t a b l e  inum hydride both more convenient the other hydrides m e n t i o n e d . 42  and  s a f e r to handle  alumthan  - 33 -  Experimental All  experimental procedures d e s c r i b e d were performed  under the g e n e r a l c o n d i t i o n s d e t a i l e d R e a c t i o n of CpCr (NO) (NO3) w i t h I. 2  t i o n of CpCr (NO) mL)  C.NO.JJ  2  "*  To a s t i r r e d green s o l u -  g, 2.8 mmol) i n benzene  ("0.66  3  i n Chapter I I .  a t room temperature was added dropwise a 0.5 M  s o l u t i o n of NaAlH (OCH CH OCH J 2  2  2  3  (I) * . 1  2  (30  benzene  The s o l u t i o n g r a d -  4  u a l l y darkened and became p u r p l e i n c o l o u r .  The p r o g r e s s  of the r e a c t i o n was monitored by IR s p e c t r o s c o p y , and the benzene  s o l u t i o n of I was  t i o n s due t o the i n i t i a l one e q u i v a l e n t of I was final  s o l u t i o n was  added u n t i l the n i t r o s y l absorpr e a c t a n t had d i s a p p e a r e d .  Exactly  r e q u i r e d f o r complete r e a c t i o n .  c o n c e n t r a t e d i n vacuo t o ^5 mL  and  The  was  t r a n s f e r r e d by s y r i n g e onto a 4 x 4 cm column of alumina (Woelm n e u t r a l , a c t i v i t y grade 1 ) .  E l u t i o n of the column  w i t h benzene developed a s i n g l e red band which was  collected  and taken t o dryness under reduced p r e s s u r e t o o b t a i n r e d purple, m i c r o c r y s t a l l i n e  CO.15 g, 31%  [CpCr (NO)2]2  yield),  r e a d i l y i d e n t i f i a b l e by i t s c h a r a c t e r i s t i c IR, H NMR, 1  and  mass s p e c t r a . 2 2  R e a c t i o n s of I w i t h CpCr (NO) C^L —C^H^) , CpCrCNO)^1  3J  2  I  ,  2 8  and CpCr(NO) (N0 )  C H C 1 , and 2  i n benzene,  28  2  2  2  [CpCr (NO) (CO) ] P F  a s i m i l a r manner.  2  4 5 g  [CpCr(NO)^\ BF^  4 3  in  i n THF were c a r r i e d out i n  In each i n s t a n c e ,  [CpCr(NO)^\  2  was  the  o n l y n i t r o s y l - c o n t a i n i n g product formed. R e a c t i o n of CpCr (NO) (N0 ) with. NaBH^ . 0  o  To a s t i r r e d green  34  s o l u t i o n of CpCr (NO) (NOg) 2  -  (0.66 g, 2.8 mmol); i n 1:1  t e t r a h y d r o f u r a n at room temperature was s o l i d NaBH  4  (0.2 0 g, 5.3 mmol).  to darken a f t e r 1 h. r e a c t i o n was  IR m o n i t o r i n g i n d i c a t e d t h a t the : a f t e r 24 h, and an  a d d i t i o n a l 0.2 0 g of NaBH^ were added.  t i o n mixture was  A f t e r an a d d i t i o n a l  adjudged t o be complete, and the r e a c -  taken t o dryness i n vacuo.  of the r e s i d u e by chromatography eluant  added an excess of  The r e a c t i o n mixture began  o n l y p a r t i a l l y completed  24 h the r e a c t i o n was  (vide supra), a f f o r d e d 0.08  g  (16% yield), of  R e a c t i o n of CpMn(CO) (NO)I w i t h I. c o n t a i n i n g CpMn(CO)(NO)I  [CpCr-  spectra.  1  2  (30 mL)  Purification  on alumina w i t h benzene as  ( N O ) ] , as i d e n t i f i e d by i t s IR and H NMR 2  benzene-  A s t i r r e d benzene s o l u t i o n  h6  (~2 mmol) was  treated  dropwise a t room temperature w i t h a benzene s o l u t i o n of I V Th.e green-brown r e a c t i o n mixture s l o w l y became r e d - v i o l e t , a solid precipitated.  The r e a c t i o n was monitored by IR  spectroscopy, and the a d d i t i o n of the r e d u c i n g agent stopped when a l l the s t a r t i n g m a t e r i a l had r e a c t e d . p o i n t , the mixture was to -10 mL  and  was At t h i s  c o n c e n t r a t e d under reduced p r e s s u r e  and t r a n s f e r r e d by s y r i n g e t o the top of a 2 x 5  cm column of alumina.  E l u t i o n of the column w i t h benzene  produced a r e d - v i o l e t band which was dryness i n vacuo. [CpMn (CO) (NO) ]  ,f 7 2  The r e s u l t i n g r e s i d u e was by i t s IR, H NMR, J  R e a c t i o n of CpCo(NO)I w i t h I. c o n t a i n i n g 0.43  g  c o l l e c t e d and taken t o identified  as  and mass s p e c t r a .  To a t o l u e n e s o l u t i o n  (1.5 mmol) of CpCo(NO)! * 1  8  a t -7 8°C  (80 was  mL)  - 35 -  added dropwise with, s t i r r i n g a Benzene-toluene  solution  c o n t a i n i n g one e q u i v a l e n t o f 1.. The o r i g i n a l green darkened,  solution  and then a t a r r y p r e c i p i t a t e d e p o s i t e d as the  a d d i t i o n proceeded.  The f i n a l r e a c t i o n mixture c o n s i s t e d  of t h i s p r e c i p i t a t e and a v i r t u a l l y c o l o u r l e s s supernatant liquid;  i t was p e r m i t t e d t o warm s l o w l y t o room temperature.  The s o l v e n t was removed under reduced p r e s s u r e , the r e s i d u e was e x t r a c t e d w i t h t e t r a h y d r o f u r a n ( 3 x 2 5 mL), the e x t r a c t s were f i l t e r e d , and the f i l t r a t e was taken t o dryness i n vacuo. The f i n a l r e s i d u e was d i s s o l v e d i n 10 mL o f C H C 1 2  and chromatographed CH2CI2  as e l u a n t .  2  on a 2 x 7 cm F l o r i s i l column w i t h A s i n g l e , dark p u r p l e band developed and  was c o l l e c t e d , and the e l u a t e was c o n c e n t r a t e d t o 50 mL under reduced p r e s s u r e .  A d d i t i o n of an equal volume o f  hexanes and slow c o n c e n t r a t i o n under reduced p r e s s u r e induced the c r y s t a l l i z a t i o n of [CpCo(NO)] "  8  2  (0.12 g, 51% y i e l d )  whose i d e n t i t y was e s t a b l i s h e d by comparison o f i t s XR, E 1  NMR,  and mass s p e c t r a w i t h those o f an a u t h e n t i c sample o f  the complex. R e a c t i o n o f [CpMo (NO) T_ ] 2  2  w i t h I.  (1.93 g, 2.17 mmol) was suspended  Solid  [CpMo (NOI T ] 2  49 2  i n benzene C200 mL) a t  room temperature, d i s s o l v i n g o n l y s l i g h t l y t o g i v e a p a l e violet solution.  A 0.45 M benzene s o l u t i o n o f I was added  dropwise over a p e r i o d of 1.5 h, the slow a d d i t i o n being r e q u i r e d t o permit the [CpMo (NO) I,,] the s o l u t i o n .  2  t o e q u i l i b r a t e with,  As I was added, a dark p r e c i p i t a t e  formed  and the s o l u t i o n turned green; with, s t i r r i n g ,  i t became  orange; then as more s t a r t i n g m a t e r i a l d i s s o l v e d , the s o l u t i o n again became v i o l e t .  The a d d i t i o n of I was stopped  when the v i o l e t c o l o u r a t i o n no longer r e t u r n e d ; two e q u i v a l e n t s of I were r e q u i r e d t o reach t h i s p o i n t .  The s o l v e n t  was then removed i n vacuo; the r e s i d u e was d i s s o l v e d i n 15 mL of CH2CT2; and the r e s u l t i n g dark s o l u t i o n was  syringed  onto a 3 x 8 cm alumina ( a c t i v i t y grade I) column. with. C I ^ C ^ developed two bands: which decomposed  Elution  a l e a d i n g p a l e green band  p a r t way down the column, and an orange  band which r e q u i r e d 3 00 mL of CH2CI2 f o r complete e l u t i o n . The e l u a t e was taken t o dryness under reduced p r e s s u r e , and the r e s i d u e was r e c r y s t a l l i z e d from hot t o l u e n e t o o b t a i n 0.25 g (18% y i e l d ) of a n a l y t i c a l l y pure, orange [CpMo(NO)I]2 Anal. Calcd f o r C N, 4.41. v  Found:  1648 c m . -1  N Q  H Mo N O I : 10 10 2 2» 2* 2*  C, 18.89; H,  C, 19.14; H, 1.68; N, 4.47. Mp  1.59;  IR ( C H ^ C l ^ :  ( i n a i r ) 135°C dec.  The r e a c t i o n between  [CpMo (NO) C ^ ]  a 2  n  d  I i n benzene  was performed and worked up i n an i d e n t i c a l manner.  No  o r g a n o m e t a l l i c products were i s o l a b l e by chromatography. Reaction of [CpCr(NO)„]„ w i t h I'. (2.6 mmol) of [CpCr (NO). ^\^  22  At room temperature. 0.91 g  were d i s s o l v e d i n benzene, and  2 e q u i v a l e n t s of I i n benzene were added dropwise t o the stirred  solution.  The r e d - p u r p l e s o l u t i o n g r a d u a l l y became  orange-brown, and a small amount of a b l a c k p r e c i p i t a t e , deposited.  A f t e r a l l the aluminum reagent had been added,  the r e a c t i o n mixture was s t i r r e d f o r an a d d i t i o n a l 0.5 h t o  -  ensure complete r e a c t i o n .  37  -  The. mixture was- then c o n c e n t r a t e d  under reduced p r e s s u r e t o *10 mL and was t r a n s f e r r e d onto a 3 x 8 cm F l o r i s i l  column.  developed two bands.  E l u t i o n o f the column w i t h benzene  The broad, dark green, f i r s t  e l u t e d w i t h ~250 mL of benzene.  The s o l v e n t was  band  removed  from the e l u a t e i n vacuo, and the r e s u l t i n g r e s i d u e  was  c r y s t a l l i z e d from dichloromethane-hexanes t o o b t a i n green (0.129 g, 15% y i e l d ) of C p C r ( N O ) ( N H 1  crystals  2  2  50  2  3  was i d e n t i f i e d by i t s c h a r a c t e r i s t i c IR, H NMR,  which  and mass  1  spectra . 1 8  The orange second band was then e l u t e d from the column w i t h dichloromethane.  A d d i t i o n of hexanes t o the  e l u a t e and slow c o n c e n t r a t i o n of the mixture under reduced p r e s s u r e r e s u l t e d i n the f o r m a t i o n o f orange c r y s t a l s g,  2% y i e l d ) of C p C r (NO) (NH ) . 2  2  2  2  2  Anal. Calcd f o r j _ o i 4 2 4 ° 2 c  N, 17.17. V  (0.02  Found:  1625 c m . -1  N Q  (br,  2H) .  Mp  1  H  C r  N  :  C  '  3 6  *  8 2 ;  C, 36.76; H, 4.20; N, 16.93.  E NMR  5 5.39  CCDClg). :  (s, 5H) ,  H  ' - '" 4  33  IR (THF)_ : 2.08  ( i n air). 130°C dec.  F i n a l l y , e l u t i o n of the column w i t h t e t r a h y d r o f u r a n produced a s i n g l e brown-orange band which was c o l l e c t e d and taken t o dryness under reduced p r e s s u r e . the  r e s i d u e from dichloromethane-hexanes a f f o r d e d orange  crystals  (0.03 g, 3% y i e l d ) of C p C r (NO) (NH ) (OH).. 2  Anal. Calcd f o r C N, 12.84. v  Found:  1 Q  H  1 3  2  Cr N 0 : 2  3  3  2  2  C, 36". 71; E,  C, 36.59; H, 3.83; N, 12.53.  1655, 1625 cm . 1  M n  C r y s t a l l i z a t i o n of  Mp  (in air)  150°C dec.  4.00;  IR (THF);:  Mass spectrum:  •r> 3 8  most i n t e n s e parent i o n m/'z  326. 97 69.  R e a c t i o n of C p C r (NO) (NH,,) w i t h I. 2  2  3  Two  e q u i v a l e n t s of I  i n benzene were added t o a benzene s o l u t i o n  (30 mLl c o n t a i n -  i n g 0.12  temperature.  g  (.0.35 mmol) of the amide a t room  As the mixture was  s t i r r e d , the i n i t i a l green c o l o u r changed  to a dark orange—brown.  IR m o n i t o r i n g of the r e a c t i o n  i n d i c a t e d t h a t most of the r e a c t a n t was min.  The f i n a l mixture was  tographed on F l o r i s i l 2  (vide supra) t o o b t a i n 0.035 g of  3  2  g of C p C r (NO) (NH > 2  -0.001 g of C p C r ( N O ) ( N H ) (OH). 2  30  c o n c e n t r a t e d i n vacuo and chroma-  unreacted C p C r (NO) (NH > , 0.010 2  consumed a f t e r  2  2  2  2  2  The y i e l d s of the  2  2  and  latter  two complexes were 12% and 1% r e s p e c t i v e l y , based on the amount C p C r (NO) (NH )  consumed.  R e a c t i o n of C p C r ( N O ) C l  w i t h NaNH .  2  2  3  2  2  c o n t a i n i n g 1.01  g  A THF  solution  (4.71 mmol) of CpCr ( N O ) C 1  was  23  2  an excess of s o l i d NaNH was  2  2  (.20  mL)  added t o  (0.65 g, 17 mmol), and the mixture  s t i r r e d a t ambient temperature.  P e r i o d i c m o n i t o r i n g of  the supernatant l i q u i d by IR spectroscopy showed a g r a d u a l disappearance of the a b s o r p t i o n s due t o the o r g a n o m e t a l l i c r e a c t a n t as the s o l u t i o n changed from o l i v e green to brown and a b l a c k p r e c i p i t a t e formed. r e a c t i o n mixture was  A f t e r 1.5  The  s o l v e n t was  cm)  fritte.  removed from the f i l t r a t e i n vacuo, the  r e s i d u a l s o l i d was mixture was  h, the  f i l t e r e d through a s h o r t (2 x 4  column of C e l i t e supported on a medium p o r o s i t y  orange-  suspended i n 10 mL  of C H C 1 , and 2  2  t r a n s f e r r e d to the top of a 2 x 6 cm  the  Florisil  -  column.  39  -  E l u t i o n of the column with. CH^Cl^ developed a s i n g l e  green band which was  c o l l e c t e d and taken t o dryness.  golden s o l i d thus o b t a i n e d O0.02 g) was r e a c t e d CpCr (NO) CT by i t s TR and 2  1  H NMR  identified  development  ected.  2 3  Removal of s o l v e n t from the e l u a t e under  C H C l - h e x a n e s a f f o r d e d 0.06 2  (NH )(OH) which was 2  *H NMR,  g  coll-  reduced  of the r e s i d u e from  (8% y i e l d ) of C p C r 2  2  (NO) ~  i d e n t i f i e d by i t s c h a r a c t e r i s t i c  2  IR,  and.mass s p e c t r a , ( v i d e s u p r a ) .  Reaction of Fe(NO)^Cl w i t h I . gen monoxide was tion  resulted i n  of a dark orange-brown band which was  pressure f o l l o w e d by r e c r y s t a l l i z a t i o n 2  as un-  spectra .  F u r t h e r e l u t i o n of the column w i t h THF the  The  (100 mL)  f o r 2 0 min.  A stream of p r e p u r i f i e d  passed over a v i g o r o u s l y s t i r r e d THF  c o n t a i n i n g 1.0 g  (3.3 mmol) of  The s t i r r e d s o l u t i o n was  nitrosolu-  [Fe(NO) C1] 2  1 6 2  then p l a c e d under a  n i t r o g e n atmosphere, and a 0.5 M benzene s o l u t i o n of I was added dropwise. of  I was  IR m o n i t o r i n g i n d i c a t e d t h a t a s l i g h t  r e q u i r e d t o r e a c t completely with the Fe(N0)gCl  generated i n s i t u , but the r e a c t i o n mixture remained throughout. was in  excess  A f t e r the r e a c t i o n was  complete, the s o l v e n t  evaporated i n vacuo; the r e s i d u a l s o l i d was 10 mL of C H C 1 ; and the suspension was 2  2  dark  suspended  transferred  onto  a 3 x 8 cm F l o r i s i l  column.  when the column was  e l u t e d w i t h a 1:3 mixture of THF:CH C1 ,  and i t was the  A s i n g l e brown band developed 2  collected.  The e l u a t e was .taken to dryness, and  remaining s o l i d was  c r y s t a l l i z e d by slow c o o l i n g of a  c o n c e n t r a t e d 10:1 CH C1 :THF s o l u t i o n from room 9  2  9  temperature  - 40 -  t o -2.0°C t o o b t a i n 0.0.4 g C5% y i e l d ) ; o f F e ( N Q ) ( N H ) , 2  Anal. Calcd f o r H Fe N 0 : 4  31.86. v  Found:  Q  1 7 6 3 , 1727 c m " .  (XCD ) C0): 3  2  spectrum:  &  1  K NMR C C D C 1 ) :  IR ( C H C 1 ) : 2  Mp ( u n d e r N ) 176°C d e c .  2  Mass  2  m o s t i n t e n s e p a r e n t i o n m/z 2 6 3 . 9 0 1 3 .  Reaction o f F e ( N 0 ) C l w i t h NaBH . 3  To a s t i r r e d  4  (20 mL) c o n t a i n i n g 3.32 mmol of F e ( N O ) C l  as d e s c r i b e d i n the p r e v i o u s s e c t i o n ) a t room added s o l i d NaBH  4  (0.25 g, 6.7 mmol).  mixture immediately darkened, evolution occurred.  solution  (prepared i n s i t u  3  was  2  6 5.15 ( b r ) ;  3  6 6.80 ( b r ) .  2  C, 0.00; H, 1.53; N,  4  C, 0.16; H, 1.52; N, 31.64. 1  N  2  4  temperature  The r e a c t i o n  heat was g i v e n o f f , and gas  The f i n a l r e a c t i o n mixture was worked  up i n a manner i d e n t i c a l t o t h a t d e s c r i b e d i n the preceeding paragraph t o o b t a i n 0.03 g (7% y i e l d ) of F e (NO) (NH ) , as 2  4  2  2  i d e n t i f i e d by i t s IR and mass s p e c t r a . In a separate experiment,  the NaBH  s m a l l p o r t i o n s , and the IR spectrum  4  was added i n  of the supernatant  l i q u i d was recorded a f t e r each a d d i t i o n .  The o n l y d e t e c t -  a b l e n i t r o s y l a b s o r p t i o n s were those a t t r i b u t a b l e t o e i t h e r the s t a r t i n g m a t e r i a l o r the i s o l a t e d R e a c t i o n of FeCNO) Cl w i t h NaNH . 3  2  product.  [Fe (NO) C1] 2  2  (0.62 g,  2.0 mmol) was d i s s o l v e d i n THF (30 mL) and converted t o F e ( N 0 ) C l as d e s c r i b e d above. 3  S o l i d NaNH  2  (0.31 g, 8.0  mmol) was added, and the r e a c t i o n mixture was s t i r r e d f o r 24 h a t room temperature  whereupon i t g r a d u a l l y darkened.  F i l t r a t i o n o f the mixture, removal of s o l v e n t , and chroma—  - 41  1-  tography of the r e s i d u e as before produced Q..0.54 g y i e l d ) of F e  (NO) ^ (NH )  2  2  which, was  2  (10%  i d e n t i f i e d by i t s IR  and  mass s p e c t r a . R e s u l t s and Reactions  Discussion  of Sodium D i h y d r i d o b i s (2-methoxyethoxy)aluminate  (a) With Monomeric Chromium N i t r o s y l Complexes.  Previous  work has e s t a b l i s h e d t h a t r e d u c t i o n of CpCr(NO)_ Cl w i t h 2  Na[AlH (OCH CH OCH ) 1 2  2  2  (I) i n toluene at room temperature  2  3  produces [ C p C r ( N O ) ] 2  b e l i e v e d t o proceed  2  ^  n  2 2 %  yield  5 1  .  This reaction i s  v i a the t h e r m a l l y u n s t a b l e  hydrido-  chromium complex CpCr (NO) H, which subsequently 2  to the observed hydrogen .  product w i t h concomitant e x p u l s i o n of  F u r t h e r support  52  f o r the involvement  hydrido i n t e r m e d i a t e i s provided by the present that  dimerizes  [CpCr (NO)2]2 ^  s  of such a observation  formed i n comparable y i e l d s d u r i n g  r e a c t i o n s of I w i t h a v a r i e t y of CpCr (NO) X p r e c u r s o r s at 2  ambient temperature, i . e .  C  ?  C  r  C  N  0  )  X = NO_,  2  benzene or C I ^ C l ,  X  N0 , o  »  [CpCr^O)^  (23)  I, rZ-C.-H.- or BF.  M o n i t o r i n g of the progress of r e a c t i o n 23 by i n f r a r e d  spec-  t r o s c o p y i n d i c a t e s t h a t the optimum s t o i c h i o m e t r i c r a t i o of r e a c t a n t s i s 1:1  and  t h a t the d i m e r i c s p e c i e s i s the o n l y  n i t r o s y l - c o n t a i n i n g product  formed.  These r e a c t i o n s a l s o  demonstrate the a b i l i t y of I t o s u b s t i t u t e H and pseudohalide  l i g a n d s and  to t r a n s f e r H  f o r both h a l i d e to a c o o r d i n a -  - 42  t i v e l y unsaturated BF^.  Reaction  -  metal c e n t r e such, as t h a t i n I CpCr (NO)^] -  23 can a l s o be e f f e c t e d i n t e t r a h y d r o f u r a n  w i t h NaBH, being employed i n p l a c e of I, but the y i e l d the d i m e r i c product  i s lower.  i s i s o l a b l e i n o n l y 15% y i e l d CpCr (NO)2 (NOg)  of  [CpCr(NO) 1  For i n s t a n c e ,  2  2  from such a r e a c t i o n when  i s used as the s t a r t i n g m a t e r i a l .  A  similar  o b s e r v a t i o n has been r e p o r t e d f o r the r e d u c t i o n of C p C r ( N O ) ~ 2  C l by e i t h e r I or NaBH^ . 51  The u b i q u i t o u s n i t r o s y l dimer a l s o r e s u l t s from the reaction I [CpCr (NO)  2  (CO) ] PF^  •  [CpCr(NO) ] 2  (24)  2  a t r a n s f o r m a t i o n which p a r a l l e l s the s y n t h e s i s of (NO)] 2 "  and  [CpFe (CO) ] 2  electronic cations respectively.  53 2  b  Y  [CpMn (CO)-  h y d r i d e a t t a c k on the i s o -  [CpMn ( C O ) ( N O ) ]  and  +  2  [CpFe(CO) ] , +  3  Presumably, r e a c t i o n 24 occurs v i a the  un-  s t a b l e CpCr(NO) H s i n c e i t i s known t h a t treatment of  the  2  analogous c a t i o n [CpW(NO) (CO)] 2  +  w i t h NaBH^ produces the  t h e r m a l l y s t a b l e complex CpW(NOy^H . 51  viewpoint,  however, r e a c t i o n s 23 and  u s e f u l s i n c e [CpCr (NO) 12 i 2  s  From a s y n t h e t i c 24 are not  best prepared  particularly  by the r e a c t i o n  of CpCr (NO)^Cl w i t h sodium amalgam i n b e n z e n e . 22  (b) With gome Monomeric I o d o n i t r o s y l Complexes. w i t h CpCr (NO)2I  J u s t as  (eq. 2 3 ) , I a l s o undergoes simple meta-  t h e t i c a l r e a c t i o n s w i t h other monomeric i o d o n i t r o s y l comp l e x e s t o produce h y d r i d o n i t r o s y l s p e c i e s which may not be t h e r m a l l y s t a b l e a t ambient temperature.  or  may  Examples  -  43  r.  of these r e a c t i o n s a r e summarized i n equations 25—2.7 r CpMn CCO) (NO) I  1  benzene  (Mecp)Mn (NO) (.pph );r  b  3  * e  J  [  e  n  C  p  M  n (  C  0  }C  N  0  1  1  2  (  2  5  }  »  e  (MeCp) Mn (NO) („PPh ) H  54  3  (2 6)  I CpCo (NO} I  •  C2 7 )  [ CpCo (NO) ]  2  t o l u e n e , -78 C Again, the optimum s t o i c h i o m e t r y of the r e a c t a n t s i s 1:1, and the t r a n s f o r m a t i o n s proceed yields.  Due t o the thermal  smoothly and i n reasonable  i n s t a b i l i t y o f CpMn (CO). (NOII , h6  a p r e c i s e y i e l d f o r r e a c t i o n 25 c o u l d not be  determined.  N e v e r t h e l e s s , an o v e r a l l y i e l d o f ~65% c o u l d be achieved f o r the c o n v e r s i o n of the manganese dimer t o the i o d i d e by the a c t i o n of ^  f o l l o w e d by r e d u c t i o n w i t h I back t o the dimer.  The d i m e r i c products formed i n r e a c t i o n s 25 and 27 again probably a r i s e from the thermal decomposition  of the  corresponding monomeric h y d r i d o n i t r o s y l complexes, but no d i r e c t p h y s i c a l evidence c o u l d be o b t a i n e d .  f o r the e x i s t e n c e of these  species  However, c o n s i s t e n t w i t h the view t h a t  CpMn CCO) (NO) H i s the l a b i l e i n t e r m e d i a t e i n reaction,. 25 i s the f a c t t h a t  (MeCp)Mn(NO) (PPh )II was subsequently 3  from r e a c t i o n 26 . 5k  electron-donating  isolated  E v i d e n t l y , I n t r o d u c t i o n o f the b e t t e r (MeCp) and PPh  3  groups i n t o the c o o r d i -  n a t i o n sphere of the manganese atom s t a b i l i z e s the l a t t e r h y d r i d e , whereas the analogous h y d r i d o c a r b o n y l complex i n r e a c t i o n 25 i s so u n s t a b l e t h a t i t cannot be d e t e c t e d b y c o n v e n t i o n a l s p e c t r o s c o p i c techniques.  -  (c) With. [CpMo CNOjXj  2  (X  44  I, CI)  -  Complexes.  the r e a c t i v i t y patterns- of I d e s c r i b e d  In view of  above, i t was  of  i n t e r e s t to i n v e s t i g a t e i t s r e a c t i o n s with complexes cont a i n i n g both b r i d g i n g and seemed reasonable  It  t h a t s e l e c t i v e s u b s t i t u t i o n of the  h a l i d e s c o u l d be achieved intact.  terminal halide ligands.  while  l e a v i n g the h a l i d e  Indeed, j u s t such a t r a n s f o r m a t i o n  [CpMo(NO)I ]2 i s t r e a t e d with two 2  terminal  bridges  does occur when  e q u i v a l e n t s of I at room  temperature, i . e .  forming the well-known dimer  [CpMo (NO) I]  By analogy with, the r e a c t i o n s d e s c r i b e d s e c t i o n s , r e a c t i o n 28 p r o b a b l y dihydrido intermediate  55  2  i n 18%  i n the  proceeds v i a the  [CpMo (NO) (I) (H) ] • 2  t i o n a green c o l o u r , perhaps due  yield.  preceeding unstable  During the  to the i n t e r m e d i a t e ,  a f t e r the a d d i t i o n of each a l i q u o t of I; but t h i s  reacappears  colour  p e r s i s t s o n l y f o r s e v e r a l seconds before being r e p l a c e d  by  the c h a r a c t e r i s t i c orange c o l o u r of the f i n a l product.  The  s p e c i e s r e s p o n s i b l e f o r the green c o l o u r i s not present  in  s u f f i c i e n t concentration spectroscopy.  t o a l l o w i t s d e t e c t i o n by  IR  - 45 -  Subsequently,  the. p r e p a r a t i o n of [CpWCNO). I' ] 5 6. 2  allowed i t s r e a c t i o n w i t h I t o be e x a m i n e d . 54  2  In t h i s  i n s t a n c e a green h y d r i d o — t u n g s t e n s p e c i e s c o u l d be i s o lated, i . e . Cp ON  ' Cp  W W / -r/ \ I I K  Cp  NO  — r benzene  x  *  ON  Cp C29)  W ,W NO ^. \jj \^ H H  I t was c h a r a c t e r i z e d by i t s IR, H NMR,  and mass s p e c t r a ,  1  5 4  although i t s thermal i n s t a b i l i t y p r e c l u d e d the i s o l a t i o n o f an a n a l y t i c a l l y pure sample.  I t was, however, f u r t h e r  c h a r a c t e r i z e d c h e m i c a l l y by r e a c t i o n with P ( O P h ) , i . e . 3  1  [CpW(NO) (I) (H)]  2  + 2P-(0Ph)  •—  3  b  e  n  Z  e  n  e  >  2CpW(N0) (I) CH) [P(OPh.) ]  C30)  3  The r e s u l t i n g tungsten h y d r i d e was f u l l y c h a r a c t e r i z e d . C u r i o u s l y , thermal decomposition  o f [CpW(NO) CI)(H) ]  2  either  i n t h e s o l i d s t a t e o r i n s o l u t i o n does not r e s u l t i n the f o r m a t i o n o f the analogous  ['CpW (NO). (I) ]  2  (vide supra)., a  complex which has y e t t o be prepared. In view o f r e a c t i o n 28, i t was hoped t h a t the r e a c t i o n between [CpMo(NO) (C1) 1 2  the s t i l l unknown [CpMo(NO) ( C l ) ] manner.  and I would a f f o r d  57  2  2  complex i n a s i m i l a r  While the two reagents do r e a c t , no o r g a n o m e t a l l i c  products can be i s o l a t e d from the f i n a l r e a c t i o n mixture. P r e v i o u s l y attempted  r e d u c t i o n s of [CpMo(NO) ( C l ) ] 2  2  with  sodium amalgam, z i n c dust, o r NaBH^ have a l s o been unsuc-  ^ 46 r-  cessful .  These f a i l u r e s - m a y r e f l e c t the i n a b i l i t y o f the  5 8  CI atoms t o b r i d g e  the Mo c e n t r e s  Cd) With [CpCr (NO). 3 . 2  i n the d e s i r e d  The 1:1 s t o i c h i o m e t r y  2  product.  o f the r e a c t -  ants i n r e a c t i o n s 23 and 24 i s important f o r the formation of  [CpCr ( N O ) ] 2  i n maximum y i e l d s  2  s i n c e the d i m e r i c  can r e a c t f u r t h e r w i t h the reducing equivalents CNO) ] 2  agent.  Hence, two  o f I a r e r e q u i r e d t o consume completely  and produce, a l b e i t i n low y i e l d s ,  2  product  [CpCr-  a mixture o f  C p C r (N0). CNH ) , C p C r (NO) (.NH) , and C p C r (NO) (NH ) (OH) 2  The  2  3  2  2  2  2  2  2  2  2  2  2  l a t t e r products appear t o be formed by the s e q u e n t i a l  r e a c t i o n s 31 and 32: [C Cr(.NO) ] P  2  2  b e n  ; ne  Cp Cr (NO) (NH ) 2  2  3  »  e  2  b e n  ~  e n  e  Cp Cr 2  (NO) (NH )  2  3  (31)  2  ^2 2 2 2>2  »  C  (N0)  Cr  (NH  +  C p C r (NO) (NH ) (OH) 2  Supporting" t h i s are the o b s e r v a t i o n s of.I•in  2  2  t h a t a s l i g h t excess-  r e a c t i o n s 23 and 24 produces j u s t a t r a c e o f  C p C r 2 (NO) (NH ) , and r e a c t i o n 32 can be performed 2  dently.  (32).  2  3  2  indepen-  The products of r e a c t i o n 3 2 do not r e a c t f u r t h e r  w i t h I under ambient The  conditions.  complex C p C r ( N O ) ( N H ) was f i r s t 2  2  3  2  isolated i n  1% y i e l d from the r e d u c t i o n of C p C r ( N O ) C l w i t h NaBH' i n 2  4  w a t e r - b e n z e n e , and a r e p o r t o f i t s i s o l a t i o n as a bypro-. 50  duct of the r e a c t i o n s o f carbanions w i t h appeared w h i l e t h i s work was i n progress. pletely  [CpCr-(NO) ] 2  59 2  Tt has been com-  c h a r a c t e r i z e d and i s known t o possess the. m o l e c u l a r  -  47 -  H  H  structure  NO-  ON  i n the s o l i d  Cp  s t a t e 6 tt In terms o f t h e i r gross s t e r e o c h e m i c a l  f e a t u r e s , the two new complexes formed i n r e a c t i o n 3 2 are probably i s o s t r u c t u r a l w i t h the monoamido complex, w i t h the b r i d g i n g NO group i n the l a t t e r being r e p l a c e d by e i t h e r an NH~ or an OH group i n the former s p e c i e s . The diamido  complex, C p C r (NO) (NH j 2  2  2  2  i s an a i r -  s t a b l e , n o n - v o l a t i l e , orange s o l i d which begins t o decompose g r a d u a l l y a t 13 0°C. dichloromethane,  I t has l i m i t e d s o l u b i l i t y i n benzene,  and t e t r a h y d r o f u r a n ; but the orange s o l u -  t i o n s formed a r e a i r - and w a t e r - s t a b l e .  An IR spectrum o f  a THF s o l u t i o n o f the complex e x h i b i t s a s t r o n g a b s o r p t i o n a t 1625 cm ^ a t t r i b u t a b l e t o the t e r m i n a l n i t r o s y l l i g a n d s . The weak  V J J  observed  i n the IR spectrum  H  a b s o r p t i o n s a t 3380 and 3330 cm  can o n l y be  of the complex i n a c o n c e n t r a t e d  N u j o l m u l l , but they occur i n the same range as those r e p o r t e d f o r C p C r (NO) ^ (NH ) . 50  2  spectrum  2  of the complex  2  The l o w - r e s o l u t i o n mass  (taken w i t h a probe temperature of  220°C and summarized i n Table II) i s c o n s i s t e n t w i t h i t s f o r m u l a t i o n as a dimer and d i s p l a y s a fragmentation p a t t e r n s i m i l a r t o t h a t observed peaks due t o metastable 125,  for [CpCr(NO)Cl]  1 7 2  .  For example, *  i o n s can be d e t e c t e d a t M  and they are a s s i g n a b l e t o the fragmentation  = 23 9 and processes  Table  Low-Resolution  II. X  =  NH  Spectral  (X  C p C r (NO) (NH ) X 0  0  0  0  = NH  z  o r OH)  n  Compl  x = OH m/z  Assignment  326  39  (C H ) Cr CNO) (NH )  296  60  (C H ) Cr (NO)  266  100  249  11  (C H ) Cr  200  17  (C H )Cr  182  70  (C H ) Cr  148  5  133  36  117  21  C H Cr  52  19  Cr  The  Data for  2  Rel abund  m/z  Mass  5  5  5  2  5  2  2  2  2  (NH )  2  2  (C H ) Cr (NH ) 5  5  5  2  5  5  2  5  5  5  2  2  2  2  (NH)  +  +  CNH ) (NH)  +  2  +  2  5  2  2  2  (C H )Cr(NH ) 5  5  + 2  2  (C H ) Cr (NO)(NH ) 5  + 2  5  2 + 2  +  2  +  5  +  assignments  involve  t h e most  abundant  Rel abund  Assignment  327  25  (C H l Cr  297  81  (.C H ) Cr  28 0  11  (  267  65  (C H ) Cr (NH )(OH)  250  100  201  11  CC H lCr (NH )0  182  79  (C H ) Cr  133.5  21  (C H ) Cr (NH )(OH)  117  19  C H Cr  52  25  Cr  naturally occurring  5  5  2  5  C  5  H  5  5  5  ( N O ) (_NH ) (OH)  2  2  2  2  )  5  C  2  (NO) ( N H ) (OH)  2  (  5  5  5  5  5  )  0  +  +  +  2  2  5  0  2  2  5  5  N  2  (C H ) Cr 0 5  +  2  2  r  2  +  2  +  2  2  2  2 +  2  +  5  +  isotopes  i n each  fragment.  49 -  C p C r (NO) (JJH I 2  2  C p C r (NH ) 1  +  2 2  2  Cp Cr , respectively. +  2  2  2  + 2  and Cp Ci? ( N H 1 2  2  2  + 2  ^  However, peaks: corresponding t o  b i m e t a l l i c i o n s are r e l a t i v e l y more abundant i n the mass spectrum o f the b i s ('amidol s p e c i e s .  The K NMR  spectrum o f  1  the compound i n CDCl^ c o n s i s t s o f a sharp resonance a t 6" 5.39 and a broad resonance a t 6 2.08 o f r e l a t i v e i n t e n s i t y  5:2  which are a t t r i b u t a b l e t o the c y c l o p e n t a d i e n y l and amido protons, r e s p e c t i v e l y . the r e l a t e d  Since c i s - t r a n s i n t e r c o n v e r s i o n s of  [CpCr (NO) ( N M e ) ] 2  2  complex are known t o begin  o n l y a t e l e v a t e d t e m p e r a t u r e s , t h i s spectrum p r o b a b l y 61  i n d i c a t e s t h a t o n l y one isomer ( e i t h e r c i s or trans), of Cp Cr (NO) (NH ) 2  2  2  2  e x i s t s i n s o l u t i o n a t ambient temperatures.  2  I s o m e r i z a t i o n c o u l d not be induced t o occur by h e a t i n g a s o l i d sample of the complex a t 125 C f o r 1.5 h. Q  The p h y s i c a l p r o p e r t i e s of the other new dichromium complex  i s o l a t e d g e n e r a l l y resemble those d i s p l a y e d by the  b i s (amido) compound. orange-brown  Thus, C p C r (NO) (NH ) (OH) i s an 2  2  I t i s moderately s o l u b l e i n benzene,  and THF t o y i e l d a i r - s e n s i t i v e s o l u t i o n s .  CH2CI2/  spectra display c h a r a c t e r i s t i c -1  2  s o l i d which can be handled i n a i r f o r s h o r t  p e r i o d s o f time.  cm  2  i n THF) and weak v . r  strong  (1655 and 1625  absorptions  TTJ  I t s IR  (3490, 3405  I.Nil O r Un.)  and 3320 cm  1  i n a N u j o l mull). ; and i t s mass spectrum  (Table  I I , probe temperature of 200°C) c o n f i r m s i t s b i m e t a l l i c nature.  [The i d e n t i t y o f the hydroxo complex was a l s o con-  firmed by h i g h - r e s o l u t i o n mass spectrometry. C  10 13 3°3 H  N  5 2 C r :  m  ^  Z  3 2 6  -  9 7 6 7  -  Found:  Calcd f o r  m/z 326.9769.]  - 50 -  I n t e r e s t i n g l y , t h e mass- spectrum a l s o e x h i b i t s - a metastable * peak a t M  = 234 i n d i c a t i v e of the fragmentation p r o c e s s  C p C r ( N H ) (0H)  +  2  2  2  + Cp Cr 0 . +  2  2  A s i m i l a r l o s s of NH^  d u r i n g the fragmentation of the b i s (amido) complex However, u n l i k e f o r Cp Cr (NO)V 2  (NH ) ,  2  2  2  the *H NMR  occurs (Table I I ) . spectrum  of the hydroxo compound i n CDCl^ c o n s i s t s of t h r e e sharp resonances a t <5 5.29, 5.48, and  5.55 due to the c y c l o p e n t a -  d i e n y l protons i n a d d i t i o n t o two weak, broad s i g n a l s a t 6 2.62 and 3.42 a t t r i b u t a b l e t o NH  2  and/or OH p r o t o n s .  A p p a r e n t l y , the complex e x i s t s i n s o l u t i o n as a mixture of isomers, these being presumably  the one t r a n s and two c i s  g e o m e t r i c a l isomers expected i f i t s m o l e c u l a r s t r u c t u r e resembles t h a t of C p C r (NO)^(NH ) (vide s u p r a ) . 2  2  These  2  isomers do not r e a d i l y i n t e r c o n v e r t i n s o l u t i o n a t temperature  s i n c e they can be p a r t i a l l y separated by f r a c - t  t i o n a l c r y s t a l l i z a t i o n from C H C l - h e x a n e s , 2  2  and the E  s p e c t r a of the c r y s t a l l i z e d m a t e r i a l s i n CDCl^ differing  ambient  l  display  i n t e n s i t y r a t i o s of the t h r e e Cp resonances.  s o l u b i l i t y d i f f e r e n c e s of the isomers are not  The  sufficiently  l a r g e , however, t o a l l o w the i s o l a t i o n of any one t h i s manner.  NMR  isomer i n  N e v e r t h e l e s s , s a t i s f a c t o r y - elemental a n a l y s e s  can be o b t a i n e d f or . any • o f - t h e c r y s t a l l i n e , species-'produced. The  f o r m a t i o n of the amido products i n r e a c t i o n s 31  and 32 can be viewed as a r i s i n g from the n u c l e o p h i l i c attack, of H  on the n i t r o g e n atom of a b r i d g i n g n i t r o s y l  The monoamido complex c o u l d t h u s r e s u l t from the mechanism on the f o l l o w i n g page:  ligand. two-step  - 51 -  Cr— —-Cr / \ / \ :  ON  N  0  NO  H~  Cr  Cr  CA)  W  ON  NO  0 H  H  cp  H N  Cr  Cr  \  ON'  Cp  NC  O  x  \  N  NO  The . 0~ r e l e a s e d i s ' scavenged - %--the'Le'wis a c i d p r e s e n t i n the r e a c t i o n mixture.  A s i m i l a r sequence  of r e a c t i o n s  i n v o l v i n g the monoamido s p e c i e s as the i n i t i a l r e a c t a n t would then a f f o r d the bis(amido) compound.  The f a c t  that  the complex t-Bu. CP  OH  CP  X  Cr ON"'"''  Cr ^ N  ^ N O O  can be prepared by the r e a c t i o n of t - B u L i with. [CpCr (HOI 3 2  and subsequent  hydrolysis  5 9  2  p r o v i d e s supporting evidence  f o r the involvement of an i n t e r m e d i a t e such as (A) which i t s e l f may be s t a b i l i z e d by a c o o r d i n a t e O+Al bond i n v o l v i n g  - 52  the b r i d g i n g HNO  group.  -  However, t h i s r a t i o n a l e i s c o n t r a r y  to the e x p e c t a t i o n t h a t the N atoms of t e r m i n a l NO  groups  should be attacked p r e f e r e n t i a l l y by n u c l e o p h i l e s ; 1 h  so i t i s p o s s i b l e t h a t the i s o l a t e d products  and  are simply  the  most thermodynamically s t a b l e s p e c i e s r e s u l t i n g from r e a r rangements of p r e c u r s o r s formed by the r e d u c t i o n of t e r m i n a l NO  l i g a n d s i n the i n i t i a l r e a c t a n t .  In t h i s  connection,  though, i t can be noted t h a t the t e r m i n a l n i t r o s y l groups of [CpCr(NO)(NH )] 2  conditions.  2  undergo no r e a c t i o n with I under ambient  Nevertheless,  the r e a c t i v i t y of these  m e t a l l i c n i t r o s y l complexes towards H r e p o r t e d f o r [CpCo (NO). ] s p e c i e s are converted  c o n t r a s t s with t h a t  and C p N i N O . 62  2  organo-  Both of the  latter  to n i t r o s y l - f r e e c y c l o p e n t a d i e n y l —  hydrido c l u s t e r s when t r e a t e d with. L i A l H ^ / A l C l ^ . i n THF 2 0°C and  then The  hydrolyzed.  o r i g i n s of the hydroxo complex, C p C r ( N O ) ~ 2  (NH )(OH), are somewhat p e r p l e x i n g at the present 2  s e v e r a l p o s s i b l e oxygen sources mixture.  at  are present  I t i s i n t r i g u i n g , nonetheless,  n i t r o s y l - c o n t a i n i n g product t r e a t e d with NaNH  2  (e) With Fe(NO)^Cl.  i n THF  2  2  time s i n c e  i n the r e a c t i o n  t h a t i t i s the  formed when CpCr (NO)  ci  only  is  at room temperature.  In view of the r e a c t i o n s of I w i t h  monomeric i o d o n i t r o s y l complexes of f i r s t - r o w t r a n s i t i o n metals d e s c r i b e d  i n s e c t i o n (b), i t was  of F e ( N O ) C l w i t h a h y d r i d i c reagent 3  hoped t h a t treatment  would produce the  as  y e t unknown b i n a r y n i t r o s y l F e ( N O ) ^ i n an analogous manner. 2  However, when e i t h e r I or NaBH. i s used as the reductant  in  53  the  -  reaction r or NaBH A • " > • ^ b e n z e n e a n d / o r THF 4  2Fe(N0) Cl 3  —  o  The Fe  2  only  of  Cp Cr  (section  (d) ) .  2  2  isolable  species  which  CNO) Fe  m  product  i n i t i a l l y  that  the  a  2  reduction way  A  n i t r o s y l  ( N O ) ^ (_NH ). 2 ,  •  1  2  (NO)  2  4  is  2  Fe  2  can  2  be  formed  CNO) g  2  formed  C.NH )  0  low y i e l d s  could  produced  CNH )  2  i n  F e „ CNO) . ( N H ) 2 4 2 2  from  also  is v i a  i n much  further  the  same  Cp Cr (N01 2  be  C33)  0  2  4  synthesized  by  ..  reaction NaNHFeCNO) Cl  T £ ^ L•  3  This  observation  dimer  and  from  the  i n i t i a l  suggests  reduction (NO)I  2  solid  which  similar  to  2  that  is Its  found  complexes  the  thermodynamic  reaction  monomeric  6 3  ,  2  is  a  sparingly  soluble  molecular for  Thus,  exhibits  strong  about  the v  N  IR Q  could  of  also  species  the  result  formed  upon  a i r -  and  i n most  [FeCNO) X] 2  is 2  (X  water-  common  probably -  I,  SEt,  or  namely  /  \  N  Fe N  N  H'  hedral.  (34).  2  s t a b i l i t y  structure  other  O N ^  geometry  i t  amido  Fe  local  33  golden-brown,  O N ^  The  2  FeCNOj^Cl. 2  solvents.  P(CF ) )  of  2  in  of  CNH )_  organic  3  that  association  Fe stable  reveals  l/2[FeCNO) CNH )]  the  Fe  spectrum  absorptions  N N  /  /  ^ N O  H  atoms of at  the  is  approximately  complex  17 63  and  i n  17 27  tetra-  CH C1 2  cm  1  2  and  54  its K  NMR  1  s p e c t r a d i s p l a y - a b r o a d r e s o n a n c e . 05"" 5,1.5 i n  C D C 1 ; & 6.8 0 i n (CD ) 3  3  mass s p e c t r u m and  C 2  ° ) due t o t h e amido p r o t o n s .  (recorded  Its-  w i t h a p r o b e t e m p e r a t u r e o f 80°C  s u m m a r i z e d i n T a b l e ITI)_ i n d i c a t e s t h a t t h e t e r m i n a l  nitrosyl during  l i g a n d s a r e l o s t p r e f e r e n t i a l l y from t h e dimer  the fragmentation  i s l o s t by t h e remaining The  T-  p r o c e s s e s a n d t h a t an NR"  group  3  F e (NR" ) 2  2  i o n (cf. Table I I I ) .  +  2  s t r e n g t h o f t h e amide b r i d g e s  i n t h e complex i s a l s o  i n d i c a t e d b y t h e f a c t t h a t F e ( N O ) CNH ). 2  4  2  2  i s not cleaved  by n i t r o g e n monoxide under ambient c o n d i t i o n s whereas t h e corresponding  halo dimers,  [Fe(NO) X] , readily 2  convert  2  t o Fe(NO)_ X i n t h e p r e s e n c e o f NO. 3  I t i s l i k e l y t h a t t h e b i s (amido) c o m p l e x was  first  p r e p a r e d i n 1960 b y t h e r e a c t i o n * 6 1  Fe  (CO)  2  (NH ) 2  + 4NO  2  benzene  ^  F  (NO)  (NH )  4  2  (35)  2  + 6CO At  that time,  however, b o t h t h e s t a r t i n g m a t e r i a l and p r o d -  u c t were i n c o r r e c t l y f o r m u l a t e d F e ( N O ) (NH) , r e s p e c t i v e l y . 2  4  2  spectrometric  as F e (CO)^(NH) 2  2  and  S u b s e q u e n t x - r a y and m a s s  studies of the carbonyl  reactant  established  i t s t r u e i d e n t i t y and l e d t h e i n v e s t i g a t o r s t o s u g g e s t t h e n i t r o s y l p r o d u c t o f r e a c t i o n 35 i s a l s o p r o b a b l y bis(amido) s p e c i e s  6 5  .  For  a  Comparison of the s p e c t r a l p r o p e r t i e s  d i s p l a y e d by an a u t h e n t i c those reported  that  sample o f F e ( N O ) ( N H ) 2  f o r "Fe (NO) (NH) " supports 2  4  2  4  2  2  with  such a view.  b o t h t h e chromium amido c o m p l e x e s d e s c r i b e d i n  - .5.5 -  Hig h-Re s o l u t i o n Mass" Spe; c t r a i Data f o r  Table I I I . FeV (NO) (NH 4  :  n  I  2  m/z Measd  Calcd  Rel. "abund  Assignment  263 . 901  2 63.899  70  Fe  2  (NO) (NH )  233.898  233.901  77  Fe  2  (NO) ( N H )  2 03.903  2 03.903  50  Fe  2  (NO) (NH )  173.906  173.906.  97  Fe (NO)(NH )  143.906  143.907  100  126.881  12 6.8 81  73  Fe  12.5.874 .  125.875  30  Fe N  +  112.878  112.878  7  Fe H  +  111.869  111.870  13  101.94 9  10.1. 952  8  4  2  3  2  2  2  2  2  Fe (NH ) 2  2  CNH)  2  + 2  +  2  2  Fe 2  +  e  Fe(NO)(NH )  +  2  The assignments i n v o l v e the most abundant n a t u r a l l y o c c u r r i n g i s o t o p e s i n each, fragment.  +  2  +  2  + 2  + 2  -  section  C d ) and F e (NO) (NH,,) , no evidence f o r the i n t e r 2  conversion terminal Cp Cr 2  2  56. -  4  o f NO and NH  2  2  l i g a n d s between b r i d g i n g  p o s i t i o n s was o b t a i n e d .  and  However, u n l i k e f o r  (N0) (NH ) , the i r o n dimer 'does r e a c t f u r t h e r with. 2  2  2  I t o produce as y e t u n i d e n t i f i e d n i t r o s y l - c o n t a i n i n g products.  CHAPTER IV REACTIONS OF BIS [ (n. -CYCLOPENTADIENYL) DINITROSYLCHROMIUM] 1  WITH LITHIUM TRIETHYLBOROHYDRIDE To  obtain  further  AND  information  a n i s m by w h i c h h y d r i d e r e d u c t i o n monoxide o c c u r s , that and  of coordinated  i n both the reducing  similar  of the hydride  isolated.  source are p o s s i b l e .  triethylborohydride  to that  of l i t h i u m borohydride.  extremely n u c l e o p h i l i c hydride,  has a r e d u c i n g  being  LiEt^BH reveals  that  42  .  10,000 t i m e s more  The r e p o r t e d  i t i s an e x c e p t i o n a l l y  for  the f a c i l e  reductive  for  the regio-  and s t e r e o - s p e c i f i c r e d u c t i o n  also reacts  carbonyl  complexes t o form,  derivatives chapter  in virtually  i s described  which LiEt^BH a c t s displays  40 t i m e s  chemistry of  clean  reagent  dehalogenation of a l k y l  smoothly with v a r i o u s  quantitative  not only  of e p o x i d e s  with  instance,  yields  modes.  6 7  .  formyl  In t h i s  [CpCr ( N O ) ] , ^  as a source o f H  unprecedented r e a c t i o n  h a l i d e s and  transition-metal  i n the f i r s t  i t s reaction  ability  However, i t i s an  t h a n l i t h i u m b o r o h y d r i d e and a b o u t  more n u c l e o p h i l i c t h a n L i A l H ^  It  Large v a r i a -  power and t h e r e l a t i v e n u c l e o - .  Lithium  nucleophilic  nitrogen  a g e n t have upon t h e y i e l d s  d i s t r i b u t i o n s of the products  philicity  r e l a t i n g t o t h e mech-  i t i s o f i n t e r e s t t o examine t h e e f f e c t s  v a r i a t i o n s i n the reducing  tions  WITH BORANE.  2  2  but a l s o  n  6 6  .  - 58 -  In c o n t r a s t t o both N a [ A l H (OCH CH OCH ) ] and 2  LiEt^BH,  BH  3  2  2  3  2  can a c t as a Lew-is a c i d as w e l l as- a h y d r i d e ^  transfer agent .  T h i s has. been suggested as a r a t i o n a l i -  6 8  z a t i o n of the g r e a t reducing  power BH^-THF e x h i b i t s f o r  a-oxygenated l i g a n d s i n g e n e r a l , and can lead t o a l t e r e d r e a c t i v i t y as i l l u s t r a t e d  by the f o l l o w i n g e x a m p l e  as o u t l i n e d i n Chapter I :  68  and  1 -.  r  (3 6)  The  r e a c t i o n of BH^• THF w i t h  [CpCr(NO) ] 2  r e p o r t e d , and the r e s u l t s obtained  2  i s thus a l s o  are compared t o the a n a l and N a [ A l H (OCH CH OCH ) 1.  ogous r e a c t i o n s i n v o l v i n g LiEt^BH  2  2  2  3  2  Experimental A l l experimental under the g e n e r a l Reaction  procedures d e s c r i b e d were performed  conditions described  of L i E t B H  with  3  [CpCr (NO) ] . 2  2  f u r a n s o l u t i o n C3 0 mL) o f [CpCr (NO) ] 2  22  2  i n Chapter I I . A stirred  tetrahydro-  (0. 90 g, 2.5 mmol).  at ambient temperature was t r e a t e d dropwise w i t h a THF s o l u t i o n of L i E t B H . 6 9  3  :  the o r i g i n a l r e d - p u r p l e yellow-brown i n c o l o u r .  re.actipn. recurred'" i j ^ e d i ; ^ ^  and  s o l u t i o n g r a d u a l l y became dark IR m o n i t o r i n g  o f the p r o g r e s s o f  -  59  the reaction, i n d i c a t e d t h a t two  e q u i v a l e n t s of L i E t ^ B H were,  r e q u i r e d t o consume c o m p l e t e l y the o r g a n o m e t a l l i c r e a c t a n t . Solvent was  removed from the f i n a l s o l u t i o n under  p r e s s u r e t o o b t a i n a brown r e s i d u e which was a minimum of benzene  (~5 mL).  redissolved in  To e f f e c t a p a r t i a l  t i o n of the p r o d u c t s , the benzene s o l u t i o n was graphed on a 3 x 8 cm column of F l o r i s i l . brown band was  The THF  e l u a t e was  r e s u l t i n g r e s i d u e was  column.  A broad  THF  g  taken t o dryness  d i s s o l v e d i n CH^C^  2  (5% y i e l d ) of orange C p C r (.NO) 2  g  2  2  the  Florisil  and removal of  2  pressure y i e l d e d  (NH )  E l u t i o n with  2  2  2  2  Both products were r e a d i l y  i d e n t i f i a b l e by t h e i r c h a r a c t e r i s t i c IR,  *H NMR,  and mass  (see Chapter I I I ) . The o r i g i n a l benzene e l u a t e was  ness i n vacuo, and the r e s i d u e was (4 x 15 mL).  The h e x a n e s - i n s o l u b l e matter  2  t i o n was  a l s o taken t o d r y -  e x t r a c t e d w i t h hexanes  C H C 1 , an equal volume of hexanes was  s l o w l y c o n c e n t r a t e d under reduced  Cp Cr (NO) (NH ) 2  acteristic  3  5 0  2  IR, H J  NMR,  was  dissolved i n  added, and the  induce the formation of green c r y s t a l s 2  and  (.2% yield), of orange-brown C p C r (NO) ~  2  of  i n vacuo, the  (~5 mL),  E l u t i o n of the column with C H C 1  (NH ) (OH) a f t e r s o l v e n t removal.  2  remaining  t r a n s f e r r e d by s y r i n g e onto a 1 x 4 cm  a f f o r d e d 0.02  spectra  orange-  THF.  the s o l v e n t from the e l u a t e under reduced 0.04  separa-  chromato-  f i r s t e l u t e d w i t h benzene, and the  products were then e l u t e d w i t h  s o l u t i o n was  reduced  pressure to  (0.13 g, 15%  which were i d e n t i f i e d by t h e i r and mass s p e c t r a .  solu-  yield) char-  - 60.  The dark-red hexanes'extracts were c o n c e n t r a t e d i n vacuo t o ^7 mL and were t r a n s f e r r e d onto a 1 x 2 0 cm column.  Florisil  E l u t i o n of the column with, hexanes developed a  y e l l o w band which a f f o r d e d ^0.04 g (5% y i e l d ) of a y e l l o w o i l a f t e r complete e l u t i o n and s o l v e n t removal. i d e n t i f i e d as C p C r ( N O ) E t  7 0  2  scopic properties NMR  (C,D^) : b b  by i t s c h a r a c t e r i s t i c  [TR (CR" C1 ) : 2  6 4.55  The o i l  v  2  (s, 5H), 1.4  spectro-  1770, 1645 c m .  U  -1  N  Q  Cm, 5H)].  was  1  A low-resolution  mass spectrum of the o i l was a l s o i d e n t i c a l to t h a t d i s p l a y e d by an a u t h e n t i c sample of CpCr(NO) Et. 2  F u r t h e r e l u t i o n of the column w i t h benzene  (.200 mL)  a f f o r d e d a red-brown e l u a t e from which the s o l v e n t removed under reduced p r e s s u r e . redissolved i n CH C1 2  2  (.5 mL)  was  The r e s u l t i n g r e s i d u e  and hexanes  was  (.20 mL) were added.  Slow c o n c e n t r a t i o n of t h i s s o l u t i o n i n vacuo r e s u l t e d i n the c r y s t a l l i z a t i o n of a n a l y t i c a l l y pure, p u r p l e - r e d C p C r (NO)^2  (EtNBEt ) 2  (.0.068 g, 6% y i e l d ) .  Anal. Calcd f o r C N, 12.84. v  Found:  Q  1 6  H  2 5  Cr N 0 B: 2  4  3  C, 44.06; H,  C, 44.06; H, 5.95; N, 12.81.  1644, 1495 c m . -1  N  2  Mp  ( i n a i r ) 151-3°C dec.  IR R  1  5.78;  (CH C1 ): 2  NMR:  2  see  Table VI, page 74. Reaction of BH., • THF with solution  (3 0 mL)  [CpCr (NO) p ] • 2  To a s t i r r e d  THF  c o n t a i n i n g 0.3 6 g (1.0 mmol) [ C p C r ( N O ) ] 2  was added 2.0 e q u i v a l e n t s of a 1 M s o l u t i o n of BH^  2  (pur-  chased from the A l d r i c h Chemical Co. as a 1 M s o l u t i o n i n THF, s t a b i l i z e d w i t h <0.05 M NaBH^).  Over a p e r i o d of 40 h  the s o l u t i o n g r a d u a l l y turned a brown-purple c o l o u r and a  - 61 -  p r e c i p i t a t e formed.  The r e a c t i o n mixture, was- f i l t e r e d  through C e l i t e , the v o l a t i l e s - were removed i n vacuo,  and the  r e s i d u e was  column  p u r i f i e d By chromatography on a F l o r i s i l  as d e s c r i b e d p r e v i o u s l y on pages 36 t o 38. unreacted  [CpCr ( N O ) ] 2  2  C22% y i e l d ) , the complexes C p C r 2  (NO) (NH ) , C p C r (NO) (NH ) 3  2  2  2  In a d d i t i o n to  2  2  2  , and C p C r (NO) (NH ) 2  2  2  (OH)  2  were i s o l a t e d i n y i e l d s of 10, 1 and 3% r e s p e c t i v e l y on unrecovered  [CpCr ( N O ) ] . 2  2  based  The products were i d e n t i f i e d  2  by t h e i r c h a r a c t e r i s t i c IR, *H NMR,  and mass s p e c t r a .  R e s u l t s and D i s c u s s i o n The Reaction of L i E t B H w i t h  [CpCr(NO)2^2*  3  In the p r e v i o u s chapter i t was of  [CpCr (NO) ] 2  2  mixture of C p C r (NO) (NH ) 2  2  3  2  and C p C r ( N O ) ( N H ) (OH) 2  2  2  c o n t a i n i n g complexes. can be viewed  treatment  w i t h two e q u i v a l e n t s of NaAlH (OCH CH OCH ).  2  i n benzene a t room temperature  2  noted t h a t 2  2  3  2  a f f o r d s , i n low y i e l d s , a (2%),  (15%), C p C r (NO) (NH ) 2  2  2  2  2  (3%) as the o n l y i s o l a b l e  nitrosyl-  The f o r m a t i o n of these amido products  as a r i s i n g from the n u c l e o p h i l i c a t t a c k of H  on the n i t r o g e n atoms of the n i t r o s y l l i g a n d s i n the metallic reactant.  organo-  With the hopes of p r e p a r i n g these pro-,  duct complexes i n higher y i e l d s and of g a i n i n g f u r t h e r i n s i g h t i n t o the mechanism of reduction, of a c o o r d i n a t e d NO group, an i n v e s t i g a t i o n of the r e a c t i o n s of [CpCr (NO)2]2 w i t h other potent h y d r i d e donors was  initiated.  c u l a r i n t e r e s t were those h y d r i d e sources which,  Of  parti-  unlike  NaAlH (OCH2CH2OCH3) , c o n t a i n o n l y one t r a n s f e r a b l e H 2  2  per  - 62 -  mole and should t h u s p r o v i d e B e t t e r d e f i n e d c h e m i s t r y For the reasons c i t e d c h o i c e was  6  7  ,  i n the I n t r o d u c t i o n / the. reagent of  LiEt^BH.  The r e a c t i o n of ' LiE't BH w i t h  [CpCr (NO)']  3  2  a t ambient  2  temperature i s q u i t e a complex p r o c e s s , i . e .  c A /° n  P  Cr—-Cr ON N Cp 0  +  2 LiEt BH 3  THF Et CD  CpCr(NO) Et  +  2  \ / ' N /™  ON  C371  BEt \ / 2 N ,N0  / 1J2 N  v  Cr—Pr N Cp 0  /'"ST  +  Cp(NO)Cr (I*) (ii)  Y * X = NO X=NH  (iii)  X=OH  V  V  Cr(NO)Cp /  2  Again, two e q u i v a l e n t s of the h y d r i d e donor are r e q u i r e d t o consume c o m p l e t e l y the o r g a n o m e t a l l i c r e a c t a n t , and the f i v e n i t r o s y l - c o n t a i n i n g products  i n d i c a t e d can be i s o l a t e d i n  y i e l d s ranging from 2 - 15%.  R e g r e t t a b l y , the y i e l d s of the  l a s t t h r e e products  are comparable t o those  Ci - i i i )  obtained when NaAlH^(OCH^CH^OCH^)  2  .  i s employed as the r e d u c t -  ant; but t h e i r formation i n t h i s r e a c t i o n n e v e r t h e l e s s i n d i c a t e s t h a t they probably r e s u l t from the u s u a l r e a c t i o n mode o f Et^BH  as a h y d r i d e source.  J u s t as f o r the t r a n s -  formation i n v o l v i n g N'aAlH^ COC^CH^OCH^) i i t  c  2  s t r a t e d t h a t C p C r CNO) (NH ) 2  2  3  2  a  n  b  e  demon-  r e a c t s f u r t h e r w i t h LiEt-jBH  - 63 -  to y i e l d both C p C r (NO) (NH ) 2  2  2  2  2  and C p C r (NO) (NH ). (OH) , 2  2  2  2  and t h a t n e i t h e r o f these l a t t e r complexes undergoes f u r t h e r r e a c t i o n w i t h excess h y d r i d e under the c o n d i t i o n s of the experiment.  Consequently,  i t seems reasonable t o conclude  t h a t s i m i l a r mechanisms f o r formation o f the b i m e t a l l i c amido compounds a r e o p e r a t i v e i n both systems.  A plausible  mechanism f o r t h e c o n v e r s i o n of an NO l i g a n d t o a c o o r d i n a ted NH  2  group by H  _  a t t a c k i s o u t l i n e d i n the p r e v i o u s  chapter. The monomeric product of the r e a c t i o n , CpCr (NO) Et, 2  i s a l s o well-known, having been s y n t h e s i z e d e a r l i e r by the a c t i o n of E t ^ A l on CpCr ( N O ) C 1 . 70  2  However, i t s formation  d u r i n g the present c o n v e r s i o n i s somewhat s u r p r i s i n g s i n c e the t r a n s f e r o f an e t h y l group from boron t o chromium i s not a common chemical occurrence. it  In t h i s c o n n e c t i o n , though,  i s of i n t e r e s t t o note t h a t treatment  of  [CpFe(CO) ] 2  2  ( i s o e l e c t r o n i c and i so s t r u c t u r a l w i t h [CpCr (NO) ] )_ with. 2  2  L i E t ^ B H i n THF-HMPA does not r e s u l t i n formation of any of the c o r r e s p o n d i n g a l k y l complex, CpFe(CO) Et, but r a t h e r i n 2  q u a n t i t a t i v e c o n v e r s i o n of the c a r b o n y l dimer t o the anion [CpFe(CO) ] 2  7 1  .  In c o n t r a s t , c a r e f u l IR m o n i t o r i n g o f  r e a c t i o n 37 p r o v i d e s no evidence f o r the formation of a n i o n i c nitrosyl  products. The most i n t r i g u i n g product i s o l a t e d from the f i n a l  r e a c t i o n m i x t u r e i s the novel complex C p C r (NO)^ ( E t N B E t ) , 2  a purple-red s o l i d  2  2  (mp 151°C dec) which d i s s o l v e s r e a d i l y i n  common o r g a n i c s o l v e n t s t o y i e l d a i r - s t a b l e ,  red—brown  T- 64 ~  solutions.  Its- I R spectrum  Cin•. .-CH^C^^~  a b s o r p t i o n s a t 1644 and 1495 cm  e x n  i & £ t s - strong  attributable to terminal  1  and b r i d g i n g NO l i g a n d s , r e s p e c t i v e l y .  I t s mass spectrum  (Table V) confirms i t s b i m e t a l l i c - nature, and i t s ambient temperature  1  H and  1 3  C NMR s p e c t r a (Table VI) i n d i c a t e the  absence of m o l e c u l a r symmetry and a r e c o n s i s t e n t w i t h the presence o f a b r i d g i n g EtNBEt2 group.  To a s c e r t a i n i t s  molecular s t r u c t u r e , a s i n g l e - c r y s t a l x - r a y  structural  a n a l y s i s of t h e complex was c a r r i e d out by Dr. R.G. B a l l The c r y s t a l s t r u c t u r e of C p C r ( N O ) ( E t N B E t ) 2  2  3  2  .  7 2  con-  s i s t s of a w e l l - s e p a r a t e d a r r a y o f d i s c r e t e molecular u n i t s , the i n t e r m o l e c u l a r d i s t a n c e s corresponding t o normal van der Waals c o n t a c t s .  The molecular packing w i t h i n the c r y s t a l i s  i l l u s t r a t e d i n F i g u r e 1.  Each molecule  (Figure 2) adopts a  t r a n s c o n f i g u r a t i o n o f the n i t r o s y l and c y c l o p e n t a d i e n y l l i g a n d s w i t h r e s p e c t t o the mean plane of the c e n t r a l , C" 2 2 fragment r  N  and has an o v e r a l l geometry s i m i l a r t o t h a t  d i s p l a y e d by t r a n s - [ C p C r ( N O ) ( N M e ) ] 2  and t r a n s - C p C r (NO) ( N H ) . 6 0  2  cyclic  2  3  2  73 2  ,  trans-[CpCr(NO) ] 2  7 4 2  S e l e c t e d bond d i s t a n c e s and  i n t e r b o n d angles a r e g i v e n i n Table IV. The i n d i v i d u a l molecular dimensions (EtNBEt ) 2  of C p C r ( N O ) 2  2  3  a r e a l s o comparable t o those found i n the other  cyclopentadienylchromium  n i t r o s y l complexes mentioned above.  S p e c i f i c a l l y , the bond l e n g t h s and angles w i t h i n each molec u l e a r e c o n s i s t e n t w i t h the views t h a t : (a)  The Cp r i n g s f u n c t i o n as formal f i v e - e l e c t r o n , donors  to the metal c e n t r e s .  [The r i n g s have normal  geometries , 7 5  ,  Bottom F i g u r e 1.  S t e r e o s c o p i c view of the c o n t e n t s of a u n i t of C p C r ( N O ) ( E t N B E t ) . 2  2  3  2  cell  The view i s down c, and  the hydrogen atoms are omitted f o r c l a r i t y .  -  F i g u r e 2.  66  A p e r s p e c t i v e view of the m o l e c u l a r structure, of C p C r CNOJ.3 CEtNBEt ). i n c l u d i n g the atom numbering 2  2  2  scheme.  Hydrogen atoms a r e omitted, and the  thermal e l l i p s o i d s ility  level.  are drawn a t the 50% probab-  C(I4)  C(3)  68 -  Table IV.  S e l e c t e d Bond D i s t a n c e s -  and Bonff A;h:gTes: "(deg).  for Cp Cr CNOly(EtNBEt ). 2  2  2  Bond  Distances  Cr(1)  - Cr(2)  2. 668 0 C8I  C r (1)  C(l).  2. 255 (4)  C r CD  - N(l)  1. 892 (.31  Cr ( D  C (21  2. 2.3 8 (41  C r CD  - N(2)  1. 67 9 (3)  Cr C D  CC3)  2. 202 (4)  C r (1) - N ( 4 )  2.068 (3)  C r CD - C ( 4 )  2. 212 (4)  C r ( 2 ) - N CD  1.924 (3)  Cr ( D  CC5)  2. 226 (41  CrC2). - NC3).  1.680 C.31  C r (2) - C ( 6 I  2. 194 (51  Cr(.2> - NC4).  2.070 (31  C r (.2) - C(71  2. 256 C5)  NCD  - 0(1)  1.196 (41  C r C2);  C(8}  2. 262 (4)  N(2) - 0 ( 2 )  1.191 (4)  C r (2) - C ( 9 )  2. 22 5 C4J  N(3) - 0(3)  1.199 (41  C r (2) - C ( 1 0 )  2. 183 (41  NC4)  1.459 (5)  CC111  - C(12)  1. 53 6 ( 6 )  N ( 4 ) - C (15)  1.498 C51  CC13)  - CC14)  1. 519 (71  B  c a n  1.578 (51  CC15)  CC131  1.601(6)  B  -  - B  —  —  CC.16).  1. 508 C.7)  Bond Angles NCD  - C r (1) - N (4)  94.1 (1)_  CrCD  - N(l)  - C r (2 )  88.7 (1)  N(.D  - C r C 2 ) - N (4 1  93.1 CD  Cr(D  - N ( 4 ) - C r (2)  8 0.3 (1)1  c a n  122. 5 (41  - B •- CC131  120.3 (3)  C r (1) - N ( l ) - 0 ( 1 )  137.6(3}  N ( 4 ) - B •-  - 0(1)  131.5 (3)  NC41  C r (1) - N ( 2 ) - 0 ( 2 )  170.0(3)  c a n  C r (2) - N ( 3 ) - 0 ( 3 }  168.4 (3)  B  C r (1) - N ( 4 ) - B  CrC2) - NCD  - B -  CC13}  116.1 (3)  c a n -  CC12}  109.2 (4)  12 9.0(2)  B - C(13) -  CC14)  1.15.7 (4)1  - B  91.6 (2)  N(4) - C(15)  B - N ( 4 ) - CC151  113.8 (3).  C r ( 2 ) . - NC41  -  - C(16)  111. 5 (41  - 69 being e s s e n t i a l l y pla,nar with, mean C-C d i s t a n c e s o f 1.39(1) R and i n t e r n a l a n g l e s o f 108 (1) °; and t h e mean Cr-r-C d i s t a n c e i s 2.22 C41 £,] (b)  Both the t e r m i n a l and b r i d g i n g n i t r o s y l groups a r e  normal t h r e e — e l e c t r o n donor l i g a n d s i n t h e i r r e s p e c t i v e bonding environments. the l i n e a r t y p e , 7 6  [The two t e r m i n a l NO groups a r e of  having  Cr-N-0 angles of  approximately  170°, a mean Cr-N d i s t a n c e of 1.680(4) R, and a mean N-0 d i s t a n c e o f 1.195(6) R.  A s l i g h t asymmetry i n the bonding  of the b r i d g i n g NO l i g a n d i s i n d i c a t e d by the d i f f e r e n c e i n the C r — N ( l ) bond lengths o f 0. 032 R (or 8a) whereas no other c h e m i c a l l y e q u i v a l e n t bonds d i f f e r by more than 3a.] (c)  A Cr-Cr  s i n g l e bond e x i s t s i n the molecule.  [The  e x i s t e n c e o f t h i s l i n k a g e i s i n d i c a t e d not o n l y by the Cr-Cr s e p a r a t i o n of 2.6680(8) R but a l s o by the d i h e d r a l angle o f 167.3° between N(l)-Cr-N(4)  planes and the acute  angles o f 88.7(1) and 80.3 ( 1 ) . ] 0  6 5  '  7 7  Cr-N-Cr  Consequently, i n  order t h a t each chromium atom i n the complex may a t t a i n the favored group  1 8 - e l e c t r o n c o n f i g u r a t i o n , the b r i d g i n g EtNBEt2  ( l i k e the b r i d g i n g NO, NH , and NMe 2  r e l a t e d complexes) a p p a r e n t l y  2  groups i n the  f u n c t i o n s as a formal  three-  e l e c t r o n donor. The most c h e m i c a l l y i n t e r e s t i n g f e a t u r e o f the s t r u c t u r e i s the novel E t N B E t v i a N i n a symmetrical Cr-N  2  ligand.  I t i s coordinated  f a s h i o n t o t h e two Cr atoms, t h e mean  bond d i s t a n c e being  2.069(4) R.  This distance i s  s i m i l a r t o the C r - N ( s p ) bond l e n g t h s o f 1.99(2) t o 2.04(2) 3  R i n [CpCr (NO) (NMe ) ] . 73  9  9  The c o o r d i n a t i o n environment  - 7 0- -  around the N atom i s d i s t o r t e d from an i d e a l t e t r a h e d r a l geometry i n a manner which, can Be viewed as- a r i s i n g a r o t a t i o n of the C (.15) -N ('4) -Cr- (2) plane. i s c o n s i s t e n t with: m i n i m i z i n g  from  Such a d i s t o r t i o n  the non—Bonded r e p u l s i o n s  Between the c y c l o p e n t a d i e n y l r i n g s and the methylene gens of the EtNBEt2 C-C, N—C,  ligand.  hydro-  Within the group i t s e l f ,  the  and B-C Bond l e n g t h s are those expected f o r normal  s i n g l e Bonds.  For i n s t a n c e , the B-C d i s t a n c e s of 1.578(5)  and 1.601(5) R are w i t h i n the range of v a l u e s , 1.577 (5) t o 1.619(3) R ,  commonly oBserved f o r s i n g l e B-C  7 8  Bonds.  However, the N(4)-B d i s t a n c e of 1.459(5) £ i s i n t e r m e d i a t e Between the v a l u e s of 1.4 4 and 1.57  R f o r B-N d o u B l e  and  7 9  s i n g l e B o n d s , r e s p e c t i v e l y , and suggests some degree of 80  m u l t i p l e Bonding Between the B and N atoms.  Consistent  with  2 t h i s view are the oBserved p l a n a r  (sp ) geometry  around the  Boron atom and the a i r - s t a b i l i t y of the compound  (rational-  i z a B l e i n terms of N->BpfT i n t e r a c t i o n ) . B i m e t a l l i c complex,  Hence, w i t h i n  there appears to Be a  competition  Between the two Cr atoms and the B atom f o r the "lone of e l e c t r o n s on N.  this  pair"  However., the r e s u l t i n g f e a t u r e of a  f o u r - c o o r d i n a t e n i t r o g e n atom engaging i n concomitant m u l t i p l e Bonding cannot Be r a t i o n a l i z e d i n terms of l o c a l i z e d , two-centre Bonds. The s p e c t r o s c o p i c p r o p e r t i e s of C p C r 2  2  (NO) ^ (EtNBEt ) 2  can Be more f u l l y understood i n terms of i t s molecular structure. parent  I t s mass s p e c t r a c o n t a i n peaks a s s i g n a b l e t o the  i o n and i o n s r e s u l t i n g from the s e q u e n t i a l l o s s of  - 71  -  l i g a n d s from both, the parent and monometallic  species a r i s -  i n g from cleavage of the parent; high.—resolution data are presented i n Table V.  S i m i l a r fragmentation patterns- have  been r e p o r t e d f o r r e l a t e d m o l e c u l e s .  Hence, i o n s r e s u l t -  8 1  i n g from l o s s e s of NO, NBCgH^^, and E t N B E t  2  C^H^  are o b s e r v a b l e ; and the occurrence of  peaks due t o metastable spectrum  (from e i t h e r N-Et or B - E t ) ,  i o n s i n the l o w - r e s o l u t i o n mass  of the complex p r o v i d e s d i r e c t evidence f o r s e v e r a l  of these fragmentation modes. 215,  176,  2  2  3  •  +  2  Cp Cr (NO) H 2  2  •  +  2  CpCr(EtNBEt )  2  +  C p C r (NO) H 2  2  CpCrCNBC H CpCr  •  2  4  2  +  + EtNBEt  2  2  2  (x = l-*-3) i s  +  x  Of p a r t i c u l a r i n t e r e s t i s the o c c u r r e n c e of the  n i t r i d e - c o n t a i n i n g ions C p C r ( N O ) ( N E t ) N , +  2  and C p C r (NEt)N . +  remain,  14  + CpCr(NO) H  +  CpCr  g  + C H  +  the whole s e r i e s of i o n s C p C r ( N O ) H  observable.  2  242,  + NBC H  +  3  )  4  •  +  2  CpCr(EtNBEt )  Indeed,  of  and 153 correspond t o the r e s p e c t i v e fragmentations  C p C r (NO) ( E t N B E t )  and  Thus, peaks a t m/z  2  2  2  Cp Cr (NEt )N , +  2  2  In each of these i o n s NEt or N E t  2  2  groups  thereby suggesting t h a t the N atom has r e s u l t e d  fragmentation of a n i t r o s y l l i g a n d . e l e c t r o n - d e f i c i e n t BEt or B E t p r e c u r s o r i o n s may In g e n e r a l , oxo  2  from  The e l i m i n a t i o n of  fragments  from the various-  a s s i s t t h i s unusual fragmentation p r o c e s s .  i o n s are more abundant than n i t r i d e i o n s i n  the mass s p e c t r a of chromium n i t r o s y l s  8 2  .  F i n a l l y , i t can  be noted t h a t m i g r a t i o n of the c y c l o p e n t a d i e n y l group between metal atoms occurs more, r e a d i l y f o r C p C r ( N 0 l ~ 2  2  3  - 72 -  T a b l e . V. Cp Cr 2  2  H i g h — R e so l u t i.on M a s s S p e c t r a l D a t a f o r  CNO)-> ( E t N B E t 1 2  m/z  Rel Abund  Assignment^  Measd^  Calcd  436.081  436.083  28  (C H  2  406.087  406.08 5  5  (C H  2  ( N 0 1 C.EtNBEt J + + Cr (NO) (EtNBEt )  376.0.88  376.087  2  (C H  2  C r ( N O ) CEtNBEt )  351.003  351.001  2  (C H  2  Cr (NO) (NEt)N  324.964  324.961  15  (C H  2  Cr (NO) H  320.040  320.044  3  (C H  2  Cr (NEt )N  319.018  319.017  3  CC H  2  Cr  2 94.964  2 94.963  3  (C H  Cr (NO) H  +  2  2 91.000  291.005  17  (C H  Cr (NEt)N  +  2  264.965  264.965  25  CC H  2  Cr (NO)H  258.100  258.100  28  (C H  C r (NO) ( N B C H )  249.973  249.978  23  (C H  2  22 9.109  229.109  100  (C H  Cr (EtNBEt )  201.078  201.07 8  75  (C H  182.019  182.019  60  (C H  Cr(NBC.H ^ +  176.975  176.976  1  (C H  C r CNO)  171.031  171.031  18  (C H  116.980  116.980  25  (C H  Cr(NBC H ) ^ + ' Cr  a  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  5  C  Cr  2  3  2  2  2  2  2  2  2  2  2  2  2  +  3  +  2  (NO) ( N B C H ) 2  2  2  2  +  2  6  Cr (NH ) 2  1 4  +  2  +  2  )  +  2 +  2  0  5  C  D  P r o b e t e m p e r a t u r e ~150°C  b  ±0.001 mass u n i t  c  The a s s i g n m e n t s i n v o l v e t h e m o s t occurring  isotopes,  e.g.  5 2  Cr,  6  i n each  fragment.  +  +  +  73 -  (EtNBEt ) than f o r C p C r 2  2  (NO) ^  18  2  (cf.  the. r e l a t i v e abund-  ances of the C p C r  +  i o n ) ; and i o n s c o n t a i n i n g two Cr atoms  are l e s s abundant  i n the mass s p e c t r a of the former compound.  2  -  The asymmetric Cp Cr 2  m o l e c u l a r s t r u c t u r e observed for-  CN0) C.EtNBEt ) i n the s o l i d  2  3  2  state apparently p e r s i s t s  i n s o l u t i o n , as evidenced by i t s a n d VI)..  Hence, i n i t s ambient-temperature  1 3  C  NMR  *H NMR  spectra  (.Table  spectrum, the  i n e q u i v a l e n c e of the c y c l o p e n t a d i e n y l r i n g s and the d i a s t e r e o t o p i c nature of the a-H atoms i n the N-Et moiety are c l e a r l y evident.  A l s o , the e t h y l groups a t t a c h e d t o the boron atom  are seen t o be i n e q u i v a l e n t , t h e i r assignments g i v e n i n Table VI being based p r i n c i p a l l y on the i n t e g r a t i o n of the spectrum.  S i m i l a r f e a t u r e s are d i s p l a y e d by the  spectrum of the complex.  However, the methylene  1 3  C  NMR  carbons  of the e t h y l groups bonded to boron g i v e r i s e t o a broad 1 3  C  s i g n a l c e n t r e d a t 6 14.0  with, t h e  1 J  B  (I = 3/2)  and  1  presumably due to c o u p l i n g s  °B (I = 3.) n u c l e i which, are  i n c o m p l e t e l y r e l a x e d by the quadrupole mechanism . 83  The  methyl carbons g i v e r i s e t o o n l y one peak, p r o b a b l y due to coincidental  overlap.  The chemical s h i f t s of the d i f f e r e n t resonances a l s o p r o v i d e i n f o r m a t i o n about the v a r i o u s n u c l e i i n the n o v e l EtNBEt  2  ligand.  That the asymmetric  n i t r o g e n atom c a r r i e s  at l e a s t a p a r t i a l p o s i t i v e charge i s i n d i c a t e d by the downf i e l d p o s i t i o n of the resonances due t o the protons a to the N  ( i . e . 6 4.62,  4.94).  These s i g n a l s occur a t s l i g h t l y  lower f i e l d s than the c o r r e s p o n d i n g resonances d i s p l a y e d  by  74  Table  VI.  NMR  Data; f o r C p , , C r H  H  B  2  C H  Q  \  3  N  Cp( NO) Cr——  \  H.  2  C H  in. CDC1  3  N  /  /  Cr( NO) Cp  0  Data a S_  Rel Intensity  Assignment  5.34  Is).  5  Cp  5.27  (s)  5  Cp  4.94  (m)  1  N-CH  4.62  (m)  1  N-CH  1.51  Ct).  3  N-CH„-CCH  J . = 12 Hz ab  J  = J. ciC  -0.06 1 3  C  6  =7  Hz  *  ^  DC  C.br, m)  8  Cbr)  2  ) C  B - E t , B-CH '2 B-CH  2  Data a  1  K  -r 1 3  C-H  Assignment  102.53 J  102.04  1  7  7  H  Z  C  Cp  I  Cp  .62.86  137 Hz  N-CH -CH  3  24.33  1 2 6 Hz  N-CH ~CH  3  B-CH -CH  3  B-CH -CH  3  14.0  (br)  2  2  —  9.27  a  b  a D  0.81  2  B ~ CHgCH^  (H ) C  1  (EtNBEtD  (NO)  yC C  -  2  1 2 3 Hz  The i n d i c a t e d  2  chemical shifts  a r e i n ppm  downfield  from  Me.Si. These  assignments  homonuclear  have  been  confirmed by a series of  and h e t e r o n u c l e a r  decoupling  experiments.  - 75 -  t y p i c a l t e t r a a l k y l ammon ium compounds (5 3.3 — 4.. 8 vs., 6; 3,0. — 3.7  f o r t e r t i a r y amines' ).. 84  The: ^ C P E ) NMR, spectrum  r e i n f o r c e s t h i s i m p r e s s i o n , the s i g n a l due t o the, a—carbon nucleus being a t 6" 62.86 v e r s u s 6' ~52 f o r Et^NX compounds and & ~48 f o r E t ^ N .  In a d d i t i o n , the e x i s t e n c e o f some  8 4  N-B m u l t i p l e bonding i s suggested by the B 11  of C p C r ( N O ) ( E t N B E t ) 2  2  3  2  i n CDC1  3  NMR spectrum  which c o n s i s t s o f a s i n g l e ,  broad resonance c e n t r e d a t -4 6.9 ppm from e x t e r n a l  BF -OEt 3  2  (peak width a t h a l f - h e i g h t = 17.6 ppm). T h i s c h e m i c a l s h i f t f a l l s i n the range  (i.e.  6 -41.8 t o -48.7) p r e v i o u s l y i  r e p o r t e d f o r a s e r i e s o f R^-^-^BR.^ compounds . 85  not s u r p r i s i n g t h a t the complex stereochemically r i g i d  I t i s thus  as a whole appears t o be  i n s o l u t i o n a t ambient  temperature.  Indeed, i t s H NMR spectrum i n dg-toluene over the range 1  -70 t o 90°C s t i l l d i s p l a y s the p r i n c i p a l s p e c t r a l listed  i n Table VI.  features  A t the upper l i m i t , however, the  o r i g i n a l l y broad peak a t 6 = -0.06 due t o the B-CH  2  protons  appears as a q u a r t e t , thereby c o n f i r m i n g i t s assignment. A d m i t t e d l y , the H NMR data do not r u l e out r a p i d J  rotation  of t h e E t B group about the B-N(4) bond because o f the 2  d i a s t e r e o t o p i c nature o f i t s methylene groups, but in.view of the o t h e r evidence f o r some N—B m u l t i p l e bonding supra), t h i s p o s s i b i l i t y i s c o n s i d e r e d t o be l e s s  (vide likely.  I n t e r e s t i n g l y , NMR i s more s e n s i t i v e than IR t o the m o l e c u l a r asymmetry as evidenced by the f a c t t h a t o n l y one t e r m i n a l NO stretch, i s observed f o r the complex s t r e t c h e s a r e expected t o be IR a c t i v e .  whereas two such,  - 76 -  The net t r a n s f o r m a t i o n e f f e c t e d b y LrEt^BH d u r i n g the f o r m a t i o n of t h i s product i s thus^  Et BEt 2  0  \  \  / £x  —  /  V/  I iFt RH  Cr  L  l  E  f  3  B  2  .Cr  H w  —Cr  namely the c o n v e r s i o n of a b r i d g i n g n i t r o s y l l i g a n d t o a bridging EtNBEt  2  group.  The mechanism of t h i s  r e a c t i o n remains unknown, but i t can be  remarkable  demonstrated  i n d e p e n d e n t l y t h a t the E t N B E t - c o n t a i n i n g product i s not 2  obtained from the f u r t h e r r e a c t i o n of LiEt^BH w i t h any of the b i m e t a l l i c amido complexes i s o l a t e d from the o r i g i n a l r e a c t i o n mixture  (vide s u p r a ) .  from the a t t a c k of B E t  I t may,  however, r e s u l t  (the by-product formed when E t ^ B H  3  -  f u n c t i o n s as a h y d r i d e source) on the o r i g i n a l o r g a n o m e t a l l i c reactant,  [CpCrCNO) ] . 2  Thus, treatment of the n i t r o s y l  2  dimer with, an equimolar amount of BEt^ i n THF-hexanes a t room temperature  does a f f o r d Cp Cr (NO). ( E t N B E t ) 2  2  3  2  i n 4%  y i e l d , but the p r i n c i p a l i s o l a b l e product i s CpCr(NO)„ Et 2  (.20% y i e l d ) .  I t was  a l s o shown t h a t CpCr(NO) Et 2  react further with B E t .  When f r e e NO  3  at - 3 0 ° C  8 6  Et BN(N0)0Et  Et BON(Et)BEt 2  2  2  i s reacted with B E t  i s o b t a i n e d , whereas a t 70°C  and E t B O N E t 2  which' cleavage of the N-0  2  are i s o l a t e d ; no p r o d u c t s i n  bond has o c c u r r e d were found  except when the r e a c t i o n mixture was w i t h c o n c e n t r a t e d E^SO^.  does not  subsequently t r e a t e d  In any event, the r e a c t i o n of  3  - 77 -  L i E t ^ B K with. [ CpCr CNO I ^]  i s c e r t a i n l y more, complex than. with,  2  analogous c a r b o n y l compounds, the l a t t e r being c l e a v e d t o anions w i t h the accompanying f o r m a t i o n of the v o l a t i l e products H  and B E t ^ .  The  6 7  2  n i t r o s y l anion,  [CpCr(NO) ] 2  f a c t t h a t the t  corresponding  i s not i s o l a b l e from the p r e -  sent r e a c t i o n probably r e f l e c t s upon i t s i n h e r e n t it  by-  instability,  being as y e t unknown .  The  18  R e a c t i o n of BH., with. [CpCr CNO) J  2 >  Very l i t t l e d i f f e r e n c e i n the o v e r a l l y i e l d s or i n the d i s t r i b u t i o n of the iii)  i s observed  [CpCr CNO) ] 2  r e 2  d u c t i o n products ( i -  when the v e r y potent n u c l e o p h i l e LiHBEt^  i s s u b s t i t u t e d f o r NaAlH,, COCH CH OCH ) 2  2  3  2  as r e d u c t a n t , d e s p i t e  the i s o l a t i o n of unexpected a d d i t i o n a l p r o d u c t s . when the e l e c t r o p h i l i c  6 8  b i m e t a l l i c amido products  r e d u c i n g agent BH^ Ci-iii)  Similarly,  i s used, the  are again o b t a i n e d i n low  y i e l d , although the r e a c t i o n i s s i g n i f i c a n t l y slower. markedly m o d i f y i n g  Thus,  the nature of the r e d u c t a n t used f a i l s  to  produce e i t h e r d i f f e r e n t r e d u c t i o n products or v a r i a t i o n s i n the y i e l d s of the compounds i s o l a t e d , and t h e r e f o r e p r o v i d e s no new  evidence  as t o the mechanism of the n i t r o s y l r e d u c t i o n .  Another p o t e n t i a l means of o b t a i n i n g m e c h a n i s t i c  information  r e l a t i n g t o t h e mode of r e d u c t i o n of the chromium n i t r o s y l dimer i s t o c a r r y out the r e d u c t i o n on the  corresponding  t h i o n i . t r o s y l compound, [CpCr CNO) CNS)] , d e p i c t e d on. the 2  f o l l o w i n g page.  The b e t t e r TT—acid l i g a n d , N S , 4 5  should  p r e f e r e n t i a l l y occupy the b r i d g i n g p o s i t i o n as does the l i g a n d i n ' t h e i s o e l e c t r o n i c complex  [CpFe CCO) CCSl] . 87  CS  N  - 78 -  Cr • ON^  •Cr  ^ N ^  ^NjO  Examination o f any r e d u c t i o n products i s o l a t e d would then a l l o w one t o i n f e r whether the i n i t i a l  s i t e of a t t a c k i s a  b r i d g i n g or a t e r m i n a l l i g a n d . Unfortunately, [CpCr (CO) (NO) \ P F 2  g  attempts t o extend the r e d u c t i o n o f  t o [CpCr (.NO) ] 2  2  (discussed i n Chapter  III) t o the t h i o n i t r o s y l analogue,  [CpCr (CO) (NO) ( N S ) ] P F  4 5 C  ,  D  u t i l i z i n g e i t h e r NaAlH (OCH CH OCH ) 2  hydride  2  2  source were u n s u c c e s s f u l .  3  o  L i E t B H as the  r  2  3  A complicating  the i n s t a b i l i t y o f [CpCr(CO) (NO) (NS)]PF_  factor i s  i n t h e presence o f  D  donor  s o l v e n t s , combined with i t s l a c k of s o l u b i l i t y i n  non-coordinating  solvents . 4 5  Although n i t r o s y l - c o n t a i n i n g  products are observed i n the i n f r a r e d s p e c t r a o f the r e a c t i o n m i x t u r e s , no n i t r o s y l - o r t h i o n i t r o s y l - c o n t a i n i n g s p e c i e s c o u l d be s u c c e s s f u l l y i s o l a t e d .  CHAPTER V A STUDY OF THE LENTS' BASE PROPERTIES OF CYCLOPENTADIENYL— TUNGSTENDINITROSYL  HYDRIDE AND THE LENTS ACID PROPERTIES OF THE  CYCLOPENTADTENYLTUNGSTENDINTTROSYL  CATION.  In l i g h t o f the l a r g e d i f f e r e n c e s i n the r e a c t i v i t i e s of the i s o s t r u c t u r a l and i s o e l e c t r o n i c complexes [CpMn(CO)(NO)] , and [ C p C r ( N O ) ] 2  2  1 8 2  i n t e r e s t t o extend t h i s comparison  '" , 7  [CpFe(CO) ] > 2  i t was o f obvious  t o the second and t h i r d  row t r a n s i t i o n - m e t a l analogues o f these compounds. u n a t e l y , although the R u  8 8  and O s  2  8 9  Unfort-  congeners of [CpFe ( C O ) ] 2  have been known f o r some time and [CpRe(CO)(NO)]  2  2  has  9 0  r e c e n t l y been s u c c e s s f u l l y prepared  , the Mo and W n i t r o s y l  complexes have not as y e t been s y n t h e s i z e d . One o f the q u e s t i o n s t o be answered concerned the s t r u c t u r e s o f the n i t r o s y l complexes —  would the n i t r o s y l  l i g a n d s a l l be t e r m i n a l , or would two b r i d g e the metal-metal bond?  In s o l u t i o n ,  [CpFe(CO) ] 2  2  has been shown t o e x i s t as  a r a p i d l y e q u i l i b r a t i n g mixture of p r i n c i p a l l y c i s and t r a n s isomers w i t h b r i d g i n g CO g r o u p s , i . e . 9 1  cp  0  \ A C  0  . \ „ / __iK cp  U  C 0  V a r i a b l e temperature NMR  c p  C 0  C 0  s t u d i e s demonstrated  °  C  AA °  the. i n t e r c o n -  9  C D  - 80 -  v e r s i o n of these isomers with concomitant  interchange of the  CO groups between b r i d g i n g and t e r m i n a l p o s i t i o n s .  These  processes were e x p l a i n e d by a c o n c e r t e d opening of the b r i d g e s to g i v e a non-bridged C p C C O ^ F e — F e f C O ^ C p  CO  intermed-  i a t e , r o t a t i o n about the F e — F e bond, and then r e c l o s i n g of the CO b r i d g e s to produce [CpMn(CO) (NO)]2  93  a  n  d  e i t h e r a c i s or a t r a n s i s o m e r . 9 2  [CpCr(NO) ] 2  have been shown t o  93 2  undergo c o r r e s p o n d i n g i n t r a m o l e c u l a r rearrangement In c o n t r a s t ,  [CpRu(CO) ] 2  was  2  observed t o e x i s t  an approximately 50/50 mixture of CO b r i d g e d and forms i n hydrocarbon  processes. as  non-bridged  s o l u t i o n a t room t e m p e r a t u r e .  Intro-  94  d u c t i o n of an aluminum a l k y l i n t o the s o l u t i o n drove the e q u i l i b r i u m completely to the b r i d g e d form, w i t h A l  coord-  R 3  i n a t i n g to a bridging carbonyl l i g a n d , i . e . 9 5  ^^ A / ° c  A1R_  3  + [CpRu(CO) 1„ 2  2  c  /  o  RU  \  -Ru  /  1  c  C p  A  The osmium c a r b o n y l complex was non-bridged  found t o e x i s t  form i n s o l u t i o n .  The  8 9  [CpRe(CO)(NO)]  2  1  R  3  s o l e l y i n the  s o l u t i o n s t r u c t u r e of  i s not as yet c l e a r l y understood, but i t  appears t o e x i s t s o l e l y i n non-bridged Mo  \  and W analogues of  [CpCr(N0) ] 2  2  forms . 9 0  Whether the  would d i s p l a y a s i m i l a r  t r e n d i n t h e i r s t r u c t u r e s and behaviour i n s o l u t i o n was q u e s t i o n t o be answered upon t h e i r p r e p a r a t i o n . Another reason f o r i n t e r e s t i n the s y n t h e s i s of [CpMo(NO) ] 2  2  and  [CpW(NO) ] 2  2  was  the known a f f i n i t y of  one  - 81, -  [CpCr ( N O 1 ^  o  halogens..  r  Previous- work, i n t h i s  f i r s t demonstrated the a b i l i t y of halogen from some i n o r g a n i c and and  [CpCr(NO) ] 2  organometallic  2  laboratory  to a b s t r a c t complexes , 18  l a t e r showed t h a t i t s e l e c t i v e l y removed halogen from a  v a r i e t y of o r g a n i c  halides .  I t was  9 6  hoped t h a t the Mo  and  W analogues would a l s o have an a f f i n i t y f o r h a l i d e s but  with,  a l t e r e d s e l e c t i v i t i e s , thus p r o v i d i n g a s e r i e s of reagents u s e f u l i n synthetic organic  chemistry.  A t h i r d reason f o r i n t e r e s t i n the p r e p a r a t i o n these b i m e t a l l i c n i t r o s y l complexes c e n t r e d of  [CpCr (NO),,]  2  described  i n the p r e v i o u s  Thus, while  i t was  coordinated  NO  information  r e l a t i n g to these conversions  I t was  on the  two  and  2  to N(Et.)BEt , no  2  2  c o u l d be  would l e a d t o the d e t e c t i o n and  i s o l a t i o n of the i n t e r m e d i a t e s of c o o r d i n a t e d  NO.  attempts would be  chapters.  The  of  mechanistic  2  t h e r e f o r e hoped t h a t the r e d u c t i o n of  [CpW(NO). ]  reactions  p o s s i b l e to e f f e c t the c o n v e r s i o n  to NH  obtained.  [CpMo(NO) ] 2  The  -I  1  st  row  a s s o c i a t e d w i t h the  reduction  b a s i s f o r optimism t h a t these  the known k i n e t i c p r i n c i p l e t h a t  ^ „nd > 2 row  success achieved  ^ _.rd > 3 row  , ... ., . , 39 t r a n s i t i o n metals .  by C a s e y , G l a d y s z , Graham 6 8  t i o n of c o o r d i n a t e d +  + H*~  —*  encouragement,.  CO  to CH^  the  the  9 7  98  t h e i r co-workers i n u n r a v e l l i n g the mechanism of the  (NO)  or  perhaps the  r e a c t i v i t y of i s o s t r u c t u r a l complexes o f t e n f o l l o w s j  2  s u c c e s s f u l whereas those on the chromium  complex were not was  order:  of  and reduc-  i n the model system CpRe ( C O ) ~  CpRe (CO) (NO) (CHD  2  was- a l s o a source of  - 82 -  The  p r e p a r a t i o n o f the compounds  [CpWCNO^^  na<  3 thus been a g o a l i n t h i s l a b o r a t o r y f o r some  time, with c o n s i d e r a b l e e f f o r t having this end .  [CpMo (NO) 2 ^ and  been expended toward  However, the r e a c t i o n s demonstrating the reduc-  9 9  t i o n of c o o r d i n a t e d NO i n [CpCr(NO) \ 2  2  rejuvenated  interest  i n these complexes, and a personal, communication from P r o f e s s o r W.A.G. Graham r e l a t i n g the s u c c e s s f u l s y n t h e s i s of [CpRe(CO) (NO)]2  (which had s i m i l a r l y d e f i e d repeated  earlier  attempts a t i t s p r e p a r a t i o n i n h i s l a b o r a t o r y ) v i a the route outlined  i n equations  38 and 39,  i.e. CH C1« 9  2CpRe(C0) (NO)H + Ph C X 3  X = BF  4  or P F  2  [Cp Re (CO) (NO) H] X~ +  g  [ C p R e (CO) (NO) 2  •  2  2  : , '_ ' H] X + N E t  2  2  2  CH C1 ?  3  [CpRe(CO)(NO)]  ?  •  + HNEt X~ +  2  (38)  3  (39)  l e d t o hope t h a t the d e s i r e d compounds c o u l d be prepared i n an analogous manner. S u c c e s s f u l completion  o f the f i r s t  step f o r both the  Mo and W analogues was f o l l o w e d by numerous attempts t o c a r r y out the subsequent d e p r o t o n a t i o n s ;  these were unsuc-  c e s s f u l , as were e f f o r t s along other r o u t e s .  In c o n j u n c t i o n  w i t h these r e a c t i o n s , an examination of the Lewis base prope r t i e s of CpW(NO) H and of the Lewis a c i d p r o p e r t i e s of 2  CpW(NO) 2  +  was c a r r i e d out.  S p e c i f i c a l l y , CpWCNO^H i s  observed s p e c t r o s c o p i c a l l y i n the presence of a v a r i e t y of soft  ( i . e . C r ( C O ) , W(CO) ,  borderline  5  5  (MeCp)Mn(CO) , H g C l , and C d C l ) ,  ( i . e . Z n C l ) , and hard 0  2  2  ( i . e . H , A1C1,, and BEt ) +  - 83 -  Lewis a c i d s  1 2  .  The Lewis base c h a r a c t e r i s t i c s o f CpW(NO) H 2  are d i s c u s s e d i n l i g h t of these r e s u l t s , and when combined with the r e s u l t s of a study o f the Lewis a c i d p r o p e r t i e s of CpW(NO) , +  2  i t i s p o s s i b l e t o p r o v i d e a r a t i o n a l i z a t i o n of  the f a i l u r e t o prepare the dimers via  [CpM(NO) ] 2  2  (M = Mo, W)  the i n d i c a t e d r o u t e .  Experimental A l l experimental procedures o u t l i n e d were performed under the g e n e r a l c o n d i t i o n s d e s c r i b e d i n Chapter I I . Reaction of CpMo(NO) C1 with N a A l H ( O C H C H O C H ) . 2  2  t i o n of NaAlH (OCH CH OCH )^ 2  2  2  3  (2 5 mL) was added dropwise CpMo(NO) C1 2  23  h  2  2  2  A solu-  (1.2 mL, 4.2 mmol) i n toluene  t o a s t i r r e d green s o l u t i o n of  (1.00 g, 3.91 mmol) i n toluene  -78°C, and the r e a c t i o n was monitored As the a d d i t i o n proceeded,  3  (80 mL) a t  by IR spectroscopy.  the s o l u t i o n became a dark  olive  green and a brown p r e c i p i t a t e formed; a d d i t i o n was terminated when the n i t r o s y l a b s o r p t i o n s due t o the i n i t i a l r e a c t a n t had disappeared from the IR spectrum solution.  While  still  of the supernatant  c o l d , the mixture was q u i c k l y  through a s h o r t (.3 x 5 cm) column of alumina n e u t r a l , a c t i v i t y grade fritte.  filtered  (Brockman  I) supported on a medium p o r o s i t y  The b r i g h t green f i l t r a t e was allowed t o warm t o room  temperature;  an IR spectrum  of the f i l t r a t e  showed two s t r o n g ,  sharp a b s o r p t i o n s i n the n i t r o s y l r e g i o n a t 17 32 and 1642 cm \  A l l attempts  t o remove the s o l v e n t from the f i l t r a t e  under reduced p r e s s u r e r e s u l t e d i n r a p i d decomposition  of the  -  84  -  green product as the l a s t of the; v o l a t i l e s were: removed, y i e l d i n g a red—brown, i n t r a c t a b l e s o l i d .  Similarly-,  stirring  the green s o l u t i o n i n a n i t r o g e n atmosphere a t ambient temperature solid  r e s u l t e d i n slow d e p o s i t i o n of the red—brown  ( h a l f - l i f e approximately 3 d a y s ) .  Thus,  subsequent  r e a c t i o n s of the product, CpMo(NO) H were c a r r i e d out on 2  f r e s h l y prepared s o l u t i o n s of the compound. Reaction of C p M o ( N O ) w i t h CH^N^.  A f r e s h l y prepared ether  s o l u t i o n of approximately 1 M C R ^ ^ Rickards) was  d r i e d over KOH  1 0 0  (provided by  G.N.  and deaerated w i t h argon.  Two  m i l l i m o l e s of diazomethane: Xaniexcess) ~_was -rfchen--added~to_ :  a s o l u t i o n of CpMo(NO) H i n t o l u e n e (95 mL)  prepared  2  0.50  g  (1.96 mmol) of CpMo(NO) Cl.  from  Over a p e r i o d of 15 min-  2  u t e s the s o l u t i o n g r a d u a l l y turned s l a t e green, and slow gas e v o l u t i o n was  observed.  A f t e r 1.5  h, gas e v o l u t i o n  appeared  to have ceased, so the v o l a t i l e s were removed i n vacuo. r e s i d u e was  then t r a n s f e r r e d as a benzene s l u r r y t o the top  of a 2 x 7 cm column of alumina grade I ) . was  The  (Woelm n e u t r a l ,  A y e l l o w band developed w i t h C H C 1 2  e l u t e d from the column w i t h THF.  2  activity elution,  The v o l a t i l e s were  removed from the e l u a t e under reduced p r e s s u r e , and green o i l was  and  the  i d e n t i f i e d by i t s c h a r a c t e r i s t i c IR and mass  s p e c t r a as CpMo(NO) Me 2  70  (0.05 g, 10% y i e l d based  on  CpMo (N0) C1) . 2  R e a c t i o n of CpMo(NO) H with. MeX. 2  mL)  To a toluene, s o l u t i o n  of CpMo(NO) H prepared from 0.50 2  g  (1.96 mmol) CpMo-  (9,5  - 85  (NO) C 1 2  the  was  -  added an e x c e s s (1.0. ml*, 11 mmol) o f Me.I,  s o l u t i o n was  stirred  a t room t e m p e r a t u r e f o r 4 days-.  D u r i n g t h i s time a red—brown  p r e c i p i t a t e formed  colour of the s o l u t i o n faded to a pale yellow. w e r e removed i n v a c u o , a short  (2 x 4 cm)  and  t h e r e s i d u e was  column of F l o r i s i l  y e l l o w band d e v e l o p e d u p o n . e l u t i o n The  band was  pressure,  (0.01 g, 2% y i e l d  toluene  t r a n s f e r r e d onto 2  CH C1 . 2  2  1 0 1  character-  i t s IR and mass s p e c t r a .  w i t h p-CH-^CgH^SO^ ( C H )NO. 3  2  was  p r e p a r e d f r o m 0.40  t r e a t e d w i t h 0.67  mmol). o f p — C H C g S O N (CH ) N O , 3  A  reduced  w h i c h was  2  2  2  The  temperature.  and, a f t e r  4 h, became c l o u d y .  solution gradually  g  (.3.14 stirred  darkened  A f t e r 2 days, the s o l u t i o n  a l m o s t c o l o u r l e s s , and a r e d - b r o w n s o l u t i o n was  g  and t h e s o l u t i o n was  3  a t ambient  concentrated  p r e c i p i t a t e had under  reduced  ure.; an I R s p e c t r u m o f t h e s u p e r n a t a n t l i q u i d absorptions  slurry.  2  of the column w i t h  s o l u t i o n C60 mL), o f CpMo (NO) H  The  volatiles  as a CH C1  b a s e d on CpMo CNO) C 1 )  o f CpMo CNO),  formed.  The  2  C.1.57 mmol). o f CpMo (NO) C 1  was  the  a s m a l l amount o f g r e e n CpMo ( N O ) 1  i z e d b y i t s m e l t i n g p o i n t and Reaction  and  c o l l e c t e d and t a k e n t o d r y n e s s u n d e r  yielding  and  press-  showed  only  a t t r i b u t a b l e t o p - C H C H S 0 N CCH ).NO and  tol-  3  6  4  2  3  uene . Reaction  o f CpW CNO),yH w i t h P h C B F .  stirred  s o l u t i o n c o n t a i n i n g CpW (NO) H  in mL)  CH C1 2  3  To a b r i g h t g r e e n ,  4  5  1  2  C80 mL)  2  of P h C B F 3  1 0 2 4  was  C_4 . 53 g , 14. & mmol I  a d d e d an o r a n g e C H C 1  (2.41 g, 7.3 0 mmol)..  2  2  s o l u t i o n (40  As t h e a d d i t i o n  - 86  proceeded, the and  -  s o l u t i o n darkened t o an. olive-green,  a green p r e c i p i t a t e began to form.  spectrum of the  colour,  M o n i t o r i n g of the  IR  supernatant s o l u t i o n showed complete l o s s of  the n i t r o s y l a b s o r p t i o n s due a l e n t s of P h C B F 3  had  4  to CpW(NO) H a f t e r 0.5  equiv-  2  been added.  C o n c e n t r a t i o n of  the  r e a c t i o n mixture i n vacuo to a volume of approximately 20 y i e l d e d f u r t h e r s o l i d and The  a p a l e green supernatant s o l u t i o n .  dark green, m i c r o c r y s t a l l i n e s o l i d was  f i l t r a t i o n , washed with C H C 1 2  (< 0. 005  Torr) to o b t a i n  H]BF  (.3.70 g,  72%  7.94.  Found: v  mull): 1422  (w) , 1359  852  for  C,  1775,  NQ  1  H  NMR  c  IR  n  W  2  N  c a r r i e d out  0.79  g  CH C1 2  (4.03  2  2  6 6.48  3  -  1 7  '  0 2  7.85.  1731,  NQ  95°C  2  '  C  :  (s, 10H),  (under N )  1716,  -8.33  4  (w), (st, br), 1649,  (s,  g  (8.06  This  2  reac-  described  mmoll CpWXNO) H 2  with a s o l u t i o n 2  1633  IH)  analogous t o t h a t  mmol) Pf^CPFg i n C H C 1  1-57;  dec.  (25 mL) 2  containing t o y i e l d green,  2  4  &  (2.82  yield). Anal. Calcd  N,  2  (Nujol  m i c r o c r y s t a l l i n e , a n a l y t i c a l l y pure [Cp W (NO) H] P F 91.6%  '  H  IR  ( i n CH^Cl.,). .  6  i n a fashion  being r e a c t e d  4  ( s t , br) , 1000  i n the preceding s e c t i o n , w i t h 2.50 i n 3 0 mL  [Cp W (NO) -  ( b r ) ; a l s o 1432  v  R e a c t i o n of CpW(NO) H w i t h P h C P F t i o n was  F  N,  1660  3  2  B  1.48;  (CH" CN) :  2  Mp  4 ° 4  (w) , 1070  (CD N0 ):  (see d i s c u s s i o n ) .  0  1707,  (w)., 1290  3  H 1  1748,  -1  1  dried in  a n a l y t i c a l l y pure  16.91; H,  ( s t , br) cm .  cm" .  and  yield).  Anal. Calcd N,  i s o l a t e d by  (3 x 5 mL),  2  vacuo 4  mL  7.33.  Found:  C,  for ] _ C  H 0  ll 2 4 4  15.70; H,  W  N  O  1.38;  P F  6'  :  N,  C  '  1 5  7.25.  - '' ' 7 2  H  IR  !- ;  (Nujol  4 5  g,  - 87 -  mull): v 1010  N  1752 ( b r ) , 1685 ( b r ) ; a l s o 1427 (m), 1068 (w),  Q  (w), 888 ( s t ) , 865 ( s t ) , 849 ( s t ) , 836 ( s t ) , 811 ( s t ) ,  and 740 (w) cm" . cm" . 1  1  H NMR  v  IR ( C H C 1 ) :  1  2  2  (see d i s c u s s i o n ) .  Mp  (under N^) 122°C,dec.  P r e p a r a t i o n of [Cp^W^(NO)^D]PF^. containing  1722 ( b r ) , 1650, 1632  N Q  6 6.48 (s, 10H), -8.33 (s, IH)  (CD N0 ): 3  2  [CpW(NO) (CO)]PF 2  101 g  To a s o l u t i o n  (4 0 mL)  (0.19 g, 4.54 mmol) was  added an excess o f NaBD^ (0.19 g, 4.5 mmol) and the s o l u t i o n was s t i r r e d  f o r 0.5 h.  The r e s u l t i n g mixture was p u r i f i e d  by the l i t e r a t u r e m e t h o d d i s s o l v e d i n 10 mL C H C 1 2  51  2  t o y i e l d CpW(NO) D. 2  T h i s was then  and t o t h i s s o l u t i o n an excess  (by IR monitoring) of Ph^CPF^ was added, producing green, microcrystalline yield).  [Cp W (NO) D]PF 2  2  A *H NMR spectrum  4  (0.21 g, 17% o v e r a l l  g  ( i n CD N0 ) confirmed t h a t the 3  deuterium l a b e l was i n f a c t p r e s e n t : -8.33  (s, <0.05H).  2  6 6.48 (s, 10H),  A N u j o l m u l l IR spectrum o f the product  was i n d i s t i n g u i s h a b l e from t h a t of [Cp W (NO)^H]PFg. 2  Treatment of  of [Cp W (NO) ^H] P F 2  [Cp W (NO) H]PF 2  2  4  2  £  w i t h Ph-^CPFg.  2  3  supernatant s o l u t i o n .  produced  S t i r r i n g the mixture f o r 4 h  no changes i n the IR spectrum of the supernatant;  as i d e n t i f i e d by i t s IR spectrum  2  2  solution  [Cp W (NO) H]PF^ 2  and decomposition  Reaction o f CpW(NO) H with C^H^BF^ 2  (20 mL)  2  (0.127 g ) , y i e l d i n g an  r e - i s o l a t i o n o f the green s o l i d y i e l d e d o n l y  CH Cl  To a suspension  (0.25 g, 0.33 mmol) i n C H C 1  g  was added one e q u i v a l e n t of Ph CPFg orange  2  2  4  point.  To a v i g o r o u s l y  stirred  (70 mL) c o n t a i n i n g 1.30 g (3.87 mmol) of  - 88 -  CpW (NO) E was added 0. 23 g (1.29 mmol) o f white C ^ B F ^  0 3  2  As the r e a c t i o n proceeded, the s o l u t i o n g r a d u a l l y and  then a green p r e c i p i t a t e , began t o form;  the  i n s o l u b l e white C^H^BF^ was s l o w l y consumed.  h no white s o l i d remained. ant  solution at t h i s point  .  darkened  concurrently, A f t e r 1.5  An IR spectrum o f the supernatrevealed  t h a t although o n l y 0.33  e q u i v a l e n t s o f C^H^BF^ had been added t o the r e a c t i o n mixt u r e , the n i t r o s y l a b s o r p t i o n s a t t r i b u t a b l e t o CpW(NO) H had 2  d i m i n i s h e d t o approximately 35% o f t h e i r i n i t i a l  intensity.  I s o l a t i o n o f the green p r e c i p i t a t e by f i l t r a t i o n  afforded  0.60 g (66% y i e l d based on C H B F ) of a n a l y t i c a l l y pure 7  [Cp W (NO) H] B F 2  2  4  7  4  (.vide s u p r a ) .  4  Reaction o f CpW(N0) H with Ph-CPF,, (in CH-CN). o  z  s o l u t i o n of P h C P F 3  j  (0.29 g, 0.74 mmol) i n CH CN  6  s o l u t i o n o f CpW(_NO) H 2  0.74 mmol) i n CH CN) (18 mL) a t -10°C. 3  mixing o f the two s o l u t i o n s ,  that  1 0 1  .  complete  [CpW(NO) (CH CN)] 2  1730 and 1649 cm "*") .was the o n l y  species p r e s e n t  After  (.0.23 g,  an IR spectrum o f the r e s u l t i n g  blue-green s o l u t i o n i n d i c a t e d N Q  (.5 mL) was  3  added dropwise t o a s t i r r e d  v  An orange  J  b  +  3  (i.e.  nitrosyl-containing  IR m o n i t o r i n g d u r i n g the a d d i t i o n  showed only n i t r o s y l a b s o r p t i o n s a t t r i b u t a b l e t o e i t h e r [CpW(NO)„(CH-CN)]PF (NO) H 2  (i.e. v  ( i . e . v.  r  -1  2  (,CHCN) ] P F 3  blue-green s o l u t i o n c o n t a i n i n g 3  6  or CpW^-  1715 and 1631 cm )..  Treatment of [CpW (NO)  CCH CN);]PF  1730 and 1649 c m ) -1  Trt  £  w i t h CpW(N0) H.  0.74 mmol  2  To a  CO.37 g) [CpWXNO) — 2  i n 35 mL CH^CN' was added an excess o f CpW (NO) H 2  - 89 -  CO. ..31,  g, IvQ- mmol I...  An IR spectrum o f the. r e s u l t i n g m i x t u r e  r e v e a l e d no i n t e r a c t i o n between the two complexes-. of the excess CH^CN under reduced p r e s s u r e y i e l d e d oil.  D i s s o l u t i o n of the o i l i n C H C 1 2  Removal a brown  (40 mL) produced a  2  c l e a r green s o l u t i o n whose IR spectrum r e v e a l e d o n l y absorbances a t t r i b u t a b l e t o CpWCNO) H and [CpW(NO) CCHgCN) ] P F 2  V  (1.e.  2  g  Q 1716, 1630 and 1729, 1648 cm , r e s p e c t i v e l y ) . 1  N  Reaction o f CpMo (NO) H with P h C P F . 2  3  A s o l u t i o n of CpMo-  6  (NO) H i n toluene (190 mL) was prepared i n the u s u a l manner 2  from 5.10 g (19.9 mmol) o f CpMo(NO) C1. 2  The s o l u t i o n was  then c o n c e n t r a t e d i n vacuo t o a volume o f approximately 3 0 mL, w i t h some attendant decomposition o c c u r r i n g as evidenced by the f o r m a t i o n of s m a l l amounts o f the red—brown  solid.  The s o l u t i o n was then s y r i n g e d onto a 4 x 9 cm column, of F l o r i s i l prepared i n CR" C1 . 2  CH C1 2  2  E l u t i o n of the column w i t h  developed a s i n g l e green band which was c o l l e c t e d , and  2  the e l u a t e was c o n c e n t r a t e d t o 105 mL under reduced p r e s s u r e . To 7 0 mL of t h i s s o l u t i o n was then added s o l i d Ph^CPFg w i t h IR m o n i t o r i n g . was  added, a green p r e c i p i t a t e formed;  Ph CPF 3  As the t r i t y l  g  hexafluorophosphate 0.5 e q u i v a l e n t s of  (0.87 g, 2.24 mmol) were s u f f i c i e n t t o b r i n g  complete  about  l o s s o f the n i t r o s y l a b s o r p t i o n s a t t r i b u t a b l e , t o  CpMo (NO) H. 2  Toluene  (10 mL) was then added t o the suspension,  and s o l v e n t was removed i n vacuo t o g i v e a f i n a l volume o f approximately 50 mL.  The green s o l i d was c o l l e c t e d by f i l -  t r a t i o n , washed w i t h t o l u e n e (2 x 5 mL), and d r i e d  (<0.005  T o r r ) t o o b t a i n 0.75 g (19% y i e l d based on CpMo(NO)~C1; 57%  - 90. -  b a s e d on P h ^ C P F g l o f a n a l y t i c a l l y p u r e Anal. Calcd f o r N, 9.53. mull): 1015  Found: v  N Q  H 1 0  ii  ( b r ) , 1675  2 4°4 N  P F  6  :  C f  ( b r ) ; a l s o 1430  ( s t , b r ) , 820  1 7 9 5 , 1 7 6 8 , 1 7 0 7 , 1695 ( s , 1 0 H ) , -9.78  M o  2  2  2 0  4  '  C, 20.24; R, 1.77; N, 9.42.  1783  (w) , 860  c  [Cp Mo (NO) H]PF .  (st) cm . 1  (s, IH).  Mp  1  H NMR 2  2  IR  CNujol  (CD N0 ) : 3  Cw) , v  119°C  N Q  6  6.37  of  AgBF  2  dec.  A s l i g h t excess 2  monitoring  1-89;  2  CO. 2.3 g , 1.18 mmol) was a d d e d t o a s t i r r e d C H C 1 (20 mL). c o n t a i n i n g 0.26 g  '  (w). , 1070 2  Cunder N )  P r e p a r a t i o n , o f [Cp MoWCNO) ^H] BF^.  H  IR ( C H C 1 ) :  - 1  (sh.) cm" .  4 2 ;  g  4  solution  2  (1.0 mmol) C p M o ( N O ) C l .  IR  2  showed t h a t t h e a b s o r p t i o n s a t t r i b u t a b l e t o  CpMo ( N O ) C 1 d i s a p p e a r e d  c o m p l e t e l y w i t h i n 45 m i n u t e s ,  2  new b a n d s a p p e a r i n g 1 7 8 3 , 1692 cm "*") .  a t ~25 cm  1  two  (i.e.  higher energy  F i l t r a t i o n y i e l d e d an u n s t a b l e  green  s o l u t i o n , w h i c h b e g a n t o become c l o u d y w i t h i n ~1 m i n u t e . A d d i t i o n o f 1 mL c y c l o o c t e n e p r o d u c e d a more s t a b l e b l u e green s o l u t i o n having v  a t 1800 and 1717 cm  N Q  o f t h e f o r m a t i o n o f t h e Mo (cyclooctene).] B F  J 4  0  "*.  indicative  1  a n a l o g u e o f t h e known  [CpWCNO) ~ 2  The s o l u t i o n was t h e n f i l t e r e d ,  1.0 mmol (.0.31 g) CpW CNO) H 2  added t o t h e f i l t r a t e ,  and  giving  a  g r e e n s o l u t i o n w h i c h e x h i b i t e d numerous p o o r l y r e s o l v e d IR absorptions i n the n i t r o s y l region 1 7 0 3 , 1 6 8 0 , and 1640 cm ^ ) . 0.5 h , w h e r e u p o n 3 0 mL  Cv  N Q  1795, 1778, 1757,  The s o l u t i o n was  hexanes were added, r e s u l t i n g  formation, of a f l o c c u l e n t green p r e c i p i t a t e . was c o n c e n t r a t e d  stirred for  The  i n v a c u o t o a v o l u m e o f "-10 mL,  c o l o u r l e s s supernatant  i n the  mixture and t h e  l i q u i d was removed by s y r i n g e and  -  discarded.  9.1 -  The r e s i d u e was then, r e d i s s o l v e d  in. 50. mL CH^Cl^  f i l t e r e d t o remove a t r a c e o f i n s o l u b l e m a t e r i a l , hexanes were added.  and 3 0. mL  The s o l u t i o n , was- concentrated  slowly  under reduced p r e s s u r e t o induce the c r y s t a l l i z a t i o n o f a dark green, m i c r o c r y s t a l l i n e s o l i d .  The s o l i d was i s o l a t e d  by f i l t r a t i o n ,  washed w i t h hexanes (2 x 10 mL),  at <0.005 Torr  for 1 h to obtain  a n a l y t i c a l l y pure  2  9.07. Found:  mull);: 1419  v  N  Q  0.353 g C57% y i e l d ) o f  [Cp MoW(NO) H]BF .  Anal. Calcd N,  and d r i e d  4  4  for C H MoWN 0 BF : 1Q  11  4  4  C, 19.37; H, L.89;  1790,  C, 19.44; H, 1.79;  4  N, 8.82.  IR (Nujol  1769 (sh) , 1756, 1718, 1660 (br) ; a l s o  (w), 1287 (w) , 1060 ( s t , br) , 1000 ( s t , br) , 850 ( s t ,  br) cm" . 1  1678,  IR ( C H C 1 ) : 2  2  1650 (sh) cm" . 1  6.37  J  v  N  1790,  Q  H NMR  1765 (sh), 1751, 1706, 6 6.47 (s, 5H) ,  (CD N0 ) : 3  2  (s, 5H), -8.33 (s, 0.2H), -8.92 (s, 0.6H), -9.78  0.2H)  (see d i s c u s s i o n ) .  Mp (under N ) 115°C dec. 2  Reaction o f [Cp W (NO) H]BF 2  2  4  pension o f [Cp W (NO) H]BF 2  2  4  4  w i t h Et^N.  4  (0.20  (40 mL) was added a l a r g e excess Et^N.  (s,  To a s t i r r e d  sus-  g, 0.28 mmol) i n C H C 1 2  (1 mL) o f dry,  2  deaerated  The s o l i d r a p i d l y d i s s o l v e d t o y i e l d a c l e a r y e l l o w -  brown s o l u t i o n whose IR spectrum e x h i b i t e d n i t r o s y l region  (1718  and 1632 cm "*") .  two bands i n the  Addition  o f 40 mL  E t 0 produced a f l o c c u l e n t , yellow-brown p r e c i p i t a t e which 2  was  i s o l a t e d by f i l t r a t i o n .  ness i n vacuo and r e d i s s o l v e d  The f i l t r a t e was taken t o d r y i n a minimum o f C H C 1 ; an IR 2  spectrum o f t h i s s o l u t i o n showed two strong the n i t r o s y l r e g i o n  a t 1718 and 163 2 cm  1 f  2  absorptions i n  attributable to  - 92 -  CpW(NO) II. 2  broad  A N u j o l m u l l o f the. .yellow-brown, s o l i d showed  IR a b s o r p t i o n a t 1720'. and 1600 cm" . 1  Reaction of [Cp W (NO) ^H] P F 2  suspension  2  g  with. P h y P ^ C ^ .  To a s t i r r e d  c o n t a i n i n g 0.28 g (.0.37 mmol) o f [Cp W (NO) H] P F 2  2  4  g  i n 15 mL C R ^ C ^ was added dropwise 1 e q u i v a l e n t o f an orange, ether s o l u t i o n o f 0.3 M P h P = C H 3  1 0 5 2  .  Immediately upon  adding  Ph P=CH , t h e s o l u t i o n darkened t o o l i v e - g r e e n , w i t h the 3  2  o r i g i n a l suspended s o l i d r a p i d l y d i s s o l v i n g .  To t h i s s o l u -  t i o n was then added 50 mL of E t 0 whereupon a t a n p r e c i p i 2  t a t e formed, which was i s o l a t e d by f i l t r a t i o n . of  the s o l i d with C H C 1 2  Extraction  gave an orange-brown s o l u t i o n  2  e x h i b i t i n g strong IR a b s o r p t i o n s a t 1728 and 1647 cm . 1  V o l a t i l e s were removed from the f i l t r a t e under . reduced  p r e s s u r e , and the r e s i d u e was then d i s s o l v e d i n  benzene and chromatographed on a 2 x 5 cm F l o r i s i l column w i t h benzene as e l u a n t t o o b t a i n CpWCNO) H, as i d e n t i f i e d 2  by i t s c h a r a c t e r i s t i c IR and *H NMR s p e c t r a . 5 1  Reaction o f [Cp^Wp CNO) ^Hj BF ^ with. (Me N). PO. 2  CH C1 2  2  suspension  [Cp W (NO) H] B F 2  2  4  4  by H.E. Morton).  3  To a s t i r r e d  C10 mL) c o n t a i n i n g 0.3 0 g CO.42 mmol) of was added 1 mL of d r y (Me N) P 0 2  The s o l i d immediately  3  (provided  dissolved giving a  dark green s o l u t i o n e x h i b i t i n g t h r e e strong IR absorbances i n t h e n i t r o s y l r e g i o n not a t t r i b u t a b l e t o CMe N) PO Ci.e. 2  v  1735, 1721, 1630 cm" !.. 1  N Q  the excess  3  Numerous attempts t o separate  (Me^Nl^PO from the. n i t r o s y i - c o n t a i n i n g species- by  means such as e x t r a c t i o n with. H 0, c r y s t a l l i z a t i o n from a 2  93  -  v a r i e t y ; of s o l v e n t m i x t u r e s ( i n v a r i a b l y y i e l d i n g o i l s ! . ,  and  chromatography on F l o r i s i l were unsuccessful.. Reaction  of  [Cp W (NO) ^H] BF^ With KOII/EtOH. 2  t i o n of KOH  i n 95% ethanol was  suspension (.2 0 mL)  of  A 0.07  2  added dropwise to a  [Cp W CNO)^H]BF^ (0.30 2  g, 0.43  2  with IR m o n i t o r i n g .  M solustirred  mmol) i n CH C1. 2  Upon a d d i t i o n of the f i r s t  few  drops, the s o l i d r a p i d l y d i s s o l v e d to g i v e a l i g h t green s o l u t i o n whose IR spectrum d i s p l a y e d a broad, weak band at -19.00 cm 1632  as w e l l as two  1  cm ,  a l l a t t r i b u t a b l e to CpWCNO) H.  -1  EtOH was  s t r o n g , sharp bands at 1718 As f u r t h e r  2  added, to a t o t a l of 1 e q u i v a l e n t of KOH,  change observed i n the n i t r o s y l r e g i o n of the IR was  a gradual diminution  and  the  only  spectra  i n i n t e n s i t y of these bands as  s o l u t i o n became more d i l u t e .  t r a n s f e r r e d as a suspension  top of a 2 x 5 cm F l o r i s i l  the  The v o l a t i l e s were removed  from the r e a c t i o n mixture under reduced p r e s s u r e , and r e s i d u e was  KOH/  column.  the  i n benzene t o the  E l u t i o n of the column  with benzene developed a green band which, when c o l l e c t e d , taken to dryness,  and  strong a b s o r p t i o n s one  at 1900  w i t h THF  cm  redissolved i n CH C1 , exhibited 2  a t 1718  and  1632  ( i . e . CpW(.NO) H).  -1  2  cm  as w e l l as a weak  E l u t i o n of the column  s l o w l y developed a y e l l o w band; with H 0 2  the band was  displayed  at 1718 of  as e l u a n t  c o l l e c t e d , the s o l v e n t removed i n vacuo,  an IR spectrum of the r e s i d u e i n THF  Reaction  1  [Cp W ?  ?  and  1610  C.N0) . H] PF  two  2  was  obtained  and  which  cm .. 1  with. C H T n  g  CNMe 1 . ?  2  Upon a d d i -  - 9.4 -  t r o n o f 1 e q u i v a l e n t CO, 05 g l of C H: CNMe. 1 1Q  &  tetramethyl—1,8—naphthalenediamine.,  2  2  (N, N,N', N' —  s o l d by A l d r i c h under  the t r a d e name Proton Spongel t o a suspension of [Cp W C N 0 ) — 2  H]PF  6  2  4  CO.18 g, 0.24 mmoll i n 10 mL of CH CT , the super2  natant s o l u t i o n immediately turned y e l l o w .  2  However, even  a f t e r being s t i r r e d f o r 3 0 minutes, the green s o l i d d i d not appear t o be d i s s o l v i n g , and the supernatant s o l u t i o n e x h i b i t e d o n l y weak IR a b s o r p t i o n s a t 1718 and 163 2 cm . 1  l a r g e excess of Proton Sponge was t h e r e f o r e added of  A ....  (a t o t a l  10 e q u i v a l e n t s ) , and the r e a c t i o n was monitored by IR  spectroscopy.  The bands a t 1718 and 1632 cm  gradually  1  i n c r e a s e d i n i n t e n s i t y as the s o l u t i o n darkened, 3 h green s o l i d  still  remained.  but a f t e r  A f t e r 18 h, the bands were  even more i n t e n s e , and o n l y a brown p r e c i p i t a t e was p r e s e n t . The  s o l i d was i s o l a t e d by f i l t r a t i o n  and e x t r a c t e d w i t h THF;  an IR spectrum of the e x t r a c t s r e v e a l e d o n l y weak, broad a b s o r p t i o n s a t 1720 and 1615 cm . 1  t r a t e d i n vacuo, 1718  and 1632 cm  The f i l t r a t e was concen-  and i t s IR spectrum 1  showed s t r o n g bands a t  and a weak band a t 1900 cm  1  Ci.e.  CpW(NO) H) as the o n l y a b s o r p t i o n s i n the n i t r o s y l r e g i o n 2  not a t t r i b u t a b l e t o the C, H,(NMe„),.. n  ± U  b  2  2  The r e a c t i o n was repeated i n CD^NO.^ w i t h H NMR 1  m o n i t o r i n g of i t s p r o g r e s s . to  I n i t i a l l y the c a t i o n  was..cleaved  y i e l d CpW(NO) H ( 5 6.13 (a, 5H);, 2.08 (s, 1HJ.I and another 2  c y c l o p e n t a d i e n y l tungsten compound  (_& 6.35 Cs-, 5H)_, but the  l a t t e r r a p i d l y decomposed t o g i v e a brown, i n s o l u b l e residue..  - 95 -  R e a c t i o n o f [Cp^W^(NO)^H]PF'g w i t h NaBH^.. [Cp W (NO) H] P F 2  2  4  A small sample o f  was- d i s s o l v e d i n 10 mL of dry- CH N0  6  3  2  to  g i v e a yellow-green s o l u t i o n e x h i b i t i n g two IR a b s o r p t i o n s (1728  (sh) , 1718 cm "*"). i n the p o r t i o n of the n i t r o s y l r e g i o n  not obscured by the s o l v e n t ( c u t - o f f -1650 cm ) . 1  stirred  To t h i s  s o l u t i o n was added 10 • e q u i v a l e n t s o f s o l i d . NaBH^;, ,,  a f t e r 48 h o n l y the band a t 1718 cm  remained.  1  Solvent  removal under reduced p r e s s u r e y i e l d e d a s o l i d which was e x t r a c t e d w i t h C H C 1 ; an IR spectrum 2  bands a t 1900 (w) , 1718, and 1632 c m CpWCNO) H.  - 1  attributable to  A f t e r chromatography o f the e x t r a c t s on F l o r i s i l  2  with. C H C 1 2  removal  o f the e x t r a c t s showed  2  as e l u a n t , a H NMR of the r e s i d u e o b t a i n e d by J  2  of the s o l v e n t i n vacuo from the e l u a t e confirmed  t h a t t h e product was indeed CpW(NO) H; o n l y a t r a c e o f impur2  i t y remained  a t t h e top of the column.  R e a c t i o n of [Cp W (NO)^H]PF 2  CH C1 2  2  suspension  [Cp W (NO) H]PF 2  of  2  2  4  Cp MoH 2  2 1 2  g  6  w i t h Cp MoH . 2  2  To a s t i r r e d  (20 mL) c o n t a i n i n g 0.10 g (.0.13 mmol) o f was added an excess  (0.035 g, 0.15 mmol)  , y i e l d i n g a y e l l o w supernatant s o l u t i o n .  No  immediate r e a c t i o n was observed, but af t e r --2 ihbur s^onl-y^r. a:browru-'Solid.-'rem.ained, -aridi'the. sup.eEnatantr.seiutionwwas almost c o l o u r l e s s .  The brown s o l i d , i s o l a t e d by f i l t r a t i o n ,  was i n s o l u b l e i n common o r g a n i c s o l v e n t s . spectrum  I t s m u l l XR  e x h i b i t e d o n l y broad peaks a t 1710 (wl and 1600  -1 cm R e a c t i o n o f [Cp W (NO)^H]PF 2  2  g  w i t h Sodium Naphthallde.  A THF  -  solution  (50 mL) c o n t a i n i n g  96 -  5.0 mmol  (0.64 g)  f o r 18 h o v e r an e x c e s s o f N a  naphthalene  was  stirred  ing  the intensely  3.3  mL o f t h e s u p e r n a t a n t s o l u t i o n was s y r i n g e d [Cp„W„(NO)„H]PF .  and t h e f i n a l which  After  4  Z  a yellow-green solution.  f o r 1 h,  onto  0.2 5 g  D  r e a c t i o n mixture consisted  was i n s o l u b l e  allow-  R e a c t i o n was immed-  r  Z  solid,  .  green r e a c t i o n mixture t o s e t t l e  (0.33 mmol) o f s o l i d iate  1 Q 6  o f a red-brown  i n common o r g a n i c s o l v e n t s , An IR s p e c t r u m  below  of the solution  showed a b s o r p t i o n s a t 1900 (w, s h ) , 1712, and 1632 cm , a l l 1  attributable  t o CpW(NO) H.  A m u l l IR s p e c t r u m  2  showed no a b s o r p t i o n s i n t h e n i t r o s y l  of the s o l i d  region.  R e a c t i o n s o f [Cp^Mo^(NO)^H]PF^ w i t h V a r i o u s E l e c t r o n Ca) W i t h  acetone.  were added detected (b). W i t h  To a C.D N0 < s o l u t i o n 3  8 e q u i v a l e n t s o f (CR~ ) C0; 3  by  X  nitrogen-containing  CD N0 3  2  of  bases.  bases N E t  2  2  instance  o f any r e m a i n i n g  several different  3  With  and C ^ g H g ( N M e ) 2  1  E NMR  spectra  [Cp Mo (NO)^H] 2  resonances  2  +  i n the cyclopentadienyl  of  3  silicate.  (0.10 g) i n C H C 1 0  z  a 2 x 4 cm F l o r i s i l  0  Z  region.  multiple  2  A suspension of [Cp Mo (NO) ~ 2  (10 mL) was t r a n s f e r r e d  column.  turned;from  and t h e p r e s e n c e  6 6.2->6.7 ppm.  (c) W i t h magnesium  (Proton  demonstrated  resonances  i n the region  2  immediately  i n (CD ) C0 again yielded  b  g  the addition of  Repeating the experiment  H]PF_  4  no i n t e r a c t i o n was  solutions of the cation  g r e e n t o brown; i n e a c h the absence  2  of [Cp Mo (NO) H]PF  E NMR.  the n i t r o g e n - c o n t a i n i n g Sponge),  2  Donors.  Elution  2  4  to the top  o f t h e column w i t h  - 97 -  CH2CT2  developed a, green band; c o l l e c t i o n of t h i s band and  concentration, of the e l u a t e under. reduced p r e s s u r e t o a volume of ~3 mL gave a s o l u t i o n of CpMo (NO) 2 by i t s IR spectrum cm "*")..  (i.e.  V  N  Q  1738,  1647;  V  M  O  Removal of the remaining s o l v e n t was  H  _  a  R  indicated  s  1805  (w)  accompanied  by  the f o r m a t i o n of a brown s o l i d ; e x t r a c t i o n of the r e s i d u e with NMR  (CD^^CO gave a green s o l u t i o n of CpMoCNO^H, whose spectrum showed resonances a t § 6.43  (s, 5H). and  1  H  3.80  (s, IH). . Treatment of [Cp W2(NO)^H]BF^ w i t h propene. 2  of propene  (~2 mL/min) was  passed over a v i g o r o u s l y  suspension of [Cp W (NO) H]BF 2  (20 mL)  f o r 4 h.  2  A slow stream  4  4  (0.10 g, 0.14  stirred  mmol) i n C H C 1 2  2  During t h i s time no changes were d e t e c t e d  i n the IR spectrum of the supernatant s o l u t i o n except f o r c o n c e n t r a t i o n e f f e c t s a r i s i n g from the e v a p o r a t i o n of some of the s o l v e n t .  A small amount of a brown s o l i d d i d form  d u r i n g the r e a c t i o n p e r i o d .  A f t e r 4 h, the v o l a t i l e s were  removed i n vacuo and the r e s i d u e d i s s o l v e d i n CD N02.  A  3  *H NMR  spectrum of t h i s s o l u t i o n showed the s t a r t i n g  i a l t o be l a r g e l y unreacted; t h e r e were a l s o s e v e r a l  matersmaller  peaks p r e s e n t which were a t t r i b u t a b l e o n l y t o decomposition products.  There was  no evidence f o r the f o r m a t i o n of e i t h e r  CpW (NO). H or [ CpW (NO) (propene) ] B F . 2  2  Reaction of [CpCr (NO) ] 2  CH C1 2  2  solution  mmol) was  added  4  2  (95 mL)  w i t h HBF • OMe •  To, a s t i r r e d  of [CpCr (NO)^]  (0.50 g,  4  an excess  (1.0 mL)  2  2 2  of HBF^OMe^-  1.41, With-  - 98 -  s t i r r i n g , the. dark p u r p l e CH^C^  phase g r a d u a l l y turned a  g o l d c o l o u r , w h i l e t h e a c i d phase darkened t o a brown, c o l o u r . A f t e r 15 minutes-, an IR spectrum of the C H C 1 2  r e v e a l e d t h a t a l l of the [CpCr(NO) ] 2  2  solution  2  had been consumed; two  new n i t r o s y l absorptions- were present a t 1828 and 1721 cm Water X150 mL) was then added, and the CH^C^  1  .  removed i n  vacuo to y i e l d a golden s o l u t i o n and a t r a c e of p r e c i p i t a t e . To t h i s suspension were then added two e q u i v a l e n t s  (1.00 g)  of NaBph^, immediately producing a f l o c c u l e n t y e l l o w p r e c i p itate.  F i l t r a t i o n of t h i s suspension was f o l l o w e d by  thorough washing of the c o l l e c t e d s o l i d w i t h R^O 3 0 mL).  (2 x  Subsequent e x t r a c t i o n of the s o l i d w i t h  (2 x 30 mL) (15 mL)  and a d d i t i o n of benzene  (.30 mL)  CH^C^  and hexanes  f o l l o w e d by slow c o n c e n t r a t i o n i n vacuo y i e l d e d  0.54 g of green m i c r o c r y s t a l l i n e IR (CR" C1 ) : 2  2  V  solid.  1828, 1721 cm" . 1  N  6 6.8-7.6 (m, 40H), 6.06  0  (s, 5H), 5.68  X  2  Mp  119-20°C.  C, 62.98; H, 4.72; N,  R e a c t i o n of [CpCr ( N O ) ] 2  2  ((.CD^CO):  (s, 5H), -5.35 (s,  IH); no change was observed with added D 0. Elemental a n a l y s i s , found:  H NMR  w i t h HPF  g  6.86.  (65% s o l u t i o n i n  water) gave comparable r e s u l t s ; a l l attempts t o c r y s t a l l i z e e i t h e r the BF. 4  or PF6  s a l t s were u n s u c c e s s f u l .  Small samples of the above s o l i d were d i s s o l v e d i n CR" C1 2  2  Ph P=CH 3  (5 mL) 2  and t r e a t e d with e i t h e r excess NEt^ or 0.3 M  (in E t 0 ) . 2  i n the IR spectrum.  In each i n s t a n c e no change was observed  - 99 -  Reaction of [CpCr (NO) purple CH C1 2  of  solution  2  [CpCr (NO) ] 2  ]  was  2  wi'tK p-CiL,C E SO ,H:,  2  £  (.40 mL)  c o n t a i n i n g 0.5:4  added 1 e q u i v a l e n t  CgH^SO^H with v i g o r o u s s t i r r i n g . the  :  4  To a darkg  (1.53 mmol).  (.0.2 65 g) of p-CH ~ 3  IR s p e c t r a l m o n i t o r i n g of  s o l u t i o n r e v e a l e d the g r a d u a l decrease i n i n t e n s i t y o f  the n i t r o s y l a b s o r p t i o n s a t t r i b u t a b l e t o [ C p C r ( N O ) ] 2  at 1667,  1505  cm "*") and the appearance  at 1829 and 1722  cm  1  of two new a b s o r p t i o n s  over a p e r i o d of ~10 minutes.  one-half of the [ C p C r ( N O ) ] 2  w  a  2  s  (i« e.  2  Only  consumed by the p - t o l u e n e -  s u l f o n i c a c i d , so an a d d i t i o n a l 1 e q u i v a l e n t was  added.  T h i s l e d t o the complete disappearance of the n i t r o s y l IR a b s o r p t i o n s a t t r i b u t a b l e t o the s t a r t i n g complex, and a change i n the c o l o u r of the s o l u t i o n from p u r p l e to dark orange.  The a d d i t i o n of an equal volume of hexanes y i e l d e d ,  upon c o n c e n t r a t i o n under reduced p r e s s u r e , a green powder which, was  subsequently i s o l a t e d by f i l t r a t i o n .  Recrystall-  i z a t i o n of t h i s s o l i d from C H C 1 / E t 0 gave C p C r ( N O ) O S 0 C H 2  2  2  2  (0.4 8 g, 4 5% y i e l d ) as a f i n e green powder, mp Anal. Calcd f o r C N, 8.04. v  N  8.30  Q  1829, Hzi)i ,  Found: 1722 7.21  1 2  H  1 2  CrN 0 S: 2  C, 40.84; H, 3.68;  cm .  E  -1  (d,  1  2H«,  7  NMR  N, 7.36.  (CDC1 ): 3  J;. = . 8.0-.Hz);j  i ;  6 7.72  2  Cr(CO) CTHF) 5  1 0 7  5  6  7  (d,  3.47;  (CH Cl ). : 2  2H> 2.36  2  J " = . - : '• (s,  3H)  A s o l u t i o n of  was generated by i r r a d i a t i n g a THF  (210 mLl of C r ( C O )  solution  (.0.65 g, 2.95 mmol). f o r 1 h. ( I n a photo-  r e a c t o r u s i n g a medium-pressure mercury housed  IR  5.75:p(sp-5H) ;  Reaction of CpW(NO) H with C r ( C O ) ( T H F ) .  7  64-6°C.  C, 41.38; H,  5  2  i n a water—cooled Pyrex immersion  lamp [Hanovia L-4 50W] well), while, g e n t l y  .  - 10.0. -  bubbling N' through, the. s o l u t i o n t o remove, the. free. CQ 2  produced.  The. r e s u l t i n g orange s o l u t i o n was; then, concen-  t r a t e d t o a volume of ^2.5 mL under reduced pressure, and cooled t o —78°C.  To t h i s s t i r r e d  (1.87 mmol). of CpW(NO) H, 2  an orange-brown  s o l u t i o n was added  0.58  g  which d i s s o l v e d r a p i d l y t o g i v e  solution.  After stirring  f o r 2 5 minutes,  an IR spectrum of the s o l u t i o n showed four bands i n the (v  n i t r o s y l region  N Q  1736,  1718,  1661;  and 1629 cm )  as  -1  w e l l as a p o o r l y r e s o l v e d envelope of bands i n the c a r b o n y l region  (v  2085 (w). , 1995  C Q  (sh) , 1975, and 1920  A f t e r 1 h, the s o l u t i o n was  (br) c m ) .  allowed t o warm t o room  - 1  tempera-  t u r e , with, no change i n the IR spectrum being d e t e c t e d . v o l a t i l e s were then removed i n vacuo t o y i e l d a s o l i d was o n l y p a r t i a l l y s o l u b l e i n C H C 1 2  the  2  or THF.  The  which  IR s p e c t r a of  r e s p e c t i v e orange supernatant s o l u t i o n s were comparable,  e x h i b i t i n g a b s o r p t i o n s a t t r i b u t a b l e t o both c o o r d i n a t e d carbonyl  (v  c  and n i t r o s y l 1634  o  (THF).: (v  N 0  2085 (w) , 2003, 1972, and 1928 cm" ),  (THF):  (w, sh) cm ) . groups. 1  1  1738  (w), 1718  (w), 1661,  and  F r a c t i o n a l s u b l i m a t i o n of the  s o l i d a t reduced p r e s s u r e (0.005.Torr) y i e l d e d f i r s t . Cr(C0)  i a 7 6  (0.20 g, 31% y i e l d ) a t 35°C and then CpW (CO \ (NO)  2 3  2  (0.12 g, 17% y i e l d based on W) a t ~55°C. i d e n t i f i e d by i t s c h a r a c t e r i s t i c  Each, product was  i n f r a r e d and mass s p e c t r a .  A m u l l IR spectrum of the i n t r a c t a b l e brown r e s i d u e which remained e x h i b i t e d broad absorptions- a t 1920 and  1660  -1 cm In  a subsequent t r i a l ,  i t was noted t h a t the decom—  - 10.1 -  p o s i t i o n o f the i n i t i a l product  and formation, o f CpW;(COL (NO), 2  o c c u r r e d d u r i n g s o l v e n t removal: completely  even i f the. s o l v e n t was not  removed the t r a n s f o r m a t i o n s t i l l o c c u r r e d .  r e a c t i o n o f CpW (NO) H with. Cr (CO) (NMe^)  10 8  2  5  The  gave comparable  results. The r e a c t i o n was a l s o c a r r i e d out i n (CDD-^CO with 1  H  NMR m o n i t o r i n g .  Thus, upon a d d i t i o n of l e s s than one  e q u i v a l e n t o f "Cr (CO) (THF) " (prepared as above, but with 5  v i r t u a l l y a l l of the excess THF removed) a t -80°:C, a* s h i f t t o lower f i e l d ' offe~the--resonance 1 attribufcable'^to'ithe c y c l o p e n t a d i e n y l protons was observed. resonance was not observed;  U n f o r t u n a t e l y , the h y d r i d e i t was l i k e l y obscured  by the  t e t r a h y d r o f u r a n or s o l v e n t peaks. Warming o f the r e a c t i o n mixture  t o 0°C f o l l o w e d by  a c q u i s i t i o n o f a spectrum r e v e a l e d t h a t c l e a n c o n v e r s i o n of a p o r t i o n o f the CpW(NO) H 2  CpW (CO) (NO). 2  (6 6.24 (s, 5H), 2.19 (s, IH))  (6 6.49) had o c c u r r e d .  l i g a n d c o u l d not be determined.  to  The f a t e of the hydride  Addition of further  " C r ( C O ) ( T H F ) " a t t h i s temperature simply r e s u l t e d i n f u r t h e r 5  formation o f CpW(CO) (NO); no i n t e r m e d i a t e was 2  observed  a f t e r the ~2 min r e q u i r e d t o mix the r e a c t a n t s and o b t a i n a spectrum. Reaction o f CpW(NO) H with W(CO) (THF) . 2  5  solution containing W(CO) (THF) 5  was prepared  1 0 7  A yellow-orange  (1.51 mmol) i n THF (15 mL)  i n a manner analogous t o t h a t used f o r Cr(CO),- —  (THF), and the s o l u t i o n was cooled t o -78°C.  Addition of a  t o t a l o f 0.43 g (1.38 mmol) CpW (NO) ~H was made incrementally-  - 1.0.2. -  with IR monitoring.. appeared i n i t i a l l y " ,  Four absorptions- i n the n i t r o s y l . r e g i o n and t h e y maintained  comparable, r e l a t i v e ,  i n t e n s i t i e s - as f u r t h e r CpW"(NO) H was- added.  The two stronger  2  Cv  absorptions  1717, 1631 cm I-were a t t r i b u t a b l e t o f r e e 1  Nu  CpW (NO) H; the other two peaks Cv N Q 1738, 1663 cm 2  approximately  h a l f as i n t e n s e .  C.5 mL). was then allowed  were  A f r a c t i o n of t h i s s o l u t i o n  t o warm t o room temperature, d u r i n g  which time i t turned from green t o orange.  The v o l a t i l e s  were removed i n vacuo t o y i e l d a gummy brown r e s i d u e . E x t r a c t i o n of the r e s i d u e with 5 mL THF r e v e a l e d t h a t p a r t of  the m a t e r i a l was no longer s o l u b l e ; an IR spectrum of  the e x t r a c t r e v e a l e d t h a t the r e l a t i v e i n t e n s i t i e s of the two p a i r s o f a b s o r p t i o n s i n t h e n i t r o s y l r e g i o n were now reversed.  Removal o f the s o l v e n t f o l l o w e d by d r y i n g under  high vacuum decomposition  C<0.005 T o r r f o r 1.5 h) r e s u l t e d i n complete o f the r e s i d u e t o produce an i n t r a c t a b l e brown  solid. The allowed  remaining  10 mL o f the r e a c t i o n mixture was then  t o warm t o room temperature t o determine the thermal  s t a b i l i t y of the products. spectrum was observable, a f t e r approximately of  Although  no change i n the IR  a brown s o l i d began t o p r e c i p i t a t e  1 h.. A f t e r 18 h the r e l a t i v e  the two p a i r s o f n i t r o s y l a b s o r p t i o n s were  equal..  One week, l a t e r the supernatant  intensities  approximately  was almost c o l o u r l e s s  and e x h i b i t e d o n l y very weak. IR absorptions- i n the n i t r o s y l region..  The brown p r e c i p i t a t e was i s o l a t e d by f i l t r a t i o n  and d i s s o l v e d i n CCE,)_SO; an.IR spectrum of t h i s s o l u t i o n  - 1.0.3  -  r e v e a l e d only- a b s o r p t i o n s a t t r i b u t a b l e t o the s o l v e n t . Reaction: of CpW (NO) H 2  C220 mL)  tion was  with  (MeCp) Mn (CO).y (THF) .  c o n t a i n i n g (MeCp)Mn (CO)  (2.0 mL,  3  A THF  solu-  13 mmol)  p l a c e d i n a p h o t o r e a c t o r and, while g e n t l y being purged  with. N ,  was  2  lamp  i r r a d i a t e d u s i n g a medium-pressure mercury  (Hanovia L-150W) housed i n a water-cooled  well.  immersion  IR s p e c t r a l m o n i t o r i n g of the r e a c t i o n showed o p t i m a l  conversion to  (MeCp)Mn (CO) (THF)  1 07  2  a f t e r 1.5  t i o n , l e a v i n g a c l e a r , dark red s o l u t i o n .  h. of The  irradia-  solution  was  t r a n s f e r r e d t o a round-bottom f l a s k and cooled to -78°C. In a separate f l a s k , i n 10 mL  THF  0.20  g  (0.64 mmol) of CpW(NO) H 2  were c o o l e d to -78°C, and to t h i s were added  20 mL  of the  (MeCp)Mn(CO) (THF)  Mn)..  At -78°C t h e r e appeared to be no r e a c t i o n .  2  warming to room temperature,  ume  The  s o l u t i o n was  of approximately  s o l u t i o n showed two (sh), 1661  cm  2 mL; new  h, and  total  After  solution  turned  some p r e c i p i t a t e  concentrated  i n vacuo to a v o l -  an IR spectrum of the  supernatant  bands i n the n i t r o s y l r e g i o n (.1725  ^) but no d e t e c t a b l e change i n the c a r b o n y l  r e g i o n of the spectrum. (THF)  (1.2 mmol of  the green-red  dark brown over a p e r i o d of 0.5 appeared.  solution  A d d i t i o n of f u r t h e r (MeCplMn(CO) ~ 2  s o l u t i o n simply r e s u l t e d i n a uniform decrease  in  i n t e n s i t y of a l l 4 bands i n the n i t r o s y l r e g i o n , but with, s t i r r i n g more p r e c i p i t a t e formed, and a l l bands i n the n i t r o s y l r e g i o n as w e l l as those a t t r i b u t a b l e to (CO) 2 CTHF). were observed s o l v e n t was  t o decrease  (MeCp)Mn-  in intensity.  The  then removed i n vacuo, and the r e s i d u e e x t r a c t e d  - 104 -  with C H C 1 2  and f i l t e r e d ; the f i l t r a t e e x h i b i t e d IR absorp-  2  t i o n s not a t t r i b u t a b l e t o the s o l v e n t a t 2020, 1900  (br),  and  were  1658 cm . 1  A l l attempts t o p u r i f y t h i s product  u n s u c c e s s f u l , but i t was c l e a r t h a t i t was no.longer the i n i t i a l l y - f o r m e d adduct a t t h i s  stage.  Reaction o f CpW(NO) H with 2  (MeCp)Mn(CO) (H)(SiPh ) 2  109  3  gave comparable r e s u l t s . Reaction o f CpW(N0) H with ZnCl,,. 2  (0.20  An excess  of Z n C l « x H 0 2  g, -1.4 mmol) was added t o a THF s o l u t i o n  2  (15 mL)  c o n t a i n i n g 0.20 g (0.65 mmol) of CpW(NO) H, and the r e s u l t 2  i n g s o l u t i o n was s t i r r e d a t room temperature f o r 48 h. monitoring  IR  d u r i n g t h i s p e r i o d showed the slow growth of  p o o r l y r e s o l v e d shoulders a t 1717 and 1631 cm  1  ( i . e . at  s l i g h t l y higher energy than the n i t r o s y l a b s o r p t i o n s of CpWCNO) H). 2  The s o l v e n t was then removed i n vacuo, with a  brown p r e c i p i t a t e forming d u r i n g s o l v e n t removal.  Following  e x t r a c t i o n of the r e s i d u e with a small amount of CDCl^, a E NMR spectrum of the e x t r a c t showed the presence of  l  CpW(NO) Cl 2  (6 6.17) and CpW(.NO) H (.6 6.00 (s, 5H) , 2.07 2  (s, 1H) ) i n a r a t i o of 3:2.  Due t o the p a r t i a l  decomposi-  t i o n of the sample d u r i n g s o l v e n t removal, the degree of c o n v e r s i o n t o the c h l o r i d e c o u l d not be r e l i a b l y a s c e r t a i n e d . The r e a c t i o n was next c a r r i e d out i n (CD^). CO with 2  :  H NMR monitoring  a t ambient temperature.  spectrum o f the CpW(NO) H/ZnCl 2  2  mixture  The i n i t i a l  showed the r e s o n -  ances a t t r i b u t a b l e t o both the c y c l o p e n t a d i e n y l and hydride  - 105 -  protons s h i f t e d t o higher f i e l d b y 4.8 and 7..8 Hz r e s p e c t ively  Cthe u n c e r t a i n t y i n t h e peak . p o s i t i o n s was- a p p r o x i -  m a t e l y 0.3 Hz), r e l a t i v e t o f r e e CpW (NO) H.  The addition, o f  2  D0 2  t o the s o l u t i o n produced no s h i f t i n these peaks,  thereby r u l i n g out the p o s s i b i l i t y t h a t the t r a c e s of H^O i n t r o d u c e d w i t h the Z n C l  c o n t r i b u t e d t o the observed  2  The c o n v e r s i o n of the h y d r i d e t o CpWCNO) Cl 2  a f t e r 11 h a t ambient  2  2  alent  was ~15% complete  temperature.  Treatment of C p W ( N O ) w i t h C d C l . CdCl  changes.  (.0.23 g, 1.23 mmol) i n THF (.0.38 g) of CpW(N0) H. 2  To a suspension of white  (90 mL) was added 1 e q u i v -  S t i r r i n g of the m i x t u r e f o r two  days a t room temperature r e s u l t e d i n no d i s c o l o u r a t i o n of the white s o l i d , and no changes were d e t e c t e d i n the IR spectrum of the supernatant s o l u t i o n .  The CpWCNO) H was r e c o v e r e d 2  q u a n t i t a t i v e l y by f i l t r a t i o n and subsequent R e a c t i o n of CpW(NO) H w i t h H g C l . 2  2  To a s t i r r e d mixture of  CpW(NO) H (0.27 g, 0.87 mmol) and H g C l 2  were added 3 0 mL THF.  s o l v e n t removal.  2  (0.23 g, 0.87 mmol)  Both s o l i d s d i s s o l v e d r a p i d l y t o  y i e l d a c l e a r , lime green s o l u t i o n .  However, w i t h i n 1 minute,  the s o l u t i o n became cloudy, and a white p r e c i p i t a t e then formed.  A f t e r 1.5 h, the suspension was f i l t e r e d t o o b t a i n  a gray s o l i d and an o l i v e - g r e e n s o l u t i o n .  The f i l t r a t e  taken t o dryness i n vacuo, and the r e s i d u e  recrystallized  from CH C1 /hexanes t o y i e l d 2  2  of CpWCNO) Cl 2  NMR,  16  was  0.2.0. g (0.58 mmol, 67% y i e l d )  as i d e n t i f i e d , by i t s c h a r a c t e r i s t i c I;R, K  and mass s p e c t r a and by elemental analysis..  1  1.06  -r.  The: gray- s o l i d was> q u a l i t a t i y e i y - i d e n t i f i e d " ' as 1  1 a  CO. 11 g, 53% y i e l d ) : By- r e a c t i n g i t w i t h NHjQH t o g i v e  HgCl  a v e r y dark gray r e s i d u e CHg••  Hg(NH ) CI) . 2  The r e a c t i o n was a l s o c a r r i e d out a t ^8 0°C i n (CD^l^CO with H NMR  monitoring . I n i t i a l l y ,  1  was  Cs,  observed a t 5 6.53  and  6.40  ( c f . 6" 6.23  5H)  a sharp peak, f o r CpW (NO) H 2  f o r CpWXNO) Cl) along* w i t h a broader peak a t 2  6 4.3 5  (s, IH) , both, a t t r i b u t a b l e t o the complex CpW (NO) H-  HgCl .  Upon warming t o 0°C a r e a c t i o n o c c u r r e d , with the  2  2  resonance a t t r i b u t a b l e t o the c y c l o p e n t a d i e n y l protons broadening and s h i f t i n g to 5.-6.40. The r e a c t i o n was  then c a r r i e d out a t -78°C i n THF;  s e v e r a l attempts t o r a p i d l y o b t a i n an IR spectrum of the r e a c t i o n mixture y i e l d e d o n l y s p e c t r a d i s p l a y i n g  nitrosyl ( j . e.  a b s o r p t i o n s i n d i s t i n g u i s h a b l e , from those of CpW (NO). C1 2  V  N Q  164 6, 1728  cm" ). 1  R e a c t i o n of CpW(N0) H w i t h Pt (PPh-,).. 2  solution added 0.50  (2.0 mL)  of CpW'CNO) H  (0.188 g, 0.609 mmol); were  2  e q u i v a l e n t s (10 mL)  C1.205 g, 1.2.3 mmol i n 4 0 mL  of a Pt CPPh- ) 3  3  1  11  solution  of t o l u e n e ) y i e l d i n g an immed-  i a t e , f l o c c u l e n t , yellow—brown ling,  To a s t i r r e d t o l u e n e  p r e c i p i t a t e and, upon s e t t -  a y e l l o w supernatant s o l u t i o n .  An XR spectrum of t h e  s o l u t i o n showed t h a t approximately one-half of the CpWCNO) H 2  had been consumed, but no new n i t r o s y l region.  absorptions- appeared  The p r e c i p i t a t e was c o l l e c t e d by- f i l t r a t i o n ,  washed w i t h t o l u e n e (2 x 10 mL), s o l i d was  in. the  and d r i e d i n vacuo.  o n l y s p a r i n g l y s o l u b l e i n THF,  The  but q u i t e C H C 1 9  9  107 ^  soluble:  TR s p e c t r a o f the s o l i d in. CH^Cl^ solution, and a s  a N u j o l m u l l showed only; weak, a b s o r p t i o n s i n the n i t r o s y l region..  A mass spectrum o f the s o l i d a t a probe temperature  of approximately  200°C r e v e a l e d no m e t a l — c o n t a i n i n g  ments, but i t should be noted  frag-  t h a t the s o l i d decomposed a t  125°C under N ; flame p y r o l y s i s y i e l d e d a metal r e s i d u e . 2  Reaction o f CpWCNCQ^H with BEt^.  To a hexanes  suspension  (10 mL) o f CpW(.N0) H (.0.20 g, 0.65 mmol) were added with 2  stirring  5 mL o f 1 M BEt^ i n hexanes.  solvent  Sufficient additional  (10 mL) was then added t o completely  CpW(.N0) H. 2  An IR spectrum o f the s o l u t i o n showed o n l y  a b s o r p t i o n s a t t r i b u t a b l e t o CpW(NO) H 2  i n the n i t r o s y l r e g i o n . began forming, colour.  d i s s o l v e the  ( v  1730, 1650 cm" ) 1  N  0  W i t h i n 10 min a brown p r e c i p i t a t e  and w i t h i n 1 h the s o l u t i o n was a p a l e green  A f t e r 16 h no IR a b s o r p t i o n s were d e t e c t a b l e i n  the n i t r o s y l r e g i o n o f the spectrum.  A d d i t i o n o f 3 mL THF  f a i l e d t o d i s s o l v e any of the s o l i d . With the a d d i t i o n o f o n l y 1 e q u i v a l e n t o f BEt^ t o a CpW (.NO). H s o l u t i o n , decomposition 2  o c c u r r e d a t a slower r a t e ;  however, no new n i t r o s y l a b s o r p t i o n s c o u l d be d e t e c t e d i n s o l u t i o n even a f t e r 1 h. Reaction of CpW(NO) H with HBF^ »OMe . 2  2  s o l u t i o n o f CpW CNO) H  (0.30 g, 0.97 mmol) i n C H C 1  2  2  was added dropwise an emulsion HBF «OMe 4  2  To a s t i r r e d , green  c o n t a i n i n g 0.5 mL  2  (25 mL).  C5.6 mmol)  i n 5 mL C H C 1 , and the progress o f the r e a c t i o n 2  2  was monitored by IR spectroscopy.  As a d d i t i o n proceeded,  - 1.08 -  the. s o l u t i o n became a dark; green, and the: n£t;ros.yl a b s o r p t i o n s a t t r i b u t a b l e t o t h e s t a r t i n g h y d r i d e d i m i n i s h e d in. i n t e n s i t y : s i m u l t a n e o u s l y , two new- bands- were observed t o grow i n a t s l i g h t l y higher energy  Cv  1733, 1648 cm' }..  consumption o f the CpW(NO) H 2  HBF «OMe2),  ( r e q u i r i n g <*1 e q u i v a l e n t  removed, t h e r e b y l e a v i n g of the o i l d i s s o l v e d  a dark green o i l . An IR spectrum  i n a minimum o f THF showed the absorp-  t i o n s s h i f t e d t o 1722 and 1641 cm  Addition  (an excess) o f d r y Et^N produced no s h i f t no c o l o u r  change was d e t e c t e d .  i s o l a t e the n i t r o s y l - c o n t a i n i n g The  H]BF  4  No attempt was made t o  product.  r e a c t i o n was a l s o c a r r i e d out a t -2 0°C i n  i n the c l e a n  16 6.47  o f HBF 'OMe 4  2  c o n v e r s i o n of CpWXNOj^H t o [Cp W (NO). ~ 2  (s, 10H), -8.33  2  4  (s, I H ) ) . Warming o f the  sample t o room temperature r e s u l t e d the  o f 0.5 mL  i n the a b s o r p t i o n s ,  C D 3 N O 2 : a d d i t i o n o f l e s s than 0.5 e q u i v a l e n t s resulted  of  the a d d i t i o n was terminated and the v o l a t i l e s  4  and  Upon complete  1  N0  i n the d e s t r u c t i o n o f  b i m e t a l l i c c a t i o n and the formation of a brown p r e c i p i -  tate. In c o n t r a s t ,  addition  of CpWCNO) H d i d not y i e l d 2  of H S 0 2  +  2  2  4  +  R e a c t i o n of CpW (NO) H with. A i d , .  in. CDCl^.  detectable.  To a CDC1  CpW(NO) H were added ~ L 2 e q u i v a l e n t s 2  a new  No other peaks attribu-s<  or f r e e H' were  2  t o a CD^NO,, s o l u t i o n  [ C p W ( N O J H ] , but r a t h e r  resonance a t 5 6.3 5 was observed. t a b l e t o e i t h e r W—H  4  3  s o l u t i o n of  o f A l C l ^ as a s o l u t i o n  A f t e r mixing w e l l , the r e s u l t i n g s o l u t i o n , was-  monitored by H NMR 1  spectroscopy a t ambient temperature.  -  1,0.9  -  Over- a p e r i o d of ~ 3 0^ min the slow- disappearan.ce: o f peaks a t 6' 5 . 9 9 (s, 5 H ) . and 2 , 0 . 7 ( > , I H ) ( a t t r i b u t a b l e t o CpW (NO) H) 2  was observed  along with, the concomitant  at 6' 6 . 1 4 due t o CpW (NO)  C 1  2  *  T  R  e  growth, o f a new peak  peak, p o s i t i o n s f o r each,  of the compounds- were i n d i s t i n g u i s h a b l e from those found i n FR m o n i t o r i n g o f the 1 : 1 r e a c t i o n of  t h e absence of A l C l ^ , CpW'(NO) H with.  A 1 C 1  2  3  i n CH:  2  C1  solution revealed only a  2  g r a d u a l s h i f t o f the n i t r o s y l a b s o r p t i o n s t o higher as- the hydride  (^ g 1 7 1 8 ,  CpW (NO) C 1 C v  1733,  2  N  N 0  1 6 3 2 cm ^) was- converted  1 6 5 0 cm" ).. 1  energy into  No evidence o f adduct  formation was d e t e c t e d . R e s u l t s and D i s c u s s i o n The P r e p a r a t i o n and Chara'cte'rizatlon of CpMo (NO) H . 2  In l i g h t o f the observed When the complexes CpCr (NO) X 2  formation of  [CpCr(NO) J 2  2  (X = C I , I, N © , N © , q ; - ^ ^ , 1  2  3  BF. , o r (CO)PF ) a r e r e a c t e d with NaAlH (OCH CH OCH ) 4  6  2  (described i n Chapter t i o n of CpM(NO) Cl  [CpM(NO) J . 2  2  3  2  3 ) , i t was a n t i c i p a t e d t h a t the reduc-  (M - Mo, W) might y i e l d the corresponding  2  dimers,  2  2  A l t e r n a t i v e l y , as the s t a b i l i t y of  i s o e l e c t r o n i c and i s o s t r u c t u r a l complexes i s known t o \ i n c r e a s e going down a p a r t i c u l a r group of t r a n s i t i o n i n the p e r i o d i c t a b l e  3 9  2  C 1  with. NaAlH:  2  metals  , the h y d r i d e compounds might them-  s e l v e s prove t o be. i.solable. CpMo (NO)  .  Indeed, the r e a c t i o n of  (0CH: CH 0CH: ) 2  2  3  2  i n toluene a t  l e a d s t o the formation o f a b r i g h t green  - 7  8°C  solution containing  the u n s t a b l e complex CpMo (NO)„H, which thus f a r has d e f i e d  - 110. -  a l l attempts a t i s o l a t i o n ' ., Toluene: s o l u t i o n s c o n t a i n i n g 5  1  CpMo CNO 1 ffs l o w l y d e p o s i t a''red—Brown s o l i d when s t i r r e d a t 2  ambient temperature i n an atmosphere of p r e p u r i f i e d n i t r o g e n , the decomposition decomposition  being complete a f t e r ^3 days.  The r a t e of  of the hydride complex is- markedly enhanced by  removal o f the s o l v e n t i n vacuo, a procedure which, o n l y a f f o r d s the. red—brown solid..  This- s o l i d does not d i s s o l v e :  y  i n any common o r g a n i c s o l v e n t s , and i t s i n f r a r e d (as a N u j o l mull) i s devoid of any a b s o r p t i o n s  spectrum  attributable  to c o o r d i n a t e d nitrogen-.monoxide . . N e v e r t h e l e s s evidence  Cv  N 0  (toluene):  1732, 1642 c m  - 1  IR s p e c t r a l  v s . 1753, 1663  cm"" f o r CpMo(N0) Cl) and the chemical p r o p e r t i e s (vide 1  2  i n f r a ) o f the green toluene  s o l u t i o n s are completely c o n s i s t -  ent with the presence o f CpMo(NO) H. 2  The r e a c t i o n s used t o c h a r a c t e r i z e CpMo (NO)^E chemi c a l l y a r e best performed u s i n g f r e s h l y prepared s o l u t i o n s of the complex.  Thus, treatment  toluene  of such a s o l u -  t i o n with an ether s o l u t i o n of diazomethane leads t o the formation o f the known compound CpMo (.NO) Me i n low y i e l d as 2  i d e n t i f i e d by i t s c h a r a c t e r i s t i c IR and mass s p e c t r a , i . e . Et„0/toluene CpMo (NO) H + C H N 2  2  •  2  CpMo (NO) Me + N 2  Comparable conversions  (.4 0.)  2  have p r e v i o u s l y been shown t o occur  when v a r i o u s c a r b o n y l hydrides-, eg. CpMo (COI^H: (M a r e r e a e t e d with d i a z o m e t h a n e  112  .  Mo, WI  A d d i t i o n a l evidence  supporting this- f o r m u l a t i o n i s obtained by r e a c t i n g the  31  ,  ^ 111 "  green, toluene, solutions-- witft excess- 'Mel: to. y i e l d , a f t e r s t i r r i n g f o r s e v e r a l days- a t ambient temperature, trace, amounts- of CpMo (NO) I s i d e n t i f i e d by- i t s - m e l t i n g p o i n t and a  s  2  i t s XR and mass- spectra," "i.e. CpMo (NO) H + Mel  • .  2  t  o  l  u  e  n  , »  e  CpMo (NO) I  (41)  2  The. r e a c t i o n o f CpMo (NO) H: with. I' t o g i v e the iodo 2  t i v e i n good y i e l d of a metal hydride  5 1  deriva-  lends- f u r t h e r support f o r the presence  l i n k , as numerous c a r b o n y l  hydrides  undergo comparable r e a c t i o n s with, halogens. Although some t r a n s i t i o n - m e t a l c a r b o n y l  hydrides a r e  known t o r e a c t with p-CH-C,H.S0 N(CH_)NO (Diazald) o  j  b  4  I.  to y i e l d  5  n i t r o s y l c o m p l e x e s , r e a c t i o n of CpMo (NO) H with D i a z a l d i n 10  2  toluene  r e s u l t s o n l y i n the slow p r e c i p i t a t i o n o f red-brown,  n i t r o s y l - f r e e decomposition products a t a r a t e comparable t o t h a t observed i n the absence of D i a z a l d , i . e . CpMo CNO) H + D i a z a l d 2  rr'  •  CpMo (NO)  C.4 2)  3  In r e t r o s p e c t , i t can be noted t h a t CpMo(NO) H was 2  p r e v i o u s l y prepared v i a the r e a c t i o n of CpMoCNO) Cl with. 2  NaBH^ i n EtOH s o l u t i o n t h i s formulation The  Preparation  1 1k  , although s u f f i c i e n t evidence f o r  i s o n l y now a v a i l a b l e . and C h a r a c t e r i z a t i o n of [Cp W_ (.NO) ^H] X 2  2  (X =• B F , P F ) . d  6  In c o n t r a s t t o CpMo(NO) H, the tungsten analogue i s 2  i s o l a b l e and has been f u l l y c h a r a c t e r i z e d , i t s chemical p r o p e r t i e s suggesting  an unexpected h y d r i d i c c h a r a c t e r o f  ~ 1.12. -  the W-H l i n k a g e CpW (NO)  ,  5 1  In. a donor s o l v e n t  such, as- a c e t o n i t r i l e . /  reacts- with, the well-known hydride  Pfi-C X~ v i a loss- of H^ +  "iYe...  51  CpW (NO) H + P h C X ~  lCpWtNO): .(eH GNI ]' X  ———-——•  +  2  3  4  +  2  (X = B F , PP ) The  abstractor  3  + Ph CH  6  (.43)  3  comparable r e a c t i o n is- a l s o known t o occur when the  i so s t r u c t u r a l and i s o e l e c t r o n i c complex CpRe (CO) (NO)H ist r e a t e d with P h C X ~ (X = B F , PFg) i n donor s o l v e n t s ( L ) , +  3  4  producing I CpRe (CO) (NO)](Ll] X~ +  2:1 s t o i c h i o m e t r y ,  9:(r  .  In C H C 1 2  s o l u t i o n with  2  however, hydride a b s t r a c t i o n b r i n g s  the formation o f the b i m e t a l l i c c a t i o n which has been c h a r a c t e r i z e d  [Cp Re (CO) CNO) H] , +  2  2  7  9  •  3  (3 8)  [Cp2Re2(CO)2(.NO) H] x"  (X = B F , P F )  +  6  2  S i m i l a r r e a c t i o n of CpW(NO) H with the h y d r i d e 2  P h C B F ~ , P h C P F ~ , or C H +  +  4  3  6  7  + 7  abstractors  B F ~ i n CH^C^ leads t o the 4  f o r m a t i o n o f a s p a r i n g l y s o l u b l e , dark green s o l i d (NO) H] X~ +  4  (X = B F  2  2  [Cp W (NO) H] X ~ + Ph CH +  6  2CpW(NO). H + C I I 7  2  :  3  (X - B F , P F )  2  ?  BF  2  4  3  (44).  4  [Cp W (NO) H] B F 2  The  2  CH C1, • —• 2  2  [Cp W -  o r PFg):  4  2CpW(.NO) H + Ph C X 4  2  9 0  CH C1  3  2  fully ,' i.e.  2CpRe (CO) (NO)H + Ph C X 4  about  2  4  4  + C IIg 7  (45)  products o f these r e a c t i o n s p r e c i p i t a t e from s o l u t i o n as  m i c r o c r y s t a l l i n e , a n a l y t i c a l l y pure s o l i d s i s o l a b l e i n good  1.1.3 -  to excellent; yields-.. lCp W (NO): H] B F 2  2  4  i s a dark; green, s o l i d  4  (mp 95®'C dec);  which can be handled i n a i r f o r short periods- o f time  with-  out the occurrence of noticeable: decomposition, and i t may be s t o r e d under  f o r periods- of a t l e a s t s e v e r a l months.  I t is- i n s o l u b l e i n p a r a f f i n hydrocarbons or i n benzene, and i s o n l y s p a r i n g l y s o l u b l e i n CH C1 .. 2  s o l u b i l i t y only  The c a t i o n has good  2  i n nitromethane and, presumably,  s t r o n g l y s o l v a t i n g but weakly donating s o l v e n t s s l o w decomposition  of the c a t i o n  i ^./2 x  ~^ ^  l  other 1 1 5  . ^  s  However, nvar  ^- ^Y a  observed i n nitromethane s o l u t i o n , although the mode o f decomposition i s u n c l e a r . donor s o l v e n t s  Treatment o f the complex with  such as (CH'O^CO o r CH^CN r e s u l t s i n the  r a p i d d i s s o c i a t i o n o f the b i m e t a l l i c c a t i o n t o g i v e monomeric products, i . e . [Cp W (NO) H] BF " + L  •  +  2  2  4  4  CpW(NO) H + 2  (X = a 2e~ donor) Thus i n CD N0 3  [CpW(NO) L ] B F ~ +  2  4  C46)  s o l u t i o n , H NMR m o n i t o r i n g of the a d d i t i o n 1  2  of the donor s o l v e n t s mentioned above r e s u l t s i n the l o s s o f the peaks a t t r i b u t a b l e t o [Cp W (NO) H]BF 2  —8.33 5 6.15  2  4  4  C$ 6.48  Cs, 10H),  Cs, IH)) and the appearance o f new resonances (at Cs, 5H), and 1.94  (s, IH)) c h a r a c t e r i s t i c of CpW(NO) H. 2  Resonances due t o the donor s o l v e n t added a l s o appear, with, s e v e r a l new peaks a t low f i e l d  along  C6> > 6.15). , presumably  a t t r i b u t a b l e t o [CpW (NO) L ] . +  2  An IR spectrum of an a c e t o n i t r i l e s o l u t i o n of  10^2^2  ^ 6 d i s p l a y s : n i t r o s y l . absorptions- a t positions? F  i n d i s t i n g u i s h a b l e from t h o s e of C p W Q K ^ H : cm ), and [CpW(NO) . (CH-CN) ] PF^. (v 2 3 6 ' NO  m  171.5, 1.631.  1730, 164 9 cm" ) i n the.  -1  same s o l v e n t .  &  1  Thus- both, the: PR and H~ NMR s p e c t r a l evidence 1  i n d i c a t e s t h a t the r e a c t i o n o f the b i m e t a l l i c c a t i o n with, donor solvents- yields- CpW(NQ) H',. with, the IR evidence  indi-  2  c a t i n g t h a t the remaining products are i n a l l l i k e l i h o o d of the type  [CpW(NO) L] X~ +  2  The (X•= B F  4  1  (X.= BF^, P F ) . g  E NMR s p e c t r a o f the compounds [Cp W (NO). H ] X ~ +  2  or PFg) a t ambient temperature  2  4  i n nitromethane  solutions- show a sharp s i n g l e t a t <5* 6.4 8 a t t r i b u t a b l e t o 10 e q u i v a l e n t c y c l o p e n t a d i e n y l protons as- w e l l as a h i g h field  a t 5 -8.33, i , e . i n the  s i n g l e t due t o one hydrogen  r e g i o n t y p i c a l o f metal—bound p r o t o n s  1 1 6  ..  S e v e r a l workers  have suggested t h a t , f o r d e r i v a t i v e s of the same m e t a l , the resonance of a b r i d g i n g hydrogen appears a t h i g h e r f i e l d hydrogen  1 1 6  .  than t h a t of a t e r m i n a l l y bonded  Examination o f some r e p o r t e d s h i f t v a l u e s f o r  hydridotungsten s p e c i e s  1 1 6  , however, r e v e a l s no such c o r r e l a -  t i o n f o r tungsten complexes.  Thus the l a r g e s h i f t of the  hydride resonance t o h i g h f i e l d s i o n of CpW(NO) H (<S _ 2  (5 _ W  ing  H  i n hydridometal c l u s t e r s  (CD^NO,,) :  W  H  (A6 = 10.27 ppm) upon conver-  (CD N0 ). : 3  2  1.94) t o [Cp W (NO) H] 2  2  +  4  —8.33) i s not a r e l i a b l e guide i n d e t e r m i n -  whether the h y d r i d e i s bonded i n a b r i d g i n g or a t e r m i n a l  f a s h i o n i n the l a t t e r  species-.  F u r t h e r evidence is- o b t a i n e d , however, by the a c q u i s i t i o n o f a spectrum with a v e r y l a r g e s i g n a l — t o — n o i s e  ratio  - 1.15 T-  ( i . e . ~1, 000:1  f o r the; main h y d r i d e resonance) in. which, s i x  s a t e l l i t e peaks are r e a d i l y apparent  (see F i g u r e 3 1 . -  A  d e t a i l e d a n a l y s i s of the t h e o r e t i c a l peak p a t t e r n s f o r a W H 2  •  117  s p i n system i s a v a i l a b l e i n the l i t e r a t u r e  , with, c o n s i d -  e r a t i o n g i v e n to a l l p o s s i b l e combinations  S_  w system w i t h 0 <  unresolved NMR  2  J  1  8  3  w  _  <  H  of a t e r m i n a l with  ^ i s s ^ ,  •  2  J  1  8  3  W  _  ( i . e . ~ 0 ) , and w i t h slow or f a s t exchange  (on the  time s c a l e ) of the h y d r i d e between the two metal  a l s o c o n s i d e r e d i s a symmetrically b r i d g i n g ^/ The p o s s i b i l i t y of a l i n e a r later paper  1 1 8  W —H—W :  centres;  system.  l i n k , considered i n a  , would y i e l d a spectrum  from t h a t expected  H  indistinguishable  f o r the b r i d g e d case.  The  observed  7-peak p a t t e r n (Figure 3) i s c o n s i s t e n t o n l y w i t h the model i n which the hydrogen atom i s t e r m i n a l l y bound  (with s p i n -  c o u p l i n g to the remote tungsten being o b s e r v a b l e ) , and  rapid  i n t r a m o l e c u l a r exchange of the hydride l i g a n d between the two metal atoms i s o c c u r r i n g : analyses are i n c o r r e c t  1 1 9  u n f o r t u n a t e l y , the  theoretical  i n t h i s p a r t i c u l a r i n s t a n c e , and  the e x c e l l e n t agreement o b t a i n e d between the p r e d i c t e d peak intensities  (0.51:12.24:0.51:73.48:0.51:12.24:0.51) and  the i n t e g r a t e d peak areas obtained e x p e r i m e n t a l l y 0.5:74.5:0.5:11.8:0.5) i s o n l y  fortuitous.  As mentioned, the analyses of the spectra where  2  1 1 7  '  1 1 8  (0.5:11.4:  theoretical  are i n c o r r e c t f o r the case i n q u e s t i o n , i . e .  J i s r e s o l v e d and r a p i d i n t r a m o l e c u l a r exchange of  the proton between the two those molecules  tungsten n u c l e i o c c u r s .  i n which both metal  c e n t r e s are  1  8  3  For VI Wa  Figure  3.  The  2  H  CD N0 3  NMR 2  -  116  Spectrum  of  The  complete  (b)  The  hydride  (c)  183  WW  2  2  4  4  in  1 8 3  W  n  spectrum, region  (amplitude  satellites,  The h y d r i d e the  [Cp W (NO) H]BF  Solution.  (a)  the  -  and  region 1 5  x  8)  showing  x  128)  and  (amplitude  NN, . - . s a t e l l i t e s .  revealing  i  11  l  111  V..  «  .  i.  6 = 6.48;  a t t r i b u t a b l e to the  ii.  6 = 4.33;  attributable  iii.  6 = -8.33;  attributable  »  (n -C H ) 5  5  t o CHD N0 2  2  5  rings,  present i n the  t o a metal-bound  solvent,  hydrogen.  iii.  The m e t a l - b o u n d h y d r o g e n , <5 = -8.33  a. The  183  WW s a t e l l i t e s ;  e q u a l s 114.2 b. The  1 8 3  W  2  separation  Hz.  satellites;  separation  e q u a l s 228.4 Hz. c. The  1 5  NN  3  satellites;  e q u a l s 63.8  separation  Hz.  a  b  F i g u r e 3b  1  I  .1  L.  I  L  I  I,  1  119 -  i n  Figure  3c  I  i  - 1,2.0 -  doublet, of doublets-, o,f main, separation. & J  and  t i o n J', was- p r e d i c t e d , each: resonance haying 2  t o t a l hydride, i n t e n s i t y .  small 0,51%  separaof the  A p p l y i n g the time—averaging  s p i n — s p i n c o u p l i n g of the proton with the two c o r r e c t l y predicts- i n s t e a d a 1:2:1' t r i p l e t  1 1 9  183  W  of the  nuclei  , with, the  outer peaks- a g a i n each, e x h i b i t i n g 0.51%, of the: t o t a l and a s e p a r a t i o n of However/ due  intensity  ( J' + J ) , as- i n the p r e v i o u s a n a l y s e s . 1  2  to the r a p i d s i t e exchange, peaks of s e p a r a t i o n  i j — J ) are not expected 1  two  2  to be present  exchange, the d i f f e r e n c e between the two  ( i . e . with  site  s i t e s vanishes  and  C - j ' - J ) goes to 0, tftds\ y i e l d i n g a peak of i n t e n s i t y  1.02%  2  c o i n c i d e n t with, the c e n t r a l  peak)..  As the two unassigned be s p i n n i n g side-bands of ing  resonances  were shown not to  by a c q u i r i n g the spectrum a t a v a r i e t y  sample s p i n n i n g speeds, the o n l y source of o r i g i n  remain-  to be c o n s i d e r e d i s s p i n - s p i n c o u p l i n g with some other-  nucleus  i n the molecule.  Coupling with a nucleus of s p i n  1/2  would produce a d o u b l e t , while c o u p l i n g with a nucleus of s p i n 1 would y i e l d  a 1:1:1  t r i p l e t , with the c e n t r e resonance  being c o i n c i d e n t with the main hydride resonance pseudo—doublet). identifies  15  N,  An examination  (1,e.  a  of a l l p o s s i b i l i t i e s  an i s o t o p e with s p i n 1/2  and a n a t u r a l  abundance of 0.37%, as the only p o s s i b l e source of the ved  spin-spin coupling.  exchange of the proton) the  1 5  N  isotopomer  Thus with 4 e q u i v a l e n t nitrosyl  obser-  (due to s i t e  l i g a n d s each. with. 0.37%  of  p r e s e n t , and o n l y those molecules- i n which,  n e i t h e r tungsten nucleus- is- W 183  c o n t r i b u t i n g t o the: in.ten.--0.  121  s i t y of tHe.se. peaks>, t h e i r c^l.cul.a,ted' ' each..  '  a  ^  e  '  0...54%  Thus, c o i n c i d e n t a l l y , the: i n t e n s i t i e s are. expected t o  be almost i d e n t i c a l t o those o f the two outermost  satellite  bands ( i . e . 0.54 v s . 0 . 5 1 % I , as- was- i n f a c t observed..  With  the aim o f o b t a i n i n g f u r t h e r evidence t o support t h i s  inter-  pretation., attempts were made t o observe the N s a t e l l i t e 1 5  bands a s s o c i a t e d with those isotopomers of [ C p W ( N O ) H ] 2  c o n t a i n i n g one intensity  183  W,  +  4  which, are o f even s m a l l e r p r e d i c t e d  (i.e. 0.091%).  I t was indeed p o s s i b l e t o observe  the o u t e r resonances a r i s i n g from the combined 15  2  183  W-H and  N-H s p i n - s p i n c o u p l i n g s a t the expected p o s i t i o n s , although  the peaks a r i s i n g from the d i f f e r e n c e of these c o u p l i n g s c o u l d not be l o c a t e d due t o t h e i r p r o x i m i t y t o the c e n t r a l h y d r i d e resonance and the l i m i t e d s t a b i l i t y o f the complex i n CD N0 . 3  2  U n f o r t u n a t e l y , t h i s r e a n a l y s i s of the t h e o r e t i c a l h y d r i d e s p e c t r a l e a d s t o the c o n c l u s i o n t h a t i t i s not p o s s i b l e , on the b a s i s of the observed i s o t o p e c o u p l i n g s , t o d i s t i n g u i s h between a t e r m i n a l l y bound hydrogen  rapidly  exchanging between the metal c e n t r e s and one which, b r i d g e s those c e n t r e s .  I t i s p o s s i b l e t o e x t r a c t a H1  183  W coupling  constant of 114.2 Hz, but i t is- u n c e r t a i n whether t h i s v a l u e r e f l e c t s a d i r e c t coupling  a  J''  a83  of  w  to a bridging  hydro-  gen, or whether this: v a l u e i n s t e a d r e f l e c t s - an averaging o f the J'i 8 3 T1  T  TT  a  n  d Ji  VV—rl  interpretation.  2  B3T7-  TT  terms which a r i s e i n the a l t e r n a t e  W—n  Similarly, Ji  5 v tT T  is- observed t o be 63.8 Hz,  N—n  but i t too may be an average: o f more than one d i s c r e t e  spin-  122. -  s p i n coupling-..  No  have been r e p o r t e d of  N-M—K  1 2 0  ,  1  1 5  literature  1  the  information  coupling  c a n be o b t a i n e d  4  reveals region  g  2  c h a r a c t e r i s t i c of terminal  portion  obvious  from t h e magnitude o f  solutions  2  the presence of 4 n i t r o s y l  Similarly,  No  a c q u i s i t i o n o f t h e IR s p e c t r a  (X = B F , P F ) i n C H C 1  +  .  1 2 1  complexes  constant.  Careful H] X~  :c©n.s,tan,ts- a p p e a r t o  a l t h o u g h , o n e study- o f the: ~N' s h i f t s  appeared i n the chemical  structural  although  of [Cp W (NO) 2  and a s N u j o l  absorptions, nitrosyl  absorption  region/  2  4  mulls  a l l i n the  groups  i n nitromethane the solvent  of the n i t r o s y l  bands a r e d e t e c t e d  1 2 2  .  obscures a  two n i t r o s y l  1  ....  a t e n e r g i e s comparable t o t h e h i g h e r  e n e r g y bands o b s e r v e d As  -J c o u p l i n g  l i g a n d s - i n a v a r i e t y ©f o r g a n o m e t a l l i c  nitrosyl  has  1  i n CH C1 2  2  solution  C s e e T a b l e VII)..  t h e r e l a t i v e i n t e n s i t i e s o f t h e bands a r e c o m p a r a b l e i n  each i n s t a n c e ,  i t i s reasonable t o conclude that  a l l four  bands a r i s e f r o m a s i n g l e s t r u c t u r a l i s o m e r o f t h e c a t i o n . A  structure  consistent  data,  as w e l l  shown  below.  w i t h b o t h t h e IR and  as i t s c h e m i c a l p r o p e r t i e s  WI  and  E NMR  (vide  spectral  i n f r a ) i s as-  s  fcW.  0N-|  In  1  j ^ N O  N  N:  0  0  t h i s - v i e w an 1 8 e ~ u n i t , CpW(NOl H:, acts- as- a Lewis- base, 2  provides  electron density  a vacant o r b i t a l  from a f i l l e d  o f t h e 1 6 e ~ CpW (.NO)  + 2  metal o r b i t a l to  u n i t , which, acts- a s a  123  T,  Table: VII.,' C h a r a c t e r i s t i c N i t r o s y l Absorptions- qf CpM(NO) ^II. :  CM = Mo,' W) Derivatives'Complex CpMo(NO) H  a  CpMo(NO) H  b  CpW(NO) H ' b  [CpW(NO) (CH CN)]PF °  1730, 164 9  CpMo(NO) Cl '  1759, 16 65  2  3  b  6  23  2  fa  23  2  [Cp W CNO) H] B F  4  [Cp W (NO) H] P F  6  [Cp W CNO) H] P F  g  2  4  4  2  4  2  1775, 1748, 1707, 1660  b  1722 Cbr), 1650, 1632  d  1752 (br) , 1685 (br)  2  4  g  4  [Cp MoW(NO) H]BF 2  4  [Cp W CNO) H] P F  g  [Cp W (NO) H] P F  6  2  2  2  4  2  4  CpW(NO) H  0  0  ( b r ) , 167 5 (br)  1728, 1718 (sh)  e  1730, 1712, 1648, 1631  C  1715, 1631  a  b i n toluene; 3  9  1790 , 1769 ( s h ) , 1756, 1718 , 1660 (br)  4  C  CH N0  1  1790, 1765 (sh), 1751, 1706, 1678, 1650 (sh)  b 4  2  in  W-H:  1795, 1768, 1707, 1695 (sh)  6  [Cp MoWCNO) H] B F 2  1783  d  4  [Cp Mo (NO) H]PF 2  V  d  [Cp Mo CNO) H] P F 2  M  1733, 1650  CpW(NO) Cl ' ''  2  2  1  „ 1805 (w) Mo-H.  V .  1718, 163 2  51  2  2  5  1738, 1647  2  2  " " "tionS ," cm"  1732, 1642.  2  2  other absorp—  .. -1 - -NO'' ^ V  i n CE  Cl ; 2  2  ° i n CH CN; 3  as a Nujol. m u l l ;  (  W  )  - 1,2.4  Lewis- acid..  .ii  An. a l t e r n a t e explanation, i s a structure, i n v o k i n g  a 3-centre—2-r-electron. W H?B6nd; on. the: B a s i s - o f cneni$ca.l. 2  evidence d i s c u s s e d less  l a t e r , t h i s - structure, i s cons-Merre.d to.-be  likely. Unfortunately-,  although  [Cp W (NO) D] P F 2  2  4  g  i s readily  prepared from the known compound CpW(NO) D , comparison, o f 51  2  i t s concentrated X  mull  IR s p e c t r a with those o f [Cp W (NO). ^H] 2  +  2  (X = BF. or PF ) g i v e s no i n d i c a t i o n o f any a b s o r p t i o n s 4 b  a t t r i b u t a b l e t o a metal-hydrogen u n i t . the deuterated  1  H NMR s p e c t r a of  c a t i o n show a decrease i n i n t e n s i t y of the  h i g h — f i e l d resonance t o < 5% o f i t s o r i g i n a l i n t e n s i t y , confirming  the s u c c e s s f u l i n c o r p o r a t i o n of the D i n t h e  desired position. [Cp W (NO) H]PF 2  2  4  g  i s a green s o l i d  (mp 122 C) which Q  e x h i b i t s a i r s t a b i l i t y and s o l u b i l i t y ^ p r o p e r t i e s s i m i l a r t o those o f the B F ~ s a l t .  In CT> N0  4  3  s o l u t i o n i t s *H NMR  2  spectrum i s i n d i s t i n g u i s h a b l e from t h a t of the B F thereby r u l i n g out any c a t i o n - a n i o n Similarly, i t s CH C1 2  nitrosyl for  stretching frequencies  [Cp W (NO) H] B F 2  2  4  The P r e p a r a t i o n  4  analogue,  interaction i n solution.  and N u j o l m u l l  2  4  IR s p e c t r a d i s p l a y  comparable t o those found  (see Table V I I ) .  and C h a r a c t e r i z a t i o n o f [Cp Mo (NO)^H]PF^.  Pale green  2  2  [ C p M o ( N O ) H ] P F , mp 119 C dec, i s G  2  2  4  g  r e a d i l y prepared i n an analogous f a s h i o n by r e a c t i n g Ph^CPFg w i t h C H C l / t o l u e n e s o l u t i o n s o f CpMo (NO) H , i,e.. 2  2  2  2C MO(NO) H + Ph C P F " P  2  3  6  t  o  CH C I / ' l  u  e  n  e  - 125 -  •  [Cp Mo CNO) H]PF 2  2  4  g  + Ph CH  (47)  3  Although the o v e r a l l y i e l d o f the c a t i o n based on CpMo(NO) C1 2  i s o n l y 19%, t h i s i s comparable t o the top y i e l d s o b t a i n e d from the r e a c t i o n s used t o c h a r a c t e r i z e CpMo(NO) H.  It i s  2  l i k e l y t h a t the low y i e l d  i s a t t r i b u t a b l e mainly t o l o s s e s  a s s o c i a t e d with the p r e p a r a t i o n and p u r i f i c a t i o n o f the CpMo(NO) H s o l u t i o n . 2  Indeed, making the l o g i c a l  assumption  t h a t Ph-CPF, r e a c t s i n a 1:2 f a s h i o n with CpMo(NO)„H as was j b £ verified  f o r the tungsten system,  the i s o l a t e d y i e l d o f  [CpMo,.(:NO) . .H]'PF ;;is::fairly,;good ; i.57.%;.based on--~the, a^o^nt, ,0f 2  2  4  6  c  A  Ph CPF, added). 3 6 0  The IR s p e c t r a o f [Cp Mo (NO) H]PF^ a r e comparable 2  to  2  4  those o b t a i n e d f o r the tungsten congener  (see Table V I I ) ,  thereby suggesting t h a t the two b i m e t a l l i c c a t i o n s a r e isostructural.  A E NMR spectrum o f the complex i n CD N0 l  3  a l s o supports t h i s c o n c l u s i o n . observed a t low f i e l d resonance  2  Thus a sharp s i n g l e t i s  ( 6 6.37, 10H) while the remaining  i s l o c a t e d a t high f i e l d  ( 6 -9.78 (s, I H ) ) .  Those  Mo i s o t o p e s which have n u c l e a r s p i n magnetic moments ( i . e . 95  Mo,  97  Mo) a r e quadrupolar n u c l e i  and no metal-hydrogen of  (I = 5/2 i n each i n s t a n c e )  s p i n - s p i n c o u p l i n g i s observed  because  the r a p i d quadrupolar r e l a x a t i o n of the quadrupolar  nucleus. The P r e p a r a t i o n and C h a r a c t e r i z a t i o n o f [Cp MoW(NO) H]BF . 2  4  The mononuclear Mo and W c a t i o n s having been s u c c e s s f u l l y prepared, i t i s c l e a r l y a l s o o f i n t e r e s t t o  4  - 126 -  synthesize, the. h e t e r o n u c l e a r analogue, [Cp MoW (NO) ^Hj  for  2  comparative: purposes-..  Since Both. CpMo OSTOI^H- and CpWXNQX^K  r e a c t immed l a t e l y - with. t h e t r i t y l c a t i o n , i t seemed u n l i k e l y t h a t e i t h e r hydride would r e a c t p r e f e r e n t i a l l y with if  i t were added t o a 1:1 mixture  Ph^C*  o f the two compounds.  + Nevertheless-, H NMR  s p e c t r a o f the compounds [Cp M-^M (CO) ^H]  1  BF ~ 4  CM = M  2  = Mo, W;  2  = Mo, M  2  2  = W) show t h a t the  v a r i o u s B i m e t a l l i c c a t i o n s do not e q u i l i B r a t e i n s o l u t i o n a f a c t which suggests  1 1 7  ,  t h a t an a l t e r n a t e route t o the mixed  n i t r o s y l c a t i o n should Be s u c c e s s f u l . The a B s t r a c t i o n of h a l i d e from the complexes CpFe(CO) X  (X = C l , Br, I) i n the presence  2  of excess  olefin  b r i n g s ahout the formation of o l e f i n c a t i o n s o f the type [CpFe(CO) (olefin)] 2  + 1 2 3  .  S i m i l a r l y , the r e a c t i o n o f  CpW(NO) Cl with AgBF^ i n the presence 2  [CpW(NO) (cyclooctene)]BF 2  104 4  of c y c l o o c t e n e produces  , i n which the o l e f i n i s o n l y  v e r y weakly c o o r d i n a t e d t o the metal c e n t r e .  Displacement  of the o l e f i n by CpMo(NO) H should t h e r e f o r e y i e l d the 2  d e s i r e d h e t e r o n u c l e a r c a t i o n ; r e v e r s i n g the r o l e s o f the Mo and W complexes should produce i d e n t i c a l r e s u l t s , i . e . [CpM (NO) (cyclooctene) ] B F 1  2  4  + CpM CNO) H  [Cp M M (NO). H] B F 2  (M^ - Mo, M  1  2  4  2  4  2  —  + cyclooctene.  »• (148)1  = W or vice: versa).  2  The use of CpW CNO). H as the hydride source i s p r e f e r a b l e 2  because i t a f f o r d s the advantage of c a r r y i n g out the reaction, with well—defined stoichiometry.  S t i r l i n g a CH C1 2  2  s o l u t i o n of CpMo (NO). C1. in, t h e 2  presence of an excess of AgBF^ f o r 4 5" -minut.es> fQ.llp.wed by filtration  and the a d d i t i o n of c y c l o o c t e n e to. the f i l t r a t e ,  y i e l d s a green s o l u t i o n of iCpM©(NO) (cyclooctenel] BF^ 2  e x h i b i t i n g n i t r o s y l absorptions- ("V 18 00, 1717 cm" ), com1  N0  p a r a b l e t o those observed f o r the W analogue 1689 c m ) ; " -1  10  (see Table V I I ) .  (v  N O  17 69,  A f t e r again f i l t e r i n g the  s o l u t i o n , 1 e q u i v a l e n t of CpW(N0) H i s added t o the f i l t r a t e . 2  M o n i t o r i n g of the IR spectrum of the mixture r e v e a l s the presence of a t l e a s t 6 p o o r l y r e s o l v e d n i t r o s y l a b s o r p t i o n s at  t h i s point  ( v  N  Q  1795, 1778, 1757, 1703, 1680, and 1640  cm ) although peaks due t o unreacted CpW(N0) H 1  2  1632  cm "S appear t o be absent.  (.V^Q 1718,  The a d d i t i o n o f hexanes  p r e c i p i t a t e s a green s o l i d which, upon r e c r y s t a l l i z a t i o n from C H C l / h e x a n e s , y i e l d s a n a l y t i c a l l y pure 2  BF ~ 4  2  [Cp MoW(NO)^H] 2  (mp 115°C'dec). M u l l and s o l u t i o n IR s p e c t r a o f t h i s complex e x h i b i t  numerous p o o r l y r e s o l v e d n i t r o s y l s t r e t c h i n g a b s o r p t i o n s (vide supra) , c o n s i s t e n t with the t o t a l o f e i g h t absorptionsexpected f o r the two isomers of the h e t e r o n u c l e a r c a t i o n d e p i c t e d below:  Cp 0N-  H -WN O  / -Mo*  H;  Cp  Cp  ON'  •NO  N O  i /  I N:  o  -Mo  Cp •NO  I N:  o  [Only 4 bands- would be. expected i f the h y d r i d e was- i n a, bridging position^].  S u r p r i s i n g l y , a H NMR 1  spectrum o f  1.2.8 -  [Cp MoW CNO) H] BF 2  4  i n CD N0  4  3  the homonuclear c a t i o n s  r e v e a l s the. presence of both, of  2  (\  6.47, -8.33; \ 6.V37, -9.78) 2 2 i n addition, to the hete'ronuclear c a t i o n ("56.47, 6.37, • •• • MoW w  TTS  -8.921, suggesting solution..  This- can. be confirmed by d i s s o l v i n g a -mixture of  [Cp Mo (NO) H] P F 2  t h a t the: complexes- are i n e q u i l i b r i u m i n  2  4  6  s o l u t i o n whose H 1  and  lCp W (NO) H]PF  NMR  spectrum i s c o n s i s t e n t with, the pre-t  2  2  4  6  in CD N© 3  2  to g i v e a  sence of a l l three c a t i o n i c complexes i n s o l u t i o n Csee Figure  4), l . e .  [Cp W (.NO) H] 2  2  +  4  + [Cp Mo (NO) H] 2  2  +  4  C D  -  3  N 0  2  2 [Cp MoW(.NO) H] 2  The  observation  of o n l y two  (.4 9)  +  4  peaks i n the  cyclopentadienyl  r e g i o n of the spectrum suggests t h a t changing the i d e n t i t y of the remote metal  (from Mo  to W or v i c e versa) does not  b r i n g about a r e s o l v a b l e s h i f t i n the resonance a t t r i b u t a b l e to the c y c l o p e n t a d i e n y l two  protons.  I n t e g r a t i o n shows t h a t  peaks are of the expected r e l a t i v e i n t e n s i t i e s ,  the  lending  f u r t h e r credence to t h i s i n t e r p r e t a t i o n . The  appearance of the hydride  heteronuclear  c a t i o n at a s h i f t p o s i t i o n intermediate  those of the d i t u n g s t e n surprising. two  The  and  observation  s t r u c t u r a l isomers- of  again  resonance of the.  dimolybdenum s p e c i e s of o n l y one  new  to  i s not  resonance when  [Cp MoW (NO) H] PF^ are p o s s i b l e i s 2  4  c o n s i s t e n t e i t h e r with exchange of the H l i g a n d between,  the two  metal centres- at a r a t e t h a t i s r a p i d on the  time s c a l e or with a b r i d g i n g hydride..  That two  NMR  isomers-  -  Figure  4.  The  129  hydride' region  [Cp M (NO) H]PFg 2  2  -  .of t h e  (Mo:W  4  *H NMR  ratio  spectrum  of  1.5:1) m i x t u r e  CD N0 . 3  (A)  2  Peaks a t t r i b u t a b l e (6  (B)  -8.33,  =  Peaks a t t r i b u t a b l e (6  (C)  =  = -8.92,  Peak (6  -  1  ,  2  J=  attributable -9.78)  to  [Cp W (NO) H] 2  114.3 to  +  4  Hz)  [Cp MoW(NO) H] 2  123.6 to  2  4  Hz)  [Cp Mo (NO) H] 2  2  4  +  +  a in  130  -  - 1.31  T-  po,ssessing t e r m i n a l l y - bound hydride?- are. in. fact, pre.s.on.t. i s , as- mentioned p r e v i o u s l y , suggested spectrum  by the: N u j o l m u l l i:R  of the complex, even though, the i n t e r p r e t a t i o n of  i t s - s o l u t i o n spectrum  is- complicated by- the: e q u i l i b r a t i o n  of the b i m e t a l l i c cations-.. A f u r t h e r i n d i c a t i o n t h a t [Cp MoW(N0). H] P F 2  s t r u c t u r e analogous  4  has a  g  to t h a t of the d i t u n g s t e n s p e c i e s i s the  s i m i l a r i t y i n magnitude of the observed  spin-spin coupling  with the  coupling  183  W  nuclei.  Thus the observed  (  1  ,  2  J i 8 3  „  T 7  W— ti  or J \ 1  of 123.6  ,  Hz  i s of comparable magnitude t o the  c o r r e s p o n d i n g v a l u e f o r the d i t u n g s t e n system, i . e .  C^IBSTT  As the Mo-H  and  bond s t r e n g t h s are not l i k e l y to be i d e n t i c a l ,  the  rr +  2  J i 8 3  T  „)/2 or  T  1  J  r  = 114.3  Hz.  v v — v v — t i -  the  W—H  observed 1  J' and  coupling  ,  2  J  would not be a t r u e average  J s p i n - s p i n c o u p l i n g s of E  2  unequal  1  with  1  l i f e t i m e s expected  f o r the two  Attempted Deprotonations of  183  W  of the  due t o the  isomers.  [Cp^M^(NO)^H]  (M = Mo,  +  W).  As mentioned p r e v i o u s l y , [ C p R e (CO) (NO) H ] X  (X =  +  2  BF^,  PFg)  i s r e a d i l y deprotonated  [CpRe (CO) (NO) ] 2 ° ( ?-  39,  cc  9  2  2  with NEt^  the c a t i o n i c  [Cp M M (CO) H ]  W;  1  2  g  +  (M  1  = M  2  = Mo,  M  1  2  1  2  6  +  + B  ——-»  complexes  = Mo,  the corresponding n e u t r a l metal c a r b o n y l s [Cp M M ( C O ) H ]  t o produce  p. 82) . • S i m i l a r l y , a - v a r i e t y of  bases are known to deprotonate 2  2  M  2  = W)  to give  , 1. e.,  12 4  l C p M M CC0)1 ] + IIB 2  1  2  +  &  (50)  The h y d r i d o c a t i o n !Cp Pe. CCOJ^K] ' a l s o reacts- r e a d i l y with. +  2  NEt  3  2  t o y i e l d the r e l a t e d dimer, {CpFe (CO)„ ] • 2  2  I : n  sharp  132  -  c o n t r a s t , r e a c t i o n o f a CH^CT^ suspension o f [Cp W (.NO) H ] 2  2  +  4  with. NE.t r a p i d l y ; r e s u l t s in. t h e formation'. o,f CpW (NQ). H. and, 3  2  presumably, lCpW~(NO)I. (JNEt^ D  Stronger bases such, as  2  (Me N) P0, KOH/EtOH, and Ph P=CH 2  3  3  2  r a p i d c l e a v a g e of the: metal-metal  l i k e w i s e b r i n g about  very  bond t o produce the u b i q u i -  t o u s CpWCNOl H: and the corresponding c a t i o n i c p r o d u c t s , i . e . 2  [Cp W (NO) H] +  2  2  4  (L = a 2e  + L  * CpW(NO) H + [CpW(NO) L] 2  +  2  (.46)  donor)  With the h i g h l y s t e r i c a l l y hindered base N,N,N',N',-tetramethyl-1,8-naphthalenediamine  (sold by A l d r i c h Chemical Co.  under the trade name Proton Sponge) r e a c t i o n 4 6 r e q u i r e s s e v e r a l hours, but once again no d e p r o t o n a t i o n occurs and CpW(.NO) H i s formed.  In nitromethane,  2  where both the tungsten  c a t i o n and Proton Sponge a r e s o l u b l e ,  [Cp W (NO) H] i s +  2  2  4  r a p i d l y c l e a v e d t o g i v e CpW(NO) H as i n d i c a t e d by H NMR 1  2  spectral monitoring.  T h i s may i n v o l v e CD N0 2  2  as the n u c l e o -  p h i l e , however, as nitromethane. i s a r e l a t i v e l y ^acidic s o l v e n t , pKa = 1 0  1 2 5  .  In s e v e r a l o f the r e a c t i o n s mentioned, the formation of a c a t i o n i c product of the g e n e r a l formula  [CpW(NO) L]  +  2  i s i n f e r r e d on the b a s i s of the IR s p e c t r a of the r e a c t i o n mixtures and the s u c c e s s f u l i s o l a t i o n o f CpW(NO) H as a 2  r e a c t i o n product.  No attempts were made t o i s o l a t e  these  c a t i o n s as they a r e known t o be q u i t e r e a c t i v e , and p r e v i o u s attempts  t o i s o l a t e s o l i d PF^  [CpW(NO) (CH CN) J  +  2  3  s a l t s of the cations-  and [CpW(NO) ( ( C H ) C O } ] 2  3  2  +  by other workers  ^ 133 -  were u n s u c c e s s f u l  1 0 1  ,  The a d d i t i o n of a, THF to a s o l i d  solution, of sodium*-naphthal.ene  sample of [ C p W ( N O ) H ] P F 2  2  4  g  a f f o r d s a s m a l l amount  of CpW'CN0l H: along with- a n i t r o s y l — f r e e red—brown  solid.  2  Reaction, of [Cp W (NO) H] 2  2  4  w i t h NaBH  4  i n nitromethane  results  i n the r e d u c t i o n of the c a t i o n to again produce CpW(NO) H, 2  i.e. [Cp W (NO) H] P F 2  2  4  6  + NaBH  CH-NO„ i-*  4  2CpW(N0) H  Treatment of the c a t i o n with, the Lewis base Cp MoH 2  e d l y r e s u l t s i n the decomposition  (51)  2  unexpect-  2  of both s p e c i e s to produce  a red-brown, n i t r o s y l - f r e e s o l i d which i s i n s o l u b l e i n common organic solvents. The  i n t e r a c t i o n of a C H C 1 2  suspension of  2  (NO) H]PFg with a column of F l o r i s i l 4  [Cp Mo 2  ( i . e . magneslum  2  fluoro-  s i l i c a t e ) r e s u l t s i n the formation of monomeric products analogous to those formed by the tungsten system. e l u t i o n of the column with C H C 1 2  g i v e s a green C H C 1  2  2  cm  "*") and metal-hydride  frequencies.  (-V  M  2  solu-  N Q  1732,  2  t i o n of CpMo(NO) H, as i d e n t i f i e d by i t s n i t r o s y l 1642  Thus  H  1805  cm ) 1  IR  CV  stretching  T h i s method of p r e p a r a t i o n of CpMo(NO) H a l l o w s 2  the d e t e c t i o n of the weak Mo—H absorbance whereas the p r e v i o u s l y d e s c r i b e d route i n v o l v e s the use of toluene as s o l v e n t , which obscures under reduced  this;peak.  Removal of the C H C 1  pressure a t low temperature  2  C< 0 C) G  2  results in  some decomposition, of the h y d r i d e , but does- allow- a switch, to C C D ^ 12CO as s o l v e n t , t h e r e b y p e r m i t t i n g the a c q u i s i t i o n , f o r  - 13 4 -  t h e f i r s t , time of a  NMR;  spectrum  o,f t h e complex.„  A  sharp  s i n g l e t a t t r i b u t a b l e , t o t h e c y c l o p e n t a d i e n y l protons- is- found at  6' 6.A3  C5H)  w h i l e t h e hydride resonance  is- found at <$' 3.8 0  C1H)1; a s f o r CpWCNOl^H; , t h e h y d r i d e resonance 51  occurs- a t  u n u s u a l l y low- f i e l d , . The a d d i t i o n of acetone  t o a CD^NC^ s o l u t i o n of  [Cp Mo CNO) H]PFg w i t h concomitant 2  2  4  spectrum  m o n i t o r i n g of the E  NMR  1  of the mixture r e v e a l s no i n t e r a c t i o n between the  v a r i o u s a c i d and base s p e c i e s , i n c o n t r a s t with the complex.  tungsten  However, with the bases NEtej and Proton Sponge  r a p i d cleavage of the b i m e t a l l i c c a t i o n t o produce CpMo(NO) H 2  and, presumably, [CpMo (NO) L ] , : ' i s o b s e r v a b l e . +  2  Summary of the P r o p e r t i e s of [Cp^-^M,, (NO) ^H] Mo,  W;  M  -  ±  Mo,  M  2  =  +  (M^ = M  2  =  W).  To summarize, the s o l u t i o n p r o p e r t i e s of the [Cp M (NO)^H] 2  2  +  c a t i o n s are as f o l l o w s .  E  1  NMR  i s c o n s i s t e n t with these compounds being Lewis  spectroscopy acid—Lewis  base adducts, with the metal p o s s e s s i n g the t e r m i n a l h y d r i d e l i g a n d f u n c t i o n i n g as a formal Lewis base and p r o v i d i n g e l e c t r o n d e n s i t y from a m e t a l - c e n t r e d o r b i t a l t o a vacant o r b i t a l , a l s o m e t a l - c e n t r e d , of the f o r m a l l y 16e~ CpM(NO)_ p o r t i o n of the molecule. time s c a l e  At a r a t e t h a t i s r a p i d on the  + 2  NMR  ( i . e . k g r e a t e r than about 4 00 sec "*") a t ambient  temperature,  the h y d r i d e l i g a n d i s exchanged between the  two  metal c e n t r e s , thereby r e v e r s i n g t h e i r acid—base, r o l e s i n the complex. time s c a l e  Simultaneously, a t a r a t e t h a t i s slow on the. NMR ( i . e . k l e s s than about 300  sec ^). but  sufficiently  1,3 5  T.  T.  r a p i d that, e q u i l i b r i u m between, the. dimolybdenum and didlingsten, c a t i o n s is- e s t a b l i s h e d within, the time: r e q u i r e d to d i s s o l v e the compounds and o b t a i n a spectrum  (>5 min),  the; acid-base  p a i r s are e q u i l i b r a t i n g with, each o t h e r , probably v i a a I An a s s o c i a t i v e mode of exchange seems  d i s s o c i a t i v e pathway-,  u n l i k e l y f o r s t e r i c reasons,]  The  c o n c e n t r a t i o n of the  proposed monomeric s p e c i e s shown i n equation low,  52 must be  however, as- the s p e c i e s CpM(NO) H and/or CpM(NO) 2  are not d e t e c t a b l e i n the s o l u t i o n H  NMR  1  very  + 2  s p e c t r a of the  complexes: [Cp W (NO) H] 2  2  -  +  4  [Cp„Mo (NO) „H] Z Z 4 [Cp MoW (NO) H]  «  +  0  2  -  2  ^  +  2  CpMo (NO) „H + CpMo (NO) Z  5  *  4  [Cp MoW(NO) H] 2  CpW(.NO) H + CpW(.NO)  CpMo(NO) H + CpW (NO) 2  ^  4  CpW (NO) H 2  * Z  + CpMo (NO)  (  5  of i n t e r a c t i o n can be observed.  Nevertheless-,  v a r i e t y of C, N, and 0 bases do not deprotonate allic  )  2  Even upon a d d i t i o n of weak donors such as o l e f i n s or THF evidence  2  2  no a  the bimet-  s p e c i e s ; i n every i n s t a n c e monomeric products  result.  T h i s system i s thus i n marked c o n t r a s t t o the. c a t i o n s [Cp Fe (CO) H] , +  2  2  (M^ = M  4  2  = Mo,  W;  [ C p R e ( C O ) ( N O ) H ] , and +  2  M^  2  = Mo,  2  M  2  2  = W)  [Cp^^  (CO). H]  +  6  i n which, the proton a l s o  i n t e r a c t s d i r e c t l y with the b i m e t a l l i c c o r e , but the combined s t r e n g t h of the metal-metal l i n k and the a c i d i t y of the metal hydride are s u f f i c i e n t to a l l o w d e p r o t o n a t i o n  to the  respec-  t i v e dimers by a v a r i e t y of bases. Although  a p p a r e n t l y no attempt has- been made to  - 136.  deprotonate. {Cp Ru (COl^Hj 2  T-,  , i t . can. also, be. prepared by-  2  pro ton.ation, of the: neutral; *dimer? - » 2  ^HrNM^R, s t u d i e s of  e  the p r o t o n a t i o n of t h e n e u t r a l dimer s- [Cp M (CO) ^] 2  (M = Fe,  2  Ru) y i e l d e q u i l i b r i u m constants- K" f o r the p r o t o n a t i o n 2  reaction,, equation  53, of 10 ^" ^ L mol -  [Cp M CCO); ] + H S 0 2  2  4  2  ,  4  f o r M = Fe and a  1  [Cp M CCO) H] [ H S 0 ] "  (53)  +  2  2  4  4  { [Cp M (CO) H] [HS0 ] "} M co). ]}{H S0 } +  2  (M = Fe, Ru)  K  .  2  lower l i m i t of  4  2 (  { [ C p 2  2  2  4  4  2  4  -1 '  ~10  L mol  f o r the Ru compound.  Poten-  t i o m e t r i c s t u d i e s , c a r r i e d out o n l y f o r M = Fe, y i e l d a pK^ of 7.5 ± 0.3 f o r [ C p F e (CO) ] . 2  2  4  I t i s thus apparent t h a t  the Ru complex i s s i g n i f i c a n t l y more b a s i c than the i r o n system.  In l i g h t of t h i s o b s e r v a t i o n , i t becomes of i n t e r e s t  to see whether t h i s t r e n d c a r r i e s over t o the n i t r o s y l analogues. Attempted S y n t h e s i s of [ C p C r ( N O ) H ] . +  2  2  4  In hope of p r e p a r i n g the corresponding cation,  chromium  [ C p C r ( N O ) H ] , dichloromethane s o l u t i o n s of +  2  [CpCr(NO) ] 2  2  2  4  can be t r e a t e d with aqueous s o l u t i o n s of e i t h e r  HPFg or H B F « O M e . 4  S t i r r i n g b r i n g s about a r a p i d c o l o u r  2  change i n the C H C 1 2  2  l a y e r from i t s i n i t i a l dark p u r p l e t o  a golden y e l l o w c o l o u r .  Solvent removal f o l l o w e d by c r y s t a l -  l i z a t i o n attempts u n f o r t u n a t e l y f a i l t o y i e l d a c r y s t a l l i n e s o l i d f o r e i t h e r product. a d d i t i o n of NaBPh  4  Metathesis  of the c o u n t e r i o n v i a  t o aqueous s o l u t i o n s of e i t h e r compound  a f f o r d s a f l o c c u l e n t y e l l o w s o l i d which, upon c r y s t a l l i z a t i o n ,  - 1.37  -  yields.- C, K, and N analyses-which., the  *H NMR  and  a b l e chemical The  PR  s p e c t r a l data,  when, examined along  fail  to suggest, any  2  novel complex is- a green s o l i d  and  2  i n donor solvents- such as  An. IR spectrum of i t s C H C 1 2  t i o n s at 1828 s y l groups  122  and  1721  ., A H 1  NMR  cm  1  ,  hydrogen  (s, 5H)  Q  has- good (CH^). C0  solubility and  2  THF.  a t t r i b u t a b l e to t e r m i n a l 3  and  5.68  (>, 5H) ) and  ions- are present  CS 6.8+1..6  The  the sample produces no change i n i t s H 1  singlets-  S i m i l a r l y , IR s p e c t r a l m o n i t o r i n g s o l u t i o n s : of the complex with. NEt^  in solution. (m,  NMR  spectrum, t h e r e protons. CH Cl 2  2  with Ph'P=CH.' r e v e a l s 3  i n t e r a c t i o n between the chromium complex and  2  these  Thus f a r attempts to o b t a i n a pure sample of compound with a counter i o n other than BPh^  bases. this  have, been unsuc-  c e s s f u l , as have attempts- to grow s i n g l e c r y s t a l s - of No molecular  4 0.H'H 2  of the treatment of and  reson-  a d d i t i o n of D<D t o  by i n d i c a t i n g the absence of s t r o n g l y a c i d i c  salt.  C0  a metal-bound  isomers- p r e s e n t  p e r p a i r of c y c l o p e n t a d i e n y l r i n g s .  BPh^  2  inequiValent cyclopentadienyl  s i d e of each, of the c y c l o p e n t a d i e n y l  tetraphenylborate  nitro-  spectrum of the complex i n (CD )  ances- suggests t h a t t h e r e are two  no  119-20 C)  CS —5,3 5 Cs-, I f f ! I; the presence of small  on the low- f i e l d  Two  (mp  s o l u t i o n e x h i b i t s strong absorp-  2  indicates- the presence of two rings: (.6 6. 06  reason-  formulation.  which, i & s l i g h t l y s o l u b l e i n benzene and in CH C1  with,  the  s t r u c t u r e c o n s i s t e n t with, the:  p r e s e n t l y a v a i l a b l e i n f o r m a t i o n i s r e a d i l y - apparent.  In  l i g h t , of t h e r e s i s t a n c e of the complex to d e p r o t o n a t i o n ,  the  T*  a  138 -  1  H: NMR d a t a , and the elemental;. r a t i o s - found, . i t does seem  c e r t a i n t h a t [ C p C r CNOL H3 2  of  2  is- n o t formed b y protonation,  4  [CpCr (NO) 2^2" When [CpCr CNO)! J 2 i s protonated 2  with, the c o o r d i n a t i n g  a c i d p-CH^CgH^SO-jH, t h e dimer i s r a p i d l y c l e a v e d t o y i e l d CpCr (NO) C0 SC H ~pCH ) , the W analogue o f which, has been 2  3  6  4  3  p r e v i o u s l y reported : . 5  1  I f l e s s than two e q u i v a l e n t s o f a c i d  are added, o n l y the unreacted are observed  dimer and the f i n a l  product  i n the IR s p e c t r a o f the s o l u t i o n ; no i n t e r m e d i CpCr(NO) C0 SCgH -pCH ) can be i s o l a t e d  ates are d e t e c t e d .  2  3  4  3  by p r e c i p i t a t i o n with hexanes t o y i e l d an a i r - s t a b l e green solid  (mp 64-6°C) whose s o l u t i o n IR spectrum  Cv  N 0  (Cr^C^) •  182 9, 1722 cm "*") i s c o n s i s t e n t with the presence of two t e r m i n a l n i t r o s y l groups.  I t s H NMR spectrum i s completely 1  c o n s i s t e n t with, the presence of a pentahapto c y c l o p e n t a dienyl ring  (_$ CCDC1 ): 3  5.7 5 Cs, 5H) ) and a p - t o l u e n e s u l -  fonate l i g a n d QS 7.7 2 Cd, 2.H) , 7.21 Cd, 2H) , and 2.3 6 Cs, 3H)) I t s l o w - r e s o l u t i o n mass spectrum  (.see Table VIII)  confirms  the monomeric nature o f t h i s complex. The  I n t e r a c t i o n o f CpWCNO^H With. Lewis A c i d s . One  p o t e n t i a l way t o g a i n an i n s i g h t i n t o the b a s i s  of the d i f f e r e n c e s i n s t a b i l i t y found upon comparing the Mo and W n i t r o s y l hydride c a t i o n s t o the Mo, W, Re., Fe, and Ru hydrido c a t i o n s d i s c u s s e d p r e v i o u s l y i s t o i n v e s t i g a t e , the Lewis base p r o p e r t i e s o f CpWCNOj^H and the Lewis- a c i d  prop-  e r t i e s - o f CpW (NO) 2 1 and then make comparisons with, t h e i r +  carbonyl  counterparts..  -  Table  Low-Resolution  VIII.  C p C r (NO)  CO, S C H - p C H ) 6  0  m/ z  4  139  -  Mass S p e c t r a l  a  Assignment  abund.  318  8  288  100  224  16  206  7  ( C H _ ) C r (NO) b o 5  5  of  174  and  y  7  5  7  involve  the most  i n each  observed  +  7  +  y  +  5  +  5  (C H )Cr  isotopes  190,  5  (C H )CrO 5  Also  3  (C H )Cr (C H )  18  assignments  5  (C H )Cr(OC H )  5  117  o  (C H )Cr(0 SC H )  18  133  (0 SC_H_) 3 11  c  5  occurring  for  3  Rel  The  Data  +  5  abundant  naturally  fragment.  are m e t a s t a b l e peaks  corresponding to  the  M*  a t m/z  following  values  fragmentation  processes: (C H,-)Cr ( 0 S C H ) 5  3  7  (,C H )Cr ( 0 C H ) 5  5  ?  7  •  +  7  +  »  (  C  5 5 H  ) C  r  (°  C  H 7  7 )  (C H )Cr (C H ) 5  5  7  5  +  +  +  +  {  s  0  2^  {H 0} 2  140 -  In, examining  the, inte'ract.ion. of Lewis- a c i d s with.  CpWCN'Ol^HT, i t is- Important  t o keep in.-mind t h e p o s s i b i l i t y  of c o o r d i n a t i o n occurring' a t any of a v a r i e t y of sites-.. Thus Lewis- acids- a r e known t o i n t e r a c t with t r a n s i t i o n  metal  complexes- t o form adducts- v i a both, the metal c e n t r e and the ligands..  The mode of r e a c t i o n i s dependent upon the r e l a r  1  tive. b a s i c i t i e s of t h e metal atom and the ligands-, as w e l l as the nature of the acceptor and the s o l v e n t .  The same  t r a n s i t i o n metal complex can i n t e r a c t i n d i f f e r e n t ways w i t h d i f f e r e n t Lewis a c i d s ; c o m p e t i t i o n between s i t e s  resulting  rn the simultaneous formation o f adducts o f d i f f e r e n t  types  i s also possible. At p r e s e n t , e x t e n s i v e q u a l i t a t i v e data concerning the b a s i c i t y o f t r a n s i t i o n metal complexes a r e a v a i l a b l e  1 2 7  ,  but t h e r e a r e v i r t u a l l y no q u a n t i t a t i v e data based on the study of the k i n e t i c s and thermodynamics of t h e i r with e l e c t r o p h i l e s .  interaction  The s t r u c t u r e of acid-base adducts i s  u s u a l l y a r r i v e d a t s o l e l y on the b a s i s of s p e c t r o s c o p i c data, with the e q u i l i b r i u m p o s i t i o n being i n f e r r e d from  such d a t a .  qualitatively  The r e l a t i v e b a s i c i t i e s of complexes- can be  e s t a b l i s h e d i n accordance  with the occurrence o r non-occur—  rence of an i n t e r a c t i o n w i t h a standard Lewis a c i d under identical conditions. Complexes c o n t a i n i n g the. CO l i g a n d have been, most w i d e l y i n v e s t i g a t e d because, the. CO s t r e t c h i n g f r e q u e n c i e s are extremely s e n s i t i v e t o changes i n the electron, d e n s i t y at the m e t a l .  The i n t e r a c t i o n of an acceptor molecule  with.  - 141  T>  the c e n t r a l -metal atom, leacls- t© an. i n c r e a s e ing frequencies- of the CO groups..  0  f the. s t r e t c h y  This- is- a s s o c i a t e d  with,  the decrease of the e l e c t r o n dens-ity at the metal atom which brings- about a weakening of the d^. (M) -•p,^ (CO) and  an i n c r e a s e of the CO  a frequency- s h i f t  bond order  backbonding  i n the complex.  ( g e n e r a l l y 100->150 cm  Such,  "*") i s b e l i e v e d to  be. a c h a r a c t e r i s t i c f e a t u r e of the involvement of the metal atom i n c o o r d i n a t i o n to the Lewis a c i d c o o r d i n a t i o n of an acceptor i n the IR  1 2 7  .  Other types of  l e a d to q u i t e d i f f e r e n t changes  spectra.  In adducts i n v o l v i n g c o o r d i n a t i o n at a l i g a n d other than CO,  the e l e c t r o n d e n s i t y on the metal c e n t r e  reduced, but to a s m a l l e r extent;  i s again  consequently the observed  hypsochromic s h i f t i s g e n e r a l l y s m a l l e r . t i o n of the Lewis a c i d to a hydride  However,  coordina-  l i g a n d i s u n l i k e l y as i t  possesses no lone p a i r of e l e c t r o n s ; few metal—H-metal l i n k s i n the absence of metal-metal bonding are A d d i t i o n to a c y c l o p e n t a d i e n y l electrophile is H  +  known  1 1 6  '  1 2 8  .  r i n g , while common when the  or a carbonium i o n , i s uncommon f o r other  electrophiles. Another type of i n t e r a c t i o n of Lewis a c i d s t r a n s i t i o n metal complexes i n v o l v e s the formation v i a a non—bonding p a i r of e l e c t r o n s on one atoms-, eg., the 0 atom of the NO  with of adducts  of the l i g a n d  groups i n CpW (NO) H. 2  Inter-  a c t i o n of the e l e c t r o p h i l e with, the; n i t r o s y l l i g a n d isc h a r a c t e r i s t i c of the hardest boron and  Lewis a c i d s , t y p i f i e d by  aluminum d e r i v a t i v e s  1 2 7  , as w e l l as  lanthanide  7  -  complexes .„  142.  I n t e r a c t i o n , wifchv/te^^ina/l CQ  1 5  N'  f  2 f  or NQ  ligands,  leads to a s i g n i f i c a n t decrease: of'tRe s t r e t c h i n g -vibration. frequency- of the c o o r d i n a t e d group and s t r e t c h i n g v i b r a t i o n frequenciesto the and  v  electrophile.  N Q  = 1660  while v„„ CO  cm"  = 2010  For  129  .  may  and  1  v  NO  AT  v„ ^ - 1450 NO T  2  cm  2 011  not  and  1712  cm  •= 1786  and  1688  cm"  1  1  r e s u l t i n an For  to  (i.e. their vibra-  increase  nitro-  i n the  other  example, f o r CpCr(NO) C1 2  -1  3  1 1 5  .  2  v i a the metal c e n t r e , ( p o s s i b l y  i n t e r a c t i o n w i t h the  cm  for  As CpW(NO) H i n t e r a c t s with the Lewis a c i d s W)  attached  w h i l e f o r CpCr (NO) ( C D CNO+ErCp )  - 1818  (M = Mo,  the  solution,  thus adduct formation v i a one  related v i b r a t i o n frequencies. N Q  2  always independent  t i o n s are coupled). , and  v  = 192 9 and  CQ  of  However, a b s o r p t i o n s a t t r i b u t a b l e  a g i v e n l i g a n d are not  etc.)  example \>  2055 cm  3  (or CO,  of those ligands- not  2  CpW ( C O ) C N 0 ^ A 1 C 1 )  syl  increase  f o r CpW(CO) (NO) i n C H C 1  1  and  2  to an  CpM(NO)  + 2  with concomitant  h y d r i d e l i g a n d to y i e l d a bridged p r o d -  uct) , i t i s l o g i c a l to f i r s t examine i t s i n t e r a c t i o n w i t h s o f t Lewis a c i d s , which are the metal Ca)  The  and  With  a l s o expected to c o o r d i n a t e at  centre , 1 2  Interaction  of CpW (NO) H 2  With. M (CO)  CM = Cf,  W)  (MeCp)Mn (CO) . 2  Cr (CO)  6  , W(CO)  6  , and  c a r b o n y l l i g a n d upon UV s o l u t i o n to y i e l d Cr CCO) (CO) (THF) r e s p e c t i v e l y  (MeCp)Mn (CO)  3  each, l o s e  one  i r r a d i a t i o n i n tetrahydrofuran. 5  1 3  2  i s l a b i l e , thus p r o v i d i n g  (THF)., WCCO) (THF) , and 5  0  .  (MeCp)Mn-  In each compound, the THF  ligand  a convenient source of a s o f t Lewis  143  T.  T.  a c i d ; e x t e n s i v e use; h a ^ Been made o f these and e l e c t r o p h i l e s t o demonstrate  similar  t h e presence o f base s i t e s i n  a v a r i e t y o f t r a n s i t i o n metal c o m p l e x e s  1 2 7  .  Due t o the  l a b i l i t y of the. THF l i g a n d , however, these s p e c i e s cannot be i s o l a t e d but i n s t e a d a r e generated and used i n s o l u t i o n s . As the CO r e l e a s e d from one molecule may recombine  to give  t h e s t a r t i n g m a t e r i a l , t h e THF adducts are t y p i c a l l y  gener-  ated by i r r a d i a t i o n with, a f l o w of an i n e r t gas being passed through the s o l u t i o n t o h e l p purge i t o f f r e e CO.  Even so,  complete c o n v e r s i o n i s not g e n e r a l l y achieved; t h i s l e a d s t o u n c e r t a i n t y as t o the a c t u a l c o n c e n t r a t i o n of the e l e c t r o p h i l e i n the s o l u t i o n . The presence of unreacted s t a r t i n g m a t e r i a l a l s o i n t e r f e r e s w i t h the IR s p e c t r a l m o n i t o r i n g of t h e c a r b o n y l region.  Thus i n the r e a c t i o n s with CpW(NO) H, the n i t r o s y l 2  IR a b s o r p t i o n s p r o v i d e the most a c c e s s i b l e evidence o f what i n t e r a c t i o n s are o c c u r r i n g i n s o l u t i o n .  As i s r e a d i l y  apparent from the data d i s p l a y e d i n Table IX, comparable s h i f t s of the n i t r o s y l a b s o r p t i o n s a r i s e from the i n t e r a c t i o n of CpW(.NO) H w i t h each of C r ( C O ) , WCCO) , and 2  (MeCp)Mn CCO) .  5  g  That t h e new n i t r o s y l bands a r e a t h i g h e r  2  e n e r g i e s than those o f f r e e CpW(NO) H immediately r u l e s 2  out i n t e r a c t i o n v i a the n i t r o s y l oxygen. The a d d i t i o n of CpW(NO) H: t o a -78°C s o l u t i o n , o f 2  orange C r ( C O ) ( T H F ) / C r ( C O ) 5  g  produces an orange  d i s p l a y i n g four PR a b s o r p t i o n s i n the n i t r o s y l a t t r i b u t a b l e t o f r e e CpW(NO) H 0  Cv  solution region,  1718, 1629 cm"" ): as w e l l 1  -  Table  IX.  Characteristic  144 -  Nitrosyl  Absorptions  o f CpW(NO)  Adducts. a mixture'  Reaction  v  CpW(NO) H 2  CpW(NO)„H 2  + Cr (CO) (THF)  CpW(NO) H  +  W(CO) (THF)  CpW(NO) H  +  ( M e C p ) M n (CO) ( T H F )  c  2  2  2  ,  cm  -1  1718,  1632  1736,  1718, 1661, 1629  1738,  1717, 1663, 1631  D  2  [Cp W  N Q  5  (NO) H]PF 4  [CpW(NO) ]BF 2  CpW(NO) H  +  2  CpW(NO) Gl ' b  1725  ( s h ) , 1 7 1 8 , 1 6 6 1 , 1634  2  b 4  '  1 0 4  HBF -OMe 4  2  1715,  1632  1762,  1675  1733,  1648  1733,  1650  1783,  1692  1800,  1717  1769,  1689  6  2  3  2  [CpMo(NO) ]BF 2  b 4  [CpMo(NO) (cyclooctene)]BF 2  [CpW(NO) ( c y c l o o c t e n e ) ] B F 9  2  in  THF s o l u t i o n  in  CH C1 2  2  unless  solution  b 4  ' 4  b  10  "*  otherwise  specified  ^ 14 5  T-,  a s t o the adduct Cp (NO) - (H.) W*Cr (CO); _ fV. ~ 173 6 , T  4-  5  2.  .  NO  1,661 cm  ) ,.  •  —  No change i n the IF, spectrum is- d e t e c t a b l e upon a l l o w i n g the. s o l u t i o n t o warm t o room temperature.. reduced  Solvent removal under  pressure does- b r i n g about f u r t h e r r e a c t i o n , however,  w i t h much, o f the r e s i d u e obtained being no longer s o l u b l e i n THF.  F r a c t i o n a l s u b l i m a t i o n of the r e a c t i o n r e s i d u e a t  reduced  pressure y i e l d s f i r s t Cr (CO)^  ( e i t h e r formed by  r e a c t i o n of Cr CCO)!,. with. CO f r e e d d u r i n g s o l v e n t removal, or present throughout the r e a c t i o n sequence) and then, a t s l i g h t l y higher temperatures,  CpW(CO) (NO). 2  The absence of  a, c a r b o n y l a b s o r p t i o n i n the r e g i o n 2005-2050 c m i n i t i a l r e a c t i o n mixture  2  i n the  r u l e s out the p o s s i b i l i t y t h a t the  n i t r o s y l a b s o r p t i o n d e t e c t e d a t 1661 cm butable t o CpW (CO) (NO)  - 1  Cv  1  was i n f a c t  2011, 1929 cm" ; v 1  c o  attri-  1660 c m ) . - 1  N  Q  Thus the f o l l o w i n g sequence of r e a t i o n s a p p a r e n t l y  occurs  i n the r e a c t i o n mixture:  The  r e a c t i o n may a l s o be c a r r i e d out i n (CD )_„CO a t  -8 0 C; m o n i t o r i n g  of the H NMR 1  spectrum r e v e a l s o n l y one  c y c l o p e n t a d i e n y l resonance, s h i f t e d t o lower f i e l d ,  upon  a d d i t i o n o f l e s s than one e q u i v a l e n t of C r ( C O ) ( T H F ) as a THF  s l u r r y , . The. o b s e r v a t i o n of o n l y one resonance, a t t r i b u -  t a b l e t o c y c l o p e n t a d i e n y l protons  r e q u i r e s t h a t the. free, and  complexed: CpW (NO) 2H species- are e q u i l i b r a t i n g a t a r a t e t h a t i s f a s t on the NMR time s c a l e , even a t —80. C, i.e.. G  -  14 6  CpW(NO) H. + Cr (CO) (S) 2  —  Cp (NO). (H) W**Cr CCQ)  5  2  (S == CCD l CO 3  5  + S  or THF);  2  (55)  A l s o c o n s i s t e n t with, this- conclusion, is- t h e o b s e r v a t i o n t h a t the size, of the s h i f t is- dependent upon the amount of Cr CCOXg. CTHF-)! s o l u t i o n added, although, no s h i f t i s observed when THF i s added.. cannot be observed  U n f o r t u n a t e l y , the hydride resonance i n the presence  of the excess THF.  This  i n i t s e l f argues a g a i n s t the Cr (CO)^ being c o o r d i n a t e d t o the h y d r i d e , however, s i n c e the few examples of metal-H-metal l i n k s known a l l e x h i b i t hydride resonances field  (eg. (CO )„ ^ Re—H-W (CO)  Re(CO) H  1 2 8 a  c  The  , 6  R  -14.4  v s . 6 -5.7 f o r  1 1 6  ). a d d i t i o n o f CpW(NO) H t o a -78 C s o l u t i o n con-, Q  2  t a i n i n g W(CO)  (THF) b r i n g s about changes i n the n i t r o s y l  r e g i o n of the IR spectrum which a r e almost observed  s h i f t e d to high  with. Cr (CO) (THF) 5  (see Table I X ) .  i d e n t i c a l t o those Thus two n i t r o s y l  a b s o r p t i o n s are found a t p o s i t i o n s a t t r i b u t a b l e t o f r e e CpW(NO) H 2  ( V Q 1717, 1631 cm "*") along w i t h two a d d i t i o n a l N  bands a t higher energy CV^Q 1738, 1663 cm "*") a s s i g n a b l e t o Cp (NO) (H) W+W (CO) . 2  5  As a d d i t i o n a l CpW(NO)_ H i s added a l l 2  four bands i n c r e a s e i n i n t e n s i t y but t h e i r r e l a t i v e  inten-  s i t i e s remain c o n s t a n t , again i n d i c a t i n g t h a t t h e f r e e and complexed CpW (NO). H e n t i t i e s a r e i n e q u i l i b r i u m . 2  the mixture  Warming  t o room temperature and concentration, of t h e  s o l u t i o n i n vacuo b r i n g about a s h i f t i n the e q u i l i b r i u m i n favour of the complexed h y d r i d e , but complete s o l v e n t removal b r i n g s about decomposition, t o produce an. i n f r a c t —  -  a b l e brawn, s o l i d .  1.47;. -  Simply warming t h e o r i g i n a l , s o l u t i o n t o  room temperature: under a n i t r o g e n ^atmosphere - a.lsp: i n i t i a t e s p r e c i p i t a t i o n of the brown..decomposition much, slower r a t e  ( x  r  v  2  product, but a t a  days)!.  The a d d i t i o n of a r e d THF s o l u t i o n of (MeCp)Mn (CO) ~ 2  (THF) t o a green, -7 8°C s o l u t i o n of CpW(NO) H i n THF p r o 2  duces no apparent i n t e r a c t i o n of the t r a n s i t i o n metal complexes as judged by the absence of new n i t r o s y l a b s o r p t i o n s i n the IR spectrum of the r e a c t i o n mixture.  Upon warming  to room temperature, the red-green s o l u t i o n t u r n s brown over a p e r i o d of approximately 0.5 h and some p r e c i p i t a t e forms  C (MeCp)Mn (CO). CTHF) i t s e l f 2  temperature  1 3 0  ).  s l o w l y decompses a t room  At t h i s p o i n t the supernatant s o l u t i o n  e x h i b i t s four n i t r o s y l IR a b s o r p t i o n s , a t 1718 and 1635 cm Ci.e. CpWCNO) H) and a t 1725 2  to Cp CNO) (.HlW^-Mn (CO) (MeCp) . 2  2  (sh) and 1661 cm"  1  1  attributable  S o l v e n t removal under  reduced  p r e s s u r e r e s u l t s i n the p a r t i a l decomposition of the mixture to produce an i n t r a c t a b l e s o l i d ; the s o l u b l e f r a c t i o n e x h i b i t s IR absorbances a t 2020, 1900 CH C1 . 2  2  Attempts  ( b r ) , and 1658 c m  t o i s o l a t e t h i s , product  •/'[ in  -1  ( a p p a r e n t l y not  a simple adduct) were u n s u c c e s s f u l . I t has been noted i n the chemical l i t e r a t u r e , t h a t i n some i n s t a n c e s photogenerated (THF)  13 1  (and presumably  s p e c i e s such as  (MeCp)Mn(CO)  _ 2  Cr (CO) CTHF) and W(CO),- (THF) ) may 5  contain, t r a c e s of i m p u r i t i e s i n the solutions- which, c a t a l y z e the decomposition of the complexes prepared from these; solutions.  To r u l e out t h i s p o s s i b i l i t y , Cr (CO) ,- QSIMe-, )  20 : 8  -  and  (MeCp);Mn. (COL CS-iPhJl C r i p  14 8  can. be. prepared and i s o l a t e d ,  1 0 : 9  2  and the; analogous  -  H: c a r r i e d out...  r e a c t i o n s with. CpW (NO)  The  reactions- proceed v e r y much as- do the. reactions- i n v o l v i n g the THF species-, but unfortunately- decomposition  of the  CpW (NO) H adducts formed again occurs- upon removal 2  solvent  of the  i n vacuo..  (b) The I n t e r a c t i o n of CpW(NO) H With MC1 2  (M = Zn, Cd, Hg).  2  Numerous examples of Group IIB metal and Hg) h a l i d e s are known.  ( i . e . Zn, Cd,  i n t e r a c t i n g w i t h t r a n s i t i o n metal  There are no examples o f c o o r d i n a t i o n  lone p a i r s of l i g a n d s  complexes v i a the 1  such as CO, NO, N , CN or halogen by 2  Group IIB d e r i v a t i v e s , although c o o r d i n a t i o n s u l f u r atom o f the CS l i g a n d i s k n o w n  127  .  of HgX  There  2  t o the  i s also a  p o s s i b i l i t y - of the m e r c u r a t i o n o f i T - c o o r d i n a t e d aromatic l i g a n d s with the f o r m a t i o n o f a C-HgX bond, which i s chara c t e r i s t i c of f e r r o c e n e and CpM(.CO)  3  A p a r t i c u l a r l y relevant  (M = Mn or R e )  1 2 7  .  example o f acid-base complex  f o r m a t i o n i s p r o v i d e d by the i n t e r a c t i o n o f t h e Group IIB h a l i d e s with Cp MH 2  2  i n THF t o y i e l d the adducts Cp MH •EX •THF 2  (M = Mo, W; E = Zn, Cd, Hg; X = C l , B r )  1 3 2  .  2  In each  2  instance  the adduct forms i n v i r t u a l l y q u a n t i t a t i v e y i e l d , with the product p r e c i p i t a t i n g from s o l u t i o n . of Cp MH 2  solved  and E X  2  2  Thus equimolar  amounts  can be weighed out, mixed, and then d i s -  i n THF; the. adduct r a p i d l y p r e c i p i t a t e s from  solution  (for C d C l , because o f i t s low s o l u b i l i t y , the. hali.de; i s 2  dissolved  first  and then added t o the dihydride)...  A crystal  s t r u c t u r e of the d e r i v a t i v e Cp MoH • ZnBr -DMF confirms- the 0  0  9  1-4 9  -  existence. o.f a Mo—Zn bond,. The: same: procedure:, y i e l d s d i f f e r e n t results-..  when, a p p l i e d t o CpW (NO). H/ 2  I.h t h e presence of a two-fold  excess- o f Z n C l , no PR s p e c t r a l evidence 2  CpW'(NOl.H: i s detectable:.. 2  of c o o r d i n a t i o n t o  Over a p e r i o d o f two days, the .-r  slow growth, o f p o o r l y r e s o l v e d shoulders  i s observed  on the  high, energy s i d e of the n i t r o s y l IR a b s o r p t i o n s of CpW (NO) Removal of the s o l v e n t r e s u l t s i n some decomposition  H.  occur-  r i n g ; e x t r a c t i o n o f the red-brown r e s i d u e with CDCl^ p r o v i d e s a s o l u t i o n whose H NMR r e v e a l s the presence o f CpW(.NO) Cl 1  2  (6 6.17) i n a d d i t i o n t o unreacted and  CpW(NO) H 2  (6 6. 00 (s, 5H)  2.07 (s, I H ) ) , i . e . CpW(NO)„H + ZnCl„  ^  *  CpW (NO)  V  H • ZnCl„  (56)  CpW(NO) Cl + 'ZnCl' 2  This, i s c o n s i s t e n t with the TR s p e c t r a l o b s e r v a t i o n s , a s CpW(NO) Cl d i s p l a y s n i t r o s y l a b s o r p t i o n s a t s l i g h t l y  higher  2  energy 1636  (v  1728, 1647 c m ) -1  N Q  cm "*") .  than does CpW(NO) H  s o l v e n t removal can be confirmed (CD )2 3  C O  N 0  1717,  That the c h l o r o complex does not a r i s e as a  r e s u l t o f the p a r t i a l decomposition  in  (V  2  a  n  d  monitoring  which occurs  by c a r r y i n g out the r e a c t i o n  the H NMR spectrum. 1  during  T h i s exper-  iment demonstrates the slow formation o f CpW(NO) C1 (>15% 2  conversion  i n 11 h. a t ambient temperature) in. the absence o f  any d e t e c t a b l e decomposition.  I t a l s o reveals- a small but  s i g n i f i c a n t s h i f t t o low f i e l d  of. the resonances a t t r i b u t a b l e :  to  the c y c l o p e n t a d i e n y l and- hydrido protons- CA: 4,8 ± 0...3 and  15 0  7,8  ±. Q-,.3  Hz,  r e s p e c t i y e l y l of CpVTCNOL^H;, a, fea,ture CQn.sist.T-  ent with, t r a n s i e n t adduct ifo-rmation. a c t i o n with, the c y c l o p e n t a d i e n y l  A, 'reversible i n t e r -  r i n g is- u n l i k e l y , so t h i s  s h i f t presumably- r e f l e c t s - an i n t e r a c t i o n of ZnCl^ at metal  centre.. In the presence of C d C l , no c o o r d i n a t i o n 2  i s detectable  by IR s p e c t r a l m o n i t o r i n g .  The  i s no evidence of any  a d d i t i o n of THF  CpWCNO) H and 2  HgCl  2  days a t  reaction.  to an equimolar mixture of  gives, b r i e f l y , a clear solution.  s o l u t i o n r a p i d l y becomes cloudy, however, followed p r e c i p i t a t i o n of a white s o l i d . perature,  2  in v i r t u a l l y  2  q u a n t i t a t i v e y i e l d ; there  t o CpW (NO) H  A f t e r two  ambient temperature, the CpW(NO) H i s r e c o v e r a b l e  and  the  CpW(NO) Cl 2  properties  be i s o l a t e d i n good y i e l d  Qualitative testing identifies  p r e c i p i t a t e formed as HgCl.  from  the  A r e p e t i t i o n of the r e a c t i o n  -78°C w i t h s e v e r a l attempts to o b t a i n an TR i n i t i a l product y i e l d s o n l y  the  h a t ambient tem-  ( i d e n t i f i e d by i t s s p e c t r a l  by elemental a n a l y s i s ) can  the r e a c t i o n mixture.  A f t e r 1.5  by  The  spectra  spectrum of  at  the  i n d i s t i n g u i s h a b l e from  t h a t of CpW(.NO) Cl. 2  R e p e t i t i o n of the r e a c t i o n at -8 0°C 1  H  NMR  i n (CD^^CO with.  m o n i t o r i n g r e v e a l s a l a r g e s h i f t to low  cyclopentadienyl respectively) .  and  hydrido resonances  Warming the  sample to O^C  f i e l d of  CO.3 0 and  2.4 0  the ppm  r e s u l t s - i n broaden-  i n g of the peaks (as a r e s u l t of the formation of a p r e c i p i t a t e i n the sample tube! and  a s h i f t i n g of the  cyclopenta-  d i e n y l resonance to higher f i e l d while the hydrido resonance.  -  15-1  -  l o s e s i n t e n s i t y and is- e v e n t u a l l y lost, in, the: baseline, noise... I t t h e r e f o r e appears t h a t CpW (NO) H i n t e r a c t s - w i t h 2  HgCl  2  t o form i n i t i a l l y ^ an adduct  (presumably- of the type  Cp(NO) (H)W-*HgCl -S; S = THF or acetone) , which, subsequently 2  2  reacts- f u r t h e r t o produce CpWXNO) Cl, HgCl, and presumably 2  1/2H , i . e . 2  CpW (NO) „H + HgC 1  <^r -8Q°C  9  Cp CNO)  (H) W—»HgC 1 • S 0  (  5  7  )  (S = THF o r acetone) Cp(NO) (H)W—*HgCl -S 0  — -  9  Z  +  CpW(NO)„Cl  + HgCl C58I  1  + {1/2H } 2  U n f o r t u n a t e l y , r e a c t i o n 58 o c c u r s too r a p i d l y t o a l l o w an IR spectrum o f the adduct t o be o b t a i n e d . The f a i l u r e o f CpWCNO) H t o form strong adducts w i t h 2  either ZnCl  2  or C d C l  2  r e f l e c t s a l i m i t e d a b i l i t y on i t s p a r t  to a c t as a Lewis base, as s t e r i c f a c t o r s are not l i k e l y t o be a f a c t o r i n l i g h t of the v a r i e t y of e l e c t r o p h i l e s shown to i n t e r a c t w i t h the metal c e n t r e .  The c o n v e r s i o n o f  CpW(NO) H>adduct t o CpW(NO) Cl c o n t r a s t s s h a r p l y w i t h the 2  2  known s t a b i l i t y o f the Cp MH • EX • THF adducts.. 2  2  It i s  2  p o s s i b l e t h a t the r a p i d p r e c i p i t a t i o n o f the Cp MH 2  from s o l u t i o n prevents f u r t h e r  2  complexes  reaction.  In p a s s i n g , i t may be noted t h a t two a d d i t i o n a l r e a c t i o n s aimed a t the f o r m a t i o n of adducts unexpectedly l e a d o n l y t o decomposition p r o d u c t s .  The treatment o f  t o l u e n e and hexanes s o l u t i o n s o f CpW(NO) H w i t h P t ( P P h O 2  3  and BEt_ r e s p e c t i v e l y y i e l d o n l y n i t r o s y l - f r e e decomposition,  products,, (cl; T h e Reaction of" CpW^NO^H: With: tr*'.. P r o t o n a t i o n o f t r a n s i t i o n metal complexes- is- known to be quite, a g e n e r a l r e a c t i o n , with, the p o s s i b l e sites- o f attack, being o l e f i n i c or ^—aromatic l i g a n d s , the metal c e n t r e , or other ligands- (eg.. ^CO '+• H When a metal c e n t r e possesses  +  —\>  ^COH  + 1 33  ) .  a lone p a i r of e l e c t r o n s ,  p r o t o n a t i o n a t the metal i s a common means of demonstrating i t s presence.  Some hydrido  r e a d i l y protonated  t r a n s i t i o n metal complexes are  t o g i v e q u i t e s t a b l e d e r i v a t i v e s , as i s  the case f o r - Cp^ReHl a n d 13  Cp MH 2  (M = Mo,,. W) . 13 5  2  r e q u i r e v e r y s t r o n g l y a c i d i c environments. C p W ( C O ) i s n o t protonated be protonated Still  Others,  For instance,  i n t r i f l u o r o a c e t i c a c i d , but can  i n BF^,H 0—CF^COOH t o g i v e  CpW(CO) H  2  3  + 1 1 7 2  .  other complexes a r e b e l i e v e d t o undergo p r o t o n a t i o n a t  the m e t a l c e n t r e , but hydrogen e v o l u t i o n f o l l o w s so r a p i d l y t h a t no s p e c t r o s c o p i c evidence (eg. CpMo(CO) H + H 3  +  f o r p r o t o n a t i o n can be obtained  — » - CpMo (CO)  +  3  + H  1 1 7 2  ).  The f a c t o r s  which, determine whether o r not hydrogen e v o l u t i o n w i l l  occur  upon, p r o t o n a t i o n a r e not f u l l y understood, but i t i s c l e a r t h a t , going down a group of i s o s t r u c t u r a l complexes, the protonated TT H  s p e c i e s g a i n k i n e t i c s t a b i l i t y a g a i n s t l o s s of  117  2  Prot.on.at.ion. o f CpWCNO)„ H: with, l e s s than Q.„5 e q u i v a 2  l e n t s of HBF «OMe 4  loss- o f E  2  2  i n CD N0 3  at  2  t o produce CpW (NO)  2  -2  0®C  r e s u l t s - i n the immedi-  , as evidenced  by- t h e appear-  ance of H: NMR resonances a t t r i b u t a b l e t o [Cp W (NOI^H] , 1  9  0  -  -  153  lye...  CpW'(NO).H + H  . --i »  +  2  {CpW (NO)  H  2  + 2  ^  cpw(No 1  CpW(.NO)  +  2  + CpW(NO) H  T  ^~ ^  + 2  T  •+ { H }  [Cp W (NO) ^H]  (€01  +  2  2  (5 9);  2  2  Upon warming the sample t o room temperature, the b i m e t a l l i c c a t i o n i s l o s t , however; t h i s presumably a r i s e s because of the Me 0 p r e s e n t i n the r e a c t i o n mixture.  With H^SO^ as  the a c i d , p r o t o n a t i o n i s again immediate,  but the b i m e t a l l i c  2  2c a t i o n does n o t form i n t h e presence of SO^  .  The c l e a n  appearance of a s i n g l e peak i n the E NMR a t 6 6.35 i n 1  C D N 0 s o l u t i o n i n s t e a d suggests the f o r m a t i o n o f [CpW(NO). ] so . 3  2 2  2  4  The p r o t o n a t i o n o f CpW(NO) "H i n C H C 1 2  HBF *OMe 4  2  2  solution with  produces a s t a b l e green s o l u t i o n e x h i b i t i n g IR  2  s p e c t r a l a b s o r p t i o n s s h i f t e d t o h i g h e r energy from 1718,  1632 cm"  1  t o 1733,  i t y o f the r e s u l t i n g [CpW(NO) (OMe )] 2  2  +  1648 cm" ). 1  (  v N  Q shift  While the s t a b i l -  s o l u t i o n suggests the f o r m a t i o n of  (CpW(NO)  + 2  i s known t o be v e r y u n s t a b l e  1 o h  ),  the p o s i t i o n o f the IR absorbances suggests the formation o f CpW(.NO) Cl 2  (v  N 0  1733,  1650 c m "  116  ) i n the IR c e l l  (NaCl  windows) as has been noted p r e v i o u s l y w i t h [CpW (NO) ~ 2  (CH CN1] 3  + 1a i  . . .  .  •(;d): The R e a c t i o n of CpW(NO) H With A i d . , ^ 2  Like. H; , A1.C1  3  i s a s t r o n g , hard Lewis- a c i d  ,  Thus-,  u n l i k e the Group ITB metal chlorides- discus-sed previously-, A1C1  3  might be expected; t o form an adduct with, a n i t r o s y l 0  - .153 -  atom w h i c h , i s : e x p e c t e d t o Be: the; h a r d e s t B a s e s i t e - i n . the. molecule..  Numerous- examples- ©.£.. the; f o r m a t i o n , o f i;s©carB©nyl  l i n k a g e s - have. Been d o c u m e n t e d .  1 2 7  .  I t is- therefore  somewhat  s u r p r i s i n g t h a t no e v i d e n c e o f a d d u c t f o r m a t i o n , i s - o B s e r v e d By e i t h e r  J-R o r H : NMR s p e c t r o s c o p y - when CpWCNO^H" i s 1  r e a c t e d with. 1 e q u i v a l e n t o f A l C l ^ . do r e a c t t o p r o d u c e CpWCNO) C 1 2  3 0. m i n u t e s a t a m B i e n t of  T h a t t h e s e t w o compounds  over a period o f approximately  temperature i s l e s s s u r p r i s i n g  theresults discussed  i n light  earlier.  ( e l Summary a n d C o n c l u s i o n s On  t h e B a s i s o f t h e aBove e x p e r i m e n t s  investigating  the. L e w i s B a s e p r o p e r t i e s o f C p W ( N 0 ) H a s w e l l a s t h o s e 2  relating  t o t h e Lewis a c i d i t y  o f CpM(NO)  W) d e s c r i B e d h e r e a n d e l s e w h e r e categorize these  1 0 1  *'  1 3 6  (M = C r , Mo, a n d  + 2  , i t i s possiBle t o  species.  A m e t a l - c e n t r e d p a i r o f e l e c t r o n s f r o m CpW(NO) H h a s 2  Been shown B y s p e c t r o s c o p i c m e t h o d s t o c o m p e t e for  t h e Lewis a c i d CpW(NO)  successfully  a g a i n s t t h e v e r y weak L e w i s  + 2  B a s e s B F . , P F , a n d CH„C1„ a s w e l l a s a g a i n s t more 4  tional THF.  2. z  b  Lewis Bases  conven-  such as propene, c y c l o o c t e n e , and even  I n t h e p r e s e n c e o f ~1 e q u i v a l e n t o f t h e a b o v e - m e n t i o n e d  L e w i s B a s e s , no f r e e CpW(NO) H c o u l d Be d e t e c t e d By H NMR 1  2  i n . CD N.Q 3  2  s o l u t i o n s ' c o n t a i n i n g lCp. ^2_CNQl H] 2  L e w i s Bases- ( e g , N E t , 3  4  .. W i t h , s t r o n g e r  P r o t o n . Sponge, Harpoon. B a s e , HMPA,  p h P = C H , KOH/EtOH, o r m a g n e s i u m f l u o f o s i i i c a t e l the. 'C 3  2  B i m e t a l l i c c a t i o n is- c o m p l e t e l y d i s s o c i a t e d , demonstrating the  i n a b i l i t y o f CpWCN0)„K t o c o m p e t e w i t h , t h e s e h a r d  Lewis  -  155  ^  bases:.. The h y d r i d e is- found t o compete: with. THF s o f t L e w i s a c i d s i t e s - of in. THF  (MeCp)Mn (CO) , Cr (CO) , 2  occupied by- CpW (NO) H  and W(CO)  5  s o l u t i o n , where: r o u g h l y h a l f t h e a c i d  f o r the, 5  sites- are  i n e a c h i n s t a n c e Cby TR) even though  2  a t h o u s a n d - f o l d excess of THF  i s present.  A l s o , although  CpW(NO) H competes i n e f f e c t i v e l y with one e q u i v a l e n t of 2  (CH L CO f o r t h e Lewis a c i d CpW(NO); 3  it  2  in CD N0  + 2  3  solution,  2  i s somewhat s u c c e s s f u l i n competing f o r Cr(.CO)^ i n  (CD ) CO s o l u t i o n . 3  In THF  2  fairly  s o l u t i o n CpW(NO) H i n t e r a c t s 2  s t r o n g l y w i t h the s o f t Lewis a c i d H g C l  by the magnitude of the s h i f t s of the H 1  yet with the i s o e l e c t r o n i c Z n C l between hard and  NMR  2  (as  adjudged  resonances),  (considered i n t e r m e d i a t e  2  s o f t i n i t s Lewis a c i d p r o p e r t i e s ) an 1 2  i n t e r a c t i o n i s b a r e l y d e t e c t a b l e by E  NMR,  1  and no  inter-  a c t i o n w i t h the hard a c i d A l C l ^ can be d e t e c t e d . These o b s e r v a t i o n s are a l l c o n s i s t e n t w i t h the c o n c l u s i o n t h a t CpW(NO) H f u n c t i o n s as q u i t e a s o f t Lewis 2  base.  I t i s not found t o i n t e r a c t with hard Lewis a c i d s  (even v i a the n i t r o s y l oxygens) except i n cases where reac-r t i o n occurs  (eg. H ,  A l C l ^ , and BEt^). .  +  CpW(NO)  + 2  on the other hand appears  to i n t e r a c t only  v e r y weakly w i t h weak bases such as o l e f i n s or C O - . 10  D e r i v a t i v e s i n v o l v i n g b e t t e r cp-donating l i g a n d s such, as PPfi^, SbPh , A s P h , PCOMe) , or P 3  3  3  CQPhJ  a r y l ) , and x"~ (X = C l , Br, and 7a  first  1  , iC  0  3  I )  t r a n s i t i o n - s e r i e s - analogue,  1  0  1  CR,  a,lkyi. ©r  are more s t a b l e .  CpCr CNO) „ , +  has-very  4  The  -  r e c e n t l y been, r e p o r t e d  1 3G  156  -  t o form an adduct;. with. PFg ,  i n d i c a t i n g t h a t i t i s a v e r y hard L e w i s a c i d . ( c y c l o o c t e n e ) ' , CpCr (N0) (FPFD +1 Q  t  2  L i k e CpWrCN.O^'"  i s apparently  stable. i n  the presence, o f t h e v e r y weak, base CO; r t i s a l s o towards: styrene,  With, b e t t e r donors such a s CH^CN, CgH^CN,  p-CH C H NH , C H 3  6  4  observed.  2  &  unreactive  1;L  NC, and (,CH) C 0 adduct formation i s 3  2  A l t h o u g h d e r i v a t i v e s o f t h e type CpW(NO) X, 2  where X i s BF^ o r PF^, have as.yet d e f i e d i s o l a t i o n , i t seems l i k e l y t h a t , l i k e CpCr (NO)  + 2  , CpW(NO)  i s a strong,  + 2  hard  Lewis a c i d . I t thus seems reasonable t o r a t i o n a l i z e the observed l a b i l i t y o f the [Cp M (NO)^H] 2  u n i t on the b a s i s o f the w e l l -  +  2  documented i n c o m p a t a b i l i t y of hard Lewis a c i d s w i t h s o f t Lewis b a s e s  1 2  '  1 2 7  .  Although r e l a t i v e l y s t a b l e i n the p r e -  sence o f weakly c o o r d i n a t i n g  s o l v e n t s and c o u n t e r i o n s , the.  metal-metal bond i s very r a p i d l y cleaved  upon the a d d i t i o n  of stronger  t h e d e s i r e d depro-r  Lewis bases, thus p r e c l u d i n g  tonation reaction.  I t therefore  seems u n l i k e l y t h a t the  f a i l u r e t o o b t a i n the d e s i r e d dimers, route r e f l e c t s any i n h e r e n t  [CpM ( N O ) ] , by t h i s 2  2  i n s t a b i l i t y o f these compounds.  Although t h e evidence suggests t h a t the hydride, l i g a n d s i n the [Cp M^M (NO)^H] 2  2  +  complexes are t e r m i n a l l y  bound, t h i s evidence i s not c o n c l u s i v e . c l u s i o n s concerning  However, the con-  t h e Lewis a c i d and base p r o p e r t i e s o f  the c o n s t i t u e n t fragments of these c a t i o n s would be u n a f f e c ted i f the hydride  ligand i s i n a bridging position; only  the r a t i o n a l i z a t i o n o f the i n s t a b i l i t y of the. b i m e t a l l i c  1.57-  -  c a t i o n s , toward donor molecules: i s - dependent upon. the. l o c a t i o n of the hydride  ligand.  - 158 EPILOGUE When t h i s r e s e a r c h was view was  begun, a p r e v a l e n t p o i n t of  t h a t n i t r o s y l l i g a n d s are l a r g e l y u n r e a c t i v e , 1 k  although t h i s c o n c l u s i o n was  based almost e n t i r e l y on expe  iments performed on c o o r d i n a t i o n complexes. presented  The r e s u l t s  here demonstrate t h a t i n o r g a n o m e t a l l i c  a g r e a t v a r i e t y of c o o r d i n a t e d  l i g a n d s are  compound  preferentially  attacked  by n u c l e o p h i l e s  i n the presence of the  nitrosyl  ligand.  However, i n the absence of other r e a c t i v e s i t e s ,  n i t r o s y l l i g a n d s have, themselves been shown to undergo a t t a c k by v a r i o u s reagents  ( i . e . by NO,  NaAlH (OCH CH OCH ) , and BEt^) 2  2  products.  2  BH  to l e a d to a v a r i e t y of  3  While the o b j e c t i v e s i n the i n t r o d u c t i o n have  been achieved,  much f u r t h e r work w i l l be r e q u i r e d to  systems which can be put to use Although the acid-base carbonyl  NaBH^, LiEt^BH,  industrially. p r o p e r t i e s of  complexes have been, and continue  e x t e n s i v e l y , few  The  to be,  studied  c u r r e n t study of CpW(NO) H r e v e a l s 2  l i g a n d to be s u r p r i s i n g l y r e a c t i v e i n the  presence of the n i t r o s y l l i g a n d s , and t h a t both hard and  unexpectedly r e v e a l s  s o f t Lewis a c i d s p r e f e r e n t i a l l y form  adducts at the metal c e n t r e . considerable  organometalli  i n v e s t i g a t i o n s of n i t r o s y l complexes have  been c a r r i e d out. the hydride  find  Thus i t has been found t h a t  c a u t i o n should be e x e r c i s e d when p r e d i c t i n g  the p r o p e r t i e s of o r g a n o m e t a l l i c b a s i s of the b e t t e r - u n d e r s t o o d  n i t r o s y l complexes on  carbonyl  chemistry.  the  T  159  -  KEFERETSTCES" AND' NOTES : 1.  Cochran, N.P.  S c i . Am. 1976, 234 C5) , 24-9.  2.  Gibson, J .  Chem. Br.' 1980, 16, 26-3 0.  3..  "Hydrocarbon Synthesis- from Carbon Monoxide and Hydrogen"; Kugler, E.L. and S t e f f g e n , F.W. Eds., American Chemical S o c i e t y : Washington, D.C., 1979.  4.  Dwyer, E.G. C a t a l . Rev. 1972, 6, 261-91 and r e f e r e n c e s contained t h e r e i n .  5.  "The C a t a l y t i c Chemistry o f N i t r o g e n Oxides"; K l i m i s c h , R.L. and Larson, J.G. Eds.; Plenum: New York, 197 5.  6.. McCleverty, J.A. Chem. Rev. 1979, 79, 53-76 and r e f e r ences c o n t a i n e d t h e r e i n . 7.  I n u i , T. ; Otowa, T. and Takegami, Y. Chem. Commun. 1980, 94-5.  J . Chem. S o c ,  8..' Chem.. Eng. News March 10, 1980, 38-9. 9...  (a) Skinner, K.J. Chem. Eng. News October 4, 1976, 2235; Cb) Chatt, J . i n " B i o l o g i c a l Aspects of Inorganic Chemistry"; Addison, A.W.; C u l l e n , W.R.; D o l p h i n , D. and James, B.R., Eds.; Wiley: New York, 1977, 229-43 and r e f e r e n c e s contained t h e r e i n .  10...  C a u l t o n , K.G. Coord. Chem. Rev. 1975, 14, 317-55 and r e f e r e n c e s contained t h e r e i n .  11.  E l d e r , R.C.  12.  (a) Pearson, R.G. J . Am. Chem. Soc. 1963 , 85, .3533-9; Cb) Pearson, R.G. Science 1966, 151, 172-7; Cc) Pearson, R.G. J . Chem. Ed. 1968, 45, 581-7 and 643-8.  13.  Cotton, F.A. and W i l k i n s o n , G. "Advanced Inorganic Chemistry"; 3rd ed., Wiley: New York, 1972, Chapter 2.2...  14.  Bottomley, F. Acc. Chem. Res. 1978, 11, 158-63 and references contained t h e r e i n .  15.  Crease, A.E. and Legzdins, P. Trans. 1973, 1501-7.  J . Chem. S o c , D a l t o n  16.  Legzdins, P. and M a l i t o , J.T. 1875-8.  Inorg. Chem. 1975, 14,  Inorg. Chem. 1974, 13, 1037-42.  -'  -  160  17.  K o l t h a m m e r , B.W..S, ; L.e.gzdin.s> P.. a n d Mailt.©,, I n o r g . . C h e m , 197 7, 1 6 , 3173-8..  18.  K o l t h a m m e r , B.W. S. a n d L e g z d i n s , D a l t o n T r a n s . "1978, 31-5".  19.  P e r r i n , D.D.; A r m a r e g o , W.L.F. a n d P e r r i n , D.R. " P u r i f i c a t i o n o f L a b o r a t o r y Chemicals"'; Pergamon Press-: Oxford, 1966.  20...  S h r i v e r , D.F. "The M a n i p u l a t i o n o f A i r - S e n s i t i v e Compounds"'; M c G r a w - H i l l : New Y o r k , 1 9 6 9 .  2.1..  K i n g , R.B. "Organometallic Press: New Y o r k , 1 9 6 5 .  2.2.  K o l t h a m m e r , B.W.S. ; L e g z d i n s , P. a n d M a l i t o , J . T . I n o r g . S y n t h . 1979, 19, 208-12.  23.  H o y a n o , J . K . ; L e g z d i n s , P. a n d M a l i t o , J . T . S y n t h . 1978, 18, 126-31.  24.  Legzdins,  2.5.  C o o p e r , R.L. and Green, 1155-60.  26.  Wong, 1975,  2.7.,  F i s c h e r , E.O. a n d H a f n e r , 14 0 - 3 .  2.8.,  P i p e r , T.S. and W i l k i n s o n , 1 9 5 6 , 2, 3 8 - 4 5 .  29.  P i p e r , T.S.; C o t t o n , F.A. a n d W i l k i n s o n , N u c l . Chem. 1 9 5 5 , 1,. 1 6 5 - 7 4 .  30.  C o t t o n , F . A . ; M u s c o , A . a n d Y a g u p s k y , G. Soc 1967, 89, 6136-9.  31.  P i p e r , T.S. and W i l k i n s o n , 1 9 5 6 , 3, 1 0 4 - 2 4 .  32.  H a m e s , B.W.; 1978,  P. a n d N a z a r ,  P.  J v Chem.. Soc..,  Syntheses"  V o l . 1; A c a d e m i c  L.F., unpublished M.L.H.  J',T.  Inorg.  results.  J . Chem. S o c . (A)  1967,  K . L . T . a n d B r i n t z i n g e r , H.H. J . Am. Chem.. S o c . 97, 5143-6 a n d r e f e r e n c e s c o n t a i n e d t h e r e i n .  Legzdins,  W.  G.  G.  Z. N a t u r f o r s c h .  J . Inorg.  J . Inorg.  P. a n d M a r t i n ,  1955,  Nucl.  G.  Chem.  J . Inorg.  J . Am.. C h e m .  Nucl.  D.T.  Chem.  Inorg.  Chem.  17, 3644-7.  33.  C f . Brunner,  H...  J . Organomet.  34.  H a l l o c k , S.A. a n d W o j c i c k i , A . 1979, 182, 521-35.  BIO,  Chem.. 1 9 6 8 , 1.4, 1 7 3 - 8 . J . O r g a n o m e t . . Chem..  161  -  35..  Herber ho Id, M,; Klein;, R, and Alt,, E.G.. 197 6/77, 15, 206-9..  36.  Abraham son, K.B. and Wfighton, M.S\ 1977, 99, 5510-2.  37.  £s>r.. J .. Chem, 1  J .. Am, Chem. Soc. 1  (a) de C T . Carrondo, M.A,, A.P .;• Rudolf, P. R. ; Skapski, A.C.; Thornback, J'.R. and W i l k i n s o n , G. Inorg. Chim. A c t a 1977, 24, L95-6";,. Qb). Araneo, A.; N a p o l i t a n o , T. and M e r c a t i , G. Gazz. Chim- I t a l . " 1977, 107, 31-45; CcJ Windhorst, K.A. and L u n s f o r d , J'.H. J . Am. Chem. Soc. 197 5, 97, 1407-12;. Cd) H'aymore, B.L. and Ibers, J.A. J . Am. Chem. Soc. 1974, 96, 3325-7; and (e) G a r • gano, M. ; Giannoccaro, P;;;• R o s s i , M. ; Sacco, A, and V a s a p o l l o , G. Gazz. Chim. I t a l . 197 5, 105, 1279-90. x  :  38.  B r i n t z i n g e r , H.H.; Lohr, L . L . " J r . and Wong, K.L.T. J . Am. Chem. Soc. 1975, 97, 5146-55 and r e f e r e n c e s contained t h e r e i n .  39.  Collman, J.P. and Hegedus, L.S. " P r i n c i p l e s and A p p l i c a t i o n s o f O r g a n o t r a n s i t i o n M e t a l Chemistry"; U n i v e r s i t y Science Books: M i l l V a l l e y , Ca., 198 0.  40.  M u e t t e r t i e s , E.L.; Rhodin, T.N.; Band, E.; Brucker, C.F. and P r e t z e r , W.R. Chem. Rev. 1979, 79, 91-137.  41.  Stewart, R.P. J r . ; Okamoto, N. and Graham, W.A.G. J . Organomet. Chem. 1972, 42, C3 2-4.  42.  H a j 6 s , A. "Complex Hydrides"; E l s e v i e r S c i e n t i f i c P u b l i s h i n g Company: New York, 1979, 159-67.  43.  M a l i t o , J.T. Ph.D. D i s s e r t a t i o n , The U n i v e r s i t y o f B r i t i s h Columbia, Vancouver, B.C., 1976.  44.  N a A l H (OCH CH OCH.,). was purchased from e i t h e r t h e A l d r i c h Chemical Co. under the trade name Red-al o r from Hexcel Corp. under the t r a d e name V i t r i d e , as a 7 0% s o l u t i o n i n benzene.  45.  Greenhough, T . J . ; Kolthammer, B.W.S.; L e g z d i n s , P. and T r o t t e r , J . Tnorg. Chem. 1979, 18, 3548-54.  46.  Kolthammer, B.W.S. and L e g z d i n s , P. 18, 889-91.  47.  King, R.B. and B i s n e t t e , M.B. 7 91-6.  Inorg. Chem. 1964, 3,  48.  Brunner, H, and Wachsmann, H. 15, 409-21.  J . Organomet, Chem. 1968,  2  2  2  2  Inorg. Chem. 197 9,  - 1 1 6 2 --  4 9...  Seddon, D . , ; K i t a, WV G •. > " Br- a y, J'„ and McC l e v e r t y , J.A^ Inorg.. Synth.. 197 6, 16, 24-9".  50.  F l i t c r o f t , N.  51.  Legzdins, P. and M a r t i n , D..T. 1250-4,  52.  J . Organomet. Chem. 1968, 15, 254-6. Inorg. Chem, 1979, 18,  C f •. 'the thermal d i m e r i z a t i o n o f CpCr CC0X H" d e s c r i b e d ' i n r e f e r e n c e 31. 3  53.  Davison, A,; Green, M..L.H. and W i l k i n s o n , G, Soc, 1961, 3172-7.  54.  Hames, B.W. ; Legzdins, P. and Oxley, J.O. 1980, 19, 1565-71.  55.  James, T.A. and McCleverty, 1971, 1068-73.  56.  Legzdins, P.; M a r t i n , D.T. and Nurse, C R . Chem. 1980, 19, 1560-4.  57.  The sample used was generously provided by Dr. B.W.S. Kolthammer (prepared a c c o r d i n g t o the procedure d e s c r i b e d i n r e f e r e n c e 49).  58.  McCleverty, J.A. and Seddon, D. Trans. 1972, 2526-30.  59.  M u l l e r , J . and Schmitt, 160, 109-14.  60.  Chan. L.Y.Y. and E i n s t e i n , F.W.B. Sect. B 1970, 26, 1899-905.  Acta  61.  Ahmad, M.; Bruce, 21b, 289.  Z. N a t u r f o r s c h . 1966,  62.  M u l l e r , J . ; Dorner, H.; Huttner, G. and Lorenz, H. Angew. Chem., I n t . Ed. E n g l . 1973, 12, 1005-6 and references therein.  63.  Summerville, R.H. and Hoffmann, R. J . Am. Chem. Soc, 197 6, 98, 7240-54 and r e f e r e n c e s t h e r e i n .  64.  Hieber, W. and Beutner, 317, 63-72.  65.  Dahl, L.F.; C o s t e l l o , W.R. and King, R.B, J . Am. Chem. Soc. 1968, 90, 5422-9.  66.  Brown, H.C. and Krishnamurthy, S. A l d r i c h i m . A c t a 1979, 12, 3—11 and r e f e r e n c e s contained t h e r e i n .  S.  J.A.  Inorg. Chem.  J . Chem. Soc.  (A)  Inorg.  J . Chem. S o c , Dalton  J . Organomet. Chem. 1978,  R. and Knox, G.  H.  J', Chem.  Crystallogr.,  Z. Anorg. A l l g . Chem. 1962,  163 -  67..  Gladysz, J'..A.. Aldricfti^ti.. Acta; 1979, 1.2, 13-7 and r e f e r e n c e s contained t h e r e i n .  68.  Casey, C P . ; Andrews-, 1VI..A. ; McAlister-, D.R. and Rinz, J.E. J . Am. Chem. Soc. 1980, 102, 1927-33 and r e f e r e n ces contained t h e r e i n .  69.  Purchased from t h e Aid-rich Chemical Co. as a 1 M THF s o l u t i o n under the: t r a d e name SUper—Hydride.  70.  Hbyano, J.K.; Legzdins, P. and M a l i t o , J.T. J . Chem. S o c , Dalton Trans. 197 5, 1022-5.  71.  Gladysz, J.A. ; W i l l i a m s , G.M.; Tarn, ;W. ; Johnson, D.L.; Parker, D.W. and S e l o v e r , J.C. Inorg. Chem. 1979, 18, 553-8.  72...  B a l l , R.G.; Hames, B.W. ; Legzdins, P. and T r o t t e r , J . Inorg. Chem. 1980., 19, 3 62 6-31.  73.  Bush, M.A. and Sim, G.A.  74..  Calderon, J.L. ; Fontana, S. ; F r a u e n d o r f e r , E. and Day, V.W. J , Organomet. Chem. 1974, 64, C10-2.  75.,  (a.l C u r t i s , M.D. and B u t l e r , W.M. J . Organomet. Chem. 197 8, 155, 131-45; Cb); Prout, K. ; Cameron, T.S. ; Forder, R.A.; C r i t c h l e y , S\R.; Denton, B. and Rees, G.V. A c t a C r y s t a l l o g r . , Sect. B 1974, 30, 2290-304.  76..  Ca). Hoffmann, R. ; Chen, M.M.L.; E l i a n , M. ; R o s s i , A.R. and Mingos, D.M.P. Inorg. Chem. 1974, 13, 2666-75; Cb) K e t t l e , S.F.A. Inorg. Chem. 1965, 4, 1661-3.  77.  (a) Dahl, L.F.; de G i l , E.R. and Feltham, R.D. J . Am. Chem. S o c 1969, 91, 1653-64; (b) Davies, G.R. and K i l b o u r n , B.T. J . Chem. Soc. (A) 1971, 87-90; (.c) C o u l d w e l l , C. and Prout, K. A c t a C r y s t a l l o g r . , Sect. B. 1978, 34, 933-4 and r e f e r e n c e s t h e r e i n ; Cd) B e r n a l , I . ; Korp, J.D.; Reisner, G.M. and Herrmann, W.A. J . Organomet. Chem. 1977, 139, 321-36.  78.  (a) Z e t t l e r , F.; Hausen, H.D. and Hess, H. J.. Organomet. Chem. 1974, 72, 157-62; (b) R e t t i g , S.J. and T r o t t e r , J . Can. J . Chem. 1976, 54, 3130-41; I b i d , 1977, 55, 958-65.  79.  Harshbarger, W.; Lee, G.; P o r t e r , R.F. and Bauer, S.H, Inorg. Chem. 1969, 8, 1683-9 and references- contained therein.  80.  C o r f i e l d , P.W.R. and Shore, S.G. J . Am. Chem, S o c 1973, 95, 14 8 0-7 and r e f e r e n c e s contained t h e r e i n .  J . Chem. S o c (A) 1970, 611-6.  -  JL6-4  -  81...  Chara.lafflbQ.us-,  J., E,d... "Mas;s> SpeGtrrometry o,f M e t a l Compounds"'; Butterworth^; London.,'' 1975.  82.  M u l l e r , J..; Ludemann, P., and SChmitt, S\ Chem. 1979 , 16 9, 2 5-37.  83.  Weigert, F.J'., and Roberts-, J.D. 12, 313-6.  84..  I o n i n , B.I. and Ershov, B.A. "NMR Spectroscopy i n Organic Chemistry"; Plenum: New York, 1970.  85.  Beck, W.; Becker, W.; Noth, H. and Wrackmeyer, B. Ber. 1972, 105, 2883-97.  86.  B r o i s , S.J. Tetrahedron L e t t . 1964, 345-50.  87.  Dunker, J.W.; F i n e r , J.S.; C l a r d y , J . and A n g e l i c i , R.J. J . Organomet. Chem. 1976, 114, C49-52.  88.  F i s c h e r , E.O. and V o g l e r , A. 17b, 421-2.  89.  F i s c h e r , E.O.; V o g l e r , A. and Noack, K. Chem. 1967, 7, 135-49.  90.  Sweet, J.R. and Graham, W.A.G. 63rd Chemical Conference and E x h i b i t i o n , The Chemical I n s t i t u t e o f Canada, Ottawa, June, 1980.  91.  (a) Gansow, O.A.; Burke, A..R. and Vernon, W.D. J . Am. Chem. Soc. 1972, 94, 2550-2; (b) B u l l i t t , J.G.; Cotton, F.A. and Marks, T . J . Inorg. Chem. 1972, 11, 671-6.  92.  Cotton, F.A. and Yagupsky, G. 15-20.  93.  K i r c h n e r , R.M.; Marks, T . J . ; K r i s t o f f , J.S. and I b e r s , J.A. J . Am. Chem. Soc. 1973, 95, 6602-13.  94.  A l i c h , A.; Nelson, N.J.; Strope, D. and S h r i v e r , D.F. Inorg. Chem. 1972, 11, 2976-83.  95.  A l i c h , A.; Nelson, N.J. and S h r i v e r , D.F. S o c , Chem. Commun. 1971, 254-5.  96.  Kolthammer, B.W'. S'. ; Legzdins-, P. and Martin., D.T. Tetrahedron L e t t . 1978, 323-6.  97.  (a) Tarn, W.; Wong, W.-K. and Gladysz, J.A. J . Am. Chem. S o c 197 9, 101, 158 9—91 >ahd: r e f e r e n c e s Cb). K i e l , W.A.; L i n , G.-Y. and Gladysz, J.A. J . Am. Chem. S o c 1980, 102, 3299-3301.  J.. Organomet.  Inorg. Chem. 1973,  Chem.  Z. N a t u r f o r s c h . 1962, J . Organomet.  Inorg. Chem. 1967, 6,  J . Chem.  -  165  -  98,  Graham, W..A.G.. and Sweet, J,R. J .. Organomet. Chem., 1979, 173, C 9-1.2. and references- contained therein.,  99.  Hoya.no, J'.K. ; Kolthammer, B:.WvS\; Legzdin,s>, P.; M a r t i n , D.T. and Nazar, L.F. unpublished results-..  1  100... Moore, J.A. and Reed, D.E. Org. Synth. 1961, 41, 16-20. 101.  Stewart, R.P. J r . and Moore, G.T. 14, 26 99.-2703.  Inorg. Chem.  1975,  102.  Olah, G.A.; Svoboda, J . J . and Olah., J.A. 1972, 544.  103.  Conrow, K.  104.  L e g z d i n s , P. and M a r t i n , D.T. unpublished  105.  Dauphin, G.; David, L,; Duprat, P.; Kergomard, A. and Veschambre, H. S y n t h e s i s 1973, 149-52.  10.6.  F i e s e r , L.F. and F i e s e r , M. "Reagents f o r Organic S y n t h e s i s " V o l 1; John Wiley and Sons, Inc.: New York, 1967, p712.  107..  G e o f f r o y , G.L. and Wrighton, M.S. ''Organometallic Photochemistry"; Academic Press-: Toronto, 197 9.  108.  K o e l l e , U.  10.9.  J e t z , W. and Graham, W.A.G. 4-9.  110.  Sorum, C H . " I n t r o d u c t i o n t o Semimicro Q u a l i t a t i v e A n a l y s i s " , 4th ed.; P r e n t i c e - H a l l , Inc.: Englewood C l i f f s , N.J., 1967, p95.  111.  Ugo, R.; C a r i a t i , F. and La Monica, G. 1968, 11, 105-8.  112.  More r e c e n t l y , i t has been demonstrated t h a t another mode o f r e a c t i o n i s p o s s i b l e . Thus, C H 2 N 2 was found t o d i s p l a c e a CO l i g a n d from CpW(CO)^H ana subsequently r e a c t f u r t h e r t o y i e l d CpW (CO) (JS^MeJ . The bending of a c o o r d i n a t e d n i t r o s y l l i g a n d i n CpMo (NO)„H t o permit t h i s mode o f r e a c t i o n was not observed.  Synthesis  Org. Synth. 1963, 43, 101-4. results.  J . Organomet. Chem. 1977, 133, 53-8. Inorg. Chem. 1971,  Inorg.  10,  Synth.  1 13  2  113.  Herrmann, W.A.  Angew. Chem. 1975, 87, 358-9.  114.  L e g z d i n s , P, and.Malito, J.T, unpublished  115. ' •  Gutmann, V. " C o o r d i n a t i o n Chemistry . in.Non-aqueous S o l v e n t s " ; S p r i n g e r - V e r l a g : . New- York., 1968,  results.  - J;66 •-  116.  Kaesz, II,D. and S a i l l a n t , R. B-. Chem,. Rev, 19.72, 72, 231—81 and references: contained t h e r e i n ,  117.  Davison, A.; McFarlane, W\ ; P r a t t , L, and W i l k i n s o n , G, J . Chem. Soc. 1962, 3653-66.  118.  Hayter, R.G.  119.  B u r n e l l , E.E.  120.  Levy, G.C. and L i c h t e r , R.L. "Nitrogen-15 Nuclear Magnetic Resonance Spectroscopy"; John W i l e y & Sons: Toronto, 1979.  121.  Botto, R.E.; Kolthammer, B.W.S.; Legzdins, P. and Roberts, J.D. Inorg. Chem. 1979, 18, 2 04 9-51.  122.  C o n n e l l y , N.G.  123.  F i s c h e r , E.O. and Moser, E. 35-43.  124.  Beck, W. and S c h l o t e r , K. 1214- 22.  125.  House, H.O. "Modern S y n t h e t i c R e a c t i o n s " ; W.A. Benjamin, Inc: Don M i l l s , Ont., 1972, p4 94.  126.  H a r r i s , D.C. and Gray, H.B. 1215- 7,  127.  L o k s h i n , B.V.; Ginzburg, A.G. and Nazarova, E.B. Chem. Rev. 1980, 49, 115-30.  128.  See f o r example Ca) Foust, A.S.; Graham, W.A.G. and Stewart, R.P. J r . J . Organomet. Chem. 1973, 54, C22-4; Cb) Bau, R., ed. " T r a n s i t i o n Metal Hydrides", Adv. Chem. Ser. 167; Am., Chem. S o c : Washington, 197 8/  129.  L o k s h i n , B.V. ; Rusach, E.B. ; Kolobova, N.E;,; Makarou, V.V.; Ustynyk, N.A. ; Zdanovich, V.I".; Zhakaeva, A.Z. and S e t k i n a , V.N. J . Organomet. Chem. 1976, 108, 353-61,  130.  Strohmeier, W. and M u l l e r , F . - J . 3 608-12.  131.  Barrientos-Penna, C.F.; E i n s t e i n , F.W.B.; Sutton, D. n. and Wtllis:, A.C. Inorg. Chem. 1980, 19, 274Q-9,  132.  C r o t t y , D.E,; Anderson., T,J. ; Click., M-.D, and O l i v e r , J.P. Inorg. Chem. 1977, 16, 2346-50.  133.  H o d a l i , H.A. and S h r i v e r , D.F. i n o r g . Chem, 197 9, 1.8, 1236-41.  J'. Am. Chem. Soc. 1966, 88, 4376-82. p e r s o n a l communication.  Inorg. Chim. A c t a . Rev. 1972, 6, 47-8 9. Inorg. Synth. 1970, 12,  Z. N a t u r f o r s c h . 1978, 3 3b,  Inorg. Chem. 1975, 14, Russ.  Chem. Ber. 1969, 102,  •167  -  134,  Green., M.L.HL. ; P r a t t , L . and W i l k i n s o n , , G. Soc. 1 9 5 8 , 3 916.-22.  Chem.  135,  G r e e n , M.L.K.; M c C l e v e r t y , J.A. ; P r a t t , L , a n d WLil,kin,s o n , G. J . Chem. Soc." 1 9 6 1 , 48 5 4 - 9 .  136,  R e g i n a , F . J . and W b j c i e R i , A. 38 03-7.  I n o r g . Chem. 1 9 8 0 , 1 9 , '  

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