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New organomtallic nitrosyl derivatives of the group 6B elements Martin, David Timothy 1979

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NEW ORGANOMETALLIC NITROSYL DERIVATIVES OF THE GROUP 6B ELEMENTS  by  DAVID TIMOTHY MARTIN .Sc.,  The U n i v e r s i t y  of B r i t i s h Columbia, 1977  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF MASTER OF SCIENCE  in THE FACULTY OF GRADUATE STUDIES (Department o f Chemistry)  We accept t h i s t h e s i s as conforming to the required  standard  THE UNIVERSITY OF BRITISH COLUMBIA J u l y 1979 (c)  David Timothy M a r t i n , 1979  In p r e s e n t i n g t h i s  thesis in partial  an a d v a n c e d d e g r e e a t the L i b r a r y I further for  shall  the U n i v e r s i t y  make i t  agree that  freely  this  thesis for  It  D e p a r t m e n t nf  f i n a n c i a l gain shall  CHEMISTRY  The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 W e s b r o o k P l a c e V a n c o u v e r , Canada V6T 1W5  AUGUST 15,  BP  75-51 1 E  1979  the requirements I agree  r e f e r e n c e and copying of  this  that  not  copying or  for  that  study. thesis  by t h e Head o f my D e p a r t m e n t  i s understood  permission.  of  B r i t i s h Columbia,  extensive  s c h o l a r l y p u r p o s e s may be g r a n t e d  written  DE-6  of  available for  permission for  by h i s r e p r e s e n t a t i v e s . of  fulfilment  or  publication  be a l l o w e d w i t h o u t  my  ABSTRACT The complexes CpM(NO) Cl  (M=Cr, Mo o r W)  2  can be  reduced  u s i n g Na[A1H (OCH CH OCH ) ] to y i e l d  [CpCr(NO) ]  CpM(NO) H (M=Mo o r W),  A study o f the chemis-  2  2  2  3  2  respectively.  2  2  and  2  t r y o f CpW(NO) H shows t h a t i t a c t s as a source o f the hy2  dride ion i n polar solvents.  For example, CpW(NO) H r e a c t s 2  with anhydrous p - t o l u e n e s u l f o n i c a c i d t o form CpW(NO) S0 2  CJEJ.  The complex a l s o undergoes l o s s of H  This novel r e a c t i v i t y  3  with Ph CBF . 3  4  i s compared w i t h t h a t e x h i b i t e d by  c a r b o n y l h y d r i d e complexes o f the t r a n s i t i o n metals.  The  molybdenum congener, CpMo(NO) H, i s u n s t a b l e i n the s o l i d 2  s t a t e but can be c h a r a c t e r i z e d i n s o l u t i o n .  No d i r e c t phys-  i c a l evidence can be found f o r the e x i s t e n c e of CpCr(NO) H. 2  The r e a c t i o n o f I  2  with CpW(CO) NO r e s u l t s i n the i s o 2  l a t i o n o'f a completely decarbonylated product,  CpW(CO) NO + I 2  > 1/2[CpW(NO)I ]  2  [CpW(NO)I ] . 2  2  T h i s d i m e r i c compound r e a c t s w i t h a v a r i e t y o f reagents to form monomeric  products.  [CpW(NO)I ] 2  2  + 2L ^2CpW(N0)(I) L .L=Group 5 donor l i g a n d 2  T e r a a l l y l t i n , 'Sn (C' H i) , r e a c t s w i t h 3  [  4  [CpW (NO).'1] 2  2  to  2  form CpW(NO) (n -C.jHg)I.  An X-ray c r y s t a l l o g r a p h i c a n a l y s i s  3  of t h i s complex shows t h a t the a l l y l group e x h i b i t s c o n s i d e r a b l e a , ir d i s t o r t i o n . t i o n a t ambient  T h i s asymmetry i s a l s o e v i d e n t i n s o l u -  temperature.  a n a l y s i s of the E and 1  1 3  C  This f a c t allows straightforward  magnetic resonance s p e c t r a .  p r e v i o u s l y r e p o r t e d molybdenum  The  analogue, CpMo(NO)(n -C^H^)I, 3  can be prepared by a l l y l a t i o n of [CpMo (NO) ~L^) 2 "w;  th  S n  ^ 3 5^4 C  H  -  - iv -  ACKNOWLEDGEMENTS I wish t o thank the t e c h n i c a l s t a f f , as w e l l as the f a c u l t y , o f the Chemistry department f o r t h e i r throughout my s t u d i e s . uate students  assistance-  I a l s o wish t o thank the f e l l o w grad-  w i t h whom I shared a l a b o r a t o r y , e s p e c i a l l y  B.W. Hames and C.R. Nurse.  I am indebted  t o Margaret Wiens  for typing t h i s t h e s i s . F i n a l l y , there a r e two people f o r whom a w r i t t e n acknowledgement h a r d l y does j u s t i c e . and  Without the guidance  encouragement o f Dr. B r i a n Kolthammer and P r o f .  Legzdins,  Peter  t h i s work c o u l d not even have been attempted.  - v -  TABLE OF CONTENTS Page ABSTRACT  i i  ACKNOWLEDGEMENTS  iv  TABLE OF CONTENTS  v  LIST OF TABLES  . .  LIST OF FIGURES  vi  v i i  ABBREVIATIONS AND COMMON NAMES  viii  CHAPTER I  INTRODUCTION  1  CHAPTER I I  PREPARATION AND CHARACTERIZATION OF (n -CYCLOPENTADIENYL)HYDRIDODINI-: TROSYLTUNGSTEN  6  Experimental S e c t i o n  7  5  R e s u l t s and D i s c u s s i o n  16  CHAPTER I I I SYNTHESIS AND CHARACTERIZATION OF BIS[ (n -CYCLOPENTADIENYL)DIIODONITROSYLTUNGSTEN]  26  5  CHAPTER IV  REFERENCES  Experimental S e c t i o n  27  R e s u l t s and D i s c u s s i o n  33  PREPARATION OF (n -ALLYL) (n -CYCLOPENTADIENYL)IODONITROSYL -TUNGSTEN AND -MOLYBENUM ..  44  Experimental S e c t i o n  45  .-Results and Discussion>,  47  3  5  61  - vi -  LIST OF TABLES Table I II  Page Spectral Properties R e l a t e d Complexes  o f CpW(NO) H and 2  18  P h y s i c a l P r o p e r t i e s o f the Complexes CpW(NO) (I) L (L=PPh-., P(OPh),, SbPh-, or CO) .... T . 7  29  Mass S p e c t r a l Data f o r CpW(CO)(NO)P(OPh)  31  Mass S p e c t r a l Data f o r [ C p W ( N O ) I l  35  9  III IV V VI  2  Mass S p e c t r a l Data f o r CpW(NO)(I) P(OPh) 2  Mass S p e c t r a l Data f o r (C H ) W(NO)I 5  VII VIII  2  5  3  ....  2  49  H and C NMR S p e c t r a l Data f o r the Ehdo Isomer o f C p W ( N O ) ( n - C H ) I  55  Mass S p e c t r a l Data f o r CpMo (NO) ( n -C H -) I  57  3  5  1 3  3  3  IX  41  Mass S p e c t r a l Data f o r C p W ( N O ) ( n - C H ) I 3  :  37  5  3  3  [  - vii -  LIST OF FIGURES Figure 1.  Page The c h a r a c t e r i s t i c c h e m i s t r y of CpW(NO) H  23  2  2.  M o l e c u l a r s t r u c t u r e of CpW(NO)(n C,H )I 3  3  3.  C  50  D  27 0 MHz K FT-NMR spectrum i n the a l l y l r e g i o n o f CpW (NO) (n -C-H_)I i n CDC1 .... . .  53  270 MHz }E FT-NMR spectrum i n the a l l y l r e g i o n o f CpMo(NO) (n C^H .)I i n CDC1 7. . . .  58  1  3  3  4.  3-  c  3  - viii  -  ABBREVIATIONS AND COMMON NAMES The a b b r e v i a t i o n s used i n t h i s t h e s i s are those recommended i n the Handbook f o r Authors of Papers i n American Chemical S o c i e t y P u b l i c a t i o n s  (AGS 1978).  o  A  Angstrom  atm  atmospheres  calcd  calculated  cm  wave numbers i n r e c i p r o c a l centimetres  1  Cp  pentahapto-cyclopentadienyl  d  days  dec  decomposes  Et  ethyl  h  hours  Hz  Hertz  IR  infrared  J  magnetic resonance c o u p l i n g  m/z  mass-to-charge  Me  methyl  min  minutes  mm  m i l l i m e t r e s of mercury  mmol  millimoles  mp  melting point  NMR  n u c l e a r magnetic resonance  RT  room temperature  THF  terahydrofuran  6  NMR  n ,n 3  v  5  ratio  chemical s h i f t  t r i h a p t o , pentahapto IR s t r e t c h i n g frequency  constant  - 1 -  CHAPTER I  INTRODUCTION A f e a t u r e c h a r a c t e r i s t i c of the d-block  transition  metals i s the a b i l i t y t o form complexes w i t h n e u t r a l molecules such as i s o c y a n i d e s , phosphines, carbon monoxide and n i t r o g e n monoxide.  These l i g a n d s possess vacant -rr-orbitals t h a t a l l o w  them to s t a b i l i z e  low formal o x i d a t i o n s t a t e s of metals.  The most important iT-acceptor l i g a n d i s carbon monoxide and s t u d i e s of the p r e p a r a t i o n o f t r a n s i t i o n metal c a r b o n y l s as w e l l as t h e i r chemistry a r e w e l l documented.  1  The  chemistry of t r a n s i t i o n metal n i t r o g e n monoxide compounds i s l e s s w e l l developed.  P o t e n t i a l l y , the extent of the chemistry  t h a t may be e x h i b i t e d by n i t r o s y l complexes i s as broad as t h a t of c a r b o n y l  complexes.  Although n i t r o g e n monoxide and carbon monoxide a r e known t o bond t o t r a n s i t i o n metals i n a s i m i l a r f a s h i o n , the NO l i g a n d c o n t a i n s one more e l e c t r o n which o c c u p i e s a TT* o r b i t a l . The presence of t h i s e x t r a e l e c t r o n allows a v a r i a t i o n i n the nature of the M-N-0 ligand.  bond which  i s unknown f o r the c a r b o n y l  There are two d i f f e r e n t bonding modes which may be  d e s c r i b e d as f o l l o w s : (1) L i n e a r  The n i t r o s o n i u m i o n , N0 , i s i s o e l e c t r o n i c +  with carbon monoxide and, thus, i t has t h r e e bonding  electron  - 2 -  p a i r s between the atoms and a lone e l e c t r o n p a i r on both the n i t r o g e n and oxygen. are  p o t e n t i a l donors.  Both atoms a r e sp h y b r i d i z e d and both However, the n i t r o g e n c o o r d i n a t e s  p r e f e r e n t i a l l y , thereby a v o i d i n g a l a r g e f o r m a l charge on the more e l e c t r o n e g a t i v e element.  The n i t r o s o n i u m - i o n can be  c o n s i d e r e d as a a-donor and the r e s u l t i n g M-N=0 i s l i n e a r . Occupied metal dir o r b i t a l s p r o v i d e some degree of MTT o v e r l a p e s t a b l i s h i n g a s y n e r g i s t i c bonding  ) NOu*  relationship.  ( A l t e r n a t i v e l y , the l i n e a r group may be c o n s i d e r e d as n i t r o g e n monoxide and a metal c o n t a i n i n g an, empty and a h a l f - f i l l e d  u - o r b i t a l which i n t e r a c t s w i t h the TT*  e l e c t r o n of the NO).  When bonding i n t h i s way, the n i t r o s y l  ligand i s a formal three-electron (2) Bent of  o-orbital  A bent n i t r o s y l  donor. l i g a n d i s an analogue  an o r g a n i c n i t r o s o group o r the NO group i n C1N0. The  M-N-0 l i n k a g e c o n s i s t s of a doubly bonded NO group, a s i n g l e a-bond between the n i t r o g e n and the metal, and a lone p a i r of e l e c t r o n s on the n i t r o g e n atom. i n t h i s case i s s p system i s bent.  2  The n i t r o g e n atom  h y b r i d i z e d and the r e s u l t i n g M-N-0  When bonding i n t h i s way, the n i t r o s y l  l i g a n d i s a formal o n e - e l e c t r o n donor.  Competition between  l i n e a r and bent bonding modes of the l i g a n d i s r e s o l v e d when the e l e c t r o n p a i r i s f o r c e d t o r e s i d e e i t h e r i n an atomic o r b i t a l on the n i t r o g e n atom o r i n a l o w - l y i n g molecular  orbital. Both of these types of bonding a r e p r e s e n t i n the  - 3 -  m o l e c u l a r s t r u c t u r e of [Ru(NO),(PPh,) c 1 i 0  , shown below.  A perspective drawing of the inner coordination geometry of [ R U C 1 ( N O M P ( C , H ) > ) J ] . The estimated standard deviations for the bond lengths shown are: R u - N , 0.016; R u - P , 0.005; R u - C l , 0.005; N - O . 0 . 0 1 6 A . +  S  The b a s a l n i t r o s y l l i g a n d forms a l i n e a r M-N-0 r e l a t i v e l y s h o r t M-N bond.  l i n k with a  In c o n t r a s t , the a x i a l  nitrosyl  l i g a n d c o o r d i n a t e s w i t h a Ru-N-0 bond angle of 136° and a longer Ru-N d i s t a n c e .  Although  the i d e a l bond angle f o r  the bent system i s 120°, d i f f e r i n g amounts of i n t e r a c t i o n between the lone p a i r on the l i g a n d and the metal produce M-N-0  groups w i t h bond angles ranging from  In f a c t , tautomerism  orbitals 120°-180°.  2  between the two p o s s i b l e forms can convert  a c o o r d i n a t e l y s a t u r a t e d compound t o an unsaturated s p e c i e s without the customary requirement  of the d i s s o c i a t i o n of  a l i g a n d . I t i s t h e r e f o r e reasonable t o expect t h a t n i t r o s y l complexes should e x h i b i t d i f f e r e n t chemical p r o p e r t i e s from t h e i r i s o e l e c t r o n i c c a r b o n y l  analogues.  A r e c e n t example of t h i s unique  chemistry has been  - 4 -  shown by a comparison of the chemistry of the well-known [CpFe(CO)with [CpCr(NO) ]2•  3  T  n  i t s i s o e l e c t r o n i c n i t r o s y l analogue e  2  n i t r o s y l complex r e a c t s e f f i c i e n t l y  and  s e l e c t i v e l y with halogen-containing organic substrates.  For  example, i t performs s e l e c t i v e v i c i n a l halogen a b s t r a c t i o n from v i c - d i h a l o a l k y l h a l i d e s l e a v i n g the t h i r d halogen  unper-  turbed, e. g.  trans-dibromide of cholesteryl bromide  The  chemical t r a n s f o r m a t i o n s performed by  [CpCr(NO) ] 2  2  cannot be d u p l i c a t e d by the c a r b o n y l analogue. At the o u t s e t of t h i s r e s e a r c h there were.two g e n e r a l o b j e c t i v e s , namely 1) the p r e p a r a t i o n of new complexes,  organometallic  nitrosyl  and  2) the study of t h e i r c h a r a c t e r i s t i c p h y s i c a l and chemical p r o p e r t i e s .  To t h i s end,  chosen f o r s p e c i f i e - s t u d y .  Chapter  the Group 6B metals  were  II describes t h e - f i r s t  d e t a i l e d study of an 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 complex. Chapter  I I I d e s c r i b e s the p r e p a r a t i o n and  characteristic  - 5 -  chemistry of [CpW (NO) T_ ] . 2  2  F i n a l l y , Chapter IV d e s c r i b e s  the p r e p a r a t i o n and novel p h y s i c a l p r o p e r t i e s of the asymmetric complex CpW(NO)(n -C H )I. 3  3  5  - 6 -  CHAPTER I I  PREPARATION  AND CHARACTERIZATION  OF  (n -CYCLOPENTADIENYL)5  HYDRIDODINITROSYLTUNGSTEN AND ITS GROUP VIB CONGENERS The g e n e r a l methods f o r the s y n t h e s i s of t r a n s i t i o n metal hydrides f a l l  into s i x categories,  namely:  1) Reactions w i t h molecular hydrogen, e.g. , Os(CO)  + H  5  io  2  0  a  t  m  h  > H Os(CO) 2  4  + CO  (1)  2) Reactions of metal complexes with complex e.g.,  hydrides,  5  [CpM(CO)  + NaBH.  » CpM (CO) H + CO Mo,W ?  M =  (2)  3) Hydrogen t r a n s f e r from s o l v e n t o r c o o r d i n a t e d group, e.g.,  6  Cp TiCl 2  2  £2^2£L+  [ p TiH] C  2  2  ( 3 )  4) Hydrolyses and dehydrohalogenation, e.g., (C H )_N [CpRe(CO) NO] C Re(CO (NO)H (4) a c ^ J / w a t e r ^ 7  9  +  2  5) P r o t o n a t i o n , Cp WH 2  2  + HBr  P  e.g., :  )  0  > [Cp WH ] Br~ +  2  3  (5)  6) O x i d a t i v e a d d i t i o n of hydrogen or hydrogen h a l i d e s  - 7-  to c a t i o n i c metal  complexes, e.g.,  [Ir(CO)L ]  + H  +  4  ^p  2  Since w e l l developed n i t r o s y l complexes e x i s t ,  1 0  '  9  (  C  H  3  )  2  p ) h  [H Ir(CO)L ] 2  +  3  (6)  p r e p a r a t i v e routes t o h a l o 1 1  i t seemed reasonable  that  attempted r e d u c t i o n o f these complexes c o u l d be the b e s t route t o h y d r i d o n i t r o s y l s p e c i e s .  T h i s chapter d e s c r i b e s  the attempts t o convert some of these p r e c u r s o r s , s p e c i f i c a l l y the complexes  CpM(NO) Cl (M=Cr, Mo, W ) 2  12  t o the d e s i r e d  hydridonitrosyIs.  EXPERIMENTAL SECTION A l l chemicals used were of reagent grade or comparable p u r i t y and were e i t h e r purchased or prepared  from commercial s u p p l i e r s  a c c o r d i n g t o r e p o r t e d procedures.  Their purity  was a s c e r t a i n e d from elemental analyses and/or m e l t i n g p o i n t 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. a c c o r d i n g t o standard p r o c e d u r e s  1 3  p r e p u r i f i e d n i t r o g e n p r i o r t o use. unless otherwise  14  and thoroughly purged with A l l manipulations,  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 compounds  A l l s o l v e n t s were d r i e d  f o r the m a n i p u l a t i o n of a i r s e n s i t i v e  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 n i t r o g e n . 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  - 8 -  or 710A 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 o f p o l y s t y r e n e f i l m .  1  Routine proton magnetic  resonance s p e c t r a were recorded on V a r i a n A s s o c i a t e s T-60 or XL-100 spectrometers 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.  High r e s o l u t i o n  *H FT-NMR s p e c t r a were r e c o r d e d a t  270 MHz by Mrs. M.M. Tracey on a departmental spectrometer emp l o y i n g an Oxford Instruments superconducting magnet and N i c o l e t Instrument C o r p o r a t i o n hardware. used as an i n t e r n a l standard.  T e t r a m e t h y l s i l a n e was again  Carbon-13 NMR s p e c t r a were r e -  corded on a V a r i a n A s s o c i a t e s CFT-20 spectrometer w i t h r e f e r e n c e to the s o l v e n t used.  A l l chemical s h i f t s are r e p o r t e d i n ppm  downfield from Me^Si.  The mass s p e c t r a were recorded a t 7 0  eV on an A t l a s CH4B spectrometer w i t h t h e a s s i s t a n c e of Mr. J.W. N i p . Elemental a n a l y s e s were performed by Mr. P. Borda, and the 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. T . J . Greenhough. Reaction of CpW(NO) Cl w i t h Ka. [A1H (OCH CH OCH ) ] . 2  2  a green s o l u t i o n o f C p W ( N O ) C l  12  2  2  2  3  2  2  to 20 mL with t o l u e n e .  2  3  2  15  To  (3.00 g, 8.71 mmol) i n t o l -  uene (75 mL) a t -7 8°C was added dropwise w i t h s t i r r i n g t i o n of N a [ A 1 H ( O C H C H O C H ) ]  2  a solu-  (2.49 mL, 8.71 mmol) d i l u t e d  The r e a c t i o n mixture changed immedi-  a t e l y t o dark green, and a brown s o l i d p r e c i p i t a t e d .  After  a l l the aluminum reagent had been added, the r e a c t i o n mixt u r e 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 reaction.  complete  Without being allowed t o warm t o room temperature,  the mixture was q u i c k l y f i l t e r e d through a s h o r t  (3x5 cm) c o l -  - 9 -  umn  of F l o r i s i l  supported on a medium p o r o s i t y f r i t t e .  b r i g h t green f i l t r a t e  was  taken to dryness i n vacuo, and the  r e s i d u e was d i s s o l v e d i n 10 mL of dichloromethane. s o l u t i o n was of  The  t r a n s f e r r e d onto a 2x6 cm F l o r i s i l  The. r e s u l t i n g  column.  Elution  the column w i t h dichloromethane r e s u l t e d i n the d e v e l o p -  ment of a s i n g l e b r i g h t green band which was taken to dryness under reduced p r e s s u r e . the  r e s i d u e a t ambient  temperature  i c e - c o o l e d probe y i e l d e d 61%  and  S u b l i m a t i o n of 3  mm)  onto a d r y -  a n a l y t i c a l l y pure CpW(NO) H (1.65 g, 2  yield). A n a l . C a l c d f o r C H,WN„0„: c  2.  DO  Found: 1632  (5x10  collected  C, 19.58; H, 1.83;  cm" . 1  Mp  C, 19.37; H, 1.95;  N, 8.91.  IR  (CH C1, ) : 2  2  v (NO)  1718,  The r e a c t i o n of  2  2  9.04.  52°C.  Reaction of CpW(NO) Cl w i t h NaBH^. CpW(NO) Cl  N,  2.  (1.00 g, 2.91 mmol) i n THF  NaBH^ (0.11 g, 2.9 mmol) a t ambient  (25 mL)  with s o l i d  temperature f o r 1 h  proceeded completely a n a l o g o u s l y to the preceeding t r a n s formation. vacuo. 0.12  g  The r e a c t i o n mixture was  The r e s i d u e was  taken to dryness i n  t r e a t e d as d e s c r i b e d above to y i e l d  (13% y i e l d ) of CpW(N0) H. 2  Reaction of [CpW(NO) CO]PFgWJth NaBD^. 2  green suspension of [ C p W ( N O ) ( C O ) ] P F 2  i n THF  (60 mL)  was  16 g  To a s t i r r e d  (2.40 g, 4.98  added s o l i d NaBD^ (0.21 g, 5.02  r e a c t i o n mixture was  mmol)  mmol).  The  s t i r r e d v i g o r o u s l y f o r 1 h d u r i n g which  time i t became red-brown.  The s o l v e n t was  vacuo, and the r e s u l t i n g r e s i d u e was  then removed i n  e x t r a c t e d with ca. 10  mL  - 10 -  of  dichloromethane.  Chromatography of the dark green e x t r a c t s  on a 2x6 cm F l o r i s i l  column w i t h dichloromethane as e l u a n t  r e s u l t e d i n the development  of a s i n g l e b r i g h t green band t h a t  was e l u t e d and c o l l e c t e d .  The e l u a t e was taken t o dryness  i n vacuo t o o b t a i n CpW(NO) D (0.36 g, 23% y i e l d ) which was 2  i d e n t i f i e d by i t s i n f r a r e d and mass s p e c t r a . Reaction o f CpMo. (NO) ^ C l  w i t h Na [A1H (OCH CH OCH ) ] . 2  To a s t i r r e d green s o l u t i o n of CpMo(NO) C1  2  12  2  2  3  2  (1.00 g, 3.89  mmol) i n toluene (25 mL) a t -78°C was added dropwise a s o l u t i o n o f Na[A1H (OCH CH OCH ) J 2  2  2  d i l u t e d t o 10 mL w i t h t o l u e n e .  3  2  (1.11 mL, 3.89 mmol)  Immediately  the r e a c t i o n  mixture developed a dark green c o l o u r a t i o n , and a red-brown p r e c i p i t a t e formed.  A f t e r a l l the aluminum reagent had been  added, the 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. I t  was then q u i c k l y f i l t e r e d w h i l e c o l d through a s h o r t column o f F l o r i s i l  supported on a medium-porosity  The green f i l t r a t e  was p e r m i t t e d t o warm t o room  and was t i t r a t e d w i t h a toluene s o l u t i o n of I u n t i l the c h a r a c t e r i s t i c c o l o u r of I  2  2  (3x5 cm)  fritte. temperature  (ca. 0.2 M)  persisted.  Volatile  s p e c i e s were removed under reduced p r e s s u r e , and the remaining  r e s i d u e was d i s s o l v e d i n ca. 5 mL of dichloromethane.  Chromatography o f t h i s s o l u t i o n on a 2x6 cm F l o r i s i l  column  w i t h dichloromethane as e l u a n t r e s u l t e d i n the development of  a s i n g l e green band which was c o l l e c t e d .  The e l u a t e was  taken t o dryness i n vacuo t o o b t a i n green CpMo(N0) I 2  (0.29 g,  21% y i e l d o v e r a l l ) which 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  - 11 -  physical  properties.  1 6  Reaction of C p C r ( N O ) C l w i t h Na[A1H (OCHgCHgOCH,) ]. 2  2  A s o l u t i o n of Na[A1H (OCH CH OCH ) ] 2  2  2  3  d i l u t e d t o 10 mL w i t h t o l u e n e was  2  (1.35 mL,  2  4.72  mmol)  added dropwise a t room  temperature t o a s t i r r e d , golden s o l u t i o n of C p C r ( N O ) C 1  12  2  (0.80 g, 4.72  mmol) i n toluene (25 ml) .  The r e a c t i o n  became r e d , and a brown s o l i d p r e c i p i t a t e d . s t i r r e d f o r an a d d i t i o n a l 0.5 through a F l o r i s i l column porosity ca.  fritte.  5 mL and was  (Woelm n e u t r a l ,  A f t e r being  h, the mixture was  (3x4 cm)  The f i l t r a t e was  mixture  filtered  supported on a medium concentrated i n vacuo t o  s y r i n g e d onto a 3x4 cm column of alumina a c t i v i t y grade 1).  E l u t i o n w i t h benzene  developed a s i n g l e red 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 t o o b t a i n r e d - p u r p l e , m i c r o crystalline  [CpCr(NO) ] 2  (0.15 g, 22% y i e l d ) , r e a d i l y  2  i f i a b l e by i t s d i s t i n c t i v e p h y s i c a l Reactions o f CpW(NO) H w i t h I 2  s o l u t i o n of CpW(NO) H (0.30 g, 0.97 2  (25 mL)  at room temperature was  a p u r p l e s o l u t i o n of I (15 mL).  and B r .  2  2  To a green  mmol) i n dichloromethane  added dropwise w i t h s t i r r i n g  (1.23 g, 0.49  2  1 7  mmol) i n dichloromethane  At once the r e a c t i o n mixture turned dark green.  The f i n a l s o l u t i o n was was  properties.  ident-  c o n c e n t r a t e d i n vacuo t o c a . 5 mL  and  s y r i n g e d onto a 2x6 cm F l o r i s i l column. E l u t i o n with  dichloromethane r e s u l t e d band which was  i n the development  collected.  S o l v e n t was  i n vacuo t o o b t a i n CpW(NO) I 2  of a s i n g l e green  removed from the e l u a t e  (0.20 g, 47% y i e l d ) which  was  - 12  -  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 p h y s i c a l  A s i m i l a r experiment performed by u s i n g Br,, the analogous CpW(NO) Br  i n 48%  16  2  To a s t i r r e d  2  2  at room temperature was sulfonic acid  (0.17  g,  g,  1.0  The  mmol) i n THF  (30  1.0  mmol).  The  r e s i d u e was  r e a c t i o n mixture  h b e f o r e being taken to  dissolved  in dichloro-  methane (30 mL)  to o b t a i n  hexanes (60 mL)  to t h i s s o l u t i o n induced the d e p o s i t i o n  a blue-green s o l u t i o n .  a red-brown s o l i d which was c o n c e n t r a t i o n of the  mL)  added s o l i d , anhydrous p - t o l u e n e -  darkened w h i l e being s t i r r e d f o r 0.5 dryness i n vacuo.  afforded  yield.  Reaction of CpW(NO) H w i t h ^-CF^CgH^SC^H. green s o l u t i o n of CpW(NO) H (0.31  .1 6  properties  removed by  Addition  filtration.  of  of  Slow  f i l t r a t e under reduced p r e s s u r e  resulted  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, green CpW(NO) 02  S0 C H CH 2  6  4  (0.35  3  g, 73% y i e l d ) .  Anal. Calcd Found: 1650  cm  i o n m/z  f o r C^H-^WN^S:  C,  29.75; H,  .  Mp  1  2.51;  N,  120°C dec.  5.66.  C,  30.01; H,  IR  (CH C1 ): 2  Mass spectrum:  N,  v(NO)  2  1737,  4 80. 2  of P h C B F  1 8 4  (0.33  g, 1.0  3  4  A yellow  solution  mmol) i n a c e t o n i t r i l e (5 mL)  was  added dropwise t o a s t i r r e d s o l u t i o n of CpW(NO) H (0.31 2  1.0  5.84  most i n t e n s e parent  R e a c t i o n of CpW(NO) H w i t h P h C B F . 3  2.52;  mmol) i n a c e t o n i t r i l e (30 mL)  mixing of the two  solutions,  at -10°C.  After  the  [CpW(NO) (CH CN)] 2  to be the o n l y 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 p r e s e n t . ;  complete  an i n f r a r e d spectrum of  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  g,  +  3  1 6  Upon  - 13  a d d i t i o n of Nal  (0.15  g, 1.0  -  mmol), the r e a c t i o n mixture  immediately became o l i v e - g r e e n . taken to dryness i n vacuo, and a minimum of dichloromethane  The  r e a c t i o n mixture  the r e s i d u e was  (5 mL).  dissolved in  Chromatography of  s o l u t i o n on F l o r i s i l w i t h dichloromethane as e l u a n t provided 2 0 ml.  a green e l u a t e which was The  a d d i t i o n of hexanes  concentration  was  concentrated (20 mL)  and  this  (vide supra)  i n vacuo to  continued  slow  of the s o l u t i o n r e s u l t e d i n the p r e c i p i t a t i o n  of o l i v e - g r e e n  c r y s t a l s of CpW(NO) I (0.25  g, 57%  2  y i e l d based  on CpW(NO) H) which were c o l l e c t e d b y . . - f i l t r a t i o n . 2  The  f i l t r a t e was  taken to dryness i n vacuo to  a l i g h t green r e s i d u e .  This s o l i d was  minimum of benzene, and  the s o l u t i o n was  top of a 3x4 column was  cm  column of alumina  washed w i t h 100  less eluate.  dissolved in a transferred to  the  ( a c t i v i t y grade 1).  The  of benzene t o o b t a i n a c o l o u r -  Removal of s o l v e n t from the e l u a t e under  reduced pressure was  mL  leave  provided  Ph^CH (0.15  g,  61%  y i e l d ) which  i d e n t i f i e d by comparison of i t s p h y s i c a l p r o p e r t i e s  with those of an a u t h e n t i c The  sample.  above experiment was  repeated  by u s i n g CpW(N0) D 2  to o b t a i n a comparable y i e l d of Ph^CD which was  identified  mass s p e c t r o m e t r i c a l l y . Reaction  of CpW(NO) H with HCoCCO)^. 2  s o l u t i o n of HCo(CO) i n THF  (50  4  [prepared  To a p a l e  from Co (CO)g 2  m L ) ] cooled to -78°C was 1 9  s t i r r i n g a s o l u t i o n of CpW(NO) H (0.62 2  (0.34  g  f  yellow I.Q mmol)  added dropwise with g, 2.0  mmol) i n  THF  - 14 -  (50 mL) . A f t e r the a d d i t i o n was t u r e was  complete, the r e a c t i o n mix-  p e r m i t t e d to warm slowly to room temperature where-  upon i t s c o l o u r changed g r a d u a l l y t o red-brown. mixture was  The  s t i r r e d a t ambient temperature f o r an a d d i t i o n a l  16 h to ensure complete r e a c t i o n , and i t was through a s h o r t  (3x4 cm)  column o f C e l i t e .  then f i l t e r e d  Concentration  of 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 the removal of s o l v e n t and an orange-red, v o l a t i l e compound which was not i s o l a t e d but was  i d e n t i f i e d as Co(CO) NO by 3  a solution infrared spectrum.  A f t e r removal of a l l  20  v o l a t i l e s p e c i e s , the remaining orange-brown sublimed a t room temperature  (5x10  cooled probe to o b t a i n CpW(CO) N0 2  3  12  mm)  residue  was  onto a d r y - i c e -  (0.25 g, 37% y i e l d  based  on W) . R e a c t i o n of CpW(NO) H w i t h CpW(CO) H. 2  3  To a green  s o l u t i o n of CpW(NO) H (0.31 g, 1.0 mmol) i n THF 2  added s o l i d , y e l l o w CpW(CO) H 3  the r e s u l t i n g s o l u t i o n was f o r 48 h.  21  (30 mL)  was  (0.33 g, 1.0 mmol), and  s t i r r e d at room temperature  During t h i s time, the r e a c t i o n mixture became  red, and a c o n s i d e r a b l e amount of brown p r e c i p i t a t e The s o l v e n t was r e s i d u e was s o l u t i o n was  formed.  removed from the mixture i n vacuo, and the  e x t r a c t e d i n t o dichloromethane. (5 mL) . then chromatographed  on a 2x5 cm  The red  Florisil  column w i t h dichloromethane as e l u a n t t o o b t a i n a s i n g l e red band which was  c o l l e c t e d and taken to dryness i n vacuo.  S u b l i m a t i o n of the r e s i d u e at room temperature onto a dry  - 15 -  i c e - c o o l e d probe a f f o r d e d orange CpW(CO) N0  12  2  mmol). be  (0.14 g, 0.42  The r e d s o l i d remaining i n the sublimer was found t o  [CpW(CO) ] 3  2 2 2  (0.09 g, 0.14 mmol).  Both products were  i d e n t i f i e d by t h e i r c h a r a c t e r i s t i c p h y s i c a l p r o p e r t i e s . Treatment of  of C p W ( N O ) w i t h HPhCCHBr.  CpW(NO) H (0.10 g, 0.32 mmol) i n THF 2  w i t h an excess of neat bromostyrene mmol). for  (10 mL) was  treated  (0.10 mL, 0.14 g, 0.7 8  The mixture was allowed t o s t i r a t room  temperature  3 6 h d u r i n g which time a l a r g e amount of red-brown s o l i d  deposited. the  A s m a l l amount  The p r e c i p i t a t e was removed by f i l t r a t i o n and  s o l v e n t was removed from the green f i l t r a t e under  pressure.  reduced  The r e s i d u e was found t o c o n t a i n only unreacted  starting materials. Treatment  of CpW(NO) H with F e ( C O ) 2  5  To THF  (20..mL) . and  CpW(NO) H (0.10 g, 0.32 mmol) was added neat F e ( C O ) 2  0.07 g, 0.36 mmol). for  18 h.  5  (0.05 mL,  The s t i r r e d r e a c t i o n mixture was r e f l u x e d  At the end of t h a t time a s o l u t i o n  infrared  spectrum showed CpW(N0) H t o be the o n l y n i t r o s y l - c o n t a i n i n g 2  species present. Treatment  of CpW(NO) H w i t h C C l ^ . 2  A s m a l l amount o f  CpW(NO) H (0.10 g, 0.32 mmol) was d i s s o l v e d i n CC1 2  4  (50  mL)  and the r e a c t i o n mixture was s t i r r e d a t room temperature for  2 4 h.  During t h a t time there was no c o n v e r s i o n t o  CpW(N0) Cl, as evidenced by s o l u t i o n i n f r a r e d s p e c t r a , and 2  CpW(NO)„H was -recovered q u a n t i t a t i v e l y .  - 16 -  R e s u l t s and D i s c u s s i o n Reduction of CpM(NO) Cl  (M=Cr, Mo  2  and B i s n e t t e f i r s t r e p o r t e d i n 1963 CpCr(NO) Cl 2  affords of  or W) Complexes. King  t h a t the r e d u c t i o n of  w i t h NaBH^ i n a two phase water-benzene  [CpCr(NO) l 2  2  t h i s r e a c t i o n may  i n 5% y i e l d .  system  A plausible f i r s t  2 3  step  w e l l i n v o l v e the formation of the therm-  a l l y u n s t a b l e hydridochromium complex CpCr(NO) H, which 2  subsequently d i m e r i z e s t o the observed product w i t h e x p u l s i o n of hydrogen. * 21  concomitant  However, t h e r e have been no  r e p o r t s s i n c e t h a t time concerning the i s o l a t i o n of t h i s hydride or i t s molybdenum and tungsten The complexes CpM(NO) H  analogues.  (M=Mo or W)  2  can b e s t be  prepared by treatment of the r e s p e c t i v e CpM(NO) Cl p r e c u r s o r s 2  w i t h the r e d u c i n g agent sodium d i h y d r i d o b i s ( 2 - m e t h o x y e t h o x y ) aluminate  1 5  i n toluene a t -78°C .  C M(N0) C1  giuene,  M=Mo or W  [Al]=Na[H Al(OCH CH OCH ) ]  P  2  -78°C  >  2  C M(NO) H P  2  (7)  2  2  3  M o n i t o r i n g of the progress of r e a c t i o n 7 by  2  infrared  spectroscopy 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 the r e a c t a n t s i s 1:1. aluminohydride  I t a l s o shows t h a t an  adduct w i t h CpM(NO)  2  i s not f o r m e d ,  exact nature of the aluminum byproduct  remains  25  but the  to be a s c e r t a i n e d  The t h e r m a l l y s t a b l e complex CpW(NO) H can be'; r e a d i l y 2  obtained i n 61% y i e l d from r e a c t i o n 1, but the molybdenum  - 17 -  congener has so f a r d e f i e d a l l attempts a t i s o l a t i o n .  Bright  green toluene s o l u t i o n s c o n t a i n i n g CpMo (NO) H s l o w l y d e p o s i t 2  a red-brown s o l i d when s t i r r e d a t ambient p r e p u r i f i e d n i t r o g e n atmospheres complete i n ^3 days.  temperature  inr.a  the decomposition being  The r a t e of decomposition of the h y d r i d o  complex i s markedly enhanced by removal o f the s o l v e n t i n vacuo, a procedure which a f f o r d s only the red-brown s o l i d . T h i s s o l i d does not d i s s o l v e i n 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 spectrum  (Nujol mull) i s devoid of any absorp-  t i o n s a t t r i b u t a b l e t o a c o o r d i n a t e d n i t r o s y l group. theless, spectroscopic  Never-  (Table I) and chemical (vide i n f r a )  p r o p e r t i e s o f the green t o l u e n e s o l u t i o n s are completely c o n s i s t e n t w i t h the presence o f CpMo(NO) H. 2  Not s u r p r i s i n g l y , r e d u c t i o n of CpCr(NO) C1 w i t h 2  Na[A1H (OCH CH OCH ) ] i n toluene a t room temperature does 2  2  produce  2  3  [CpCr(NO) l 2  C Cr(NO) Cl P  2  Reaction 8 does  2  2  i n 22% y i e l d .  » [C Cr(NO) ] P  not occur a t -78°C.  2  (8)  2  No d i r e c t  physical  e v i d e n c e . f o r the e x i s t e n c e of the e l u s i v e CpCr(NO) H could 2  be  found a t e i t h e r temperature.  However, by analogy w i t h  the tungsten and molybdenum systems, i t i s probable t h a t r e a c t i o n 8 does proceed v i a t h i s hydridochromium must be very t h e r m a l l y u n s t a b l e .  complex which  The observed i n c r e a s e i n  thermal s t a b i l i t y of the CpM(NO)pH compounds from the f i r s t  - 18 -  Table I.  S p e c t r a l P r o p e r t i e s of CpW(NO)„H and R e l a t e d Complexes  Infrared, Complex  v  (NO)  a  cm  Proton NMR, <S b  1  other  C H 5  other  5  CpW(NO) H  1718 1632  1900 v (W-H)  5.05  b  CpW(NO) D  1718 1632  1372 v (W-D)  5.05  b  2  2  CpW(NO) S0 C H 2  3  7  [CpW(NO) (CH CN)]BF 2  3  2  a  In C H C 1 2  c  In CDC1  4  2  a  u n l e s s otherwise i n d i c a t e d . '  C  1770 1690 1732 1642  CpMo(NO) H  6.15  1737 1650  7  In t o l u e n e .  b  In C,D,-. 6 6  2.77  2.70 s 3H 7.41 m 4H  - 19 -  to the t h i r d t r a n s i t i o n s e r i e s p a r a l l e l s the observed  behaviour  of the analogous complexes, CpM(CO) H, f o r which the thermal 3  and o x i d a t i v e s t a b i l i t i e s a l s o i n c r e a s e i n the order Cr<Mo <W.  2I+  Conversions'7 and 8 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 furan w i t h NaBH^, but the y i e l d s of the d e s i r e d products a r e much lower. 13% y i e l d  F o r i n s t a n c e , CpW(NO) H i s o b t a i n a b l e i n only 2  i n t h i s manner.  However, i t has been found t h a t  t h i s h y d r i d o product can be formed, by r e a c t i o n 9.  a l b e i t i n o n l y 23% y i e l d ,  When NaBD^ i s employed as the r e d u c i n g agent,  [CpW(NO) (CO) ] P F 2  6  |§|^4  » CpW(NO) H  (9)  2  r e a c t i o n 9 r e p r e s e n t s a convenient route t o the d e u t e r i d e , CpW(NO) D. 2  P h y s i c a l P r o p e r t i e s of CpW(NO) H. 2  (n -Cyclopentadienyl)5  h y d r i d o d i n i t r o s y l t u n g s t e n i s a b r i g h t green, diamagnetic  solid  which can be handled i n a i r f o r s h o r t p e r i o d s of time without the occurence of n o t i c e a b l e decomposition.  I t i s freely  uble i n common o r g a n i c s o l v e n t s , but only s p a r i n g l y i n p a r a f f i n hydrocarbons,  soluble  t o g i v e a i r - s e n s i t i v e green  t i o n s , and i t sublimes r e a d i l y a t room temperature mm) onto a d r y i c e - c o o l e d probe.  sol-  solu-  (5x10  3  I t s spectral properties  (Table I) are c o n s i s t e n t w i t h the compound having the molecul a r s t r u c t u r e shown below. dichloromethane  Thus, an i n f r a r e d spectrum of a  s o l u t i o n of the complex e x h i b i t s two s t r o n g  - 20 -  ON'  1  >H  N 0  absorptions  at 1718  and  n i t r o s y l ligands.  1632  "piano  a t t r i b u t a b l e to the  1  These bands are a t f r e q u e n c i e s  lower than the corresponding precursor  cm  absorptions  terminal  slightly  of the CpW(NO) Cl 2  which has r e c e n t l y been found to adopt a s i m i l a r  1 0  s t o o l " geometry i n the s o l i d s t a t e .  there i s a broad, weak band a t 1900 t e r m i n a l l y bonded W-H  cm  1  2 6  Furthermore,  a s s i g n a b l e as  stretching absorption.  the  In accord  with  t h i s assignment i s the f a c t t h a t the i n f r a r e d spectrum of CpW(NO) D i n C H C 1 2  2  2  does not e x h i b i t t h i s band but does  show a weak a b s o r p t i o n at 1372 W-D  group.  equals  cm  a s s i g n a b l e to a t e r m i n a l  1  As expected, the observed s h i f t , s i n c e v(MH)  1.38  and  v (NO)  v(MH)/v(MD),  are not a p p r e c i a b l y mixed  i n the hydrido d e r i v a t i v e . The  X  H  NMR  spectrum of CpW(NO) H i n CgDg c o n s i s t s of 2  a sharp resonance at 6 5.05  and  a s l i g h t l y broader resonance  at 62.77 of r e l a t i v e i n t e n s i t y 5:1.  The  former s i g n a l i s  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 r i n g . l a t t e r i s assigned  The  to a hydrogen atom bonded d i r e c t l y to the  - 21 -  tungsten c e n t r e s i n c e i t does not appear i n the E  MNR  1  spectrum of CpW(NO) D recorded under i d e n t i c a l c o n d i t i o n s 2  (Table I ) . though  However,  183  W- H c o u p l i n g i s not observed even 1  such c o u p l i n g has been measured f o r the r e l a t e d CpW(CO)^H  complex.  The occurrence o f the h y d r i d e resonance a t  27  relatively  low f i e l d  i s somewhat anomalous s i n c e these  resonances a r e u s u a l l y observed a t h i g h f i e l d s , i n the range 6-5 t o - 2 0 .  2 8  typically  F o r example, CpRe(CO)(NO)H  d i s p l a y s a broad s i g n a l a t 6-8.2 due t o the h y d r i d e l i g a n d .  7  A low f i e l d resonance i s n o t unknown f o r t r a n s i t i o n metal h y d r i d e s , but t o date i t has been c h a r a c t e r i s t i c only of some b i s ( c y c l o p e n t a d i e n y l ) h y d r i d o complexes of t i t a n i u m , zirconium  2 9  and n i o b i u m *  30  The mass spectrum of CpW(N0) H e x h i b i t s a fragmentation 2  p a t t e r n s i m i l a r t o t h a t d i s p l a y e d by CpW(NO) CH^ 2  identical conditions.  31  under  Peaks a t t r i b u t a b l e t o the p a r e n t i o n  and i o n s c o r r e s p o n d i n g t o the stepwise l o s s of n i t r o s y l l i g a n d s are observable i n both cases, but i o n s r e s u l t i n g from cleavage and rearrangement  of the c y c l o p e n t a d i e n y l  r i n g appear t o be much more abundant i n the spectrum of CpW(NO) H. 2  U n f o r t u n a t e l y , o v e r l a p p i n g of some medium t o  s t r o n g i n t e n s i t y peaks i n the lower mass range makes unambiguous assignments  difficult,  e s p e c i a l l y i n l i g h t of  the p o l y i s o t o p i c nature o f tungsten. The Chemical R e a c t i v i t y of CpM(NO) H [M=Mo or W]. 2  compared w i t h metal c a r b o n y l h y d r i d e s t o which they a r e  When  - 22 -  f o r m a l l y r e l a t e d , the CpM(NO) H complexes d i s p l a y  both  2  s i m i l a r i t i e s and very s t r i k i n g d i f f e r e n c e s i n t h e i r reactivity  chemical  (Figure 1 ) . For i n s t a n c e , even though c a r b o n y l  h y d r i d e s of g e n e r a l formula CpM(CO) H [X=3, M=Cr, Mo orV/W ; 24  X=2, M=Fe  32  or R u ] can a l l be decomposed t h e r m a l l y or 3 3  o x i d a t i v e l y t o y i e l d the corresponding dimers,  [CpM(CO) ] , x  2  the green CpM(NO) H s p e c i e s only decomposes t o red-brown 2  n i t r o s y l - f r e e s o l i d s when s u b j e c t e d t o the same experimental conditions.  Moreover, CpW(NO) H does not r e a c t w i t h h a l o 2  carbons such as CHC1  3  or CC1  4  a t ambient temperature  although  such a r e a c t i o n i s o f t e n employed t o e s t a b l i s h the presence of a metal-hydrogen  bond.  28  However, l i k e numerous  c a r b o n y l h y d r i d e s , CpW(NO) H does r e a c t d i r e c t l y w i t h  halogens  2  to a f f o r d the r e s p e c t i v e h a l o d e r i v a t i v e s i n reasonable yields.  A s i m i l a r c o n v e r s i o n allows the chemical  identi-  f i c a t i o n of CpMo(NO) H as the product formed i n r e a c t i o n 7 2  above,  i.e.  CpMo(NO) H  (not i s o l a t e d ) — t o l u e n e  2  ?  CpMo (NO) * ••  (  1  0  )  2  The most s i g n i f i c a n t d i f f e r e n c e between CpW(NO) H and 2  most c a r b o n y l h y d r i d e s i s e v i d e n t i n i t s acid-base behaviour. Many n e u t r a l h y d r i d o c a r b o n y l s a r e Lowry-Br0nsted polar s o l v e n t s ,  2 8  but the h y d r i d o t u n g s t e n complex acts as a  source of H~ under these c o n d i t i o n s . demonstrated  acids i n  This fact i s c l e a r l y  by i t s r e a c t i o n w i t h anhydrous p - t o l u e n e s u l f o n i c  CpW(NO) ? X [X= Br or I ] no reaction  t  hexanes,5days  x 2  CpW(C0)2(N0) +  [c w(coy P  (h)  £E=£_  C  HCo (CO) THF  4  3  (a)  2  :; (c)  C H  3  CpW(Nq20S02C5H4CH:  S °- . S  H  THF  Ke) (d?  THF reflux, 24 h Fe(COL  to  (C H ) CBF CH CN ^ 6  5  3  4  3  CpW(CO)2(NO) + Co (CO) (NO)  4  (bl  p^(N0)2H (f)  2  CHCt dr CCl , 24 h  2  CH Cl  no reaction  [CpW(NO) 2 (CH 3 CN)] + no reaction CpW(NO)2I  F i g u r e 1. The c h a r a c t e r i s t i c chemistry of CpW(NO) H. 2  - 2.4 -  a c i d t o y i e l d the new  p - t o l u e n e s u l f o n a t o complex under  c o n d i t i o n s which leave CpW(CO) H u n a l t e r e d .  Consistent with  3  t h i s view of W(S )-H(6  ) bond p o l a r i t y i s the f a i l u r e of  +  CpW(NO) H to r e a c t w i t h 2  ( C H ) N and i t s r e a c t i o n w i t h the 2  5  3  well-known h y d r i d e a b s t r a c t o r t r i p h e n y l c a r b e n i u m t e t r a f l u o r o borate i n a c e t o n i t r i l e to a f f o r d Ph CH.  [CpW(NO) (CH^CN)]BF^ and 2  The o r g a n i c product can be i s o l a t e d i n 61%  3  yield,  but the o r g a n o m e t a l l i c complex i s o b t a i n e d as an o i l which cannot be r e a d i l y p u r i f i e d . by comparison 1690  cm  -1  However, i t can be  of i t s i n f r a r e d spectrum  identified  (v(NO) a t 1770  i n CH CN) w i t h t h a t e x h i b i t e d by  [CpW(NO) (CH CN)]PF  3  2  and by i t s r e a c t i o n w i t h Nal t o form CpW(NO) I.  16  2  s i m i l a r treatment  of CpW(NO) D w i t h P h C B F 2  3  and  4  3  As  expected,  p r o v i d e s Ph CD 3  i n comparable y i e l d s . The h y d r i d i c c h a r a c t e r of the tungsten h y d r i d e i s s u r p r i s i n g s i n c e i t i s g e n e r a l l y b e l i e v e d t h a t the  presence  of e l e c t r o n - w i t h d r a w i n g l i g a n d s on the metal c e n t r e enhances the a c i d i c c h a r a c t e r oS;: M-H  bonds.  chemistry pf CpW(N0) H resembles 2  28  N e v e r t h e l e s s , the  that t y p i c a l l y exhibited  by  t r a n s i t i o n - m e t a l t e r t i a r y phosphine h y d r i d e complexes which are a l s o not a c i d i c i n s o l u t i o n and w i l l not form sodium analagous philic  to t h o s e " o f t h e i c a r b o n y l h y d r i d e s .  Direct  salts  nucleo-  t r a n s f e r of h y d r i d e from a h y d r i d o c a r b o n y l complex  to e l e c t r o p h i l i c c e n t r e s has been observed  recently.  However, the complex i n v o l v e d , [CpV(CO) H]  , i s a n i o n i c and  3  g  3 4  t h e r e f o r e probably c o n t a i n s a l a r g e amount of e l e c t r o n d e n s i t y  - 25 -  at the metal. CpW(NO) H  I t thus appears  t h a t the n i t r o s y l l i g a n d s i n  are not p a r t i c u l a r l y e f f e c t i v e as ir-acids i n removing  2  e l e c t r o n d e n s i t y from tungsten.  C o n s i s t e n t w i t h t h i s view i s  the f a c t t h a t s e v e r a l c a t i o n s of the type (L=neutral Lewis base) are known, has y e t to be c h a r a c t e r i z e d  [CpW(NO) L]  but the anion  16  +  2  [CpW(NO) ] 2  (cf. reaction (h)).  In l i g h t of the observed h y d r i d i c behaviour of CpW(NO) H, 2  it  i s not unreasonable  t o expect t h a t i t w i l l r e a c t w i t h  a c i d i c h y d r i d o c a r b o n y l s t o form b i m e t a l l i c complexes. isolated  carbonylnitrosyl  However, these types of products have y e t to be  from such r e a c t i o n s . , Thus,-when CpW(NO) H 2  i s t r e a t e d with equimolar amounts of HCo(CO)  4  or CpW(CO) H, 3  the only c a r b o n y l - and n i t r o s y l - c o n t a i n i n g products r e s u l t from the scrambling of the two  isolated  l i g a n d s among the metal  centres, possibly v i a a b i m e t a l l i c intermediate.  A  similar  r e d i s t r i b u t i o n of l i g a n d s has been observed r e c e n t l y to occur d u r i n g r e a c t i o n s of N i ( N O ) ( P P h ) X 3  c a r b o n y l m e t a l l a t e s such as CpMo(CO)  3  2  ,  (X=Cl,Br  or I) w i t h  3 5  F i n a l l y , i t i s known t h a t s t r o n g h y d r i d e donors a t t a c k e l e c t r o p h i l e s such as metal c a r b o n y l s to produce plexes.  3 6  However, CpW(NO) H i s not s u f f i c i e n t l y 2  to r e a c t w i t h F e ( C O )  formyl comhydridic  i n refluxing tetrahydrofuran.  5  Unlike  the M-H  l i n k a g e s of many a c i d i c t r a n s i t i o n metal h y d r i d e s ,  the W-H  bond i n the n i t r o s y l h y d r i d e does not undergo simple  a d d i t i o n r e a c t i o n s w i t h unsymmetrical styrene. no new  2 8  alkenes such as bromo-  The CpW(NO) H i s consumed d u r i n g the r e a c t i o n , but 2  o r g a n o m e t a l l i c n i t r o s y l products are formed.  CHAPTER I I I  SYNTHESIS AND CHARACTERIZATION OF BIS[(n -CYCLOPENTADIENYL) 5  DIIODONITROSYLTUNGSTEN] Since  an i n v e s t i g a t i o n of the chemistry o f CpW(NO) H 2  produced some s u r p r i s i n g r e s u l t s (Chapter I I ) , i t became apparent that i t was necessary t o f u l l y evaluate of the NO groups i n that complex.  A convenient way t o do t h i s  would be t o determine the e f f e c t of v a r y i n g l i g a n d s attached  the f u n c t i o n  the other  t o the metal on the p h y s i c a l and chemical  p r o p e r t i e s of h y d r i d o n i t r o s y l complexes o f tungsten.  However,  a survey of the chemical l i t e r a t u r e r e v e a l s t h a t very few convenient s t a r t i n g m a t e r i a l s have been r e p o r t e d .  Fortunately,  c o n s i d e r a b l y more work has been done on molybdenum complexes. For example, i t has been r e p o r t e d  t h a t CpMo(CO) NO  r e a d i l y with the halogens ( X ; X=C1 , Br o r . I 37  3 8  2  CpMo(CO) NO + X 2  ).  ^ 2 — 2 — » 1/2 [CpMo(NO)X ]  2  2  These complexes, i n t u r n , provide cursors  reacts  2  convenient  (11)  2  pre-  t o many h a l o n i t r o s y l complexes of molybdenum, e.g. ~ 3 7  [CpMo(NO)X ] 2  2  + 2L  :—*2CpMo(N0) (X) L  L=Group V donor l i g a n d  2  l tc  (12)  - 27 -  [CpMo (NO) I ]  + 2T1(C H ).  2  5  * 2 (C.-H,-) 2^0 (NO) I . (13)  5  T h i s chapter r e p o r t s the r e s u l t s of attempts t o prepare some tungsten congeners of these molybdenum  complexes.  EXPERIMENTAL A l l experimental procedures d e s c r i b e d here were performed under the same g e n e r a l c o n d i t i o n s o u t l i n e d i n Chapter I I . Reaction of CpW(CO) NO w i t h ~L^. To a s t i r r e d , 2  s o l u t i o n of CpW(CO) N0  12  2  was  added s o l i d i o d i n e  (5.00 g, 14.93  (3.79 g, 14.93  orange  mmol) i n C H C 1 2  2  (100  mL)  mmol). Vigorous gas  e v o l u t i o n immediately o c c u r r e d and the r e a c t i o n mixture turned r e d - v i o l e t .  The r e a c t i o n mixture was  allowed to s t i r  at room temperature f o r 30 min b e f o r e being taken t o dryness i n vacuo.  The red-brown r e s i d u e was  crystallized  hexanes t o y i e l d dark brown, m i c r o c r y s t a l l i n e (7.52 g, 94%  v(N0)  1652  2  [CpW(NO)I ] 2  Found: cm" . 1  C, 11.26; H, 0.88; U  NMR  1  (CDC1 ): 3  Reactions o f [CpW(NO)I ] 2  2  C, 11.27; H, N, 2.53.  66.15.  2  Mp  IR  0.95; (CH C1 ): 2  2  120°C dec.  w i t h Donor L i g a n d s ( L ) .  experiments were a l l performed s i m i l a r l y  These  and the L=P(OPh)  3  r e a c t i o n i s d e s c r i b e d as an example. A s t o i c h i o m e t r i c amount o f neat t r i p h e n y l p h o s p h i t e (0.26 mL, of  2  yield).  A n a l . Cald f o r C - ^ t ^ ^ I ^ V ^ : N, 2.63.  from C H C 1 /  0.31  [CpW (NO') I 3 2  g, 1.00  (°- 3 g, 0.50 5  2  mmol) was  added to a s t i r r e d  mmol) i n C H C 1 2  2  solution  (50 mL) .  The  - 28 -  s o l u t i o n immediately turned deep r e d . added and the r e a c t i o n mixture was reduced p r e s s u r e .  Hexanes (50 mL)  s l o w l y c o n c e n t r a t e d under  T h i s 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  brown, a n a l y t i c a l l y pure CpW(NO)(I) P(OPh) 2  ^COH}  NMR  were  (CDC1 ) :  3  101.36 {s, C ^ }  3  (0.68 g, 81%  yield).  , 1 2 1 . 03 {d,  J(  C-  1 3  3.3 Hz, C,H -C } 126.01 {s, C, H -C.}, 129.79 {s, C,H -C-.}, C  150.79 {d, J (  0  1 3  c  C-  3 1  P)  12.3 Hz,  The other complexes i n y i e l d s of 78-80% Treatment  of  C  C^-C^.  ( s i m i l a r l y coloured) were o b t a i n e d  (Table I I ) . [CpW(NO)I ] 2  w i t h PhCCPh.  2  A stoichiometric  amount of diphenylethyne (0.18 g, 1.0 mmol) was s t i r r e d s o l u t i o n of (50 mL). f o r 18 h.  [CpW(NO)I l 2  2  added t o a  (0.53 g, 0.5 mmol) i n C H C 1 2  The r e a c t i o n mixture was  s t i r r e d a t room  temperature  A t the end of t h a t time a s o l u t i o n i n f r a r e d  d i d not i n d i c a t e any consumption  2  spectrum  of the n i t r o s y l - c o n t a i n i n g  reactant. R e a c t i o n of [CpW (NO) I,,]  2  w i t h CO.  Carbon monoxide was  g e n t l y bubbled through a s o l u t i o n of [CpW(NO)I ] 2  0.50  mmol) i n C H C 1 2  2  (25 mL)  f o r 30 min.  2  (0.53 g,  At the end of  t h a t time a s o l u t i o n i n f r a r e d spectrum i n d i c a t e d ca. 90% c o n v e r s i o n t o CpW(NO)(I) (CO). 2  Continued r e a c t i o n w i t h CO  d i d not appear t o consume any more of the s t a r t i n g m a t e r i a l . The r e a c t i o n mixture was  taken t o dryness i n vacuo t o  q u a n t i t a t i v e l y r e c o v e r [CpW(NO)I ] . 2  Reaction of [CpW (NO) I,,] monoxide was  2  2  w i t h NO.  Prepurified  g e n t l y bubbled through a s o l u t i o n of  nitrogen  [CpW(N0)I ] 9  9  3 1  P)  Table I I . SbPh  3  P h y s i c a l P r o p e r t i e s of the Complexes CpW(NO)(I) L 2  [L= PPh , P ( O P h ) , 3  3  or CO]  A n a l y s i s : Calcd C H  Mp  CpW(NO)(I) P(OPh) 2  3  140° dec  32.77 (32.73)  2.40 (2.33)  (Found) N  1.66 (1.58)  IR,v_(NO) (cm )  1651  Cp  5.90  a  j ( l  H  _ 3 1  p  )  3.0 Hz CpW(NO)(I) PPh 2  158° dec  3  CpW(NO)(I) SbPh 2  141° dec  3  34.74 (34.79)  2.54 (2.48)  1.76 (1.79)  1633  31.16 (31.09)  1.58 (1.60)  2.26 (2.26)  1640'  a  In N u j o l mull  b  In CDC1  3  solution  ° In C H C l , v(CO): 2  2  5.91 J( H- P) 1.2 Hz 1  1694  CpW(CO) (NO) (I)  2040 cm  1  1  NMR other  E  l  l  3 1  6.00  7.19 (15H, b) 7. 54 (15H, b) 7 .50 (15H, b)  - 30 -  (0.53 g, 0.50 mmol) i n C H C 1 2  2  (25 mL) f o r 15 min.  A large  amount o f brown s o l i d p r e c i p i t a t e d d u r i n g the course o f t h e reaction.  A t the end o f t h a t time a s o l u t i o n i n f r a r e d  r e v e a l e d t h a t a l l o f the r e a c t a n t was consumed.  spectrum  The r e a c t i o n  mixture was c o n c e n t r a t e d under reduced p r e s s u r e t o c a . 5 mL. T h i s s o l u t i o n was t r a n s f e r r e d t o t h e top o f a s h o r t F l o r i s i l column (3x5 cm). of was  E l u t i o n with CH C1 2  2  r e s u l t e d i n the development  a s i n g l e o l i v e green band which was c o l l e c t e d .  The e l u a t e  taken t o dryness i n vacuo t o y i e l d 0.12 g (28% y i e l d  based  on W) o f CpW(NO) I, 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 2  physical  properties.  1 6  R e a c t i o n o f CpW(CO) NO w i t h P(OPh) . 2  A t o l u e n e (40 mL)  3  s o l u t i o n c o n t a i n i n g CpW(CO) NO (1.43 g, 4.30 mmol) and t r i 2  phenyl phosphite (1.13 mL, 1.33 g, 4.30 mmol) was s t i r r e d a t r e f l u x f o r 16 h.  At the end o f t h a t time, the r e a c t i o n mix-  t u r e was f i l t e r e d through a s h o r t (3x5 cm) column o f alumina supported on a medium p o r o s i t y f r i t t e . to  The f i l t r a t e  dryness under reduced p r e s s u r e t o leave an orange  was taken solid.  A s m a l l amount o f unreacted CpW(CO) NO was removed by s u b l i m 2  a t i o n a t 60°C (5x10  3  mm) onto a water-cooled probe.  The sub-  l i m a t i o n r e s i d u e was r e c r y s t a l l i z e d from C H C l / h e x a n e s t o 2  y i e l d orange-yellow CpW(CO)(NO)P(OPh) Anal. Calcd f o r C H N0 PW: 24  Found:  -1  E NMR ( C D C l ) :  l  Mp 138°C dec.  3  (1.32 g, 49% y i e l d ) .  C, 46.70; H, 3.27; N, 2.27.  5  C, 46.99; H, 3.25; N, 2.29.  v(C0) 1938 c m . 15H).  2Q  3  2  IR (CR" C1 ) : 2  2  v (NO) 1625,  64.80 (s, 5H), 7.15  (b,  Mass spectrum summarized i n Table I I I .  - 31 -  Table I I I . Mass S p e c t r a l Data f o r CpW(CO)(NO)P(OPh)  a Q  m/z  Rel abund  617  100  589  45  CpW(NO)P(OPh)  524  10  CpW(CO)(NO)P(OPh)  496  22  CpW(NO)P(OPh)  310  11  P(OPh)  217  44  P!(0Ph)  Assignment  CpW(CO)(NO)P(OPh) + 3  + 2  + 3  +  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 i n each fragment. Mass s p e c t r a l data i n c l u d e s a l l fragments c o n t a i n i n g W. The spectrum a l s o i n c l u d e d peaks corresponding t o f u r t h e r fragmentation of P(OPh) . 3  + 3  + 2  -  32 -  Reaction o f CpW(CO)(NO)P(OPh)  3  w i t h I,,.  orange s o l u t i o n o f CpW(CO)(NO)P(OPh) CH C1 2  (0.62 g, 1.0 mmol) i n  3  (35 mL) was added s o l i d i o d i n e  2  To a s t i r r e d ,  (0.25 g, 1.0 mmol).  The r e a c t i o n mixture immediately began t o t u r n a dark r e d c o l o u r but was s t i r r e d a t room temperature f o r 30 min t o ensure complete r e a c t i o n .  A d d i t i o n o f hexanes (35 mL), f o l l o w e d by  slow c o n c e n t r a t i o n under reduced p r e s s u r e , r e s u l t e d i n the crystallization (o.67  of analytically  pure CpW(NO)(I) P(OPh) 2  g, 79% y i e l d ) . Reaction o f [CpW(NO)I J2 w i t h T 1 ( C H ) . 2  5  green s o l u t i o n o f [CpW(NO)I ] 2  (40  3  To a s t i r r e d ,  (0.42 g. 0.39 mmol) i n THF  2  mL) was added s o l i d T l ( C H ) 5  5  (0.21 g, 0.79 mmol).  5  The  r e a c t i o n mixture g r a d u a l l y darkened t o give a deep r e d c o l o u r and  a yellow s o l i d p r e c i p i t a t e d .  The mixture was s t i r r e d a t  room temperature f o r 1 h b e f o r e being taken t o dryness i n vacuo.  The r e s u l t i n g r e s i d u e was e x t r a c t e d i n t o  methane  (40 mL) and the e x t r a c t s w e r e . f i l t e r e d through a  short  (3x3 cm) column o f C e l i t e  porosity " f r i t t e .  dichloro-  supported on a medium  The f i l t r a t e .was c o n c e n t r a t e d under  reduced pressure t o c a . 5 mL.  A d d i t i o n o f hexanes (60 mL)  r e s u l t e d i n the p r e c i p i t a t i o n o f golden-brown m i c r o c r y s talline  (C H ) W(NO)I 5  5  2  (0.22 g, 60% y i e l d ) .  A n a l . C a l c d f o r C-^H-^INOW: I, 26.96; N, 2.97. Found: N, 3.13. IR(CH C1 ) : 2  66.16  (s) .  2  C, 25.13; H, 2.01; I, 27.00;  v (NO) 1622 cm" .  Mp 127 °C dec. f>  C, 25.48; H, 2.12;  1  1  E NMR (CDC1 ): 3  - 33 -  R e s u l t s and D i s c u s s i o n At room temperature reacts quickly  i n dichloromethane  s o l u t i o n , CpW^O^NO  and q u a n t i t a t i v e l y w i t h i o d i n e .  Monitoring  of the r e a c t i o n by i n f r a r e d spectroscopy shows a  disappearance  of the a b s o r p t i o n s due t o the r e a c t a n t (v(CO) 2010, v(NO)  1655  cm ) 1  and the appearance of a new  1925;  s e t of absorp-  t i o n s i n the c a r b o n y l and n i t r o s y l r e g i o n s (v(CO) 2040, 1694  cm  l  ).  v(NO)  These o b s e r v a t i o n s are c o n s i s t e n t w i t h the  replacement  of one c a r b o n y l l i g a n d w i t h two  The r e s u l t i n g c a r b o n y l d i i o d o n i t r o s y l  iodo  ligands.  complex i s u n i s o l a b l e .  I t decarbonylates and o l i g i m e r i z e s slowly under ambient c o n d i t i o n s and r a p i d l y under vacuum. [CpW(NO)I ] 2  2  (v(NO) 1652  r e a c t i o n can be  cm" ). 1  The f i n a l product i s  T h e r e f o r e , the o v e r a l l  summarized:  CpW(CO) N0 + I 2  C H 2  CpW(NO)(I) (CO)  2  C 1  2  * CpW(NO) (I) (CO) + CO 2  _ C H — 2—» 1/2 [CpW(NO) I ]  2  2  2  2  + CO  (14) (15)  The thermal i n s t a b i l i t y of the product formed i n Equation i s not unusual. appears  In f a c t , the l a b i l i t y of c a r b o n y l  14  ligands  to be an i n t r i n s i c p r o p e r t y of t r a n s i t i o n metal  carbonylnitrosylhalides. The complex tungsten]  1 1  bis[(n -cyclopentadienyl)diiodonitrosyl5  i s a red-brown, diamagnetic  s o l i d that i s f r e e l y  s o l u b l e i n t e t r a h y d r o f u r a n and acetone, zene, dichloromethane  l e s s s o l u b l e i n ben-  and c h l o r o f o r m and completely  insoluble  - 34  i n hexanes.  -  S o l u t i o n s are a i r - s e n s i t i v e but the s o l i d  e a s i l y be handled i n a i r f o r s h o r t p e r i o d s of time. spectrum  (THF  ing a b s o r p t i o n formulated  can  The  IR  or CH C1 ) d i s p l a y s a s i n g l e n i t r o s y l - s t r e t c h 2  2  i n the t e r m i n a l NO  as an iodo-bridged  region.  dimer  The  complex i s best  (shown below) s i n c e a  monomeric f o r m u l a t i o n would r e q u i r e a tungsten atom w i t h e l e c t r o n s l e s s than the favoured tion.  The  eighteen-electron  d i m e r i c nature i s a l s o suggested by  p h y s i c a l evidence.  The mass spectrum of  IV) does not d i s p l a y a parent  [CpW(NO)I ] 2  i o n peak (m/z=1066).  tungsten atoms ( i . e . C p W ( N O ) 2 I  2  configura-  indirect  peaks i n d i c a t i n g s i g n i f i c a n t q u a n t i t i e s of ions two  2  +  a  n  d  C p  2  are c o n s i s t e n t with a d i m e r i c molecule.  (Table  2  However,  containing  2 2^ W  N 0  ^2 2 ^ I  +  Nonetheless,  r e l a t i v e abundance of the ions CpW(NO)I  + 2  and  two  CpWI  the indicate  + 2  t h a t the dimer i s r e a d i l y c l e a v e d on v a p o u r i z a t i o n or e l e c t r o n impact. The dimeric  f a c i l e cleavage of the halogen b r i d g e s of  [CpW(NO)I ] 2  2  i s a l s o shown by i t s ready r e a c t i o n with  a v a r i e t y of Lewis bases  [CpW(NO)I ] 2  2  the  (Equation  + 2L — — 2 — 2 — >  16)  to y i e l d the monomeric  2CpW(N0) (I) L  L=P(C H ) , P(OC H ) 6  5  3  (16)  2  6  5  3  or  Sb(C H ) 6  5  3  - 35 Table IV.  m/z  Mass S p e c t r a l Data f o r [CpW(NO) 1 ] 9  R e l Abund  Assignment  812  2  Cp W (NO) I  782  2  Cp W (NO)I  533  98  503  100  438  10  wi  406  15  CpW(NO)I  376  79  CpWI  350  34  (C H )WI  311  3  WI  279  3  CpW(NO)  249  25  CpW  184  12  w  2  2  2  2  2  CpW(NO)I CpWI  + 2  + 2  + 2  + 2  + 2  +  +  3  +  3  +  +  +  +  Assignments based on 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. M a s s a s p e c t r a l d a t a i n c l u d e s only fragments c o n t a i n i n g W. a  -  complexes CpW(NO)(I) L. 2  36  -  These complexes are orange-brown  s o l i d s which are s p a r i n g l y s o l u b l e i n chloroform  and d i c h l o r o -  methane but even l e s s s o l u b l e i n benzene, t e t r a h y d r o f u r a n or acetone.  The IR s p e c t r a d i s p l a y s i n g l e  a b s o r p t i o n s i n the range 1633-1659 cm  nitrosyl-stretching  which are 30-60 cm  1  lower than t h a t e x h i b i t e d by the CpW(NO)(I) (CO)  complex i n  2  solution. P(OPh) >P0 3  The w(NO) 3  1  as L v a r i e s i n the order C 0 >  decrease  has been p r e v i o u s l y observed  i n other s y s t e m s ;  41  and i s c o n s i s t e n t with the replacement of a c a r b o n y l l i g a n d by b e t t e r e l e c t r o n donating i n e l e c t r o n donating  l i g a n d s and the r e p o r t e d v a r i a t i o n  and a c c e p t i n g a b i l i t i e s .  spectrum of CpW(NO)(I) P(OPh) 2  3  The mass  (Table V) does not d i s p l a y  a parent i o n peak but does r e v e a l a fragmentation a t t r i b u t a b l e to CpW(NO)(I)  + 2  and P ( O P h ) . 2  complexes l e d to ambiguous peaks a t h i g h v a l u e s of m/z  Attempts to  +  3  o b t a i n mass s p e c t r a of the CpW(NO) U ) L results.  pattern  (L=PPh  3  or SbPh ) 3  The s p e c t r a contained  (400-800) but they d i d not  d i s p l a y the c h a r a c t e r i s t i c i s o t o p e p a t t e r n of  tungsten.  Apparently  these complexes do not possess  sufficient  volatility  to be analyzed by c o n v e n t i o n a l  electron-impact  techniques. Assuming a " f o u r - l e g g e d piano s t o o l " geometry f o r the complexes CpW(NO)(I) L, 2  there e x i s t s the p o s s i b i l i t y of two  isomers i n which the iodo l i g a n d s are e i t h e r c i s or t r a n s to each o t h e r .  S p e c t r a l p r o p e r t i e s suggest  isomer of each complex i s formed.  The E NMR 1  t h a t only one spectra  (Table II)  - 37 "  Table V.  m/z  Mass S p e c t r a l Data f o r C p W ( N O ) ( I ) P ( O P h ) 2  R e l abund  a 3  Assignment  533  21  CpW(NO)I +  503  19  CpWI  376  17  CpWI  350  10  (C H )WI  310  37  P(OPh)  3  217  100  P(OPh)  2  2  3  + 2  +  +  3  +  +  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. Mass s p e c t r a l data i n c l u d e s a l l fragments c o n t a i n i n g W. The spectrum a l s o i n c l u d e d peaks corresponding t o f u r t h e r fragmentation of P(OPh),. a  - 38 -  trans  d i s p l a y a s i n g l e broad resonance due to the phenyl protons and a s i n g l e resonance  i n the c y c l o p e n t a d i e n y l r e g i o n .  In  those cases where the L l i g a n d c o n t a i n s a phosphorous atom the c y c l o p e n t a d i e n y l protons are coupled to the In  3 1  £  nucleus.  order t o f i n d a more s e n s i t i v e d e t e r m i n a t i o n of the  number of isomers i n s o l u t i o n , the proton-decoupled carbon-13 magnetic was  resonance  spectrum of C p W ( N O ) ( I ) ^ (OPh)^  recorded (see Experimental S e c t i o n ) .  The  assignments  of the c y c l o p e n t a d i e n y l and t r i p h e n y l p h o s p h i t e l i g a n d s are based on p r e v i o u s l y r e p o r t e d r e s u l t s and the expected chemical s h i f t s of these two constants, J (  1 3  ligands.  C - P) 3 1  The i n d i r e c t c o u p l i n g  4 2  and J (  1 3  C -  1  3 1  P ) , are based on an  2  examination of the spectrum of the f r e e l i g a n d . i m p o r t a n t l y , the  1 3  C  NMR  spectrum  of the .complex i n d i c a t e s  the presence of o n l y one isomer i n s o l u t i o n . isomer t h a t i s  Most  However, which  remains unknown a t p r e s e n t .  The complexes, CpW(NO)(I) L can be s y n t h e s i z e d by 9  - 39 -  another r o u t e . prepared  For example, CpW(NO)(I) P(OPh) 2  by the c o n s e c u t i v e  reactions  i i ^ — ) CpW (CO) (NO) P (OPh) -j + CO  CpW(CO) N0 + P(OPh) 2  CpW (CO) (NO) P (OPh)  + I  3  The CpW(CO)(NO)P(OPh)3  can be  3  2 — 2-* CpW (NO) (I) P (OPh) 2  2  reagent  3  can be r e a d i l y prepared  + CO  (17) (18)  by a  route analogous to t h a t d e s c r i b e d p r e v i o u s l y f o r the t r i p h e n y l phosphine d e r i v a t i v e .  4 3  Reaction  proceed by two routes  (Scheme).  (18) c o u l d  conceivably  The i o d i n e c o u l d d i s p l a c e  the c a r b o n y l l i g a n d t o y i e l d CpW(NO)(I) P(OPh)3  directly.  2  A l t e r n a t i v e l y , the i o d i n e c o u l d d i s p l a c e the t r i p h e n y l phosphite  l i g a n d t o generate CpW(NO)(I) C0. 2  This i n turn  c o u l d r e a c t with the l i b e r a t e d t r i p h e n y l phosphite  with the  l o s s of the c a r b o n y l l i g a n d .  CpW(CO)(NO)P(OPh)  CpW(NO)(I) P(OPh) 2  3  3  Scheme  The iodo b r i d g e s of [CpW(NO)I ] 2  2  can a l s o be c l e a v e d  by carbon monoxide.  [CpW(NO)I l 2  2  + 2C0 —££2£i-2-»  2CpW (NO) (I) C0 2  (19)  - 40 -  The product has the same p r o p e r t i e s the product of r e a c t i o n 14.  as those e x h i b i t e d by  Monitoring  of the r e a c t i o n by  s o l u t i o n IR spectroscopy i n d i c a t e s t h a t the maximum convers i o n i s only  90%.  However, i t i s p o s s i b l e t h a t c o n v e r s i o n  complete, but d e c a r b o n y l a t i o n  occurs when a sample i s removed  from a carbon monoxide atmosphere and placed infrared c e l l .  is  i n a solution *  N i t r o g e n monoxide a l s o . r e a c t s r e a d i l y w i t h  s o l u t i o n s of [CpVJ (NO) I ] 2 as shown i n r e a c t i o n 20.  Only one  2  N O  [CpW(NO)I ] 2  CH C1  2  2  }  C  2  n i t r o s y l - c o n t a i n i n g species  P ( W  N  )  0  I  ( 2 0 )  2  i s formed.  Attempts t o s y n t h e s i z e  complexes CpW(NO)(I) L  alkene or alkyne) have not been s u c c e s s f u l . treatment of [CpW(NO)I ] 2  conditions  2  (L=  2  F o r example,  w i t h diphenylethyne under the same  as s p e c i f i e d f o r the f o r m a t i o n of the t r i p h e n y l  phosphite d e r i v a t i v e does not l e a d t o the f o r m a t i o n of any new n i t r o s y l - c o n t a i n i n g Thallium  cyclopentadienide  equimolar q u a n t i t y that reported  species. r e a c t s w i t h one-half the  of [CpWCNO)^^ i n a manner analogous to  f o r [CpMo(NO)I^]2'^ °  T  h  e  P  r o d  uct,  (C H ) W(NO)I, 5  5  i s a brown, diamagnetic s o l i d t h a t i s s o l u b l e i n p o l a r solvents.  2  organic  In dichloromethane s o l u t i o n , the compound e x h i b i t s  a s i n g l e sharp a b s o r p t i o n for a l i n e a r , terminal  (1625 cm ) i n the r e g i o n 1  n i t r o s y l group.  (Table VI) d i s p l a y s a p a r e n t - i o n  expected  The mass spectrum  peak and a fragmentation  - 41 -  Table VI.  m/z  Mass S p e c t r a l Data f o r  Rel abund  (C^H-) W(NO)l  a  0  Assignment  471  18  (C H ) W(NO)I +  441  92  (C H ) WI  376  11  (C H )WI  +  314  100  (C H ) W  +  5  5  5  5  5  2  5  +  2  5  5  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 and i n c l u d e a l l fragments c o n t a i n i n g W.  - 42  pattern  -  i n d i c a t i v e of a stepwise l o s s of l i g a n d s from  metal c e n t r e .  The  proton magnetic resonance spectrum of  (C H ) W(NO)I suggests t h a t the two 5  5  the  2  C,-Hj- groups are  equiva-  l e n t at room temperature i n s o l u t i o n s i n c e only a s i n g l e resonance i s observed.  T h i s r a i s e s an i n t e r e s t i n g problem.  I f the complex i s to adhere to the the u s u a l rare-gas conf i g u r a t i o n , then the two  C,.H r i n g s must donate a t o t a l - 5  of  1  eight electrons.  However, t h i s does not n e c e s s a r i l y  t h a t each of the o r g a n i c the metal c e n t r e . i n the s o l i d  require  l i g a n d s donates f o u r e l e c t r o n s  Regardless of the bonding  to  configuration  s t a t e , r o l e exchange i s expected at room tem-  perature i n s o l u t i o n .  T h i s process would make the two  groups r e s u l t i n only a s i n g l e resonance i n the NMR  C^H^  spectrum.  In the case of the molybdenum analogue, there have been s e v e r a l attempts to d e s c r i b e each c y c l o p e n t a d i e n y l t h a t one  group.  of the r i n g s was  the other t r i h a p t o . room temperature was  4 0  The  the r e l a t i v e c o n t r i b u t i o n of O r i g i n a l l y i t was  bonded i n a pentahapto manner e q u i v a l e n c e of the two  a t t r i b u t e d to r a p i d exchange.  s p e c t r a recorded at temperatures as to i n d i c a t e any  proposed  inequivalence  low  of the two  as -120°C C^H^  and  rings at • However, failed  ligands.  4 4  T h i s l e d t o the suggestion t h a t both r i n g s were indeed bonded in a n  4  fashion.  More r e c e n t l y , i n v e s t i g a t o r s have proposed  t h a t the complex i s c o o r d i n a t i v e l y unsaturated i n s o l u t i o n and  t h a t r a p i d exchange occurs between a pentahapto and  monohapto c y c l o p e n t a d i e n y l  ring.  4 5  a  Obviously, more work must  - 43 -  be done t o deduce the c o n f i g u r a t i o n s of the c y c l o p e n t a d i e n y l groups i n (CVH-) W (NO) I. 9  CHAPTER IV  PREPARATION OF  (n -ALLYL)(n -CYCLOPENTADIENYL)IODONITROSYL3  5  TUNGSTEN AND-MOLYBDENUM Very few a l l y l n i t r o s y l complexes are known. However, those t h a t a r e known d i s p l a y some f a s c i n a t i n g chemical ties.  F o r example, the w e l l - s t u d i e d (n - C H ) Fe (CO) 3  3  has been found  5  proper  N C ) l t6  2  t o be an e f f i c i e n t c a t a l y s t f o r the dimer-  i z a t i o n of butadiene  and i s o p r e n e .  4 7  D i m e r i z a t i o n o f buta-  diene w i t h 1% by weight o f ( n - C H ) F e ( C O ) N 0 y i e l d s a n e a r l y 3  3  5  2  q u a n t i t a t i v e conversion to 4-vinylcyclohex-l-ene. a l l y l n i t r o s y l complex, R u ( N O ) ( n - C H ^ ) ( P P h ) 3  3  to  3  2  Another  i s reported  be one of the few known cases where f a c i l e c o n v e r s i o n o f  a l i n e a r t o a bent n i t r o s y l l i g a n d can o c c u r . the c a t i o n i c complex  [CpMo(CO) (NO) ( n  C-^H^)]  4 8  Furthermore,  d i s p l a y s remark  able s t e r e o s e l e c t i v i t y i n r e a c t i o n s with n u c l e o p h i l e s .  4 9  N u c l e o p h i l i c a t t a c k occurs a t the c o o r d i n a t e d a l l y l l i g a n d at  the p o i n t determined by the p o s i t i o n of lowest e l e c t r o n  density.  T h i s c o n t r o l of r e g i o c h e m i s t r y i s b e l i e v e d t o be  exerted by an e l e c t r o n i c e f f e c t a r i s i n g from the d i f f e r e n t e f f e c t i v e e l e c t r o n e g a t i v i t i e s of the c a r b o n y l and n i t r o s y l ligands. The c a t i o n i c complex mentioned above  ( and o t h e r  d e r i v a t i v e s ) has been r e p o r t e d twice i n the l i t e r a t u r e .  allyl The  - 45 -  f i r s t r e p o r t b r i e f l y mentioned the syntheses of (n -C H )] 3  3  5  +  and the n e u t r a l d e r i v a t i v e  [CpMo(CO)(NO)-  CpMo(NO)(n -C H )I. 3  3  50  5  +  CpMo(CO) NO + C H X 2  3  5  ^2  » [CpMo (CO) (NO) ( n - C H ) ] 3  3  I"  5  (21)  •4/  CpMo(NO)(n -C H )I 3  3  5  However, no experimental d e t a i l s and no p h y s i c a l data were supplied.  A more r e c e n t r e p o r t d e s c r i b e d the p r e p a r a t i o n of  [CpMo(CO)(NO)(n -C H )] 3  3  +  5  from C p M o ( C O ) ( n - C H ) ,  CpMo(CO) ( - C H ) + NOPFg 3  n  3  5  i.e.,  3  2  — 3  3  C  5  . )  N  4 9  ."(22)  [CpMo(CO) (NO) ( n ~ C H ) ] P F . 3  3  5  6  S i m i l a r tungsten complexes are d e s i r a b l e because of the i n t e r e s t i n g chemistry d i s p l a y e d by a l l y l n i t r o s y l complexes g e n e r a l and as a l l y l analogues to CpW(NO) X 2  H) i n p a r t i c u l a r .  (X=C1, Br, I or  A p o s s i b l e route to such complexes  i n v o l v e d i r e c t a l l y l a t i o n of [CpW(NO)  in  may  2*  EXPERIMENTAL SECTION A l l experimental procedures d e s c r i b e d here were performed under the same g e n e r a l c o n d i t i o n s o u t l i n e d i n Chapter I I . Reaction of [CpW (NO) I.,],, w i t h S n C C . ^ ) ^ . s o l u t i o n of [CpW(NO)I l 2  2  To a s t i r r e d  (1.07 g, 1.0 mmol) i n THF  room temperature was added neat Sn(C,H,-) . (0.25 mL,  (30 mL) a t 1.0 mmol).  - 46 -  The o r i g i n a l green s o l u t i o n g r a d u a l l y a c q u i r e d a r e d c o l o u r a t i o n w h i l e being s t i r r e d f o r 12 h.  The f i n a l r e a c t i o n mixture  was taken t o dryness i n vacuo, the r e s i d u e was d i s s o l v e d i n (20 mL), and the r e s u l t i n g s o l u t i o n was f i l t e r e d  CH2CI2  through a s h o r t  (3x5 cm) column of F l o r i s i l .  of hexanes was added t o the f i l t r a t e ,  An equal volume  and the mixture was  slowly c o n c e n t r a t e d under reduced p r e s s u r e t o induce the crystallization  of orange-brown CpW(NO)(n -C H,-)I 3  3  (0.62 g,  70% y i e l d ) . A n a l . C a l c d f o r CgH-^NIOW: Found:  C, 21.50; H, 2.26; N, 3.13.  C, 21.46; H, 2.21; N, 3.11.  1636 cm" . 1  IR ( C H C l ) : 2  2  v(NO)  Mp 165°C dec.  The molybdenum congener was obtained by r e a c t i n g Sn(C H ) 3  5  with  4  [CpMo(NO)I ] 2  3 8 2  under the same c o n d i t i o n s .  A n a l C a l c d f o r CgH^NIMoO: Found:  C, 26.76; H, 2.81; N, 3.90. IR ( C H C 1 ) : v(NO)  C, 26.73; H, 2.78; N, 3.88.  1658 cm" . 1  Mp 171°C dec.  2  Y i e l d 88%.  R e a c t i o n of [ C p W ( C O ) ( N O ) ( n - C H ) ] P F 3  3  5  pale yellow s o l u t i o n of C p W ( C O ) ( n - C H ) 3  2  i n CH CN 3  2  3  5  51  £  w i t h NaT.  To a  (0.70 g, 2.0 mmol)  (50 mL) was added s o l i d NOPF^ (0.35 g, 2.0 mmol).  The s o l u t i o n was s t i r r e d a t room temperature f o r 2 h d u r i n g which time i t g r a d u a l l y changed c o l o u r t o orange. end  A t the  of t h a t time? .. s o l i d Nal (0.30 g, 2.0 mmol) was added  to the r e a c t i o n mixture.  The s o l u t i o n was s t i r r e d a t room  temperature f o r an a d d i t i o n a l 18 h before being taken t o dryness i n vacuo.  Work up as d e s c r i b e d above y i e l d e d 0.51 g  - 47 -  (63% y i e l d ) of C p W ( N O ) ( n - C H ) I as c h a r a c t e r i z e d by i t s 3  3  5  distinctive physical properties. Treatment of CpW(NO)(n -C H )I w i t h PPh .  A benzene  3  3  solution  5  3  (30 mL) c o n t a i n i n g CpW (NO) .(fi -C H^) I (0.45 g, 1.0 3  3  mmol) and P P h  (0.26 g, 1.0 mmol) was s t i r r e d a t r e f l u x  3  f o r one week.  A t the end of t h a t time almost a l l o f the  CpW(NO)(n -C H )I was recovered 3  3  5  unaltered  (there was a s m a l l  amount of decomposition) and no new n i t r o s y l s p e c i e s were  containing  detected.  Treatment o f C p W ( N O ) ( n ~ C H ) I w i t h L i ( H B E t ) .  To an  3  3  5  3  orange s o l u t i o n of C p W ( N O ) ( n - C H ) I (0.34 g, 0.76 mmol) i n 3  3  THF  5  (25 mL) a t -78°C was added 0.80 mL o f 1M s o l u t i o n  Li(HBEt )  i n THF.  3  f o r 15 min.  The r e a c t i o n mixture was allowed  disappeared  due t o the r e a c t a n t  The s o l v e n t was removed from the r e a c t i o n  mixture i n vacuo t o leave a brown o i l . 2  2  to s t i r  but there was no i n d i c a t i o n of a new n i t r o s y l -  containing species.  in CH C1  of  A t the end o f t h a t time a s o l u t i o n IR spectrum  showed t h a t the n i t r o s y l a b s o r p t i o n s had  5 2  T h i s was d i s s o l v e d  t o g i v e a s o l u t i o n t h a t d i d not e x h i b i t any  absorptions  i n the n i t r o s y l r e g i o n of the IR spectrum.  A  s i m i l a r experiment u s i n g Na[A1H (OCH CH OCH ) ] proceeded 2  2  2  3  2  w i t h the same r e s u l t s .  R e s u l t s and D i s c u s s i o n The  new o r g a n o m e t a l l i c  complex CpW(NO) ( n C H , _ ) I can 3_  3  be c o n v i e n t l y prepared i n 7 0% y i e l d by the treatment of  - 48 -  [CpW (NO) 1 2 hydrofuran  w:  "-  th  a  equimolar amount of SnfC^Hj-^ i n t e t r a -  n  a t ambient temperature, i . e .  |g|£-3%U—*  [CpW(NO)I ] 2  2  2CpW(NO) ( - C H ) I .  (23)  3  n  3  5  The complex i s an orange-brown, diamagnetic s o l i d which d i s s o l v e s i n p o l a r o r g a n i c s o l v e n t s t o g i v e reasonably a i r stable solutions.  I t s IR spectrum  strong a b s o r p t i o n a t 163 6 cm nitrosyl ligand.  1  ( i n CH C1 ) e x h i b i t s a 2  2  a t t r i b u t a b l e to a terminal  I t s l o w - r e s o l u t i o n mass spectrum  d i s p l a y s a p a r e n t - i o n peak and a fragmentation corresponding  (Table VII)  pattern  t o 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  centre. The complex has been c h a r a c t e r i z e d by s i n g l e - c r y s t a l X-ray d i f f r a c t i o n .  5 3  The gross s t e r e o c h e m i c a l  (Figure 2) a r e not unusual. s t o o l " geometry and the a l l y l  The molecule adopts a  c a l l y i n t e r e s t i n g f e a t u r e of the molecular of the a l l y l  "piano-  l i g a n d i s i n the endo c o n f o r -  mation r e l a t i v e t o the r e s t o f the molecule.  marked asymmetry  features  ligand.  The most chemi-  s t r u c t u r e i s the  The C ( l ) - C ( 2 )  length  o  of 1.43(1) A  i s i n d i c a t i v e o f p r i n c i p a l l y a s i n g l e bond  between the two atoms whereas the C(2)-C(3) d i s t a n c e of o  2.244(7) A  falls  i n the range expected f o r s i n g l e W-C  a-bonds whereas the W-C(2) and W-C(3) bond lengths are somewhat longer. and  The geometries of the c y c l o p e n t a d i e n y l  n i t r o s y l l i g a n d s are completely  consistent with  their  - 49 -  Table V I I .  m/z  Mass S p e c t r a l Data f o r CpW (NO) ( n — C , H _ ) l -5 5 3  Rel  abund  a  Assignment  447  100  417  83  CpW(n -C H )i  389  40  (C H ) WI +  350  26  (C H )Wl"  CpW(NO)(n -C H )I 3  Q  3  3  3  3  3  c  +  5  2  3  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 and i n c l u d e a l l fragments c o n t a i n i n g W.  +  - 50 -  F i g u r e 2.  M o l e c u l a r s t r u c t u r e of CpW(NO)(n -C H )I.  S e l e c t e d bond lengths  3  3  (A):  5  C(1)-C (2), 1.43(1); C ( 2 ) - C ( 3 ) ,  1.34(1); W-C(l), 2.244(7); W-C(2), 2.329(8); <W-C(3), 2.411(7).  - 51  functioning  as f i v e - a n d  t o the metal c e n t r e .  three-  t o p r o v i d e the metal atom w i t h  favoured e i g h t e e n - e l e c t r o n  As  configuration,  i s b e s t represented  a n t i c i p a t e d , the C-C  The  as:  l i g a n d which  to  better  ligand. asymmetry of the t u n g s t e n - a l l y l l  the complex  (Figure  3 and  e x h i b i t s resonances due atoms which can  and  Table V I I I ) .  1 3  linkage.persists  C The  NMR 1 3  to three i n e q u i v a l e n t  spectra  C  NMR allyl  of  spectrum carbon  be a s s i g n e d on the b a s i s o f t h e i r chemical  The/resonance a t t r i b u t a b l e to C ( l ) has  a chemical  s h i f t which resembles those c h a r a c t e r i s t i c of ca. hybridized  has  (C(2)-C(3)) i s s i t u a t e d t r a n s  s o l u t i o n , as evidenced by the E  shifts.  the  tungsten-allyl  group which i s acknowledged t o be the  ir-acceptor  in  the  bond of the a l l y l  more double bond c h a r a c t e r the NO  e l e c t r o n donors, r e s p e c t i v e l y ,  Consequently, t o account f o r the diamag-  netism of the complex and  linkage  -  carbon atoms i n t r a n s i t i o n - m e t a l  sp 3  a l k y l s , while  the  - 52 -  C(2) and C(3) resonances occur a t lower f i e l d expected f o r ca. metals.  i n the region-  s p carbon atoms bonded t o t r a n s i t i o n 2  C o n s i s t e n t w i t h the t u n g s t e n - a l l y l bonding d e p i c t e d  4 2  on page 51, the E NMR spectrum confirms t h a t the hydrogen' l  atoms bonded t o C ( l ) and C(3) a r e i n d i f f e r e n t the  environments,  chemical s h i f t s o f the l a t t e r r e f l e c t i n g t h e i r predominantly  v i n y l i c character.  The observed AGMRX p a t t e r n f o r t h e a l l y l  l i g a n d c o n t r a s t s w i t h the A M X p a t t e r n d i s p l a y e d by the 2  symmetric of  n -C^H^  2  group o f CpW (CO) (n -C H,-) . 3  3  55  2  3  Assignments  the resonances t o i n d i v i d u a l protons have been made on  the  b a s i s o f c o u p l i n g c o n s t a n t s and on the assumption  that  the  endo conformer i s the p r i n c i p a l s p e c i e s i n s o l u t i o n . The  i n d i c a t e d assignments and c o u p l i n g c o n s t a n t s have been sup-. ported by a s e r i e s o f homonuclear l  E  of  d e c o u p l i n g experiments. The  and C NMR s p e c t r a a l s o i n d i c a t e t h e presence i n s o l u t i o n 1 3  another isomer o f CpW(NO)(n -C H,-)I, presumably  the exo  3  3  conformer, but the resonances a r e not s u f f i c i e n t l y w e l l r e s o l v e d t o permit d e t a i l e d assignments. of  The observed r a t i o  endo/exo conformers i s c.a. 7/1. It  route.  i s p o s s i b l e t o prepare CpW (NO) (n -C H,-)I by another 3  3  The treatment o f CpW(CO) (n -C H ) w i t h NOPF 3  2  3  5  g  fol-  lowed by Nal r e s u l t s i n the i s o l a t i o n o f CpW(NO)(n -C H,_) I . 3  3  T h i s sequence  o f r e a c t i o n s probably proceeds through the  p r e v i o u s l y unknown c a t i o n  [CpW(CO) (NO) (n  CpW(CO) ( n - C H ) + NOPF 3  2  3  5  g  £H CN 3  C-^H^)] ,  >  i.e.,  (24)  - 53 -  F i g u r e 3. 270 MHz E FT-NMR spectrum i n t h e a l l y l 1  CpW(NO) (n -C^H,-) I i n CDC1-. 3  region of  Table V I I I .  E  l  and C NMR 13  S p e c t r a l Data f o r the Endo Isomer of CpW(NO) (n -C-.H _) I . 3  E  1  Cp  H  65.96  l l  H  62.08  NMR  Data  12 62.90  b  H  21  H  65.44  31  H  63.92  J(ll-21)  10.1  J(12-21) 6.6  J(31-21) 14.3  J(32-21) 7.3  J(ll-12)  2.6  J(12-32) 3.8  J(31-ll)  J(32-ll)  C NMR  Gp  ^_1  699.84  637.52  1.8  Data  S 6111.13  S 676.47  3i  The  32 64.53  J(31-32) 1.0  1 3  a  [  s o l v e n t was CDCl^, and the chemical s h i f t s are accurate t o + 0.01 ppm.  k Coupling c o n s t a n t s a r e i n Hz; those i n v o l v i n g whereas the other h a v e r e r r o r s o f c a , + 0.5 Hz.  are accurate to + 0.1 Hz,  1.0  - 56 -  [ C p W ( C O ) ( N O ) ( n - C H ) ] P F ^ + CO 3  0  [CpW(CO) (NO) ( n - C H ) ] P F 3  3  5  g  ™ M C  + Nal 3  (25)  + NaPFg.  3  5  the course of r e a c t i o n (24) the IR a b s o r p t i o n s due  to the r e a c t a n t  (v(CO) 1934, 1844 cm" ) are r e p l a c e d by a 1  new s e t of c a r b o n y l and n i t r o s y l a b s o r p t i o n s v(NO)  »  3  CpW(NO)(n -C H )I  During  c  1714 cm" ).  (v(CO) 2135,  These i n t u r n a r e s l o w l y r e p l a c e d  during  reaction  (25) by a s i n g l e a b s o r p t i o n i n the n i t r o s y l  region  (v(NO):  1636 cm" ).  1  A f t e r the completion  1  o f t h i s work, i t  was l e a r n e d t h a t a s i m i l a r scheme has been used t o prepare the s e r i e s of complexes C p M o ( N O ) ( n - a l l y l ) X  [X=NCO, CN or I;  3  allyl=C H 3  5  or C ^ ] .  5  6  CpMo (NO) (n-C H<-) I can be prepared  by a route  3  3  [CpMo (NO) I ] -k i . e . ,  to r e a c t i o n (22) u t i l i z i n g  [CpMo(NO)I ] 2  2  |g^3-5U  2  similar  2  > 2CpMo(N0) (  3 n  - C H ) I . (26) 3  5  The p h y s i c a l p r o p e r t i e s of CpMo (NO) (n -C Hj.) I a r e s i m i l a r t o 3  3  those d i s p l a y e d by the tungsten  analogue.  The orange-brown  diamagnetic s o l i d d i s s o l v e s i n p o l a r s o l v e n t s t o g i v e s o l u t i o n s t h a t decompose only slowly i n a i r .  The s o l u t i o n IR spectrum  (CH C1 ) d i s p l a y s the expected strong t e r m i n a l 2  2  absorption  (1658 cm" ). 1  The mass spectrum  nitrosyl  (Table IX)  c o n s i s t s of peaks a s s i g n a b l e t o s e q u e n t i a l l o s s of l i g a n d s from the parent  ion.  I t sE l  (Figure 4) and  1 3  C NMR  spectra  - 57 Table IX. Mass S p e c t r a l Data f o r CpMo (NO) (n -C H .) i 3  3  a  c  m/z  R e l abund  Assignment  361  100  CpMo(NO)(n -C H  331  55  CpMo (ji2-C,H_) I  290  64  CpMoI  264  18  (C H )MoI  234  21  CpMo(NO) ( n - C H  163  24  CpMo  3  3  3  +  +  3  3  3  +  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 and i n c l u d e a l l fragments c o n t a i n i n g Mo.  +  - 58 -  F i g u r e 4.  27 0 MHz H FT-NMR spectrum i n the a l l y l 1  of CpMo (NO) (n -C,H,-) I i n CDC1,. 3  region  - 59 -  - .60 -  i n d i c a t e t h a t the a l l y l  l i g a n d i n t h i s complex a l s o e x h i b i t s ,  a s i g n i f i c a n t O-TT d i s t o r t i o n .  The  e x h i b i t s a s i n g l e resonance due carbon atoms (101.29) and 81.24  and  C(3) has  and  1 3  C  spectrum  to the  ( i n CDCl^)  cyclopentadienyl  a separate resonance  (112.14,  45.29) f o r each of the a l l y l carbon atoms C(l) respectively).  The  (C(2),  asymmetry of the a l l y l  been confirmed by a s t r u c t u r a l determination  and  full  a n a l y s i s of the proton magnetic resonance s p e c t r u m . recently reported allyl  1  H  NMR  The  56  s p e c t r a of the complexes CpMo(n 3  ester)(CO)(PPh^) a l s o i n d i c a t e d i s t o r t i o n of the  ligands. general  5 7  I t thus appears t h a t d i s t o r t i o n s may  f e a t u r e of a l l y l  ligand  l i g a n d s attached  allyl  w e l l be  to metal  a  centres  having e l e c t r o n i c asymmetry. Attempts to reduce the W-I have so f a r been u n s u c c e s s f u l .  bond of CpW(NO)(n -C H )I 3  3  5  Treatment of the compound  with e i t h e r Li(HBEt^) or Na[H A1(OCH CH OCH ) ] at -78°C 2  does not r e s u l t i n the formation containing  species.  2  of any  2  new  3  2  nitrosyl  A p o s s i b l e reason i s t h a t the  hydride  reagents p r e f e r e n t i a l l y a t t a c k a p o r t i o n of the molecule other  than the W-I  bond.  Recently,  r e d u c t i o n of  l i g a n d s by these reagents have been o b s e r v e d . conversion an n  1  of the a l l y l  nitrosyl Finally,  58  l i g a n d of CpW(NO)(n -C H )I to 3  3  5  c o n f i g u r a t i o n does not appear to be a f a c i l e  as evidenced by the l a c k of a r e a c t i o n w i t h PPh benzene.  3  process  in refluxing  - 61 -  REFERENCES  (1)  F o r example see Pino, P.; Wender, I . "Organic S y n t h e s i s v i a Metal Carbonyls", V o l . I; Wiley: New York, 1968; V o l . I I ; Wiley: New York, 1977.  (2)  a) P i e r p o i n t , C.G.; Van Derveer, D.G.; Durland, W.; E i s e n b e r g , R. J . Am Chem. Soc. 1970, 92, 4760. b) G r i f f i t h s , W.P. Adv. Organomet. Chem. 19 68, 7, 211.  (3)  Kolthammer, B.W.S. Ph.D. T h e s i s , U n i v e r s i t y o f B r i t i s h Columbia, 1979.  (4)  L ' E p l a t t e n i e r , F.; C a l d e r a z z o , F. 6j_ 2092.  (5)  T r e i c h e l , P.M.; Shubkin, 1328.  (6)  B r i n t z i n g e r , H.  (7)  Stewart, R.P.,Jr.; Okamoto, N.; Graham, W.A.G. J . Organomet. Chem. 1972, 42, C32.  (8)  Green,-M.L.H.; McCleverty, J.A.; P r a t t , L.; W i l k i n s o n , G. J . Chem. Soc. 1961, 4854.  (9)  Deeming, A.G.; Shaw, B.L.  Inorg. Chem. 19 67,  R.L. Inorg. Chem. 1967, 6,  J . Am. Chem. Soc. 1966, 88, 4305.  J . Chem. Soc. A. 197 0, 3356.  (10)  Legzdins, P.; M a l i t o , J.T.  Inorg. Chem. 197 5, 14, 1875.  (11)  Kolthammer, B.W.S.; L e g z d i n s , P.; M a l i t o , J.T. Chem. 1977, 16, 3173.  (12)  Hoyano, J.K.; Legzdins, P.; M a l i t o , J.T. Synth. 1978, 18, 126.  (13)  P e r r i n , D.D.; Aremego, W.L.F.; P e r r i n , D.R. " P u r i f i c a t i o n o f Laboratory Chemicals"; Pergammon P r e s s : Oxford, 1966.  (14)  S h r i v e r , D.F. "The M a n i p u l a t i o n of A i r - S e n s i t i v e Compounds"; McGraw-Hill: New York, 1969.  (15)  Purchased  from the A l d r i c h Chemical  Inorg.  Inorg.  Co. as a 70%  - 62 -  benzene s o l u t i o n under the trade name Red-al. (16)  Stewart, 2699.  R.P.,Jr.; Moore, G.T.  Inorg. Chem. 1975, 14,  (17)  Kolthammer, B.W.S.; Legzdins, P.; M a l i t o , J.T. Synth. 1979, 19, 208.  (18)  Olah, G.A.; Svoboda, J . J . ; Olah, J.A. 544.  (19)  a) Gilmont, P.; Blanchard, A.A. Inorg. Synth. 1946, 2,238. (b) E d g e l l , W.F.; L y f o r d , J . Inorg. Chem. 1970, 9, 1932.  (20)  King, R.B. "Organometallic Syntheses"; New York, 1965; V o l . 1, 168-9.  (21)  Ibid,  (22)  B a r n e t t , K.W.; Slocum, D.W. 44, 1.' • /  (23)  King, R.B.; B i s n e t t e , M.B. J . Am. Chem. Soc. 1963, 85, 2527; Inorg. Chem. 1964, 3, 791.  (24)  C f . the thermal d i m e r i z a t i o n o f CpCr(CO) H: P i p e r , T.S.; W i l k i n s o n , G. J . Inorg. N u c l . Chem. 1956, 3_j_ 104.  (25)  F o r the f i r s t such adduct t o be c h a r a c t e r i z e d see: McNeese, T . J . ; Wieford, S.S.; Foxman, B.M. J . Chem. Soc. Chem. Commun. 197 8, 500,.'  (26)  Greenhough, T . J . ; Kolthammer, B.W.S.; Legzdins, P.; T r o t t e r , J . Inorg. Chem., submitted f o r p u b l i c a t i o n .  (27)  F a l l e r , J.W.; Anderson, A.S.; Chen, C.C. J . Chem. Soc. D. 1969, 719.  Inorg.  S y n t h e s i s 1972,  Academic Press:  156-8. J . Organomet. Chem. 197 2,  3  (28) ... See f o r example, (a) Kaesz, H.D.; S a i l l a n t , R.B. Chem. Rev. 197 2, 72, 231 and r e f e r e n c e s t h e r e i n ; (b) Shunn, R.A. i n "The Hydrogen S e r i e s " , V o l . 1, M u e t t e r t i e s , E.L. Ed., Marcel Dekker, Inc., New York, 1971, 203-69. (29)  Bercaw, J . E . Adv. Chem. S e r . 1978, 167, 136 and references therein.  (30)  Labinger, J.A.  Adv. Chem. S e r . 1978, 167, 11.  - 63 -  (31)  Hoyano, J.K.; Legzdins, P.; M a l i t o , J.T. J . Chem. S o c , D a l t o n Trans. 1975, 1022.  (32)  Green, M.L.H.; S t r e e t , C.N.; W i l k i n s o n , G. f o r s c h . 1959, 14b, 1595.  (33)  Davison, A.; McCleverty, J.A.; W i l k i n s o n , G. 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J . Chem. S o c , Dalton Trans.1978, 474. c) Hunt, M.M.; McCleverty,J.A. J . Chem. S o c , Dalton Trans. 1978, 480.  (46)  King, R.B. In "The Organic Chemistry of I r o n " ; Koerner von G u s t o r f , E.A.; G r e v e l s , F.W.; F i s c h l e r , I . , Ed.; Academic P r e s s : New York, 1978, 482-5.  (47)  C a n d l i n , J.P.; Janes, W.H. 1856.  J . Chem. Soc. (C) 1968,  - 64 -  (48)  a) Schoonover, M.W.; E i s e n b e r g , R. J . Am. Chem. Soc. 1977, 99, 8371. (b) Schoonover, M.W. ; Kubiak, C P . ; Eisenberg, R. Inorg. Chem. 1978, 17, 3050.  (49)  a) F a l l e r , J.W.; Rosan, A.M.: J.Am. Chem. Soc. 1976, 98, 3388. b ) Adams, R.D.; Chodosh, D.F.; F a l l e r , J.W.; Rosan, A.M. J . Am. Chem. Soc. 1979, 101, 2570.  (50)  B a i l e y , N.A.; K i t a , W.G.; M c C l e v e r t y , J.A.; Murray, A.J.; Mann, B.E.; Walker, N.W.J. J . Chem. S o c , Chem. Commun. 1974, 592.  (51)  Cousins, M.; Green, M.L.H.  (52)  Purchased from the A l d r i c h Chemical Co. under the trade name Super-Hydride.  (53)  Greenhough, T.J.; Legzdins, P.; M a r t i n , D.T.; T r o t t e r , J. Inorg. Chem., submitted f o r p u b l i c a t i o n .  (54)  P a u l i n g , L. "The Nature of the Chemical Bond", 3rd ed.; C o r n e l l U n i v e r s i t y P r e s s : I t h a c a , N.Y., 1960; 232-9.  (55)  F a l l e r , J.W.; Chen, C.C.; M a t t i n a , M.J.; Jakubowski, A. J . Organomet. Chem. 1973, 52, 361.  (56)  Faller,  (57)  C o l l i n , J . ; C h a r r i e r , C ; Pouet, M.J.; C a d i o t , P.; Roustan, J . L . J . Organomet. Chem. 1979, 168, 321.  (58)  Hames, B.W.;  J.W. p e r s o n a l  J . Chem. Soc. 1963, 889.  communication.  Legzdins, P.  unpublished o b s e r v a t i o n s .  

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