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Rhodium(I) polysiloxyphosphine complexes as hydrogenation catalysts Brzezińska, Zofia Carolina 1978

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RHODIUM(I) POLYSILOXYPHOSPHINE COMPLEXES AS HYDROGENATION CATALYSTS by ZOFIA CAROLINA BRZEZINSKA Warsaw T e c h n i c a l U n i v e r s i t y , 1970  M.Sc,  A THESIS SUBMITTED IN PARTIAL FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY 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 r e q u i r e d standard  THE  UNIVERSITY OF BRITISH COLUMBIA September 1978  c ) Z o f i a C a r o l i n a B r z e z i n s k a , 1978  In p r e s e n t i n g t h i s  thesis  an advanced degree at  further  for  freely  available  the  requirements  for  this  representatives. thesis for  It  Department  this  .  U n i v e r s i t y o f B r i t i s h Columbia  1 1 t h October 1978.  or  i s understood that copying or p u b l i c a t i o n  Chemistry  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  that  thesis  f i n a n c i a l g a i n s h a l l not be allowed without my  of  for  reference and study.  agree t h a t p e r m i s s i o n f o r e x t e n s i v e copying o f  written permission.  The  of  s c h o l a r l y purposes may be granted by the Head of my Department  by h i s of  fulfilment  the U n i v e r s i t y of B r i t i s h Columbia, I agree  the L i b r a r y s h a l l make it I  in p a r t i a l  ii  Abstract A new  s y n t h e t i c r o u t e to i n s o l u b l e c a t a l y t i c  phosphine)rhodium complexes has been d e v e l o p e d . s y n t h e s i z i n g the c h a r a c t e r i z a b l e monomeric  chloro(polysiloxy-  T h i s was  a c h i e v e d by  complexes,  [C£ Si-(CH ) -P(C H ) ] Rh(CO)C£, 3  2  2  6  5  2  2  [C£ Si-(CH ) -P(C H ) ] RhC£, 3  2  2  6  5  2  3  [C£ Si-(CH )g-P(C H ) ] RhC£, 3  and  2  6  5  2  3  [ C 2 , S i - (CH ) ~ P ( C ^ ) 3  2  ] Rh CJt ,  2  4  2  2  which were s u b s e q u e n t l y homopolymerized  and c o p o l y m e r i z e d w i t h CJ^Si-CH  or an excess of a l i g a n d by h y d r o l y s i s i n water/dioxane m i x t u r e . idealized  The  formulae of the p r o d u c t s o b t a i n e d a r e the f o l l o w i n g : {[0  3 / 2  {[0  3 / 2  Si-(CH ) -P(C H ) ] Rh(CO)C£} , 2  2  6  5  2  2  x  Si-(CH ) -P(C H ) ] RhC£.(0 2  n  6  5  2  3  3 / 2  Si-CH ) } 3  m  x  n = 2,8 and m = 2-200,  {[0 and  U0  3 / 2  3 / 2  Si-(CH ) -P(C H ) ] 2  2  6  5  2  3 > 7  RhCU  x  Si-(CH ) -P(C H ) ] Rh C£ .(0 2  2  6  5  2  4  2  2  3 / 2  Si-CH ) } 3  m  x  m = 0,200 x = v e r y l a r g e but undetermined f o r a l l the polymers. The n a t u r e of the m e t a l c e n t r e s i n the polymers was  probed by  s t u d y i n g r e a c t i o n s of the polymers w i t h hydrogen and carbon monoxide. All  the polymers, w i t h the e x c e p t i o n of the c a r b o n y l complex, a r e  a c t i v e c a t a l y s t s f o r the h y d r o g e n a t i o n of o l e f i n s . activity  Their  catalytic  towards s t y r e n e and cyclohexene d e c r e a s e s upon r e c y c l i n g .  iii Copolymerization of the trisphosphine species with Ci^Si-CH^ allows higher a c t i v i t y to be maintained  over a l a r g e r number of cycles. Copolymeri-  z a t i o n with an excess of a phosphine (P/Rh>3) r e s u l t s i n i n i t i a l l y lower a c t i v i t y but prevents i t s f u r t h e r decrease. the length of the spacer "arm"  An increase of  between the matrix and the metal centre  causes an increase of the o v e r a l l l i f e - t i m e of the trisphosphine c a t a l y t i c complexes. Deactivation of the trisphosphine complexes i s postulated to be p a r t l y due to d i m e r i z a t i o n of the s t a r t i n g complexes to d i - y - c h l o r o tetraphosphine  species and the phenomena described above are thought  to be the r e s u l t of improved m e t a l l i c s i t e i s o l a t i o n which i n turn prevents the d i m e r i z a t i o n . Soluble siloxyphosphinerhod iura(I) complexes were also synthesized to serve as study models f o r the polymeric analogues.  They are also  e f f e c t i v e hydrogenation c a t a l y s t s but t h e i r a c t i v i t y i s considerably higher than that of the polymers.  iv  TABLE OF CONTENTS Page Chapter  1.  1-1. 1-2. 1- 3. Chapter  2.  2- 1. 2-2. 2-3. 2-4. 2-5. 2-6. 2-7.  Introduction  1  Supported C a t a l y t i c Systems. Syntheses o f O r g a n o s i l o x a n e s . T h i s Work.  1 8 12  Experimental  13  A b b r e v i a t i o n s and Symbols. Techniques and I n s t r u m e n t a t i o n . Reagents. Gas Uptake Apparatus. Syntheses o f Ligands and S o l u b l e Complexes. Syntheses o f P o l y m e r i c Complexes. R e a c t i o n s o f S o l u b l e Complexes, w i t h H , CO and HCJl(g).. R e a c t i o n s o f P o l y m e r i c Complexes w i t h H , CO and HC2,(g). Hydrogenation o f O l e f i n s w i t h S o l u b l e Complexes. Hydrogenation o f O l e f i n s w i t h P o l y m e r i c Complexes. E l e c t r o n Microscope S t u d i e s .  13 14 16 17 24 32 41  51 53 83  Discussion  90  Syntheses and I d e n t i f i c a t i o n o f t h e L i g a n d s and t h e i r S o l u b l e Complexes. Syntheses o f the P o l y m e r i c Complexes.  90 105  R e a c t i o n s o f the Complexes w i t h H , CO, and H C £ ( g ) .  118  Reactions with H . R e a c t i o n s w i t h CO. R e a c t i o n s w i t h HCJl(g).  120 125 128  2  2-8.  47  2  2-9. 2-10. 2- 11. Chapter  3.  3- 1. 3- 2. Chapter  4.  4- 1. 4-2. 4- 3. Chapter  5.  5- 1. 5-2.  2  2  C a t a l y t i c Hydrogenation  of O l e f i n s .  Hydrogenation o f Styrene w i t h the S o l u b l e S i l o x y p h o s p h i n e Complexes. Hydrogenation of O l e f i n s w i t h the P o l y m e r i c Complex  131 136 136  2-75Hydrogenation o f Styrene w i t h the P o l y m e r i c Complexes. 139 Hydrogenation of Styrene and Cyclohexene w i t h 150 the P o l y m e r i c Complex R -0 i - S o l u t i o n s of D i f f e r e n t Volumes. R  5-3. 5-4.  n  2  5-5.  E l e c t r o n Microscope Studies.  151  Conclusions.  155  Bibliography.  158  V  TO MY MOTHER  vi  Acknowledgement  In w r i t i n g t h i s t h e s i s , I was e s p e c i a l l y those mentioned here, who a d v i s o r s to  I w i s h to express my  I am  have a c t e d as both f r i e n d s and  g r a t i t u d e to P r o f e s s o r W.  main a d v i s o r , f o r h i s h e l p and  work.  people,  me.  First, my  a s s i s t e d by a number of  To P r o f e s s o r B. R. indebted  R.  Cullen,  guidance d u r i n g the course of  James and  Doctors  G.  S t r u k u l and D.  f o r many s t i m u l a t i n g d i s c u s s i o n s and  this  J . Patmore,  suggestions,  and  to  P r o f e s s o r J . L e j a i n the M i n e r a l E n g i n e e r i n g Department and h i s a s s i s t a n t Mrs.  S. F i n o r a f o r t h e i r h e l p w i t h the e l e c t r o n microscopy.  For  con-  s t r u c t i n g and m a i n t a i n i n g most of the apparatus used i n t h i s work, I g r a t e f u l to the s t a f f of the M e c h a n i c a l Department, i n p a r t i c u l a r Mr. ence were extremely Laboratory difficult My all  helpful;  at the Chemistry  Workshop at the  P.  experi-  Borda of the M i c r o a n a l y t i c a l  Department f o r p e r s i s t i n g w i t h some  analyses. thanks and  a p p r e c i a t i o n go a l s o to Mr.  R.  the i l l u s t r a t i o n s i n t h i s t h e s i s ; to Dr. N. P.  r e a d i n g t h i s t e x t and  Thayer f o r drawing C. Westwood f o r  o f f e r i n g many h e l p f u l s u g g e s t i o n s ,  A. Wong f o r t y p i n g the  d u r i n g the course of my  and  to  Mrs.  manuscript.  I a l s o want to thank Dr. K.-E.  simply  Chemistry  B. Snapkauskas, whose s k i l l and to Mr.  am  J . H a l l i n f o r h i s h e l p and  fortitude  s t u d i e s and Dr. R. T. Oakley f o r h i s a d v i c e  and  f o r b e i n g a good p a l . To my  mother, I express my  and u n f l a g g i n g f a i t h i n me  and my  To b e a u t i f u l Vancouver and  g r e a t e s t thanks f o r her  encouragement  work. the mountains - what more can I say?  -1CHAPTER 1 INTRODUCTION 1-1.  Supported C a t a l y t i c Systems. The b a s i c p r i n c i p l e b e h i n d t h e i d e a of " h e t e r o g e n i z i n g  homogeneous  c a t a l y s t s " i s t o combine t h e v e r s a t i l i t y and s e l e c t i v i t y of s o l u b l e c a t a l y t i c compounds w i t h t h e t e c h n o l o g i c a l advantages of heterogeneous systems.  C o n v e n t i o n a l heterogeneous c a t a l y s t s though w i d e l y used  t r i a l l y , e x h i b i t c e r t a i n disadvantages.  indus-  L i m i t e d knowledge about t h e  n a t u r e of t h e c a t a l y t i c a l l y a c t i v e s i t e s a l l o w s f o r improvements o f mainly e m p i r i c a l nature. c a t a l y t i c precursors  The m o l e c u l a r c o m p o s i t i o n o f t h e homogeneous  i s usually w e l l defined  and t h e r e f o r e by v a r y i n g  the s t e r i c as w e l l as e l e c t r o n i c environment o f t h e m e t a l c e n t r e  i t is  p o s s i b l e t o r e g u l a t e the c o u r s e o f t h e c a t a l y z e d r e a c t i o n as d e s i r e d . The s o l u b l e c a t a l y s t s , however, c r e a t e problems o f t h e i r own w h i c h i n c l u d e : (1) s e p a r a t i o n  from t h e r e a c t i o n m i x t u r e and r e c o v e r y o f t h e s e  u s u a l l y e x p e n s i v e compounds; (2) p l a t i n g o f t h e r e a c t o r w a l l s ; and (3) c o r r o s i o n of t h e r e a c t i o n v e s s e l s . A s o l u b l e complex a t t a c h e d  t o an i n s o l u b l e m a t r i x  t a k e s on p r o p e r t i e s  of a heterogeneous s p e c i e s a t a b u l k l e v e l , but t h e i n t e r a c t i o n s t a k i n g p l a c e around t h e m e t a l c e n t r e a r e p r o b a b l y v e r y s i m i l a r t o t h o s e f o r t h e s o l u b l e homogeneous compound; t h e e x t e n t o f t h e l a t t e r e f f e c t i s governed by t h e l e n g t h o f a " s p a c e r arm" between t h e p o l y m e r i c m a t r i x centre.  A s o l u b l e c a t a l y s t immobilized  of b o t h homo- and heterogeneous systems.  and t h e m e t a l  t h i s way w i l l combined t h e p r o p e r t i e s Hopefully,  i t s h o u l d be p o s s i b l e  to enhance t h e d e s i r e d f e a t u r e s and m i n i m i z e t h e n e g a t i v e ones. u l t i m a t e such c a t a l y s t would c o n s i s t o f a w e l l d e f i n e d  complex  The uniformly  d i s t r i b u t e d over a s o l i d phase of known p h y s i c a l p r o p e r t i e s , and one w h i c h  -2-  would e x h i b i t o p t i m a l a c t i v i t y , s e l e c t i v i t y and e f f i c i e n c y . approaches t o o b t a i n i n g such a product have been  Various  e n u n c i a t e d by a  1-4 number o f w o r k e r s .  Both t h e s o l i d support and the s o l u b l e c a t a l y s t  p o r t i o n of a h e t e r o g e n i z e d complex must be t a i l o r e d t o s u i t t h e needs of t h e r e a c t i o n which i s t o be c a t a l y z e d .  The i n s o l u b l e m a t r i x  must  e x h i b i t m e c h a n i c a l and heat s t a b i l i t y and c h e m i c a l i n e r t n e s s t o r e agents . So f a r l e s s a t t e n t i o n has been p a i d t o i n o r g a n i c than  organic  s u p p o r t s such as polystyrene''" polyvinylpyridines^ , polycarboxyla4,15,16 , „ ... 16 . . , . 11,17 tes , poly-8-diketonates , and p o l y a l c o h o l s . Among t h e ... 1,2,4,12,14,18 . ... 11 , . . 19 inorganic supports s i l i c a , p o l y s i l i c o n e s , and a l u m i n a have been i n v e s t i g a t e d most. There a r e b a s i c a l l y f o u r ways o f a t t a c h i n g f u n c t i o n a l groups t o polymers.  They a r e p r e s e n t e d s c h e m a t i c a l l y  1 2 20 ' ' i n F i g . 1.  F i g . l . V a r i o u s methods o f a t t a c h i n g a complex t o a p o l y m e r i c  (b)  %  * <*M.  m ( ^ . ) (C)  (d)  m<~L  m  L  +  > M L '  +  M L '  m o n o m e r  + ML'  n  n  — > ( ^ - > )  — , ( ^ - »  L  L 'n-  m  m  M L  M L '  n  _  n  ML  m  —  _  m  m  y^monomerL  n  / monomen \  (  support.  »JML'  / . \M L  n  (tH n -m m  m  -3-  Method (a) r e f e r s t o polymers w h i c h a l r e a d y c o n t a i n c o o r d i n a t i n g groups capable o f r e a c t i n g d i r e c t l y w i t h a m e t a l complex.  A good  example i s i r o n p e n t a c a r b o n y l  double bonds  w h i c h r e a c t s w i t h conjugated  21 of polybutadiene  t o g i v e macromolecular complexes v i a double-bond  isomerization:  - ( C H ) ^ CH ^ \  CH - ( C H ) -  2  2  Fe(CO)  n  J 3  m  1 22 23 Chromium h e x a c a r b o n y l containing Cr(CO) rings.  Polymeric  reacts with polystyrene  functions coordinated  3  '  t o g i v e a macrocomplex  t o t h e polymer v i a t h e p h e n y l  s i l o x y p h o s p h i n e s have been complexed w i t h m e t a l s by  l i g a n d exchange Method (b) i n v o l v e s attachment o f t h e l i g a n d t o t h e support  first^  w h i c h i s then complexed w i t h a s o l u b l e m e t a l compound. F u n c t i o n a l i z a t i o n of an o r g a n i c polymer such as p o l y s t y r e n e i s exemplified"'" i n F i g . 2. Inorganic supports  such as s i l i c a a r e e a s i l y f u n c t i o n a l i z e d v i a s i l a n e  26—28 condensation w i t h t h e -OH groups on t h e s u r f a c e o f s i l i c a >-0H 1-0  \  •OH + X,Si-(CH,) - P ( C , H . ) + 3 I n o 5 I 0  'A  •0-Si-(CH ) -P(C H )  •OH  where X=-C£, - 0 C H  (1) 2  3>  -OC H 2  5>  and -OCOCHg.  A l t e r n a t i v e l y , l i g a n d s can be a t t a c h e d  n  6  5  2  •0  t o s i l i c a i n a r e a c t i o n between 18  chloromethylphenylated  s i l i c a and l i t h i u m d e r i v a t i v e o f a phosphine  Once l i g a n d s a r e a t t a c h e d t o t h e polymer they can r e a c t w i t h m e t a l complexes  F u n c t i o n a l i z a t i o n of polystyrene with  F^PX Lewis acid  PR.  ligands.  -5to form complexes of t h e i r own example  v i a l i g a n d exchange  1,2,29,30  For  31  (2) ^ - 0 - S i - (CH ) -P ( C H ) R h ( a c a c ) (CO) 2  2  6  5  2  Phosphine complexes, which have been s t u d i e d most, have l a b i l e T h i s c a l l s f o r m u l t i p l e l i n k a g e to the polymer i n order i s not  lost  from the support.  a l l o w more than one  t h a t the  complex  I f the polymer i s f l e x i b l e enough i t  anchored l i g a n d to i n t e r a c t w i t h  centre, e f f e c t i v e l y creating chelated Heterogenization  ligands.  may  a p a r t i c u l a r metal  complexes.  can a l s o be achieved  by employing method  (c) which  i n v o l v e s the r e a c t i o n of a polymer w i t h a preformed l i g a n d - m e t a l  complex.  The  utilized  l i g a n d s c o n t a i n f u n c t i o n a l groups which are capable of b e i n g  subsequently i n b i n d i n g to a s o l i d employed o n l y w i t h  support.  inorganic s u p p o r t s ^ ' .  T h i s technique has For  been  example:  (3)  X=C£, 0 C H . 2  5  I t i s a good method f o r i n c r e a s i n g the l i k e l i h o o d of m u l t i p l e attachment of the m e t a l to the In the f i r s t to a polymeric  support. t h r e e methods the manner of the attachment of a complex  matrix  i s not w e l l d e f i n e d .  I t i s p o s s i b l e to determine  o n l y an o v e r a l l anchored l i g a n d to m e t a l r a t e s . degree of c o o r d i n a t i o n at any F o l l o w i n g method molecular  However, the  p a r t i c u l a r metal c e n t r e  actual  i s not w e l l  defined.  (d) g i v e s a much b e t t e r chance of s y n t h e s i z i n g a macro-  species with m e t a l l i c centres  i n an e s s e n t i a l l y unchanged  -6-  environment of c o o r d i n a t i n g l i g a n d . m e t a l complex i s p o l y m e r i z e d .  Here a w e l l c h a r a c t e r i z e d monomeric  Assuming t h a t the process o f p o l y m e r i z a t i o n  does not a p p r e c i a b l y change the environment o f the m e t a l c e n t r e i t i s p o s s i b l e t o produce a w e l l d e f i n e d p o l y m e r i c complex. Method (d) has been e x p l o r e d r e l a t i v e l y l i t t l e .  However, a few  i n t e r e s t i n g o r g a n o m e t a l l i c m a c r o m o l e c u l a r complexes have been s y n t h e s i z e d v i a the p o l y m e r i z a t i o n and c o p o l y m e r i z a t i o n of the v i n y l i c f u n c t i o n of 33 the l i g a n d . II-(diene a c r y l a t e ) t r i c a r b o n y l i r o n _2, v i n y l c y c l o p e n t a d i e n y l 34 34 manganese t r i c a r b o n y l 3_, H - ( b e n z y l a c r y l a t e ) c h r o m i u m t r i c a r b o n y l 4_, II-styrene chromium t r i c a r b o n y l  34  polymerized  w i t h each o t h e r , w i t h s t y r e n e , o r w i t h m e t h y l  and c o p o l y m e r i z e d  5_, and v i n y l f e r r o c e n e  35  6_ were s u c c e s s f u l l y  acrylate.  0  Fe(CO)  Mn(CO)  3  2  3  3  0 Fe  -7-  The a p p l i c a t i o n of the .physicochemical a n a l y t i c a l techniques i s l i m i t e d w i t h regard to i n s o l u b l e macromolecular substances. Therefore the polymeric products obtained may be hard to characterize.  Some  information about t h e i r nature can be obtained i n d i r e c t l y from t h e i r chemical r e a c t i v i t y as compared with that of the monomeric analogues. The porosity of the support, i t s s w e l l i n g p r o p e r t i e s , polymer c r o s s - l i n k i n g , f l e x i b i l i t y of the network, and r e l a t i v e p o l a r i t i e s of the polymer and substrates are the major properties of the polymer which influence the o v e r a l l properties of the macrocomplex.  The e f f e c t  of the i s o l a t i o n of m e t a l l i c centres by f i x i n g them to a r i g i d matrix 36 was observed  f o r atitanocene complex.  Titanocene species which form  i n a c t i v e dimers i n s o l u t i o n proved to be 60 times more a c t i v e when supported on 20% divinylbenzene-styrene copolymer.  However, the heterogen3 6~'3 9  ized c a t a l y s t s synthesized to date are, w i t h a few exceptions . ' , c a t a l y t i c a l l y l e s s a c t i v e than t h e i r homogeneous analogues.  The decreased  a c t i v i t y i s most l i k e l y due to the d i f f u s i o n b a r r i e r s caused by the aforementioned properties of the polymeric backbone. The influence of the polymer has been very c l e a r l y demonstrated i n experiments done by 38 39 40 J. K. S t i l l e et a l ' and H. B. Kagan et a l . An i n s o l u b l e c h i r a l rhodium complex analogous to the soluble Rh(I)-DI0P complex, supported on a  copolymer of styrene and divinylbenzene, catalyzes asymmetric hydro-  generation of various o l e f i n i c bonds with much lower o p t i c a l y i e l d s and 40r e a c t i o n rates '  " than the soluble analogue. I t was suggested that  contraction of the r e s i n i n the polar solvent system (benzene/ethanol) used f o r hydrogenation of polar a-acetamid'ocinnamic acid was responsible f o r the i n a c t i v i t y of the c a t a l y s t .  On the other hand, when the complex was  -8-  supported on a more p o l a r support the o p t i c a l y i e l d s of the c a t a l y z e d r e a c t i o n s were the same as f o r the s o l u b l e analogue  38  .  Moreover,  hydrogenations w i t h the same c a t a l y s t supported on a polymer which c o n t a i n e d asymmetric c e n t r e s of i t s own  gave o p t i c a l y i e l d s w i d e l y  39 different  depending  on the c o n f i g u r a t i o n of the asymmetric c e n t r e  of the p o l y m e r i c backbone. I t can be seen c l e a r l y from the e x i s t i n g evidence t h a t both supported metal complex and the m a t r i x i t s e l f p l a y important  the  roles.  The r e l a t i o n s between the s u b s t r a t e s , s o l v e n t s and both components of the macromolecular  c a t a l y s t have to be c o n s i d e r e d when d e s i g n i n g a  h e t e r o g e n i z e d c a t a l y t i c system 1-2.  Syntheses  for a particular  reaction.  of O r g a n o p o l y s i l o x a n e s .  O r g a n o p o l y s i l o x a n e s are r e a d i l y prepared by h y d r o l y s i s of c h l o r o s i l a n e s , a l k o x y s i l a n e s , a c e t o x y s i l a n e s , or s i l a z a n e s , f o l l o w e d by d e n s a t i o n of r e s u l t i n g  silanols.  2ESiC£ 2  E  S  1  0  2HC£ 2E iOH  R  S  2 H 0 R  +  2ESiOAc  2H0Ac  2HSiN=  2HN=  H  V>"  E x t e n s i v e monographs have been p u b l i s h e d about i n general  41-44  ,SiOSiE  45-49 and p o l y s i l o x a n e s in particular.  Here, the f a c t o r s  41  + H ?  0  (4)  polycondensation reactions  r e a c t i o n s f o l l o w a g e n e r a l p a t t e r n of i n t e r f a c i a l reactions.  con-  K i n e t i c s of these  polycondensation  of main i n f l u e n c e a r e : r e l a t i v e  reactivities  -9-  of the f u n c t i o n a l groups i n the monomers, monomer concentrations,  reaction  temperature, r e a c t i o n time, nature of the solvent, nature of the c a t a l y s t , and mechanical f a c t o r s . High concentrations weight polymers.  of monomers promote formation of high molecular  However, i t i s very important that the monomer s o l u t i o n  i s not too viscous since t h i s would prevent good mixing of the reagents. At low monomer concentrations  oligomerization to small rings predominates,  which i s disadvantageous i f the desired product i s a polymer of high molecular weight. D i l u t i o n on the other hand allows better heat d i s s i p a t i o n which i s an important consideration since most of the polycondensation reactions are exothermic.  Use of a solvent also renders the r e a c t i o n  less violent. The h y d r o l y s i s of c h l o r o s i l a n e s i s an extremely f a s t r e a c t i o n and the r e l a t i v e rates depend on the nature and number of substituent groups. I t has been found that the rates of h y d r o l y t i c polycondensation of members of a series of compounds R SiC&, are i n the f o l l o w i n g order: x 4-x SiC£.>RSiC£ >>R SiC£ >R SiC£ 4 5 1 2 5 0  0  0  0  The h y d r o l y s i s of t e t r a - and' o r g a n o t r i c h l o r o s i l a n e s y i e l d s hydrochloric a c i d whereas the products of h y d r o l y s i s of organodichlorosilanes  are mainly s o l u b l e ,  44 51 e i t h e r l i n e a r or c y c l i c  '  , and of r e l a t i v e l y low molecular weight.  For a  given degree of s u b s t i t u t i o n the rate of hydrolysis i s determined by the inductive e f f e c t of the substituent groups.  I t i s important i n copolymeri-  z a t i o n to choose the s t a r t i n g monomers so that t h e i r r e a c t i v i t i e s are very similar.  Since s i l a n e h y d r o l y s i s proceeds v i a an i o n i c mechanism the  -10-  p o l a r i t y o f t h e monomers and t h e i r i o n - p a i r s t r u c t u r e become the f a c t o r s of o v e r r i d i n g importance"^ ,but v e r y b i g d i f f e r e n c e s i n the s t r u c t u r e ^ 4  of the s t a r t i n g monomers would r e s u l t i n low y i e l d of the mixed p r o d u c t . The  s t e r i c and e l e c t r o n d o n a t i n g c h a r a c t e r  of s u b s t i t u e n t  groups  52 53 '  as w e l l as the number of c h l o r o s i l a n e groups i n each type of the monomeric molecules have t o be c o n s i d e r e d of mixed product. made by a d j u s t i n g  when p r e p a r i n g  a polymer w i t h h i g h  content  Allowance o f d i f f e r e n c e i n monomer r e a c t i v i t y can be reactant  ratios.  In h y d r o l y t i c .polycondensation o f c h l o r o s i l a n e s water i s one o f the s t a r t i n g reagents as w e l l as the e l i m i n a t i o n p r o d u c t .  The o v e r a l l  e q u i l i b r i u m h i g h l y f a v o u r s f o r m a t i o n o f s i l o x a n e =Si-0-Si= bonds but may be upset by proper c h o i c e  o f c o n d i t i o n s . A l a r g e excess of water which  promotes h y d r o l y s i s w i l l a l s o r e s u l t i n s u p p r e s s i o n of the c o n d e n s a t i o n p r o c e s s y i e l d i n g polymers of lower m o l e c u l a r weights.  Removal o f water 54  as the product may be e f f e c t e d by e i t h e r Dean-Stark d i s t i l l a t i o n heating  the product t o h i g h e r  The  o r by  temperatures.  r e l a t i o n s h i p between the m o l e c u l a r weight of the polymer and  the r e a c t i o n temperature i s complex. I n g e n e r a l i n c r e a s e s w i t h the i n c r e a s e d  temperature.  r e a c t i o n s a l s o proceed f a s t e r .  the r a t e of p o l y c o n d e n s a t i o n  However, the r e v e r s e 55 56  I t has been r e p o r t e d  '  and s i d e  t h a t upon  heating  to h i g h e r temperatures m e t h y l p o l y s i l o x a n e s undergo thermal rearrangement from h i g h e r t o lower m o l e c u l a r weight s t r u c t u r e s .  I t has a l s o been noted"^  t h a t e v o l u t i o n o f hydrocarbons predominates over the p r o c e s s of condens a t i o n o f -OH groups i n p o l y s i l o x a n e s  containing  organic  substituents  with a negative inductive e f f e c t . S i n c e the s t a r t i n g monomers a r e h i g h l y r e a c t i v e the o v e r a l l r a t e s o f  -11-  i n t e r f a c i a l p o l y c o n d e n s a t i o n r e a c t i o n s are determined phase i n t e r m i x i n g . weight  by the r a t e of  Rapid mixing promotes f o r m a t i o n of  high-molecular  polymers. The n a t u r e of the s o l v e n t i n which the o r g a n o c h l o r o s i l a n e  monomer i s d i s s o l v e d p r i o r to mixing w i t h ^ t h e water phase i s v e r y  important  41 There i s a number of t h e o r i e s  ,  some c o n f l i c t i n g , as to the s e l e c t i o n of  a s o l v e n t which would ensure maximum m o l e c u l a r weight of the polymer product.  In most cases the s o l v e n t i s s e l e c t e d by t r i a l  and  error.  U s u a l l y the r a t e s of h e t e r o l y t i c r e a c t i o n s which i n v o l v e i n a t l e a s t one  stage a p r o t o n c l e a v a g e are a c c e l e r a t e d by the presence  with high d i e l e c t r i c constants.  of s o l v e n t s  Solvents with higher d i e l e c t r i c  constants  promote f o r m a t i o n of h i g h - m o l e c u l a r weight polymer as w e l l as s i d e p r o d u c t s . In  h y d r o l y t i c . c o n d e n s a t i o n of c h l o r o s i l a n e s hydrogen c h l o r i d e i s e v o l v e d . 53 58  Hence the b a s i c s o l v e n t s capable of a c t i n g as HC£ a c c e p t o r s f o r m a t i o n of the h i g h - m o l e c u l a r weight p r o d u c t s . e l e c t r o n d o n a t i n g reagents  '  enhance  A d d i t i o n of other  such as p y r i d i n e " ^ ' ^ has a s i m i l a r  effect.  a c i d - Hor bo a ls ye s- ic sa t a l y zc e s i an n st ydr of hd l. oroH s iy ld ar noelsy,s ias i or noincg lrye a c it di io cn , medium can be f ae vi ot uh re sr p r o d u c t i o n of c y c l i c or low-molecular  weight polymers  48  whereas the  b a s e - c a t a l y z e d p o l y m e r i z a t i o n g i v e s p r o d u c t s of h i g h - m o l e c u l a r weight Rearrangement of i n i t i a l l y  formed s m a l l c y c l i c molecules  48,61,62  to h i g h e r polymers  63 o f t e n takes p l a c e .  The mechanisms proposed  catalyzed processes  i n v o l v e n u c l e o p h i l i c a t t a c k at s i l i c o n w i t h a sub-  sequent  cleavage of a S i - 0 bond. 63  tetrachloride  f o r both a c i d - a n d base-  Lewis a c i d s a l s o c l e a v e Si^O bonds. T i n  6A , dibutyltin  ,  bis(diorganophenoxyphosphinoxy)dibutoxy-  t i t a n i u m * ^ , and o t h e r t i t a n i u m ^ and p l a t i n u m * ^ compounds of such c h a r a c t e r  -12catalyze c h l o r o s i l a n e polycondensation r e a c t i o n s . All  t h e f a c t o r s mentioned above have t o be c o n s i d e r e d i n s y n t h e s i -  zing organopolysiloxanes.  The i d e a l c o n d i t i o n s f o r p r o d u c i n g a h i g h l y  c r o s s - l i n k e d i n s o l u b l e polymer of h i g h m o l e c u l a r weight w i l l be found by t r i a l and e r r o r .  1-3.  T h i s Work . The aim of t h i s work was t o produce i n s o l u b l e p o l y s i l o x a n e -  phosphine rhodium(I) complexes which c o u l d be used the h y d r o g e n a t i o n  of o l e f i n s .  ' Method  as c a t a l y s t s f o r  (d) d i s c u s s e d p r e v i o u s l y i n  t h i s chapter was chosen as one which would produce a w e l l d e f i n e d p o l y m e r i c complex.  Because rhodium(I) phosphine complexes a r e known  to be good h y d r o g e n a t i o n  c a t a l y s t s rhodium(I) complexes w i t h  C£^Si-(CH2) ~P(CgH^)^ l i g a n d s would be s y n t h e s i z e d as s o l u b l e monomers. n  The v e r y r e a c t i v e S i C J ^ f u n c t i o n a l groups o f t h e l i g a n d s would a l l o w , by means of h y d r o l y t i c p o l y c o n d e n s a t i o n , p r o d u c t i o n of h i g h l y c r o s s linked  i n s o l u b l e polymers.  . Carbonylchlorbbis(phosphine)rhodium  would  be employed as a p o l y m e r i z a t i o n " p i l o t " compound s i n c e t h e i n f r a r e d  carbonyl  s t r e t c h i n g frequency would s e r v e as an i n d i c a t o r o f t h e i n f l u e n c e o f t h e p o l y m e r i z a t i o n p r o c e s s on the metal c e n t r e .  The c a t a l y t i c a c t i v i t y o f t h e  p o l y m e r i c complexes would be compared w i t h those o f model s o l u b l e s i l o x y phosphine complexes s p e c i a l l y prepared  for this  purpose.  -13CHAPTER 2 EXPERIMENTAL 2.1.  A b b r e v i a t i o n s and Symbols. EM IR UV EPR NMR ppm s d dd t dt q m Cp acac NBD DMF DMA DMSO DVB COE DIOP  A B C D E F G H J K L M N P Rn-m S 2-m T  e l e c t r o n microscope infrared ultraviolet e l e c t r o n paramagnetic resonance n u c l e a r magnetic resonance part per m i l i o n singlet doublet double d o u b l e t triplet double t r i p l e t quartet multiplet cyclopentadiene acetylacetonate norbornadiene dimethylformamide dimethylacetamide dimethylsulphoxide divinylbenzene cyclooctene 2,3-0-isopropylidene-2,3-dihydroxy-l,4-bis(diphenylphosphino)butane (CH ) Si-(CH )2-P(C H5)2 [(CH3) Si-0-]2(CH3)Si-(CH2)2-P(C H ) C£ (CH )Si-(CH )2-P(C6H5)2 C£ Si-(CH )2-P(C H ) C£ Si-(CH ) -P(C H ) {[(CH ) Si-0-] (CH )Si-(CH ) -P(C H ) }Rh(NBD)C£ {[(CH ) Si-0-] (CH )Si-(CH ) -P(C6H5) }2Rh(CO)C£ {[(CH ) Si-0-]2(CH )Si-(CH2)2-P(C H5) }3RhCJl {[(CH ) Si-0-] (CH )Si-(CH )2-P(C6H5)2>4Rli2CS.2 [C£ Si-(CH ) -P(C H ) ]2 ( °) [C£ Si-(CH ) -P(C H ) ] RhC£ [C2. Si-(CH )8-P(C6H5)2]3RhCK. [C£ Si-(CH ) -P(C H ) ]4Rh C£ {[0 / Si-(CH )2-P(C6H5)2]2 ( ) Jx {[0 / Si-(CH ) -P(C H5)2]3 hC£. ( 0 / 2 S i - C H ) } {[0 2Si-(CH2)2-P(C H5)2]3.7 x { [ 0 / 2 S i - ( C H 2 ) 2 - P ( C 6 H ) 2 ] 4 h 2 W 2 - (°3/2Si-CH ) } 3  3  2  6  3  2  3  3  2  3  6  2  3  3  8  6  3  3  2  3  3  5  2  5  2  3  2  2  3  3  2  3  2  2  5  2  2  2  5  c  C ! i  2  2  6  5  2  2  6  5  2  3  2  2  2  6  2  6  2  2  R h  3  2  6  3  2  3  3  2  3  2  3  5  2  R h  3  6  2  c o  C £  2  R  3  2  2  n  6  3  3  m  x  R h C J l }  3 /  6  R  3  5  3  m  x  -14-  2-2.  Techniques  and I n s t r u m e n t a t i o n .  In a l l the syntheses of oxygen and/or m o i s t u r e s e n s i t i v e compounds Schlenk tubes and f i l t e r s were used. siloxanes  Except f o r h a n d l i n g of n o n - c h l o r o v i n y l -  a l l o p e r a t i o n s were done e i t h e r i n a dry-box under h e l i u m or  i n the Schlenk apparatus under n i t r o g e n . I n f r a r e d s p e c t r a were r e c o r d e d on P e r k i n - E l m e r models 457 225  spectrophotometers.  path l e n g t h 0.25  mm.  The s o l u t i o n s were h e l d i n KBr c e l l s w i t h the  Neat samples and N u j o l m u l l s were h e l d between  C s l p l a t e s w i t h the path l e n g t h 0.1 mm. 1601  cm ^ was  used f o r c a l i b r a t i o n s .  The p o l y s t y r e n e spectrum band a t I n f r a r e d samples of a l l the  were prepared i n the form of N u j o l m u l l s by combining itfith 2 drops  (always the same s i z e ) of N u j o l .  done i n a . h e l i u m atmosphere i n a  C^D^,  25 mg  of the  polymers polymer  H a n d l i n g of a l l the samples  was  dry-box.  P r o t o n and phosphorus magnetic 30°C i n deuterobenzene  and  resonance  s p e c t r a were measured a t  unless otherwise i n d i c a t e d .  The  spectra  31 were r e c o r d e d on a V a r i a n model XL-100 spectrometer. decoupled from the p r o t o n s . g i v e n i n ppm  All  P NMR  s p e c t r a were  The p r o t o n resonance peak p o s i t i o n s were  d o w n f i e l d from an e x t e r n a l t e t r a m e t h y l s i l a n e  (6 s c a l e ) .  The  m u l t i p l i c i t y , c o u p l i n g c o n s t a n t s , i n t e g r a t e d peak a r e a s , and p r o t o n a s s i g n ments are i n d i c a t e d i n parentheses or f o l l o w the r e p o r t e d peak p o s i t i o n s . A multiplet  c e n t e r e d at e.g. 6=5.35 i s noted as 5.35(m).  Negative n o t a t i o n  i n the phosphorus s p e c t r a i n d i c a t e s c h e m i c a l s h i f t d o w n f i e l d from 85% H^PO^.  external  The peak m u l t i p l i c i t y and c o u p l i n g c o n s t a n t s a r e i n d i c a t e d i n  p a r e n t h e s e s , the i n t e g r a t e d areas p r o p o r t i o n s f o l l o w the r e p o r t e d peak positions. Low  r e s o l u t i o n mass s p e c t r a were determined  on Varian/MAT CH4B and  -15-  A.E.I. MS902 mass s p e c t r o m e t e r s . E l e c t r o n microscope micrographs were r e c o r d e d on an ETEC Autoscan microscope w i t h ORTEC M u l t i c h a n n e l X-Ray a n a l y z e r model 6200. Column chromatography  was  done on F l o r o s i l  purchased from F i s h e r S c i e n t i f i c Co. deoxygenated  p r i o r to use.  c o l l e c t i o n were done under  The s o l v e n t s and F l o r o s i l were  Column p r e p a r a t i o n and product e l u t i o n and nitrogen.  T h i n l a y e r chromatography of 13181  was  done on Eastman Chromatogram s h e e t s  s i l i c a gel with fluorescent indicator  Gas l i q u i d  chromatography  A-90-P gas chromatograph  (100-200 mesh)  was  (No.  6060).  done u s i n g an Aerograph  model  from Wilkens Instrument and Research Inc.  equipped w i t h a 2 m l o n g column  ( i n t e r n a l diameter 4.5 mm).  Helium  the c a r r i e r gas. . The column p a c k i n g used f o r s e p a r a t i o n of v i n y l was  10% FFAP on Chromosorb W-AW  and the column  temperature  60/80 mesh.  The gas f l o w r a t e was  was  siloxanes 15 mL/min,  150°C.  For the s e p a r a t i o n of s a t u r a t e d and u n s a t u r a t e d hydrocarbons the column p a c k i n g used was  10% carbowax  1500  on Chromosorb W-AW  60/80 mesh.  The c o n d i t i o n s f o r s e p a r a t i o n of h y d r o g e n a t i o n p r o d u c t s from each o t h e r and from the s t a r t i n g d e f i n e s were as f o l l o w s : styrene  140°  , the f l o w 50 mL/min.  cyclohexene  60°  , the f l o w 50 mL/min.  1-octene  50°  the f l o w 25 mL/min.  1-heptene  50°  the f l o w 25 mL/min.  Ultraviolet lamp  i r r a d i a t i o n r e a c t i o n s were done w i t h a 200 Watt mercury  (Hanovia S-654 A36)  by a stream of a i r .  i n a heavy g l a s s w a l l C a r i u s tube which was  cooled  -16-  Th e c o n s t a n t temperature baths were t h e r m o s t a t i c a l l y  controlled  w i t h t h e r m o r e g u l a t o r Jumbo-MS (from H o p l e r , West Germany) and  solid  s t a t e r e l a y s c o n s t r u c t e d i n the M e c h a n i c a l Shop of the Department of Chemistry, U n i v e r s i t y of B r i t i s h  Columbia.  The f i n e r e g u l a t i o n of gas admission i n the gas uptake apparatus shown i n F i g . 3 was All  a c h i e v e d w i t h an Edward's vacuum n e e d l e v a l v e  (#OSID).  the stopcocks used i n the C a r i u s tubes and i n the m o d i f i e d v e r s i o n  of the apparatus i n F i g . 3 (used f o r HC£(g) uptake measurements) were purchased from Kontes  ( t e f l o n vacuum v a l v e s K-826600 and K-826610). The  c o n n e c t i n g p o i n t s Q and R of the same apparatus ( F i g . 3) were 0 - r i n g connectors Kontes K-671'750. Microanalysis  (C,H,C£) were performed by Mr. P. Borda of the  M i c r o a n a l y t i c a l L a b o r a t o r y , Chemistry Department, Columbia,  U n i v e r s i t y of B r i t i s h  and by A l f r e d Bernhardt M i k r o a n a l y t i s c h e s L a b o r a t o r i u m , E l b a c h -  i i b e r - E n g e l s k i r c h e n , West Germany (Rh,P,Si).  2-3.  Reagents. 7 - 0 c t e n y l t r i c h l o r o s i l a n e was  purchased from S i l a r  Laboratories;  a l l o t h e r c h l o r o s i l a n e s , from P e n i n s u l a r Chem Research; d i p h e n y l p h o s p h i n e , from Strem Chemicals Inc.,Rhodium t r i c h l o r i d e t r i h y d r a t e , f r o m  Johnson  Matthey and M a l l o r y L t d . ; s t y r e n e , from Matheson Colman and B e l l ; hexene, from M a l l i n c k r o d t Chemical Works; 1-heptene and 1-octene, A l d r i c h Chemical Co.;  cyclofrom  carbon monoxide and hydrogen c h l o r i d e gases, from  Matheson of Canada L t d . ; n i t r o g e n , h e l i u m , and hydrogen gases, from Canadian L i q u i d A i r L t d . A l l liquid olefins  were passed through an A d s o r p t i o n Alumina  -17-  (purchased  from F i s h e r S c i e n t i f i c Co.) column p r i o r t o use i n r e a c t i o n s . 67  Di-y-chlorotetracarbonyldirhodium(I) and  ,  di-y-chlorotetraethylenedirhodium(I)were  prepared  by p u b l i s h e d method  The  petroleum  e t h e r used was t h e 30-60°C bp f r a c t i o n .  All  s o l v e n t s used i n column and t h i n l a y e r chromatography were  deoxygenated by p a s s i n g n i t r o g e n through them. dioxane were d r i e d by prolonged atmosphere.  Benzene, t o l u e n e , and  r e f l u x i n g w i t h LiA£H^ i n n i t r o g e n  Dichloromethane and d e u t e r a t e d  by the f r e e z e - and-thaw method. 2-4.  norbornadienechlororhodium(I)  Deuterated  s o l v e n t s were deoxygenated benzene was d r i e d w i t h  ^2^5"  Gas Uptake Apparatus.  2-4-1.  Apparatus f o r Hydrogen Uptake Measurements. A constant  p r e s s u r e gas uptake apparatus shown i n F i g . 3 was  constructed. A Pyrex round-bottom /  25 mL f l a s k w i t h a s i d e arm was connected  v i a a g l a s s s p i r a l w i t h a tap F t o the o i l manometer ^ through t h e tap (J.  The o i l manometer was made of t h i c k w a l l c a p i l l a r y t u b i n g  filled  w i t h n - b u t y l p h t h a l a t e , a l i q u i d w i t h n e g l i g i b l e vapour p r e s s u r e . was  S^  connected t o t h e mercury manometer J_ which c o n s i s t e d of a c a l i b r a t e d  burette i n the l e f t  s i d e and a mercury r e s e r v o i r i n t h e r i g h t .  The  r i g h t arm of t h e mercury manometer was i n t u r n connected v i a an Edward's high-vacuum needle v a l v e and a shut o f f m e t a l tap p a r t of the apparatus. the gas i n l e t  t o t h e gas h a n d l i n g  T h i s p a r t c o n s i s t e d of t h e mercury manometer U,  tap 0, t h e c o n n e c t i n g  tap M, and tap N c o n n e c t i n g  t h e system  to a pump. The  r e a c t i o n f l a s k was thermostatted i n a g l y c e r i n e bath W.  The  J/igure 3.  Apparatus f o r c o n s t a n t gas-uptake measurements  -19-  bath consisted of a c y l i n d r i c a l  g l a s s c o n t a i n e r surrounded by p o l y s t y r e n e  i n s u l a t i o n and e n c l o s e d i n a wooden box on f o u r s u p p o r t s . s t i r r e r _P was p l a c e d under the box. n a t i v e means of m i x i n g the r e a c t i o n Both the manometers  A shaker Y_ was used f o r an a l t e r solution.  and T_ were immersed i n a water b a t h X i n a  transparent P l e x i g l a s s container.  Both the baths were i n d e p e n d e n t l y  r e g u l a t e d by t h e r m o r e g u l a t o r s w i t h r e l a y c o n t r o l c i r c u i t s . was p r o v i d e d by 25 W e l o n g a t e d e l e c t r i c of mechanical s t i r r e r s  A magnetic  l i g h t bulbs.  The heat  These w i t h t h e a i d  ensured temperature c o n t r o l w i t h i n ±0.1°C.  cathetometer was used t o f o l l o w the l e v e l  changes i n the mercury  A gas  burette.  2-4-2.  Apparatus  f o r Hydrogen C h l o r i d e Uptake Measurements,.  A m o d i f i e d v e r s i o n of the apparatus shown i n F i g . 3 was used. the  Here  ground-glass stopcocks and the metal v a l v e s were r e p l a c e d by g r e a s e l e s s  t e f l o n stopcocks.  The c o n n e c t i o n s a t p o i n t s Q and R were made w i t h 0 - r i n g  connectors.  2-4-3.  Procedure f o r a T y p i c a l Gas Uptake Experiment  U s i n g t h e Apparatus  shown i n F i g . 3. Experiments  i n v o l v i n g c a t a l y s t s not s e n s i t i v e t o a i r .  The r e q u i r e d amount o f the complex was weighed out i n t o t h e f l a s k A.  The s i d e arm C^ was stoppered and the f l a s k was connected through the  s p i r a l and the tap _F t o the g a s - h a n d l i n g p a r t of the apparatus a t Q. system was evacuated and r e f i l l e d w i t h n i t r o g e n . through t h e tap CL  The  The gas was admitted  The r e q u i r e d amount of a s o l v e n t (and s u b s t r a t e i f r e q u i r e d )  -20-  was  i n t r o d u c e d through the s i d e arm C_.  C was  closed.  The c o n t e n t s of the f l a s k were degassed thaw method.  D u r i n g t h i s o p e r a t i o n the v a l v e  gaseous r e a c t a n t was  was  closed.  and then taps F_ and M were  The f l a s k and the s p i r a l were d i s c o n n e c t e d from (} and  to R; the f l a s k b e i n g p l a c e d i n the thermostated bath W. the f l a s k were s t i r r e d w i t h the magnetic thermal e q u i l i b r i u m . were opened and was  The  i n t r o d u c e d through tap C J , a t a p r e s s u r e somewhat  lower than t h a t r e q u i r e d f o r the experiment closed.  by the f r e e z e - a n d -  The c o n t e n t s of  s t i r r e r and a l l o w e d to come to  In the meantime the taps (3, H, J_, K, Z_, L_, and  t h i s whole p a r t of the apparatus evacuated.  c l o s e d and the gaseous r e a c t a n t was  The  was  Then tap F was  Tap Cj was  opened and the p r e s s u r e i n the whole apparatus  a d j u s t e d to the d e s i r e d l e v e l .  Taps Cj, h  f  and a r e a d i n g o f the mercury l e v e l i n the l e f t taken.  tap N_  admitted through the tap O a t a  p r e s s u r e s l i g h t l y lower than t h a t r e q u i r e d f o r the experiment. closed.  reconnected  The e l e c t r i c timer was  Z_, J_, and H were c l o s e d arm o f the manometer _T was  started.  Any gas uptake r e s u l t e d i n a r a i s i n g of the o i l l e v e l i n the arm of the manometer ^ .  In o r d e r t h a t the o i l l e v e l i n both the arms  remained the same gas was  admitted  through the taps L and Z.  c o r r e s p o n d i n g r i s e of the mercury l e v e l i n the l e f t The change of h e i g h t of the mercury was the l e f t of  arm of the manometer T_ was  the gas which r e a c t e d was  Experiments  arm  left  This resulted  in a  of the manometer T_.  r e c o r d e d as a f u n c t i o n of time. S i n c e  made of a c a l i b r a t e d p i p e t t e the volume  known.  Involving Catalysts A i r Sensitive i n their Solid State.  F l a s k A used were supposed  i n these experiments had a bottom w i t h i n d e n t a t i o n s which  to break the l i q u i d s u r f a c e thereby h e l p i n g i n m i x i n g of the  -21shaken r e a c t i o n s o l u t i o n .  The r e q u i r e d amount of the c a t a l y s t was weighed  out i n a glove-box i n t o a bucket.  The bucket was suspended  J3 i n t h e s i d e arm C^, and t h e f l a s k was s t o p p e r e d a t 15. amount of s o l v e n t  on t h e hook  The r e q u i r e d  (and s u b s t r a t e i f needed) was i n t r o d u c e d through t h e  neck B under a stream of n i t r o g e n .  The s p i r a l was connected t o t h e  apparatus a t Q so t h a t a continuous stream o f n i t r o g e n flowed through it.  The f l a s k A was q u i c k l y connected t o t h e s p i r a l by t h e j o i n t 15. The  c o n t e n t s of the f l a s k were degassed by t h e freeze-and-thaw method. From t h i s p o i n t t h e procedure was t h e same as f o r the n o n - a i r - s e n s i t i v e w i t h one e x c e p t i o n .  samples,  A f t e r the p r e s s u r e i n t h e whole system was brought  to a d e s i r e d l e v e l t h e bucket c o n t a i n i n g t h e c a t a l y s t was dropped the s o l u t i o n by t u r n i n g the hook JJ i n t h e s i d e arm CL  into  The timer was  s t a r t e d s i m u l t a n e o u s l y . The gas uptake measurements were done i n the same way f o r a l l t h e experiments.  2-4-4.  Atmospheric P r e s s u r e Hydrogenation  Apparatus.  When t h e p o l y m e r i c c a t a l y s t s were used a double m a n i f o l d apparatus was employed f o r t h e h y d r o g e n a t i o n r e a c t i o n s c a r r i e d out a t atmospheric pressure.  U s u a l l y a few r e a c t i o n s were c a r r i e d out s i m u l t a n e o u s l y . Each  r e a c t i o n v e s s e l c o n s i s t e d of a 25 mL round bottom (Fig.4).  f l a s k K w i t h a s i d e arm  The s i d e arm was stoppered w i t h a t e f l o n - r u b b e r septum p l u g .  The f l a s k was connected by t h e j o i n t M t o t h e w a t e r - c o o l e d condenser N which  i n t u r n was a t t a c h e d v i a a two way tap A t o the double m a n i f o l d .  The f l a s k c o u l d be evacuated by opening t h e taps A and E_ t o t h e pump. Opened taps 15 and l i n e Y.  allowed continuous f l o w of hydrogen  through the gas  F i g u r e 4.  Apparatus f o r h y d r o g e n a t i o n i n the presence of p o l y m e r i c c a t a l y s t s .  -23-  D u r i n g the r e a c t i o n c o n s t a n t atmospheric p r e s s u r e was by opening the taps A t o the c o n t i n u o u s v e r y slow stream of i n the l i n e Y.  maintained hydrogen  The f l a s k s K were immersed i n the g l y c e r i n e bath Ii i n  a t r a n s p a r e n t P l e x i g l a s s c o n t a i n e r e n c l o s e d i n a t h r e e - s i d e d wooden frame on f o u r s u p p o r t s .  A magnetic  s t i r r e r was  p l a c e d under each  The h i g h t of the bath c o u l d be r e g u l a t e d w i t h a l a b - j a c k . was  bath  thermostated by a t h e r m o r e g u l a t o r w i t h a r e l a y c o n t r o l c i r c u i t .  heat was aid  The  flask.  p r o v i d e d by a 25W  elongated e l e c t r i c  l i g h t bulb.  of a m e c h a n i c a l s t i r r e r ensured the temperature  The  T h i s w i t h the  control within  ±0.1°C.  2-4-5. Procedure f o r a T y p i c a l Hydrogenation R e a c t i o n U s i n g P o l y m e r i c Catalysts. The r e q u i r e d amount of the c a t a l y s t was weighed out i n a glove-box i n t o a f l a s k K.  The s i d e arm L_ was  stoppered w i t h a t e f l o n - r u b b e r septum  and the o t h e r neck w i t h a g l a s s s t o p p e r . stream of hydrogen was condenser N.  A s m a l l ( c a u t i o n ! ) continuous  a l l o w e d to f l o w out through the tap A and  Taps Ji and C^ were opened permanently.  connected q u i c k l y t o the condenser by the neck M.  The f l a s k K  the was  The c o n t e n t s of the  f l a s k were immediately evacuated by t u r n i n g the tap A to the vacuum Z_, tap  E b e i n g open.  gas l i n e Y.  Hydrogen was  r e a d m i t t e d by t u r n i n g the tap A to the  The t e f l o n - r u b b e r septum was  removed from the s i d e arm L_ and  a s m a l l ( c a u t i o n ! ) continuous stream of hydrogen was The r e q u i r e d amount of a s o l v e n t and an o l e f i n the  s i d e arm JL.  The septum was  replaced.  a l l o w e d to f l o w out.  were i n t r o d u c e d through  The c o n t e n t s of the f l a s k were  degassed by the freeze-and-thaw method and hydrogen was f l a s k was  line  admitted.  The  then immersed i n the g l y c e r i n e b a t h thermostated a t 35°C.  The r e a c t i o n m i x t u r e was  s t i r r e d w i t h a magnetic  s t i r r e r (3.  The  -24-  p r e s s u r e was m a i n t a i n e d c o n s t a n t a t 760 mm Hg by h a v i n g t h e t a p A opened t o t h e gas l i n e Y_. through Y throughout  A v e r y slow c o n s t a n t stream o f hydrogen was f l o w i n g t h e experiment.  U s u a l l y t h r e e r e a c t i o n s were c a r r i e d  out s i m u l t a n e o u s l y ; then t h e r e a c t i o n f l a s k s were s e t up i n a s e r i e s . The p r o g r e s s o f t h e r e a c t i o n was m o n i t o r e d by GLC, samples b e i n g withdrawn p e r i o d i c a l l y through t h e septum.  2-5.  Syntheses  o f L i g a n d s and S o l u b l e Complexes.  2-5-1. P r e p a r a t i o n o f V i n y l S i l o x a n e s , C h l o r o t r i m e t h y l s i l a n e (108 g, 1 mol) and m e t h y l v i n y l d i c h l o r o s i l a n e (72 g, 0.5 mol) d i s s o l v e d i n 200 mL o f d i e t h y l e t h e r were added s l o w l y t o 400 mL o f water a t such a r a t e as t o m a i n t a i n t h e r e a c t i o n at 6-10°C.  temperature  The r e a c t i o n v e s s e l was c o o l e d i n an i c e - s a l t - w a t e r b a t h .  The m i x t u r e was n e x t s t i r r e d f o r an a d d i t i o n a l l h w h i l e t h e temperature was a l l o w e d t o i n c r e a s e t o ambient.  The e t h e r l a y e r was  s e p a r a t e d , washed w i t h water and t h e s o l v e n t was f l a s h - e v a p o r a t e d l e a v i n g 84.3  g of a c o l o u r l e s s o i l .  The presence o f a t l e a s t t h r e e major components  i n t h e p r o d u c t m i x t u r e was d e t e c t e d by GLC. Three f r a c t i o n s , a l l c o l o u r l e s s l i q u i d s , were s e p a r a t e d by r e p e a t e d d i s t i l l a t i o n a t a reduced p r e s s u r e as f o l l o w s : a) F i r s t f r a c t i o n i d e n t i f i e d as ( C H ^ S i - O - S K C H ^ ^ , : b p 35-.37°C (74 mm)-, [lit l00.1°C (757 mm)], 3.7 g. ' 71  A n a l  -  C  a  l  c  d  f o r  C  6 18° 2 H  C, 44.4; H, 11.1. Found: C, 44.0; H, 10.9. Mass spectrum: m/e 1  H NMR:  S ±  :  162(M ). +  0.07(s,Si(CH ) ). 3  3  b) Second f r a c t i o n i d e n t i f i e d as [(OLj) S i - 0 - ] ^SiCOLj) (CH=CH ) : bp 3  2  72 100°C(77 mm), l i t  164-6(760 mm), 34 g(27.5% y i e l d ) .  Anal. Calcd f o r  -25-  C H o  y  o /  0 S i _ : C, 43.6; H, 9.8. Z J o  Found: C, 43.6; H, 9.7.  Mass  spectrum:  ZH  m/e 248(M ).  "*"H NMR: 0.10 ( s , 1 8 H , S i ( C H ) ) ; 0.12(s,3H,Si-(CH )) ;  +  3  3  3  5.9(m,3H,Si-(CH=CH )). 2  c)  T h i r d f r a c t i o n i d e n t i f i e d as ( C H ) S i - [ O S i ' ( C H ) (CH=CH ) ] - O - S i 3  ( C H ) : b.p. 122-4°C(77 mm). 3  5.5 g.  3  H, 8.6.  Found: C, 42.9; H, 8.8.  3  3  2  A n a l . C a l c d f o r C ^ H ^ O ^ i g : C , 42.9;  Mass spectrum: m/e 420(M ). +  1  H NMR: 0.10  ( s , 1 8 H , S i ( C H ) ) ; 0.13(s,9H,Si-(CH ) ) ; 5.9(m,9H,Si-(CH=CH )). _ 3  3  2  3  Higher s i l o x y p o l y m e r s •'• b.p. >140°(1x10  mm), 40.2 g remained  i n the  s t i l l pot. 2-5-2.  P r e p a r a t i o n o f Phosphine  All  phosphine  Ligands.  l i g a n d s were prepared by u l t r a v i o l e t  a mixture o f d i p h e n y l p h o s p h i n e  i r r a d i a t i o n of  (1 mol) and the a p p r o p r i a t e v i n y l s i l a n e  (1.2 mol). In 19.2  a t y p i c a l r e a c t i o n 12 g (64.5 mmol) o f d i p h e n y l p h o s p h i n e and  g (77.5 mmol) o f [ ( C H ^ S i - 0 - ] S i ( C H ) (CH=CH) were i n t r o d u c e d i n t o 2  3  a C a r i u s tube which had p r e v i o u s l y been evacuated and then f i l l e d nitrogen.  with  The m i x t u r e was then c o o l e d i n l i q u i d n i t r o g e n , degassed on  the vacuum l i n e , and subsequently r e f i l l e d w i t h n i t r o g e n .  The tube was  c l o s e d and i r r a d i a t e d w i t h a mercury lamp f o r 48h, w h i l e c o n t i n u o u s l y shaken and c o o l e d w i t h a stream of a i r . When the r e a c t i o n was completed the products were t r a n s f e r r e d i n t o a n i t r o g e n f i l l e d d i s t i l l a t i o n  apparatus.  D i s t i l l a t i o n y i e l d e d the a i r s e n s i t i v e , c o l o u r l e s s l i q u i d  i d e n t i f i e d as  [ ( C H ) S i - 0 - ] ( C H ) S i - ( C H ) - P ( C H ) : b.p. 1 4 2 ° ( 1 0 ~ m m ) ,  71.4% y i e l d . A n a l .  3  3  3  Calcd f o r  2  c  3  i 35°2 H  2  2  3  P S i  :  spectrum: m/e 434(M ). +  C  ' 1  5 8  2  6  - > > 1  H  8  5  2  - 1  Found: C, 57.9; H, 8.2.  H NMR: 0.11(s,18H,Si(CH > ); 3  3  0.08(s,3H,Si-(CH )); 3  0.60(m,2H,Si-CH -); 2.09(m,2H,P-CH -); 7.38(m,10H,P(C H ) ). 2  2  Mass  6  5  2  3 1  P NMR:+9.14(s).  -26-  The f o l l o w i n g were prepared i n the same way: (CH ) Si-(CH ) -P(C,H )„: 0  Q  0  _} J  0  Z Z  Calcd f o r C ^ H ^ P S i :  b.p. 1 2 8 ° C ( l x l O ~ m m ) ,  +  Found:  3  7.40(m,10H,P(C,H )„).  3 1  C  D  J  C£ (CH )Si-(CH ) -P(C H ) : 3  2  C, 71.6; H, 8.4.  Mass  2  6  5  3  2  P NMR:+10.32(s).  Z  b.p. 1 4 2 ° C ( l x l 0 ~ m m ) , 86.2% y i e l d . 3  2  A n a l . C a l c d f o r C ^ H ^ C ^ P S i : C, 55.2; H, 5.2; C£, 21.5. H, 5.4; CI,  Anal.  H NMR: 0 . 1 4 ( s , 9 H , S i ( C H ) ) ; 0.68(m,2H,Si-CH -);  1  Z  2  79.6% y i e l d .  3  _> Z  C, 71.4; H, 8.4.  spectrum: m/e 286(M ). 2.48(m,2H,P-CH„-);  c  o  21.2. Mass spectrum: m/e 326(M ). +  1  H NMR:  Found: C, 55.4;  0.83(s,3H,Si-CH ); 3  I. 29(m,2H,Si-CH -); 2.33(m,2H,P-CH ~); 7.45(m,10H,P(C H ) ). P NMR:+10.38(s) , — "\ 28 77 C £ S i - ( C H ) „ - P ( C H ) : b.p. 142°C(lxlO mm), [ l i t . ' 142-144°C o z z b 5 z 3 1  2  0  (lxl0 CI, 1  2  0  £  c  30.6.  5  2  0  mm)], 85.6% y i e l d .  _ 1  6  A n a l . C a l c d f o r C ^ H ^ C ^ P S i : C, 48.4; H, 4.0;  Found: C, 48.6; H, 4.0; CI,  30.4. Mass spectrum: m/e 347(M ). +  H NMR: 1.63(m,2H,Si-CH -); 2.35(m, 2H.,P-CH ") ; 7 .45(m, 1 0 H , P ( C H ) ) . 2  2  6  5  3 1  2  P  NMR:+10.35(s) . C £ S i - ( C H ) - P ( C H ) : b.p. 210-215°C(6.5x10 0  0  0  2. o  j  £  c  _1  Found:  l I  98 77  [lit.  '  218-221°C  A n a l . C a l c d f o r C ^ H ^ C ^ P S i : C, 55.6; H, 6.0; C£,  C, 56.1; H, 6.3; CI,  1.42(m,14H,Si-(CH„)-,-);  —1 mm),  O -> Z  (5xl0 mm)] , 30.6% y i e l d . 24.7.  0  24.6. Mass spectrum: m/e 431(M ). H +  2.30(m,2H,P-CH -) ; 7.36(m,10H,P(C,H_) .) . Z O J z  3 1  P  1  NMR:  NMR:  +16.08(s). 2-5-3.  P r e p a r a t i o n o f (NBD) { [ (CH > S i - 0 - ] ( C H ) S i - (CH ) ~ P ( C ^ ) > R h C £ , F. 3  2  3  2  2  2  [Bicyclo-(2,2,l)-hepta-2,5-diene]di-y-chlorodirhodium, (0.461 g, 1.0 mmol) was i n t r o d u c e d sequently  evacuated and f i l l e d w i t h n i t r o g e n .  i n 8 mL o f d i c h l o r o m e t h a n e . P(CgH,-)  2  i n t o a Schlenk tube.  [(NBD)RhC£] ,  The tube was sub-  The compound was suspended  A s o l u t i o n of [ ( C H ^ S i - O - ] (CH ) S i - (CH,,) ~ 2  3  (0.868 g, 2.0 mmol) i n 8 mL o f dichloromethane was g r a d u a l l y  duced w i t h a s y r i n g e i n t o the s u s p e n s i o n .  2  intro-  The r e a c t i o n v e s s e l was c l o s e d  -27-  and the c o n t e n t s were s t i r r e d w i t h a magnetic b a r , at room  temperature  for l h . The r e a c t i o n product was  p u r i f i e d by column chromatography  and  was  e l u t e d as a y e l l o w band w i t h acetone i n petroleum e t h e r s o l v e n t m i x t u r e (15% v / v ) .  A f t e r e v a p o r a t i o n of the s o l v e n t s the product was  redissolved  i n petroleum e t h e r and c o o l e d t o -75°C thereby g i v i n g l g (75.0% y i e l d ) o f yellow s o l i d . Anal. Calcd. for C H C £ 0 P R h S i : 2 8  Found: C, 50.8; H, (s,3H,Si-CH ); 3  6.6;  CZ,  5.3.  4 3  H,  6.5;  664(M ), H +  1  CZ,  5.4.  NMR:  0.08  0.12(s,18H,Si(CH ) ),: 1.40(m,2H,Si-CH -); 2.30(m,2H,P-CH ") ; 3  6  NMR:  C, 50.6;  2  Mass spectrum: m/e 3  7.23(m,10H,P(C H ) ) ; 1.40(m,2H, ^ to CZ);  2  5  2  3.72(m,2H, ^  2  2  CH (NBD)); 3.03(m,2H, ^ 2  CH(NBD) t r a n s  CH(NBD)); 5.23(m,2H,^ CH(NBD) t r a n s to P ) .  3 1  P  -31.45(d,J(Rh-P)=171.6 H z ) .  2-5-4.  P r e p a r a t i o n of { [ ( C H ) S i - 0 - ] ( C H ) S i - ( C H ) - P ( C g H ^ ) } R h ( C O ) C £ , G. 3  To a degassed  3  2  2  2  2  f o r 4h under n i t r o g e n .  starting  2  i n 8 mL  g (4.0 mmol) of { [ ( C H ) S i - 0 - ) ( C H ) S i 3  of benzene was  added.  3  2  3  The m i x t u r e was  refluxed  The r e a c t i o n was monitored by IR s p e c t r o s c o p y :  samples were taken p e r i o d i c a l l y and the v(C=0) r e g i o n was r e a c t i o n was  2  2  ( C H ) ~ P - ( C g H ^ ) } i n 8 mL 2  2  s o l u t i o n of 0.389 g (1.0 mmol) of [ R h ( C O ) C £ ]  of benzene a s o l u t i o n o f 1.736 2  3  observed.  The  t e r m i n a t e d w i t h the d i s a p p e a r a n c e of the c a r b o n y l peaks of the  material.  The s o l u t i o n was  c o o l e d t o room temperature.  The y e l l o w p r o d u c t  p r e c i p i t a t e d out upon the a d d i t i o n of e t h y l a l c o h o l .  TLC u s i n g acetone/  petroleum e t h e r m i x t u r e (1:9 v/v) as e l u e n t i n d i c a t e d the presence of o n l y one component  (1.25 g, 60.0%  0 P R h S i : C, 49.9; 5  2  6  spectrum: m/e  450  H,  6.8;  y i e l d ) , mp CZ,  3.4.  39-44°C.  Found: C, 50.3; H,  (M ), probe not heated; m/e +  Anal. Calcd f o r C  1034  6.8;  CZ,  4 3  y o  3.2.  (M ), probe temp. +  H  C£ Mass  300°C.  -28IR: v(CEO) 1968 cm" . 1  1  0.70-1.50 (m) and 2.96 -CH -CH ~); 7.16 2  6  5  3 1  2  P  0.14(s,6H,Si-CH >,  NMR:  0.18(s,36H,Si(CH ) ) ;  3  (m), ( t o t a l 8H, r e l a t i v e  (m) and 7.97  2  P(C H ) ).  H NMR:  3  intensities  ( m ) ( t o t a l 20H, r e l a t i v e  2:1,  intensities  2:1,  -29.44 ( s ) ; -29.65(d,J(Rh-P)=124.6 H z ) , r e l a t i v e  i n t e n s i t i e s v a r y from 1:5 t o 2:7 f o r d i f f e r e n t  preparation batches.  2-5-5. P r e p a r a t i o n of {[(CU ) Si-0-] (CH >Si-(CH > ~P(CgH 3  2  3  2  ) > R h C £ , H.  2  2  3  The compound was prepared by the r e a c t i o n of 4.557 g (105 mmol) of [(CH ) Si-0-] (CH )Si-(CH ) -P(C H ) 3  3  2  (C H ) Rh C& 2  4  4  2  2  reduced to czi.  3  2  2  6  5  and 0.681 g (17.5 mmol) of  2  i n 120 mL of benzene.  The volume of the s o l u t i o n  was  20 mL by e v a p o r a t i o n of the s o l v e n t at a reduced  pressure.  The r e a c t i o n m i x t u r e was s t i r r e d f o r 45 min a t room temperature a f t e r which time i t was f i l t e r e d and evaporated to dryness i n vacuo.  Evacuation  f o r two days was n e c e s s a r y i n o r d e r t h a t a l l t h e s o l v e n t c o u l d be removed. The product o b t a i n e d was a v i s c o u s , d a r k r e d o i l (4.75 g, 94.0% y i e l d ) . A n a l . C a l c d f o r C , H „ C £ 0 , P R h S i : C, 52.5; H, 7.3; C£, 2.5; 63 105 6 3 9 0  7.2; P, 6.5. 0.07  1.12  C  o  n  Found: C, 52.2; H; 7.3; C£, 2.6; Rh, 6.9; P, 6.3.  (s,21H,Si-(CH ) and S i ( C H ) ) ; 3  C H ~ ) ; 7.88 2  1  0.72  3  ( m , 1 0 H , P ( C ^ ) ) ; and 0.18 2  (m,4H,Si-CH -);  2.72  2  (m, 2H, Si-CH -.); 1.48 2  (s,42H,Si-(CH ) and 3  (m,4H,P-CH - ) ; 7.06  Rh,  "hi NMR:  (m,2H,P-  Si(CH ) ); 3  (m, 20H,P ( C ^ ) ) .  3 1  2  3  P  NMR:  -29.75 (dd, J(P-P)=39.0 Hz, J(Rh-P)=140.0 Hz); -44.97 ( d t , J(P-P)=39.0 Hz, J(Rh-P)=188.0 Hz); -29.92 ( s ) ; r e l a t i v e v(Rh-C£) 260 (w)  intensities  20:10:1.  IR  (neat):  cm" . 1  2-5-6. P r e p a r a t i o n of { [ ( C H ) S i - 0 - ] ( C H ) S i - (CH ) ~ P ( C ^ ) > R h C £ , J . 3  3  2  3  2  2  2  4  The compound was prepared by r e a c t i o n of ( C H ) R h C £ 9  A  A  9  2  9  2  (0.487 g, 1.25  -29mmol) and [ (CH ) S i - 0 - ] ( C H ) S i - (CH ) ~ P ( C ^ ) 3  3  2  3  2  50 mL o f r e f l u x i n g benzene.  2  (2.172 g, 5.00 mmol) i n  2  A f t e r 3h the r e a c t i o n m i x t u r e was c o o l e d  to room temperature and i t s volume was reduced t o oa. 20 mL by e v a p o r a t i o n of the s o l v e n t under reduced p r e s s u r e . and evaporated t o dryness i n vacuo.  The s o l u t i o n was then f i l t e r e d  E v a c u a t i o n f o r two days was n e c e s s a r y  i n order that a l l t h e s o l v e n t c o u l d be removed.  The product was o b t a i n e d  as a v e r y v i s c o u s dark r e d o i l (2.34 g, 93.0% y i e l d ) . Anal Calcd f o r C Rh, 10.2; P, 6.2. 1  8 4  H  l 4 0  C£ 0gP Rh Si 2  4  2  :  1 2  C, 50.1; H, 7.0; C£, 3.5;  Found: C, 50.5; H, 7.2; C£, 3.8; Rh, 10.1; P, 6.4.  H NMR: 0.12 (s,84H,Si-CH  3  and SiCCH^) ); 1.00 (m,8H,Si-CH -); 2  (m, 8H, P-CH ~); 7.22 (m) and 7.90 (m), ( t o t a l 40H r e l a t i v e 2  2.14  intensities  2:1, P ( C H ) ) . 6  3 1  P  5  2  NMR: -47.02 (d, J(Rh-P)=196.5  Hz).  I R ( n e a t ) : v(Rh-C£) 255(m-w) cm" . 1  2-5-7. P r e p a r a t i o n o f [C£„Si-(CH„)_-P(C,H )J Rh(C0)C£, 5  Z Z  o  j  C  K.  o  Z Z  The complex was prepared i n the r e a c t i o n between amounts of  (C0) Rh C£ 4  2  2  and C ^ S i - ( C H ) ~ P ( C ^ ) . 2  2  2  stoichiometric  The phosphine (1.400 g,  4.0 mmol) was d i s s o l v e d i n 8 mL of benzene and added t o the s o l u t i o n o f (C H ) Rh C£ 2  4  4  2  2  (0.389 g, 1.0 mmol) i n 8 mL of benzene.  The m i x t u r e was  r e f l u x e d and the extent of the r e a c t i o n was monitored by IR s p e c t r o s c o p y (v(C=0) r e g i o n ) . was  The r e a c t i o n was completed a f t e r 4h.  c o o l e d t o room temperature and f i l t e r e d .  The r e a c t i o n m i x t u r e  The product p r e c i p i t a t e d out  of the s o l u t i o n upon t h e a d d i t i o n of petroleum e t h e r .  The complex, an  oxygen and m o i s t u r e s e n s i t i v e y e l l o w s o l i d , was p u r i f i e d by r e p r e c i p i t a t i o n w i t h petroleum e t h e r out o f a benzene s o l u t i o n  (1.65 g, 96.0% y i e l d ) , mp  52-75°C. Anal. Calcd f o r C H g C £ 0 P R h S i : 2 g  2  7  2  2  C, 40.0; H, 3.3; C£, 28.9; Rh,  -30-  12.0; P, 7.2.  Found: C, 40.4; H, 3.3; CZ, 28.6; Rh, 12.1; P,  IR(C,D,); v(CHO) 1970(s) cm" . b o 1  "4  NMR:  1.92  33  -30,00 (d, J (Rh-P)=127.5 H z ) ,  "P NMR:  (m,4H,Si-CH -); 2.98  7.1.  (m,4H,P-CH "); 7.-10 (m) and 7.74  2  (m),  2  ( t o t a l 20H, r e l a t i v e i n t e n s i t i e s 3:2, P ( C , H ) „ ) . C  O  2-5-8.  5 Z  P r e p a r a t i o n of [ C J ^ S i - ( C H ) ~ P ( C g H ^ ] R h C £ , L, and 2  2  2  3  [ C £ S i - ( C H ) g - P ( C H ) ] R h C £ , M. 3  2  6  5  2  3  The c h l o r o t r i s ( t r i c h l o r o s i l y l p h o s p h i n e ) r h o d i u m prepared i n the r e a c t i o n between s t o i c h i o m e t r i c and  complexes were  amounts of ( C H ) R h C £  2  In a t y p i c a l r e a c t i o n 0.934 g (2.4 mmol) of C J ^ S i - ( C H ) ~ P ( C ^ )  2  2  4  4  2  the a p p r o p r i a t e phosphine. 2  dissolved  i n 4 mL of benzene was added t o 0.156 g (0.4 mmol) of  (C H ) Rh C& 2  4  4  2  2  2  i n 8 mL benzene.  turned dark r e d .  The i n i t i a l l y  orange s o l u t i o n  immediately  I t was s t i r r e d a t room temperature of l h and then  filtered.  The orange product was o b t a i n e d by e v a p o r a t i n g the s o l u t i o n to dryness under the vacuum  (0.900 g, 95.3% y i e l d ) , mp  Anal. Calcd f o r C 7.9; Rh, 8.7. -28.53  4 2  H  4 2  C  1 Q  170-210°C (decomp).  P RhSi : 3  3  C, 42.7; H, 3.6; CZ, 30.1; P,  Found: C, 42.4; H, 3.7; CZ; 29.8; P, 7.7; Rh, 8.9.  3 1  P  NMR:  (dd, J(P-P)=39.9 Hz, J(Rh-P)=136.2 H z ) ; -42.97 ( d t , J(Rh-P)=187.1 Hz,  J(P-P)=40.0 Hz); -25.88 (dd, J(Rh-P)=97.6 Hz, J(P-P)=26.4 H z ) ; -39.49 ( d t , J(Rh-P)=142.3 Hz, J(P-P)=25.4 H z ) ; - 4 9 . 3 4 ( s ) ; - 4 8 . 7 7 ( B ) ; -43.89(S).  1  H NMR:  (-CH -CH -); 7.06 2  2  1.38(m), 1.96(m), (m), 7.74  2095 (w) cm" ; 1  2.71(m), and 4 . 1 2 ( m ) ( t o t a l 12H. ,  (m), and 8.36(m) ( t o t a l 30H,  r e l a t i v e i n t e n s i t i e s 1:3:1:1:10:4:1;  -44.37(s);  -13.96(m,Rh-H).  P(C H ) ); 6  5  I R ( C D ) : v(Rh-H) 6  6  ( N u j o l ) : v(Rh-H) 2095(w); v(Rh-C£) 260(w), 280(w)  In a s i m i l a r r e a c t i o n  2  cm" . 1  [ C £ S i - ( C H ) g - P (C^-H^),,] R h C £ was o b t a i n e d i n 3  2  3  -31-  93.2% y i e l d , mp 147-172°C. H, 5.4; CI, Rh, 3 1  P  6 0  H gC£ 7  1 0  P R h S i : C, 50.2; 3  3  Found: C, 50.5; H, 5.7; CI,  24.8; Rh, 7.2; P, 6.5.  7.3; P, NMR:  Anal. Calcd f o r C  24.4;  6.5.  -26.25  (dd, J(Rh-P)=139.2 Hz, J(P-P)=39.9 H z ) ; -40.94 ( d t ,  J(Rh-P)=188.0 Hz, J(P-P)=40.1 H z ) ; -34.55(m); -30.06(m); -25.35(m); -22.86(m); -22.30(m); r e l a t i v e the peaks 4:1.  1  H NMR:  intensities  of dd p l u s dt t o the r e s t of  1.05(m), 1.93(m), 2.45(m), and 3.93(m) ( - ( C H ) - ) ; 2  7.05(m), 7.87(m), and 8.35(m)(P(C,H )„); r e l a t i v e i n t e n s i t i e s  72:10:5:1:  C  o 5  20:9:1; -14.32(m), Rh-H)  z  IR(C,D,); v(Rh-H) 2090(m); 2170(sh) cm" ; 1  —  g  (Nujol);  DO  v(Rh-H) 2090(m); 2170(sh); v(Rh-C£) 260(w), 280(w)  cm" . 1  The p r e p a r a t i o n of [C£„Si-(CH„)_-P(C,H )A „RhC£ was repeated i n C  Z z  5  D 5 z  5  glassware p r e t r e a t e d w i t h t r i m e t h y l c h l o r o s i l a n e . following 3 1  The s p e c t r a showed the  pattern:  P  NMR:  -42.67  ( d t , J(Rh-P)=186.8 Hz, J(P-P)=39.8 H z ) ; -28.27  (dd, J(Rh-P)=140.4 Hz, J(P-P)=39.3 H z ) ; -40(m); -37(m); -27(m); -24(m); relative  intensities  •""H NMR:  of the (dt and dd) to a l l the m u l t i p l e t s 5:2.  1.46(m), 1.90(m), 2.72(m) and 4.16(m) ( t o t a l 12H, -CH -CH -) ; 2  7.04(m), 7.72(m), and 8 . 3 6 ( m ) ( t o t a l 2:2:2:1:13:5:trace; -14.00 {"^P} !! NMR:  I R ( C D ) : v(Rh-H) 2095(w) 2-5-9.  6  5  2  intensities  (m, Rh-H). r e g i o n ; -14.00  (d, J(Rh-H) = 10 H z ) .  cm" . 1  P r e p a r a t i o n of [ C £ S i - ( C H ) - P ( C H ) ] R h C £ , N. 3  The complex was o b t a i n e d C£ Si-(CH ) -P(C H ) 3  6  no change i n the d o w n f i e l d  1  6  30H, P ( C H ) ) ; r e l a t i v e  2  2  2  6  5  2  2  2  6  5  2  4  2  2  i n the r e a c t i o n of 0.695 g (2.0 mmol) of  w i t h 0.195 g (0.5 mmol) of ( C ^ ) R h C £ 4  2  2  i n 15 mL of  -32-  benzene.  The s o l u t i o n was r e f l u x e d f o r 3h, c o o l e d , and f i l t e r e d .  An orange product was o b t a i n e d by e v a p o r a t i n g the s o l u t i o n o f dryness i n vacuo (0.76 g, 91.0% y i e l d ) , decomp 210-230°C. Anal. Calcd f o r C ^ H ^ C  P  P R h S i : C, 40.3; H, 3.4; C£, 29.8; 4  2  4  Found: C, 40.4; H, 3.5; CI,  Rh, 12.4; P, 7.4. 3 1  1 4  29.5; Rh, 12.4; P, 7.2.  NMR: -72.22(m), -68.77(m), -46.91(m), -43.95(m), -26.67(m), -24.20(m);  a l l o f approximately the same i n t e n s i t i e s . and  3 . 8 ( m ) ( t o t a l 16H, -CH -CH -); 2  2  "4l NMR: 1.4(m), 2.2(m), 3.3(m),  7.1(m), 7.6(m), 7.9(m), and 8.3(m)  ( t o t a l 40H, P ( C g H ) ) ; r e l a t i v e i n t e n s i t i e s 6:6:3:1:30:6:2:2; 5  2  -15.72  (dt, J(Rh-H)=14 Hz, J(P-H)=18 H z ) , -13.95(m), ( r e l a t i v e i n t e n s i t i e s 4:1, Rh-H).  I R ( C D ) : v(Rh-H) 2090(m); ( N u j o l ) : v(Rh-H) 2090(m); v(Rh-C£) &  6  290 (w,br), 265 (w,br) cm" . 1  2-6. Syntheses o f P o l y m e r i c Complexes. 2-6-1.  D i f f e r e n t Methods of P o l y m e r i z a t i o n o f [ C J ^ S i - ( C H ) ~ P ( C g H ^ ] ~ 2  2  2  2  Rh(C0)C£. A.  A benzene s o l u t i o n  ( c a . 3.5 ml) o f 5.931 g (6.89 mmol) o f  [ C £ S i - ( C H ) - P ( C g H ^ ) ] R h ( C 0 ) C £ prepared i n s i t u was i n t r o d u c e d dropwise 3  2  2  2  2  i n t o 5 mL of a v i g o r o u s l y s t i r r e d m i x t u r e o f dioxane and water (4:1 v / v ) . The s u s p e n s i o n o f t h e r e s u l t a n t 2h.  p a l e y e l l o w p r e c i p i t a t e was s t i r r e d f o r  A s o l u t i o n o f 4 g of NaHCO^ i n c_a. 50 mL o f water was added t o the  suspension.  The product was f i l t e r e d o f f , washed w i t h water, 10%  aqueous o f NaHCO^, water, dioxane, and benzene, and d r i e d 24h.  i n vacuo f o r  -33-  The s o l i d product was t r a n s f e r r e d  t o a Soxhlet e x t r a c t o r and  e x t r a c t e d w i t h r e f l u x i n g d i c h l o r o m e t h a n e f o r 24h. The i n s o l u b l e polymer was d r i e d i n vacuo f o r 24h (3.92 g, 81.7% y i e l d ) ,  decomp.  255-265°C. Anal. Calcd f o r C ^ H ^ C i Rh, 14.8; P, 8.9.  O^RhSi^  C, 50.0; H,4.3; C£, 5.1;  Found: C, 50.0; H, 3.8; C£, 12.3; Rh, 14.8; P, 9.1.  IR ( N u j o l ) : v(C^O) 1965(s) cm" . 1  B.  A benzene s o l u t i o n  ( c a . 1.5 ml) o f [ C J ^ S i - ( C H ) ~ P ( C g H , . ) J ~ 2  2  2  2  Rh(C0)C£ (0.086 g, 0.1 mmol) prepared i n s i t u was added dropwise i n t o 1 mL o f an aqueous s o l u t i o n of 0.1 g KOH. formed immediately. and then d r i e d  A pale yellow p r e c i p i t a t e  I t was f i l t e r e d o f f , washed w i t h water, benzene,  i n vacuo f o r 24h.  I R ( n u j o l ) : v ( C E 0 ) 1965(s) cm" . 1  C.  Triethylamine  P(C H ) J Rh(CO)C£ 6  5  2  2  (0.1 g, 1.0 mmol) was added t o  [CJ^Si-(CH ) ~ 2  2  (0.086 g, 0.1 mmol) which had been prepared i n s i t u  i n 1.5 mL o f benzene.  The m i x t u r e was added dropwise t o c a . 2 mL o f water.  A p a l e y e l l o w p r e c i p i t a t e formed immediately.  I t was f i l t e r e d o f f , washed  w i t h water, benzene, and then d r i e d i n vacuo f o r 24h. IR(Nujol):v(CE0)  1965(s) cm" . 1  2-6-2. D i f f e r e n t Methods o f P o l y m e r i z a t i o n o f [ C i ^ S i - ( C H ) ~ P ( C H ) ] R h C £ . 2  A.  2  Homopolymerization o f [ C £ „ S i - ( C H „ ) - P ( C , H ) J „ R h C £ 3 Z Z o D Z 3 0  c  g  5  2  3  i n the  presence o f N ( C H ^ ) . 2  3  T r i e t h y l a m i n e (0.5 g, 1 mmol) was added to [ C J ^ S i - ( C H ) ~ P ( C ^ ) ] R h C £ 2  2  2  3  -34-  (0.316 g, 0.3 mmol) prepared i n s i t u i n 1.5 mL of benzene. was  then added to 2 mL of water.  V i g o r o u s s t i r r i n g w i t h a magnetic b a r  was maintained throughout the r e a c t i o n . immediately.  The s o l u t i o n  An orange product  precipitated  I t was f i l t e r e d o f f , washed w i t h water and benzene, and  d r i e d i n vacuo f o r 24h.  C o p o l y m e r i z a t i o n of i n the presence o f N ( C H ^ ) 2  [ C ^ S i - ( C H ^ ~ P ( C ^ ) ] R h C £ with C£ £i-CH 2  2  3  3  3 >  A number o f copolymers were produced which d i f f e r e d p r o p o r t i o n s of C £ S i - C H a n d 3  3  [ C ^ S i - (CH ) ~ P ( C g H ^ ] R h C £ .  3  2  2  2  procedures were analogous f o r a l l o f them.  i n the s t a r t i n g  The p r e p a r a t i o n  3  The procedure f o l l o w e d f o r t h e  copolymer w i t h the p r o p o r t i o n o f C £ S i - C H to [ C J ^ S i - (CH ) ~ P ( C ^ ) ^ \ R h C £ 3  3  2  2  3  100:1 was t y p i c a l . C £ S i - C H (4.069 g, 27.2 mmol) and t r i e t h y l a m i n e 3  3  (10 g, 0.1 mol)  were added to 1.5 mL o f a benzene s o l u t i o n of [C£„Si-(CH„)„-P(C,H )„]„RhC£ C  5  L  I  D  J  Z  j  (0.321 g, 0.27 mmol) prepared i n s i t u .  The s o l u t i o n was i n t r o d u c e d dropwise  i n t o 2 mL of v i g o r o u s l y s t i r r e d water.  A p a l e y e l l o w p r e c i p i t a t e formed  immediately.  I t was f i l t e r e d o f f , washed w i t h water, benzene, and d r i e d  i n vacuo f o r 24h. See T a b l e I f o r the p r o p e r t i e s of the p r o d u c t s . B.  Copymerization o f [ C J ^ S i - ( C H ) ~ P ( C ^ ) ] R h C £ w i t h C£ Si-CH . 2  2  2  3  3  3  i n the presence o f KOH(aq). The procedure f o l l o w e d f o r the polymer i n which the s t a r t i n g p o r t i o n of C £ S i - C H a n d 3  3  pro-  [ C £ S i - ( C H ) ~ P ( C H ) ] R h C £ was 100:1 was t y p i c a l 3  2  2  6  5  2  3  and was repeated f o r the r e a c t i o n s u s i n g d i f f e r e n t component p r o p o r t i o n s . Methyltrichlorosilane  (3.73 g, 24.9 mmol) was added t o c a . 1.5 mL of  -35-  a benzene s o l u t i o n of [C£_Si- (CH„) „-P(C,H,) „] R h C £  (0.295 g, 0.25 mmol)  0  j  prepared i n s i t u . stirred  o _> z _>  Z Z  The s o l u t i o n was added dropwise to a v i g o r o u s l y  s o l u t i o n of 4.5 g KOH i n 6 mL o f water.  formed immediately. then d r i e d  A p a l e orange  precipitate  I t was f i l t e r e d o f f , washed w i t h water, benzene, and  i n vacuo f o r 24h.  See T a b l e I I f o r the p r o p e r t i e s of t h e p r o d u c t s . C.  Homopolymerization o f [ C £ S i - ( C H ) - P ( C H ) ] R h C £ 3  2  2  6  5  2  i n a DMF/  3  Water M i x t u r e . A benzene s o l u t i o n  (1.5 mL) o f [C£ Si-(CH„)„-P(C,H )„]„RhC£ 0  C  Z Z  _>  D  J  Z  (0.373 g,  j  0.32 mmol) prepared i n s i t u was i n t r o d u c e d s l o w l y i n t o 5 mL o f a v i g o r o u s l y stirred  m i x t u r e o f DMF and water  ated immediately. and then d r i e d  (4:1 v / v ) .  A p a l e y e l l o w product p r e c i p i t -  I t was f i l t e r e d o f f , washed w i t h water, DMF, and benzene  i n vacuo f o r 24h.  During t h i s procedure t h e c o l o u r  changed  to orange. Copolymerization of [ C £ S i - ( C H ) - P ( C H ) ] R h C £ with C £ S i - C H 3  2  2  6  5  2  3  3  3  in  DMF/Water M i x t u r e . A m i x t u r e o f 3.370 g (22.5 mmol) of C^Si-CLL^and 1.5 mL of a benzene s o l u t i o n of 0.267 g (0.23 mmol) of [ C i ^ S i - ( C H ) ~ P ( C ^ ) ] R h C £ prepared i n 2  2  2  3  s i t u , was i n t r o d u c e d s l o w l y dropwise i n t o 10 mL of a v i g o r o u s l y m i x t u r e o f DMF and water filtered  (4:1 v / v ) .  stirred  The r e s u l t i n g y e l l o w p r e c i p i t a t e was  o f f , washed w i t h water, DMF, and benzene.  On d r y i n g i n vacuo f o r  24h t h e product became orange. For  r e s u l t s see T a b l e I I I .  D.  Homopolymerization of [ C £ S i - ( C H ) ~ P ( C H ) ] R h C £ 3  2  2  &  5  2  3  i n Dioxane/  Water M i x t u r e . A benzene s o l u t i o n  (1.5 mL) o f 0.402 g (34.1 mmol) o f [ C J ^ S i - ( C l i p ~  P(C H,-) ] ,RhC£ prepared i n s i t u was i n t r o d u c e d dropwise i n t o 4 mL o f a t  9  2  -36-  v i g o r o u s l y s t i r r e d m i x t u r e of dioxane and water  (3:1 v / v ) . The  suspension of the r e s u l t i n g p a l e y e l l o w p r e c i p i t a t e was s t i r r e d f o r an a d d i t i o n a l 2h. addition  The p r e c i p i t a t e changed c o l o u r t o orange upon  o f c a 8 mL o f an aqueous s o l u t i o n of 0.5 g o f NaHCO^. ;  The  product was f i l t e r e d o f f , washed w i t h water, 10% aqueous NaHCO^, water, dioxane, and benzene, and then d r i e d i n vacuo f o r 24h. C o p o l y m e r i z a t i o n of [ C J ^ S i - ( C H ) ~ P ( C g H ^ ] ^ R h C Z w i t h 2  2  2  C£ Si-CH 3  3  i n Dioxane/Water M i x t u r e . Methyltrichloros'ilane  (4.030 g, 27.0 mmol) was added t o 1.5 mL o f a  benzene s o l u t i o n of [C£„Si-(CH_)„-P(C,H,)_]„RhC£ 3  z  Z  o  -> /  (0.318 g, 0.27 mmol)  3  prepared i n s i t u . The s o l u t i o n was added dropwise i n t o 11.5 mL o f a m i x t u r e of dioxane and water (4:1 v / v ) . y e l l o w p r e c i p i t a t e was s t i r r e d  The s u s p e n s i o n o f the r e s u l t i n g p a l e  f o r an a d d i t i o n a l 2h.  I t s c o l o u r changed  to orange a f t e r a d d i t i o n o f ca_.100 mL o f an aqueous s o l u t i o n o f 8 g of NaHC0  3  i n t o the s u s p e n s i o n .  The product was f i l t e r e d o f f , washed w i t h  water, 10% aqueous NaHC0 , water, dioxane, and benzene, and then d r i e d 3  i n vacuo f o r 24h. For  r e s u l t s see T a b l e I I I .  E.  Homopolymerization o f [ C J ^ S i - ( C H ) ~ P ( C ^ ) ] R h C £ 2  2  2  3  i n Dioxane/  Water M i x t u r e ; F o l l o w e d by E x t r a c t i o n . A benzene s o l u t i o n  (3.5 mL) o f 5.427 g (4.59 mmol) of  [C£„Si-(CH ) -P(C,H )„] RhC£ 3 z z o _> z J 0  0  c  0  prepared i n s i t u was i n t r o d u c e d dropwise •-—•  i n t o 5 mL o f a v i g o r o u s l y s t i r r e d dioxane and water m i x t u r e (4:1 v / v ) . The s u s p e n s i o n o f the r e s u l t i n g p a l e y e l l o w p r e c i p i t a t e was s t i r r e d f o r 2h.  A d d i t i o n o f NaHC0 , 4 g i n 50 mL of water, changed t h e c o l o u r o f the  p r e c i p i t a t e to orange.  3  The product was f i l t e r e d o f f , washed w i t h water, 10%  -37-  NaHCO^ (aq), water, dioxane, and benzene, and d r i e d i n vacuo f o r 24h. The s o l i d product was t r a n s f e r r e d  to a Soxhlet e x t r a c t o r and  e x t r a c t e d w i t h r e f l u x i n g dichloromethane was  f o r 24h.  The i n s o l u b l e polymer  d r i e d i n vacuo f o r 24h. C o p o l y m e r i z a t i o n o f [C£ Si-(CH.)„-P(C,H )_]_RhC£ and C £ S i - C H „ 0  C  J  Z Z  n  0 3 / 3  3  3  i n Dioxane/Water M i x t u r e ; Followed by E x t r a c t i o n . M e t h y l t r i c h l o r o s i l a n e (10.914 g, 73.0 mmol) was added t o 1.5 mL of a benzene s o l u t i o n o f [ C J ^ S i - ( C H ) - P ( C ^ ) ] 2  prepared i n s i t u . vigorously  ^hsZl  (0.862 g, 0.73 mmol)  The s o l u t i o n was i n t r o d u c e d dropwise  s t i r r e d m i x t u r e of dioxane and water  p r e c i p i t a t e formed immediately; 2h.  2  i n t o 25 mL o f a  (4:1 v / v ) .  i t s s u s p e n s i o n was s t i r r e d  A pale yellow f o r an a d d i t i o n a l  The product became orange a f t e r a d d i t i o n o f 20 g o f NaHCO^ d i s s o l v e d  i n 250 mL o f water t o the s u s p e n s i o n .  The polymer was f i l t e r e d o f f , washed  w i t h water, 10% NaHCO^aq), water, dioxane, and benzene, and then d r i e d i n vacuo f o r 24h. The product was subsequently t r a n s f e r r e d and e x t r a c t e d w i t h dichloromethane  over a p e r i o d  i n t o a Soxhlet of 24h.  extractor  The i n s o l u b l e  polymer was then d r i e d i n vacuo f o r 24h. For r e s u l t s see T a b l e IV. F.  R e a c t i v i t y o f the P o l y m e r i c Complexes w i t h Hydrogen Gas -  a S t a b i l i t y Test. The apparatus  shown i n F i g . 3 was used  f o r measurements of hydrogen  -2 uptake.  The p o l y m e r i c complex (4.5 x 10  mmol based  on Rh atoms) produced  by any o f the methods d e s c r i b e d above was suspended i n 3 mL o f t o l u e n e a t 60°C.  Hydrogen a t 690 mm Hg was allowed t o r e a c t w i t h t h e polymer i n  s u s p e n s i o n f o r 24h.  Any c o l o u r changes of the polymer were noted.  -38-  T a b l e I.  Hydrogen uptake by polymers prepared i n the presence of  N(C H ) . 2  5  3  C£ S i - CH / [ C5, S i - CGH )--P ( C , H ) ] R h C £ 3  3  3  2  i n i t i a l molar  2  ratio  c  O  J  0  0  J  Z  H„uptake per Z  Rh atom  0  1.82  darkens  20  1.37  darkens  80  -  no s o l i d polymer produced no c o l o u r change  0.99  100  1.28  Table I I .  ,  darkens slightly  Hydrogen uptake by polymers prepared i n the presence of KOH(aq).  C£„Si-CH /[C£ Si-(CH ) -P(C,HjJ RhC£  H  i n i t i a l molar r a t i o  per Rh atom  0  Polymer c o l o u r - change a f t e r reaction  0  0  0  0  uptake  Polymer  colour  reaction  50  1.39  darkens  60  2.05  darkens  70  0.60  darkens  100  1.31  remains y e l l o w  130  0.45  darkens  200  1.53  darkens  -39-  T a b l e I I I . Hydrogen uptake by polymers prepared i n dioxane/water m i x t u r e by procedure D.  C£-SiCH_/[C£_Si-(CH ) -P(C,H )_]_RhC£ J j J z z o j / j . , , ^. i n i t i a l molar r a t i o 0  0  c  organic i solvent/ water r a t i o  H. uptake i per Rh atom  Polymer colour after reaction(b)  DMF/water h y d r o l y s i s 0  0.06  orange  0.16 100  dioxane/water h y d r o l y s i s  0  0.27  yellow  1.00  yellow  200 200  ^a  unfiltrable gel produced  130  4  100  4  0.75  50  4  0.50-0.97  C  yellow  100 (a) h y d r o l y s i s i n l a r g e excess o f water/dioxane. (b) i n i t i a l l y orange. T a b l e IV. Hydrogen uptake by polymers prepared i n dioxane/water m i x t u r e by procedure E.  C£,Si-CH,/ [C£,Si-(CH„) _-P(C,H,-) ] „RhC£ . 4 . , J i ~> . z z D J Z J i n i t i a l molar r a t i o 0  (a) i n i t i a l l y  d i o x a n e / H uptake water per Rh ratio atom 2  Polymer colour after reaction(a)  0  4  0.12  light  orange  100  4  0.56  light  orange  orange.  -40-  2-6-3.  Homopolymerization of D i f f e r e n t Rh(I) Phosphine Complexes and their  Copolymerization with  C^Si-CH-}'  A l l the p o l y m e r i c complexes used f o r any f u r t h e r prepared a c c o r d i n g t o the procedure  B  r e a c t i o n s were  d e s c r i b e d above.  A l l the homo-  polymers proved to be p y r o p h o r i c upon exposure t o a i r . { [ 0 ^ S i - ( C H ) - P ( C H ) l R h C £ } : 8 5 . 3 % y i e l d , decomp. 220-230°C. A n a l . 3  2  2  Calcd f o r : C  2  6  H  4 2  4 2  5  C£0  2  3  x  P R h S i : C, 54.0 H, 4.5; C£, 3.8; P, 10.0; Rh, 11.0;  g / 2  3  3  Found: C, 50.8; H, 4.5; CI,  S i , 9.0.  IR(Nujol):v(Rh-C£) 285fw); 255(sh)  6.2; P, 9.5; Rh, 10.5; S i , 8.9.  cm" . 1  {[0Si(CH )-(CH )„-P(C,H )„]_RhC£} : not a n a l y z e d ; the product was completely 3 z z, o 5 z 3. X ^ o  o  c  soluble i n C H C £ . 2  2  {[0„ ,„Si-(CH„) -P(C,Hj J „ R h C £ }  3 / z  z  Calcd f o r C S i , 7.1.  H  6 0  o o _ 5 z 3  0  7 g  C£0  : 84.1% y i e l d , decomp. 185-195°C.  3  3  Found: C, 59.2; H, 6.3; C£, 4.6; P, 7.6; Rh, 8.4; S i , 6.9. cm" .  {[0  2  IR(Nujol):  1  S i - ( C H ) - P ( C H ) ] R h C £ } ; 70.2% y i e l d , decomp. 220-230°C. A n a l . 2  Calcd f o r C S i , 8.4.  5 6  2  H  5 6  6  5  4  2  2  x  C £ 0 P R h S i : C, 50.3; H, 4.2; C£, 5.3; P, 9.3; Rh, 15.4; 2  6  4  2  4  Found: C, 50.6; H, 4.5; C£, 6.6; P, 9.0; Rh, 15.1; S i , 8.3.  IR(Nujol):v(Rh-C£) 290(w); 265(sh)  cm" .  {[0  Si-(CH ) -P(C H ) ]  3 / 2  Anal.  P R h S i : C, 60.8; H, 6.6; C£, 3.0; P, 7.7; Rh, 8.7;  g / 2  v(RhC£) 285(w) 255(sh) 3 / 2  x  Si-(CH ) -P(C H ) ] RhC£. [0 2  2  6  5  2  3  1  3 / 2  2  decomp. 260-265°C.Anal. C a l c d f o r C  C 1  H .  0  2  6  „ C£ 0  c  5 1 . o  5  C  C[  2  0 f 7  . P.  5 1 . o  J.JD  C, 55.6; H, 4.6; C£, 3.2; P, 10.3; Rh, 9.2; S i , 9.3.  } ; x  n  78.9% y i e l d ,  Rh S i . \ n  5.1  5.1  Found: C, 50.3;  H, 4.8; C£, 6.6; P, 10.2; Rh, 9.1; S i , 9.1. ( ( 0 ^ S i - C H ) . { [ 0 ^ S i - ( C H ) - P ( C H ) ] R h C £ } ) : 73.5% y i e l d , 3  2  255-265°C.  3  7 5  3  2  2  Anal. Calcd f o r C  P, 1.6; Rh, 1.7.  2  1 1 7  6  H  2 6 9  5  C£  2  3  0  x  1 1 7  P RhSi 3  7 g  ;  decomp.  C, 23.6; H, 4.5; C£, 0.6;  Found: C, 23.6; H, 5.3; C£, 1.4; P, 1.5; Rh, 1.7.  -41((0.  3 / 2  Si-CH ) 3  1 5 ( )  .{[0  3 / 2  Si-(CH ) -P(C H ) ] RhC£}) : 2  255-265°C. A n a l . C a l c d f o r C  2  6  5  H C£ 192 492 i n o  2  0  / n o  3  78.2% y i e l d ,  x  decomp.  „ P RhSi : C, 21.0; H, 4.5; 229.5 3 153 o o  r  0  l c o  Found: C, 20.2; H, 4.5 ((0  3 / 2  Si-CH ) 3  2 0 0  .{[0  3 / 2  Si-(CH ) -P(C H ) ] RhC£}) : 2  2  6  5  2  3  71.2% y i e l d ,  x  decomp.  255-265°C. A n a l . C a l c d f o r C„,„H,.„C£ 0 . P R h S i : C, 20.3; H, 4.5. 242 642 304.5 3 203 o n  c  0  o n o  Found: C, 20.2; H, 4.3. ((0  3 / 2  Si-CH ) 3  1 0 ( )  .{[0  Si-(CH ) -P(C H ) ] RhC£}) :  3 / 2  2  8  6  5  2  250-260°C. A n a l . C a l c d f o r C,-„H„-, C£ 0 0  160 3/8  3  86.8% y i e l d ,  x  1 C /  r  P Rh S i , 0  J  154.5  decomp.  : C, 24.4; H, 4.8.  103  Found: C, 24.4; H, 4.8. ((0  3 / 2  Si-CH ) 3  2 0 ( )  .{[0  3 / 2  Si-(CH ) -P(C H ) ] Rh C£ }) : 2  2  6  5  2  4  2  2  x  70.2% y i e l d ,  decomp.  270-280°C. A n a l . C a l c d f o r C . H . , C £ 0 _,P.Rh„Si„„. : C, 20.9; H, 4.5; 256 656 2 306 4 2 204 01  CI,  t  £1  0  o  Found: C, 21.0; H, 4.4; CI,  0.5; P, 0.8; Rh, 1.4; S i , 38.8.  0.2;  P, 0.8; Rh, 1.5; S i , 38.6. 2-6-4. P o l y m e r i z a t i o n o f C £ S i - ( C H ) _ - P ( C , H ) „ . 0  0  z Z  3 A benzene s o l u t i o n  C  b  D  Z  (3 mL) o f 1.740 g (5.0 mmol) of C J ^ S i - ( C H ) ~ P ( C ^ ) 2  2  2  was i n t r o d u c e d dropwise i n t o a v i g o r o u s l y s t i r r e d m i x t u r e (2.5 mL) o f dioxane and water  (4:1 v / v ) .  was s t i r r e d  The s u s p e n s i o n o f the white p r e c i p i t a t e which was formed  f o r an a d d i t i o n a l  of water was added t o i t .  2h.  A s o l u t i o n o f 1.5 g o f NaHC0  3  i n 20 mL  The product was then f i l t e r e d o f f , washed w i t h  water, 10% NaHC0 (aq), water, dioxane, and benzene, and then d r i e d 3  i n vacuo  A n a l . C a l c d f o r { 0 , _ S i - ( C H ) - P ( C , H ) } : CI, 0.0; and f o r 3/2 2 2 6 5 2 n {0(C£)Si-(CH )„-P(C,H )„ : C£, 12.1. Found: Cfc, 9.2. z z b J z n 2-7. R e a c t i o n s o f t h e S o l u b l e Complexes w i t h H , CO, and H C £ ( g ) . for  24h.  o  0  0  c  0  v  o  c  ?  The r a t e s o f the r e a c t i o n s were not f o l l o w e d by the gas uptake  -42-  measurements due  to extremely h i g h s o l u b i l i t y of the complexes even i n  s o l v e n t vapours.  The  complexes s t a r t e d r e a c t i n g , as r e c o g n i z e d by  the  c o l o u r changes, w i t h the gaseous reagents b e f o r e b e i n g i n t r o d u c e d i n t o the l i q u i d  solvent.  T h i s d i d not a l l o w o b s e r v a t i o n s of the b e g i n n i n g  s t a g e s or even most of the r e a c t i o n p r o g r e s s .  2-7-1.  R e a c t i o n of { [ (CH ) S i - 0 - ] (CH )Si-(CH > "P ( C ^ ) 3  The  complex was  under n i t r o g e n .  3  3  2  2  2  > RhC£ w i t h H 3  d i s s o l v e d i n d e u t e r a t e d benzene i n an NMR  The NMR  tube was  shown i n F i g . 3.  The  and  introduced.  hydrogen was  2  connected  s o l u t i o n was  degassed  The  i n d i c a t e d the r e a c t i o n p r o g r e s s .  to the gas uptake  c o l o u r change from dark red to y e l l o w As the gas d i f f u s e d through  the  solution  from the top meniscus  f u r t h e r c o l o u r changes were observed  throughout.  over a p e r i o d  of 2h.  The NMR  4  -8.5(m); -10.1(m); -17.9(m); ( r e l a t i v e i n t e n s i t i e s 1:1:2, Rh-H).  NMR:  { P} 31  X  E  NMR:  and  No  tube,  apparatus  to the bottom of the tube. A f t e r 8h the s o l u t i o n became y e l l o w then shaken.  .  by the freeze-and-thaw method  and r e a c t e d w i t h the complex the c o l o u r change p r o g r e s s e d  I t was  2  -9.3(m, p a r t l y d e c o u p l e d ) ;  i n t e n s i t i e s 1:1, -20.17(dt, 16:8:1.  IR s p e c t r a of the s o l u t i o n were r e c o r d e d .  R h - H ) . P NMR: 31  -41.03(dd, J(P-P)=20 Hz,  I R ( C D ) : v(Rh-H) 2075(s), 6  6  2160(sh)  then evaporated  i n d e u t e r a t e d benzene i n the same NMR The NMR  and  o r i g i n a l Rh(I) The and  (relative  J(Rh-P)=110 Hz);  J(P-P)=20 Hz,J(Rh-P)=90 Hz); -29.9'2(s); r e l a t i v e  The s o l v e n t was  lh.  -17.9(d, J(Rh-H)-23 Hz);  intensities  cm" . 1  i n vacuo.  The complex was  tube and remained i n N  2  IR s p e c t r a of the s o l u t i o n showed s i g n a l s due  redissolved  atmosphere f o r t o the  complex o n l y .  same NMR  tube was  a g a i n a t t a c h e d to the gas-uptake  r e h y d r o g e n a t i o n of the complex was  apparatus  c a r r i e d out i n the same manner.  The  - 4 3 -  NMR  and IR s p e c t r a of the r e s u l t i n g  the o r i g i n a l l y hydrogenated  2-7-2.  s o l u t i o n were the same as those of  compound.  3  3  2  The r e a c t i o n procedure was 3  2  3  2  A f t e r the f i r s t following pattern  2  6  3  2  6  5  2  4  i d e n t i c a l with that f o r  {[(CH )3S1-O-] (CH )Si-(CH ) ~P(C H )  "4 NMR:  with H .  R e a c t i o n of { [ ( C H ) . S i - 0 - 0 ] . ( C H ) S i - ( C H ) - P ( C H ) } R h  5  2  > RhC£. 3  h y d r o g e n a t i o n the NMR  and IR s p e c t r a showed the  ( F i g . 39a and b),:  -16.1(m); -17.8(m); - 1 9 . 8 ( t , J(P-H)=24 Hz), -20.1(dt, J(Rh-H)=24 Hz,  J(P-H)=16 H z ) ; ( a l l Rh-H). { P } 31  4  NMR:  j(Rh-H)=15 Hz); - 1 9 . 8 ( s ) ; -20.1(d, -43.95(B);  -41.85(B);  -38.88(B);  -16.1(d,  J(Rh-H)=24 H z ) .  -49.38(B);  J (Rh-H) =15 3 1  P  -44.56(B);  NMR:  Hz);  -17.8(d,  -48.76(s);  -42.22(B);  -39.50(B);  - 2 9 . 6 2 ( s ) ; -21.26(m); -19.04(m); r e l a t i v e i n t e n s i t i e s  83:74:100:70:24:27:  25:25:20:27:25. IR(CgD ):v(Rh-H) 2102(a), 2165(sh)  -1  6  cm .  A f t e r removal of hydrogen by pumping,NMR and IR s p e c t r a of the s o l u t i o n were r e c o r d e d .  Only s i g n a l s due t o the o r i g i n a l Rh (I)  complex  were p r e s e n t . On r e h y d r o g e n a t i o n the same s p e c t r a showed the same p a t t e r n as the o r i g i n a l l y hydrogenated  2-7-3.  complex.  R e a c t i o n of { [ (CHg) Si-0-.] ( C H ) S i - ( C H g ) ~ P ( C ^ ) ^ R h ^ 3  An NMR  g  3  2  with  tube w i t h a s o l u t i o n of the complex i n deuterobenzene  connected to the gas uptake apparatus shown i n F i g . 3. degassed by the freeze-and-thaw method and carbon  The s o l u t i o n  monoxide was  As the r e a c t i o n p r o g r e s s e d the c o l o u r of the s o l u t i o n changed hydrogenation r e a c t i o n s described  above.  CO.  was was  admitted.  as i n the  -44-  After was  24h the r e a c t i o n  performed.  appeared  to be complete  and s p e c t r a l  The s p e c t r a showed p a t t e r n s c h a r a c t e r i s t i c  analysis  of  {[(CH ) Si-0-] (CH )Si-(CH ) -P(C » ) } Rh(CO)CA. 3  3 1  P  2  NMR:  30:1.  1  3  2  2  6  5  2  2  -29.81(d, J(Rh-P)=124.7 Hz); -30.00(s); r e l a t i v e H NMR:  0.19(s,42H,Si-CH  and S i ( C H ^ ) ) ; 1.15(m,4H,Si-CH -);  Q  Q  9  2.98(m,4H,P-CH -); 7.16(m) and 8.00(m), ( t o t a l 20H,  relative  2  3:2,  6  5  2  cm" . 1  D O  2-7-4.  R e a c t i o n of { [ (CH ) S i - 0 - ] (CHg) S i - (CH ) ~P ( C J ^ ) ^ R h C A w i t h 3  The r e a c t i o n dirhodium.The P  intensities  P(C H ) ); IR(C,D,):v(C=0) 1965(vs)  3 1  intensities  NMR  NMR  3  2  procedure was  2  2  the same as f o r the d i - y - c h l o r o b i s p h o s p h i n e -  and IR s p e c t r a showed the f o l l o w i n g  ( C J ) , , 3 5 ° C ) : -30  CO.  pattern:  to -3(m); -29.94(s).  D D 3 1  P  NMR  [ ( C D ) C O , - 6 0 ° C ] : -47 3  Si(CH )  and  3  2  cm  1  (CgDg): 0.18(s,63H,  1  S i ( C H ) ) ; 1.05(m,6H,Si-CH,-); 2.71(m,6H,P-CH ~); 7.13(m) and 3  3  7 . 8 5 ( m ) ( t o t a l 30H, (vs)  to -13(m). H NMR  2  r e l a t i v e i n t e n s i t i e s 3:2,  P(C H ) ).IR(C D ):v(C=0) g  5  2  6  fi  1965  .  2-7-5. R e a c t i o n of' { [ ( C H ) S i - 0 - ] ( C H ) S i - ( C H ) - P ( C H ) } R h ( C O ) C J l 3  3  2  3  2  2  6  5  2  2  with  { [ ( C H ) S i - 0 - ] ( C H ) S i - ( C H ) -P ( C J ^ ) > . 3  3  2  3  2  2  2  -2 The f r e e phosphine (9.1 x 10 tube.  2  -  g, 8.8  The spectrum  -2  (3.8 x 10  g, 8.8  x 10  mmol) and the complex  2 x 10  mmol) were d i s s o l v e d  of the s o l u t i o n was  i n benzene-d^ i n an  NMR  recorded.  P NMR: -20 to -3(m); -29.41(s); r e l a t i v e i n t e n s i t i e s 4:1. 2-7-6. R e a c t i o n of { [ ( C H ^ S i - O - ] (CH ) S i - (CH > ~P ( C ^ ) > R h C £ w i t h H C £ ( g ) .  3 1  2  An NMR  tube w i t h the s o l u t i o n  to the m o d i f i e d gas uptake apparatus  3  2  2  2  3  of the complex i n benzene was  connected  equipped w i t h T e f l o n s t o p c o c k s , as shown  -45-  in Fig.  3. The s o l u t i o n was degassed by the freeze-and-thaw method and HC£(g)  was  introduced.  The r e a c t i o n r e s u l t e d  a yellow, insoluble  i n the immediate p r e c i p i t a t i o n of  solid.  The p r e c i p i t a t e was  f i l t e r e d , washed w i t h benzene, d r i e d  of n i t r o g e n f o r 8h, and f i n a l l y d r i e d non-crystalline pale yellow s o l i d ,  i n vacuo f o r l h .  i n a stream  The product was a  i n s o l u b l e i n benzene, t o l u e n e , acetone,  dichloromethane, 1 , 2 - d i c h l o r o e t h a n e , petroleum e t h e r , d i m e t h y l s u l p h o x i d e , d i m e t h y l a c e t a m i d e , and carbon d i s u l p h i d e . I R ( N u j o l ) :v(Rh-H) 2110(m) :v (Rh-C£) 253(m),  273(w) cm"" . 1  Anal. Calcd f o r { [ ( C H ) S i - 0 - ] ( C H g ) S i - ( C H ) ~ P ( C ^ ) > R h C £ . H C £ i . e . 3  C  63 106 H  C £  2°6 3 P  R h S i  3  :  C  '  5 1  '  2 ;  H  3  '  7  { [ 0 (CH ) S i - (CH ) - P ( C H ) ] [ 0 3  C  4 5  H  5 2  2  2  6  C£ 0 ^ P RhSi : 3  5  2  3  5  2  2  2  ' ' 2  1 / 2  C l  2  >  4  '  8 ,  C  a  l  c  d  f  o  2  2  3  r  (CA) (CH ) S i - (CH^) ~ P ( C ^ ) ] R h C £ .HC£ }^ i . e . 3  2  2  C, 53.0; H, 5.1; C£, 10.5. Found: C, 53.7; H, 7.3;  3  9.5. The compound was  h e l d i n vacuo f o r 24h i n order t h a t the hydrogen  c h l o r i d e c o u l d be removed.  The product was  any of the s o l v e n t s mentioned i n the f i r s t  an orange s o l i d  p a r t of t h i s experiment.  I R ( N u j o l ) : a l l t h r e e peaks v(Rh-H) 2110, had d i m i n i s h e d  (Rh-C£) 253, and  2  (CH ) -P(C H ) ]RhC£> 7.2.  2  6  5  273  intensity.  Anal. Calcd f o r { [ 0 ( C R ^ S i - C H ) ~ P ( C H ) ] [ 0 2  insoluble i n  2  _i^_e. 4 C  x  Found: C, 53.6; H, 5.3;  H 5  C J i 5 1  C£,  2  g  2 3/2 3 0  9.4.  P  R h S i  5  3  2  :  2  C  '  5  1 / 2  (C£)(CH )Si-  5  9  -  3  '  H  '  5  * ' 2  C  1  ,  CZ,  -46-  2-7-7. with  R e a c t i o n o f { [ (CH ) S i - 0 - ] ( C H 3  )Si-(CH )^(CJ^)^Rl^C^  2  2  HC£(g). The  r e a c t i o n procedure  was t h e same as f o r t h e analogous  phosphinerhodium d e s c r i b e d above.  chlorotris-  The product was a l s o a y e l l o w  solid  i n s o l u b l e i n any o f t h e common s o l v e n t s . IR(Nujol):v(Rh-H) 2100(m);v(Rh-C£) Anal. Calcd f o r { [ ( C H ^ S i - O - ] i.e.  255(m), 275(w) cm" . 1  ( C H - j ) S i - ( C H ) ~ P ( C J ^ ) ) R h C £ . 2HC£ 2  2  2  C-.H, . - C J l . O o P . R h - S i ^ : C, 48.3; H, 6.8; Cfc, 6.8. 84 142 4 8 4 2 12  {[0(CH )Si-(CH ) -P(C H ) ] [0 2  3  2  6  5  2  3  1 / 2  m  /U  112.  c  j  4  0  /  2  2  Calcd f o r  ( C £ ) (CH^) S i - ( C H ) ~ P ( C ^ ) ] R h C £ . 2 H C £ > 2  i . e . C-~H- C& 0-, ,„P.Rh Si. : C, 49.1; H, 4.8, CI, DU  4  2  £  2  2  x  12.1. Found: C, 47.8;  4  H, 5.0; C%, 10.8. The  compound was h e l d i n vacuo f o r 24h i n o r d e r t h a t t h e hydrogen  c h l o r i d e c o u l d be removed.  The product  was an orange s o l i d  insoluble i n  common s o l v e n t s . I R ( N u j o l ) ; the peaks v(Rh-H) 2100, and v(Rh-C£) 255, 275 cm" had  diminished  intensity.  Anal. Calcd f o r { [ 0 ( C H ) S i - (CH^ ~ P ( C g H j ) ] 3 ^ 2  3  P(C H ) ]Rh C£ 6  5  2  2  2  2  i.e. C JiggC^O^-^Rh^Si^: &  Found: C, 48.2; H, 6.3; CI, 2-7-8.  1  /  2  (C£) (CH > S i - ( C H ) ~ 3  C, 51.7; H, 4.9; CI,  2  2  7.6.  9.8.  R e a c t i o n of [ ( C H ^ S i - O - j S i ( C H ) C H = C H 2  3  2  w i t h HC£(g) .  A f l a s k w i t h 2 mL o f ca. 50% (w/w) s o l u t i o n o f t h e s i l o x a n e i n benzene was  exposed t o HC£(g) i n t h e manner d e s c r i b e d above.  f o r m a t i o n o f an i n s o l u b l e c o l o u r l e s s g e l was  observed.  A f t e r 30 min the  -47-  2-8. R e a c t i o n s of the P o l y m e r i c Complexes w i t h H^,  CO and H C £ ( g ) .  2-8-1. R e a c t i o n s of P o l y m e r i c Complexes w i t h CO i n Toluene Suspension. The r e a c t i o n s were c a r r i e d out i n the apparatus shown i n F i g . The amount of the homopolymeric complexes used was  1.33 x 10  1  3.  mmol and  -2 of the copolymeric complex 5.4 x 10  mmol.  i n 3 mL of t o l u e n e i n the f l a s k A at 60°C. was  760 mm  3 days.  Hg.  Each compound was  suspended  The carbon monoxide  The t o t a l gas uptake was measured  pressure  f o r each complex  after  The degree of c o n v e r s i o n was c a l c u l a t e d by comparison of the  observed gas consumption and the expected carbon monoxide uptake v a l u e f o r one m o l e c u l e of CO f o r each atom of Rh. Each complex was  f i l t e r e d , washed w i t h benzene, and d r i e d  The IR s p e c t r a were r e c o r d e d .  i n vacuo.  The r e s u l t s a r e p r e s e n t e d i n T a b l e V.  T a b l e V. R e a c t i o n s of P o l y m e r i c complexes w i t h carbon monoxide  S t a r t i n g Complex,(Symbol)  Conversion  i n toluene.  v(C=0) cm  1  {[0  3 / 2  Si-(CH ) -P(C H ) ] RhC£} ,(R _ )  0.36  1965(s)  {[0  3 / 2  Si-(CH ) -P.(C H ) ] RhC£} ,(R _ )  0.40  1965(s)  {[0  3 / 2  Si-(CH ) -P(C- H ) ] Rh C£ } ,(T _ )  0.43  1 9 6 8 ( B ) , 2080(w)  0.91  1968(s), 1995(s), 2080(m)  100  1965(s), 1 9 9 5 ( B ) , 2080(m)  2  2  2  6  8  2  2  5  6  2  5  6  3  2  5  x  3  2  2  x  4  2  2  0  8  0  x  2  0  {[0. Si-(CH ) -P(C,H.).]-RhCA.[0 Si-CH 1 } 3/2 2 2 6 5 2 3 3/2 3 75 x /o  o  o  (R _ ) ?  7 S  a  a: r e a c t i o n a t 70°C. 2-8-2. R e a c t i o n s of the P o l y m e r i c Complexes w i t h CO i n the Absence of any Solvent. The p r o c e d u r e d e s c r i b e d below as a p p l i e d to b o t h the complexes to the t e s t .  subjected  -48-  The p o l y m e r i c complex { [ 0 ^ S i - ( C H ) - P ( C H ) ] R h C U 3  2  2  6  5  3  x  (0.140 g,  0.15 mmol) was weighed out i n t o a 5 mL round bottom f l a s k , which i n t u r n was  connected t o t h e gas uptake apparatus ( F i g . 3) v i a the  s p i r a l at the p o i n t Q.  The complex was degassed and CO was  i n t o the system (760 mm  Hg p r e s s u r e ) .  introduced  The procedure was r e p e a t e d  twice.  The complex remained exposed to the CO atmosphere f o r 3 days a f t e r which time a sample was removed remaining complex was  f o r IR a n a l y s i s .  The f l a s k w i t h the  reweighed and then evacuated f o r 24h.  After  time i t was weighed a g a i n and an IR spectrum of the complex was The degree of c o n v e r s i o n was  this  recorded.  c a l c u l a t e d by comparison of the weight  g a i n w i t h the v a l u e p r e d i c t e d f o r consumption of 1 m o l e c u l e of CO per each atom of Rh.  The r e s u l t s a r e presented i n T a b l e V I .  T a b l e V I . R e a c t i o n s of P o l y m e r i c Complexes w i t h Carbon Monoxide without any s o l v e n t  Starting Complex (Symbol)  Before Evacuation v(C=0) Conversion cm~l  { [ 0 „ S i - ( C H ) - P ( C , H ) ] „ R h C i i } (R„ ) 2 2 6 5 2 3 x 2-0 / / o2  3  o  o  q  o  1970(b,vs)  n  2  0  8  0  (  m  0.27  U  1  9  1  2  2-8-3. R e a c t i o n s of { [ 0  3 / 2  2  2  2  6  5  2  0  8  0  (  m  2  3  x  2  6  with H  The apparatus shown i n F i g . 3 was  2  5  2  3  3 / 2  0  8  0  (  m  Si-CH ) > 3  7 5  x  0.25  )  1970(b,vs) 2080(m)  )  Si-(CH ) -P(C H ) ] RhC£.(0  U0 / Si-(CH ) -P(C H ) ] RhC£} 3  1.30  n  2  1970(b,vs)  )  { [0 ,„Si- (CH„)„-P (C,H,-) ], Rh„C£„ } . (T„ ) 1970 (b ,vs) 6 ^ Z 4 Z z x z U i  A f t e r Evacuation V(CEO) Conversion cm~l  and  i n toluene suspension.  used f o r m o n i t o r i n g the gas uptake.  0.86  % reacted 100 T  80  -50-  The r e a c t i o n s were c a r r i e d out w i t h 0.124 g (1.33 x 10 {[0. Si-(CH ) -P(C,H )„] RhCU 3/  / 0  0  Z  z z  0  O  J  c  Z  0  J  and 0.269 g (4.5 x 1 0 ~ mmol) o f 2  x  .. -  {[0 ^ Si-(CH ) -P(C H ) ] RhC£.[0 3  2  2  2  6  5  2  mmol) o f the  3  3 / 2  S±-CH ]  ^ . T h e a i r s e n s i t i v e homopolymeric  3  complex was weighed out i n t o a bucket i n the f l a s k A under oxygen-free conditions.  The copolymer complex was weighed out i n the a i r .  Each compound was suspended i n 3 mL of t o l u e n e a t 60°C. p r e s s u r e was 690 mm Hg. cedure d e s c r i b e d  The hydrogen  The gas uptake was monitored a c c o r d i n g t o the p r o -  earlier.  A f t e r the r e a c t i o n was stopped the complexes were f i l t e r e d , washed w i t h benzene, and d r i e d i n a stream of n i t r o g e n f o r 2h. The IR s p e c t r a of the products were r e c o r d e d . The gas uptake r e s u l t s a r e r e p o r t e d i n F i g . 5. v(Rh-H)  No peaks i n the IR  r e g i o n were observed f o r e i t h e r o f the p r o d u c t s .  2-8-4. R e a c t i o n of {[0„ Si-(CH„)„-P(C,H J „ ] R h C J 0 w i t h H_ i n the Absence 3/z Z Z o D Z _> x Z /0  o  of any S o l v e n t . The complex  (0.140 g, 0.15 mmol) was weighed out i n t o a 5 mL round  bottom f l a s k which was then connected v i a the g l a s s s p i r a l t o the gas uptake apparatus ( F i g . 3) a t t h e p o i n t Q. and subsequently f l u s h e d w i t h H an atmosphere o f H  2  2  The c o n t e n t s o f t h e f l a s k were degassed  t h r e e times.  The complex was exposed t o  f o r 3 days a f t e r which time an IR spectrum showed no peak  i n the v(Rh-H) r e g i o n . 2-8-5.  R e a c t i o n of the P o l y m e r i c Complexes w i t h HCA(g) i n Toluene Suspension. The m o d i f i e d v e r s i o n o f the gas uptake apparatus i n F i g . 3 was used.  In the experiments 0.269 g (4.5 x 1 0 ~ mmol) o f { [ 0 2  (0  3 / 2  SiCH )  RhC£}  3  7 5  >  x  o r 0.124 g (1.33 x 1 0  and 3 mL o f t o l u e n e were used.  _ 1  3 / 2  Si-(CH ) -P(C H ) ] RhC£-  mmol) o f { [ 0  2  3 / 2  2  6  5  2  3  Si-(CH ) ~P(C^) ] ~ 2  2  2  3  The gas p r e s s u r e was 760 mm Hg and the  -51-  temperature 60°C. manner.  The s o l v e n t and the complex were degassed i n the u s u a l  However, a f t e r the bucket c o n t a i n i n g the complex was dropped  i n t o the s o l v e n t i n s t e a d of gas consumption r a p i d gas e v o l u t i o n p e r s i s t e d f o r 3h.  No net gas a b s o r p t i o n was  observed at any time.  o f f , washed w i t h benzene and d r i e d i n the stream of N the stream of HC£(g) f o r ca,. 1 min.  w i t h HC£(g) i n the  o  Z  f o r 2h and f i n a l l y i n  intensities.  R e a c t i o n of {[0 ,„Si-(CH„)„-P(C,H.)_]„RhC£}  51 Z  2  filtered  The IR s p e c t r a d i d not show any n o t i c a b l e  i n c r e a s e of the v(Rh-C£) or v(Rh-H) peak 2-8-6.  The polymer was  Z  O 3  Z  3  X  Absence of S o l v e n t . The complex  (0.140 g, 0.15 mmol) was weighed out i n t o a 5 mL round  bottom f l a s k which was  then connected v i a the g l a s s s p i r a l to the m o d i f i e d  gas uptake a p p a r a t u s ( F i g . 3 ) . The c o n t e n t s of the f l a s k were degassed and subsequently w i t h HC£(g) t h r e e times.  The complex was  flushed  exposed to the atmosphere of  HC£(g) f o r 3 days a f t e r which time the f l a s k was reweighed and an IR spectrum of the polymer was f o r 24h, and reweighed.  recorded.  The f l a s k was weighed evacuated  The IR spectrum of the polymer was  The observed uptake of HC£(g) was  recorded.  compared w i t h the v a l u e p r e d i c t e d f o r  a b s o r p t i o n of 1 m o l e c u l e of HC£(g),per atom of Rh. of the p r e d i c t e d HC£(g) a b s o r p t i o n ; no s i g n i f i c a n t no appearance of v(Rh-H). A f t e r e v a c u a t i o n : 2.17  B e f o r e pumping:  2.23  i n c r e a s e i n v(Rh-C£) and  of the p r e d i c t e d  HC£(g)  a b s o r p t i o n ; no change i n the IR spectrum. 2-9.  Hydrogenation of O l e f i n s  with Soluble  Complexes.  The r e a c t i o n s were c a r r i e d out i n the gas uptake apparatus shown i n F i g . 3, at 35°C, and 760 mm The complex  Hg hydrogen p r e s s u r e , i n the u s u a l manner. _3 (3.0 x 10 mmol, based on Rh(I) atoms) and s t y r e n e  % reacted 100 T  hours F i g u r e 6.  H y d r o g e n a t i o n o f s t y r e n e i n benzene i n t h e presence o f s o l u b l e complexes H and J . R e a c t i o n c o n d i t i o n s ; temp. 35°C; 3 mL benzene; 3.0x10-3 mmol o f complex as R h ( I ) ; 3 . 0 x l 0 mmol o f s t y r e n e . O H; • J. - 1  -53-2 (3.1 x 10  -1 g, 3.0 x 10  mmol) were d i s s o l v e d  i n 3 mL o f benzene.  Percent c o n v e r s i o n as a f u n c t i o n o f time i s shown i n F i g . 6. 2-10.  Hydrogenation o f O l e f i n s  w i t h P o l y m e r i c Complexes.  A l l r e a c t i o n s were c a r r i e d out i n the apparatus shown i n F i g . 4, a c c o r d i n g t o the procedure d e s c r i b e d e a r l i e r .  Samples of each  catalyst  used i n d i f f e r e n t experiments were taken from the same s y n t h e t i c b a t c h . 2-10-1. Hydrogenation o f V a r i o u s O l e f i n s w i t h {[0. ,.Si-(CH )„-P(C,H )„] 3/ Z Z Z o 3 Z 3 0  C  RhCA.(0, Si-CH )__} . 3/Z 3 /5 x /o  Q  I n t h e experiments summarized i n T a b l e V I I the o l e f i n benzene s o l u t i o n  (3 mL) was s t i r r e d w i t h 0.0793 g (1.33 x 10  on the number o f Rh(I) atoms) o f the p o l y m e r i c c a t a l y s t H£.  The temperature was m a i n t a i n e d a t 25°C.  mmol, based  i n an atmosphere o f  The r e a c t i o n was stopped  23h, and the r e s u l t i n g s o l u t i o n was i n v e s t i g a t e d by GLC. i d e n t i f i e d by comparing  (3 mmol) i n  The p r o d u c t s were  the r e t e n t i o n times w i t h those o f a u t h e n t i c samples.  The r e s u l t s a r e g i v e n i n T a b l e V I I .  Table VII.  Hydrogenation of d i f f e r e n t o l e f i n s '  {[03 Si-(CH ) -P(C H ) ] RhC£.(0 /2  Substrate  2  Conversion %  2  6  5  2  3  Y i e l d of saturated product  7  cyclohexene  after  i n the presence o f 3/2  Si-CH ) r, 3  75  R ^  Y i e l d of i s o m e r i z a t i o n product %  8.1  8.1  styrene  88.5  88.5  1-heptene  86.4  46.3  40.1  1-octene  88.8  42.9  45.9  -54-  2-10-2.  Hydrogenation  of Styrene w i t h { [ 0  3 / 2  Si-(CH ) -P(.C H ) ] RhC£. 2  2  6  5  2  3  (0„ ,_Si-CH_)-,,-} i n D i f f e r e n t S o l v e n t s . 3/2 3 /5 x Styrene  (0.312 g, 3.0 mmol) i n benzene s o l u t i o n  (3 mL) was s t i r r e d  -2 w i t h 0.179 g (3.0 x 10 temperature tested.  mmol) of the c a t a l y s t i n an atmosphere o f H,,.  was m a i n t a i n e d a t 35°C.  The  F i v e d i f f e r e n t s o l v e n t systems were  The r e a c t i o n was stopped a f t e r 23h.  The r e s u l t s a r e summarized  i n Table V I I I .  Table V I I I .  E f f e c t of d i f f e r e n t s o l v e n t s on the c a t a l y s t R i n hydrogenation of styrene.  ^  2  S o l v e n t system  Colour o f the c a t a l y s t , a f t e r the r e a c t i o n  benzene  light  orange  toluene  light  orange  benzene/N(C H ) ^ 2  5  used  R  2  grey  3  benzene/ethanolgrey ethanol  (a) i n i t i a l l y  black^  l i g h t orange; (b) 3.0 x 10  3 mL b a t c h ; (c) 50:50. (d) blackened a d d i t i o n o f the s o l v e n t .  2-10-3.  Hydrogenation  mole o f N ( C H ) 2  immediately  5  3  in  a f t e r the  o f Styrene w i t h { [ O ^ S i - ( C H ) ~ P ( C H ) ] R h C & . 2  2  g  5  2  3  (°3/2  Si-CH  at 35° and 60°C. Styrene the c a t a l y s t  (0.312 g, 3.0 mmol) i n t o l u e n e s o l u t i o n  -2  (0.179 g, 3.0 x 10  35°C and a t 60°C were f o l l o w e d .  mmol).  (3 mL) was s t i r r e d  The p r o g r e s s o f t h e r e a c t i o n s a t  The d a t a a r e g i v e n i n F i g . 7.  with  3) 75}  %  reacted  0 hours F i g u r e 7.  5  10  15  20  H y d r o g e n a t i o n o f s t y r e n e i n t o l u e n e w i t h R -75 f u n c t i o n of temperature. R e a c t i o n c o n d i t i o n s : t o l u e n e 3 mL; s t y r e n e 3.0 mmol; 2-75 3 . 0 x l 0 mmol. Temperature: O 35°C, and • 60°C. a s  2  R  - 2  a  no. moles X 10 reacted 40 1  30 4  hours gure 8.  H y d r o g e n a t i o n o f s t y r e n e w i t h R-2-75 i benzene a t d i f f e r e n t s t y r e n e c o n c e n t r a t i o n s . R e a c t i o n c o n d i t i o n s : temp. 35°C; benzene 4 mL; amount o f Rh(I) 4 . 0 0 x l 0 mmol. Amount of s t y r e n e : • 3 . 0 x l 0 mmol, • 1.0 mmol, • . 3.0 mmol, O 10.0 mmol, ( i . e . Styrene/Rh(I)=7.5,25,75, and 250). n  - 2  _ 1  no. moles X 10  hours F i g u r e 9.  H y d r o g e n a t i o n o f s t y r e n e i n benzene w i t h d i f f e r e n t amounts o f the c a t a l y s t R-2-75- R e a c t i o n c o n d i t i o n s , temp. 35°C. [Styrene]=0.75M; amount of Rh(I) i n the 4 mL s o l u t i o n : • 4.00x10"^ mmol;D 8.00x10"^ mmol; # 1 . 3 3 x l 0 ~ mmol; O 4 . 0 0 x l 0 mmol, ( i . e . styrene/Rh(I)= 750,375,225, and 75). 2  - 2  -58-  2-10-4.  Hydrogenation  o f Styrene w i t h { [ O ^ S i - ( C H ) ~ P ( C ^ ) 2  ( 0 „ S i - C H ) - , } a t D i f f e r e n t O l e f i n and C a t a l y s t 3/2 I 75 x /0  0  c  Styrene i n benzene s o l u t i o n  2  2  ] RhC£.3  Concentrations.  (4 mL) was s t i r r e d w i t h the c a t a l y s t  at 35°, i n an atmosphere of H,,.  I n one s e r i e s o f experiments  t h e con-  c e n t r a t i o n o f s t y r e n e was changed w h i l e the amount of t h e c a t a l y s t suspended i n t h e r e a c t i o n  s o l u t i o n was m a i n t a i n e d c o n s t a n t .  o t h e r s e r i e s of experiments  the c o n c e n t r a t i o n o f s t y r e n e  In the  remained  c o n s t a n t and t h e amount o f t h e c a t a l y s t i n t r o d u c e d i n t o t h e 4 mL of the s o l u t i o n was v a r i e d . The r e s u l t s a r e summarized i n F i g s . 8 and 9. 2-10-5. Hydrogenation  of S t y r e n e w i t h D i f f e r e n t P o l y m e r i c Complexes o f Rh(.I) -2  In each r e a c t i o n  3.0 x 10  mmol (based on the number o f Rh(I)  atoms)  of t h e a p p r o p r i a t e c a t a l y s t was suspended i n 3 mL o f a s o l u t i o n of s t y r e n e (0.312 g, 3.0 mmol) i n benzene.  The r e a c t i o n  temperature  Every c a t a l y s t was r e c y c l e d a few times. washed w i t h benzene, and d r i e d  reaction  atmosphere.  s o l u t i o n was noted a f t e r each r u n .  F i g s . 10-19 and T a b l e IX.  I t was f i l t e r e d o f f ,  i n vacuo i n between c y c l e s .  m a n i p u l a t i o n s were done i n an oxygen-free  was 35°C.  A l l the  The c o l o u r o f t h e  The d a t a a r e p r e s e n t e d i n  f  0 hours F i g u r e 10.  1 5  1  1  10  15  r  20  F i r s t c y c l e of h y d r o g e n a t i o n o f s t y r e n e i n benzene w i t h d i f f e r e n t polymers. R e a c t i o n c o n d i t i o n s : temp.35°C; benzene 3 mL; s t y r e n e 3.0 mmol; c a t a l y s t as R h ( I ) 3.0x10 mmol. • -100' ' 8-0' •:D . R _ ; • R2-0; .A 2-200^ > 2-oR  R  8  T  2  75  T  % reacted  0  5  10  15  20  25  hours F i g u r e 11.  R2_Q.Reaction c o n d i t i o n s as i n F i g . 10.  A  3rd; . A  4th;  •  5th.  Cycles:  •  1 s t ; O"  %  reacted  0  5  1 0  1 5  2 0  2 5  hours F i g u r e 12.  Rs-fj* R e a c t i o n c o n d i t i o n s as i n F i g . 10. C y c l e s : • 1 s t ; O .'2nd; • 3rd; A 4th; • 5th; • 6th; X 1 s t , catalyst s t i r r e d i n benzene under H f o r 24 h, > p r i o r t o i n j e c t i o n of s t y r e n e . 2  % reacted 100  1  hours F i g u r e 13.  T 2 _ Q . R e a c t i o n c o n d i t i o n s as i n F i g , 10. C y c l e s :  •  1st;  O  2nd;  A  3rd.  % reacted 100 -i  80 A  hours F i g u r e 14.  S. R e a c t i o n c o n d i t i o n s as i n F i g . 10. A4th; • 5th.  Cycles: •  1st; O  2nd;  A  3rd;  %  reacted  100 i  hours F i g u r e 15.  R _75. R e a c t i o n c o n d i t i o n s as i n F i g . 10. A 3rd; A 4 t h ; • 5th. 2  Cycles:  •  1st-  O  2nd*  % reacted  100 ,  hours  F i g u r e 16. 2-150* R  O  R e a c t i o n c o n d i t i o n s as i n F i g . 10. 2nd; A 3 r d ; A 4 t h ; • 5 t h .  Cycles:  #  1  % reacted 100T  A  3rd; A 4th;  •  5th.  %  reacted  hours F i g u r e 18.  R  8-100* R e a c t i o n c o n d i t i o n s as i n F i g . 10. O .2nd; A 3 r d ; A 4th.  Cycles:  •  1  % reacted 100  -  80  hours F i g u r e 19.  T _2Q02  R e a c t i o n c o n d i t i o n s as i n F i g . 10.  Cycles:  •  1st;  O  2nd;  A  3rd.  -69-  Table  IX.  Colour  o f the f i l t r a t e upon r e c y c l i n g the c a t a l y s t .  Cycle  Catalyst 1st R  2nd  3rd  4th pale orange  2-0  R/ 8-0  5th  6th  strong orange pale orange  strong orange  very pale orange  "2-0  2-75  very pale orange  orange  2-150  very pale orange  strong orange  2-200  very pale orange  s trong orange  R 8-100 2-200  2-10-6.  Hydrogenation o f Styrene w i t h  { [0„ ,„Si- (CH„) „-P(C^H,-) J R h C £ } 0  511  Z Z  O 3 Z  5  Exposed  X  to A i r Upon R e c y c l i n g . The r e a c t i o n s were c a r r i e d out i n 3 mL benzene s o l u t i o n s i n the u s u a l manner w i t h t h e e x c e p t i o n t h a t t h e c a t a l y s t was f i l t e r e d o f f and d r i e d between c y c l e s as u s u a l but was exposed t o a i r f o r about l h b e f o r e being used i n the next  cycle. The r e s u l t s a r e shown i n F i g . 20.  %  reacted  100  %  reacted  hours F i g u r e 21.  R  2-0* ^ ^^ °f s o l u t i o n volume i n the f i r s t c y c l e . Reaction c o n d i t i o n s as i n F i g . 10; the amounts of s t y r e n e and c a t a l y s t a r e p r o p o r t i o n a l t o the volume. S o l u t i o n volume: • 3 mL; A 9 mL; A 12 mL. e  e  ect  t n e  %  reacted  100 -\  hours  F i g u r e 22.  ^2-0'  a s  ^ i g . 21.  Second c y c l e .  S o l u t i o n volume: •  3 mL;  O  6 mL.  % reacted 100 T  80 i  hours  F i g u r e 24.  S, as i n F i g . 21.  F i r s t cycle.  S o l u t i o n volume: # 3  mL; A  9 mL;  A  12  mL.  % reacted 100 ..  80  4  hours F i g u r e 25.  S, as i n F i g . 21.  Second c y c l e .  S o l u t i o n v o l u m e : A 9 mL;  •  -3  mL.  % reacted 100 T  80 A  60 \  40  20  0  hours F i g u r e 26.  S, as i n F i g . 21.  Third cycle.  S o l u t i o n volume: •  3 mL;  O  7  mL.  % reacted 100 ,  80 4  60  40  20  1  1  1  1  0  5  10  15  1  20  hours F i g u r e 27.  T  2-200'  a s  ^i-S- 21.  F i r s t cycle.  S o l u t i o n volume: • 3 mL,  O  6 mL.  % reacted 100 i  80 4  % reacted 100 -i  hours  F i g u r e 29.  T  2-200>  a s  i n  F i  S*  2 1  •  Third cycle.  S o l u t i o n volume: • 3 mL; O  6 mL.  % reacted 100 -.  80 -  60 -  40 -  20 4  0 0 hours F i g u r e 30.  5  10  15  20  25  H y d r o g e n a t i o n o f cyclohexene i n benzene w i t h R2-0* R e a c t i o n c o n d i t i o n s temp. 35°C; benzene 3 mL; R h ( I ) 3 . 0 x l 0 mmol; cyclohexene 3.0 mmol. C y c l e s : • 1 s t ; O 2nd. - 2  % reacted 50 i  hours F i g u r e 31.  The e f f e c t o f the s o l u t i o n volume i n the f i r s t c y c l e of h y d r o g e n a t i o n cyclohexene^ C o n d i t i o n s as i n F i g . 30; the amounts of cyclohexene and the c a t a l y s t p r o p o r t i o n a l t o the volume. S o l u t i o n volume: • 3 mL; • 9 mL; A 12 mL. 1  hours F i g u r e 32.  As i n F i g . 31.  Second c y c l e . S o l u t i o n volume:  •  3 mL;  A  9 mL.  -83-  2-10-7.  Hydrogenation of Styrene i n S o l u t i o n s of D i f f e r e n t Volumes. Styrene was  hydrogenated  i n the presence of t h r e e d i f f e r e n t  catalysts  2-0  = a0  S  :  R  T  2-200  :  3 / 2  Si-(CH ) -P(C H ) ] RhC£}  {[0 { [  2  3 / 2  S/2  S i  2  6  5  2  3  Si-(CH ) -P(C H ) ] 2  -  ( C H  2 2)  2  6  P ( C  5  6 5 2 4 H  )  ]  2  R h  3 7  2  x  RhCU  C £  2-  ( 0  x  3/2  S 1  -  C H  3 200 x )  }  i n the same manner as i n the experiments d e s c r i b e d immediately above except t h a t the volume of the r e a c t i o n s o l u t i o n was 12 mL.  The amount of the c a t a l y s t  v a r i e d from 3 to  (as Rh(I) atoms) was  p o r t i o n t o the volume of the r e a c t i o n  varied  i n pro-  solution.  The r e s u l t s a r e summarized i n F i g s . 21-29. 2-10-8.  Hydrogenation of Cyclohexene w i t h  {[0 ^ Si-(CH ) -P(C H ) ] RhC£> . 3  2  2  2  6  5  2  3  x  These r e a c t i o n s were a l s o c a r r i e d out a t 35°C i n the apparatus shown _2 i n F i g . 3, u s i n g the u s u a l procedure. mmol) of the c a t a l y s t was i n benzene s o l u t i o n 3 mL  to 12 mL  In a t y p i c a l run 0.028 g (3.0 x  10  s t i r r e d w i t h 0.246 g (3.0 mmol) of cyclohexene  (3 mL).  The volume of the s o l u t i o n was  varied  from  and the amounts of the c a t a l y s t and cyclohexene were v a r i e d  i n p r o p o r t i o n to the volume of the r e a c t i o n The p e r c e n t c o n v e r s i o n vs time was  solution.  r e c o r d e d and the d a t a are p r e s e n t e d  i n F i g s . 30-32. 2-11.  E l e c t r o n Microscope Studies. A sample of the f r e s h l y prepared complex R_y^,,{ [0.^ S i - ( C H ) ~ 2  2  2  2  P(C,H ) „] „RhC£. [0. ,„Si-GH ] } and a sample of the complex from the same D J Z J ill J o x C  0  b a t c h which had been used i n a h y d r o g e n a t i o n r e a c t i o n a s o l v e n t ) were examined u s i n g an e l e c t r o n microscope. s u b j e c t e d to the e l e c t r o n beam of power from 2.5  (benzene/ethanol as The samples were  to 20 kV.  The m a g n i f i c a t i o n s  F i g u r e 33. Secondary image E M m i c r o g r a p h s o f polymer R2-75(a) b e f o r e hydrogenation,beam power 5 kV, m a g n i f i c a t i o n 2205(b): a f t e r h y d r o g e n a t i o n , 5 kV, magn. 440.  -85-  i u r e 34.  1  9.1 ym  E M m i c r o g r a p h s o f R-2-75 ( a ) : b e f o r e , 5 kV, magn. 1100; ( b ) : a f t e r h y d r o g e n a t i o n , 5 kV, magn. 1100.  -86-  «  1  9.1 ym  F i g u r e 35. E M m i c r o g r a p h s o f R2-75- (a) b e f o r e , 5 kV, magn. 2200; (b) a f t e r h y d r o g e n a t i o n , 5 kV, magn. 1100.  -87-  i F i g u r e 36.  ' 2.3  p  EM m i c r o g r a p h s o f R2-75 a f t e r h y d r o g e n a t i o n . (a) beam power 5 kV, magn. 1100; (b) 10 kV, magn. 4400.  F i g u r e 37.  E M m i c r o g r a p h o f R-2-75 a f t e r h y d r o g e n a t i o n , 20 kV, magn. 11,200.  -89-  a c h i e v e d v a r i e d from 220'to Tl,200 f o l d . Samples which were used f o r micrographs showing the s u r f a c e of the polymer beads were prepared i n the f o l l o w i n g way. d e p o s i t e d on an aluminum  A few beads were  specimen stub which had been coated w i t h a  c o l l o i d a l d i s p e r s i o n of g r a p h i t e i n i s o p r o p y l a l c o h o l .  Then the s;pubwas  p l a c e d i n a vacuum carbon e v a p o r a t o r where i t s s u r f a c e was  covered w i t h a  t h i n l a y e r of g r a p h i t e . Samples which were used f o r t a k i n g micrographs showing the c r o s s s e c t i o n of the polymer beads were embedded i n Spurr L o w - V i s c o s i t y  Epoxy  73 Embedding  Medium  .  The t i p of the epoxy cone c o n t a i n i n g the polymer  beads was  shaved o f f so t h a t the c r o s s s e c t i o n s of the beads c o u l d be  examined. The r e p r o d u c t i o n s of the micrographs a r e shown i n F i g s . 33-37~.  -90-  CHAPTER 3 DISCUSSION  3-1.  Syntheses and I d e n t i f i c a t i o n o f t h e L i g a n d s and t h e i r S o l u b l e Complexes. The compounds o f main i n t e r e s t i n t h i s work a r e c h l o r o t r i s p h o s p h i n e -  rhodium and d i - u - c h l o r o t e t r a k i s p h o s p h i n e d i r h o d i u m a r e Cl (ClLj)Si-(CH ) ~P(CgH^ , 2  2  2  CJ^Si-(CH ) -P(Cg^)  2  2  [(CH )Si-0-] (CH )Si-(CH ) -P(CgH ) . 3  2  3  where t h e phosphines  2  2  5  n  (n=2,8) and  The s y n t h e s e s o f (NBD)chloro(phos-  2  p h i n e ) r h o d i u m and c a r b o n y l c h l o r o b i s p h o s p h i n e r h o d i u m ligands are also described.  2  w i t h some o f these  The c h l o r o s i l y l p h o s p h i n e s were chosen so t h a t  t h e i r complexes c o u l d be p o l y m e r i z e d  and t h e s i l o x y p h o s p h i n e was chosen  so t h a t i t would have s t e r i c and e l e c t r o n i c p r o p e r t i e s s i m i l a r t o those o f the p o l y m e r i c  s i l o x a n e analogues.  3-1-1. P r e p a r a t i o n o f V i n y l S i l o x a n e s . The  s y n t h e s i s o f 1,1,1,3,5,5,5-hepta m e t h y l - 3 - v i n y l t r i s i l o x a n e r e p o r t e d 72  i n the l i t e r a t u r e  i s achieved  with diethoxymethylvinylsilane.  by c o h y d r o l y s i s o f t r i m e t h y l c h l o r o s i l a n e  The p r e p a r a t i o n i n v o l v e s t h e a d d i t i o n o f  water i n two s t a g e s and h e a t i n g a t t h r e e d i f f e r e n t t e m p e r a t u r e s .  In this  work, i n o r d e r t o s i m p l i f y t h e p r o c e d u r e , t h e compound i s p r e p a r e d h y d r o l y s i s o f two c h l o r o s i l a n e s i n a l a r g e excess o f w a t e r , eq. HO (CH =CH)Si(CH )C2, + 2 C J l S i ( C H ) a* > ( C H ) S i - 0 - S i ( C H ) (CH=CH )0-Si(CH ) 2  3  3  +  3  2  3  3  3  2  3  (5);  3  3  3  + (CH^Si-O-SiCCH^  (CH ) Si-0-[Si(CH )(CH=CH )] -0-Si(CH ) 3  by c o -  2  3  3  3  (5)  + h i g h e r polymers  the temperature o f t h i s h i g h l y e x o t h e r m i c r e a c t i o n has t o be c o n t r o l l e d o n l y during the a d d i t i o n of the s i l a n e s t o water.  -91-  The d e s i r e d p r o d u c t ,  l , l , l , 3 , 5 , 5 , 5 - h e p t a m e t h y l - 3 - v i n y l t r i s i l o x a n e was  o b t a i n e d i n 27.5% y i e l d . (5).  The o t h e r p r o d u c t s  a r e as i n d i c a t e d i n e q u a t i o n  A l l t h r e e v o l a t i l e f r a c t i o n s can be i s o l a t e d by d i s t i l l a t i o n and  were i d e n t i f i e d by t h e i r 4  NMR and mass s p e c t r a , and C and H m i c r o a n a l y s i s .  The n o n - v o l a t i l e h i g h e r p o l y m e r i c f r a c t i o n s were n o t c h a r a c t e r i z e d . The m i c r o a n a l y t i c a l d a t a agree  w e l l with the c a l c u l a t e d values.  P a r e n t peaks i n mass s p e c t r a correspond  w i t h the molecular weights of  the compounds; no peaks a t m/e v a l u e s h i g h e r than those c o r r e s p o n d i n g t o the parent  ion M  +  are present.  The 4  NMR spectrum o f 1,1,1,3,3,3-hexa-  m e t h y l d i s i l o x a n e shows o n l y one s i n g l e peak a t 0.076, i n t h e r e g i o n c h a r a c t e r i s t i c o f s i l i c o n - m e t h y l groups.  The 4  NMR s p e c t r a o f b o t h  the v i n y l s i l o x a n e s a r e almost i d e n t i c a l , t h e o n l y d i f f e r e n c e b e i n g , as expected,  t h e r e l a t i v e p r o p o r t i o n s o f t h e peak areas a s s o c i a t e d w i t h t h e  p a r t i c u l a r groups. The two s i n g l e t s a t 0.10 and 0.126 a r e a t t r i b u t e d t o the SiCCH^)^ and SiCCH^) m o i e t i e s r e s p e c t i v e l y . c e n t e r e d a t 5.96 i s a s s i g n e d  to the v i n y l  The u n r e s o l v e d m u l t i p l e t  protons.  I t i s of i n t e r e s t that the v o l a t i l e f r a c t i o n s (CH=CH )] -0-Si(CH ) 2  n  3  3  (CH ) Si-0-[Si(CH )3  3  3  c o n t a i n o n l y two compounds w i t h n = l and 3; no compound  w i t h n=2 i s produced.  3-1-2. P r e p a r a t i o n o f t h e P h o s p h i n e s . A g e n e r a l method f o r t h e p r e p a r a t i o n o f phosphines w i t h d i f f e r e n t r a d i c a l s i s t h e a d d i t i o n o f compounds w i t h phosphorus-hydrogen bonds t o m o l e c u l e s c o n t a i n i n g carbon-carbon double bonds. e i t h e r base  74  ,. ,. , , ,75,76 or f r e e - r a d i c a l - c a t a l y z e d  R PH + CH =CH-R" -> R P-CH -CH -R" 2  2  2  2  2  Such r e a c t i o n s can be , (eq.6) (6)  -92-  A number of s i l y l a l k y l p h o s p h i n e s have been synthesized by uv l i g h t 28" 77 induced a d d i t i o n of secondary phosphines to o i - a l k e n y l s i l a n e s  '  The products always contain phosphorus attached to the terminal carbon atom as i n eq. (6). . In t h i s work the uv-induced reactions between diphenylphosphine  and  d i f f e r e n t v i n y l - and o c t e n y l s i l a n e s are described (eq. (7)). The com28 7 7 pounds Ci> Si-(CH ) -P(C,H )„ (n=2,8) have been previously reported ' . 3 / n o J Z the others are new. 0  (C H ) PH + 6  5  2  C  R|R 'Si-(CH ) 2  2  2  = CH  -CH  2  uv  >  (7) >  R'R"Si-(CH ) 0  12  . 2 n  A: R' and R" = CH  3>  -P(C,Hc)  6 5 2  n = 2  B: R' = CH , R" = 0 - S i ( C H ) , 3  C:  R'  = CH , 3  3  R"-CSL,  0  3  n =2  n = 2  D: R' and R" =  CI,  n =2  E: R' and R" =  CH,  n=8  A l l the s p e c t r a l and other a n a l y t i c a l data show that the products  obtained  are pure and contain phosphorus attached to the terminal carbon atom. M i c r o a n a l y t i c a l data f o r C and H, and f o r CI where a p p l i c a b l e agree w e l l with the c a l c u l a t e d values.  The parent peaks i n the mass spectra  correspond w i t h the appropriate molecular weights; no peaks of m/e values + higher than those c a l c u l a t e d f o r the parent ion M are found.  131 The { H} P  NMR spectra of each phosphine contain only one s i n g l e peak i n the region +9 to +16 ppm u p f i e l d from 80% ^ P O ^ .  The l a c k of any peaks due to CH-CH  moieties i n the 4 NMR spectra confirms the a d d i t i o n of phosphorus to the  3  -93-  t e r m i n a l carbon atom. The 7.36  aromatic  resonances due  to the p h e n y l groups are i n the  to 7.456 f o r a l l the phosphines.  The  and m e t h y l d i c h l o r o s i l y l p h o s p h i n e s A and the S i - C H types two  groups at 0.14  3  0.836 r e s p e c t i v e l y .  s i n g l e peaks at 0.08  f o r S i - ( C H ) and 3  In the equal  NMR  Si(CH > 3  and  trimethylsilyl-  C show s i n g l e resonances f o r  of methyl groups i n the s i l o x y p h o s p h i n e  different  1:6,  and  s p e c t r a of  region  0.116  The  two  different  B are r e s p o n s i b l e f o r with r e l a t i v e  intensities  respectively.  3  spectrum of B t h e r e a r e two  i n t e n s i t y which can be a s s i g n e d  unresolved  m u l t i p l e t s of  to the -Ct^-CH^-moiety.  A  partially  31 P decoupled spectrum shows a n o t i c e a b l e d i f f e r e n c e i n the p a t t e r n of the m u l t i p l e t c e n t e r e d  at 0.606.  The m u l t i p l e t c e n t e r e d  affected.  I t has been r e p o r t e d  J(P_-C-H).  Thus the m u l t i p l e t c e n t e r e d  S i - C H - protonsand the one 2  to 2.486.  the S i - ( C H ) ~  group and  2  n  '  7 9  t h a t J(P_-C-C-H) i s g r e a t e r  m u l t i p l e t s due  t h a t at lower f i e l d  s p e c t r a of a l l  to the S i - ( C H ) - P protons 2  The m u l t i p l e t at h i g h e r  b a s i s of the assignment made f o r the  than  at 0.606 can be a t t r i b u t e d to  at 2.096 to the P-CH^. The  the other phosphines show two the r e g i o n 0.60  7 8  at 2.096 i s not  field  n  in  i s a t t r i b u t e d to  to the P-CH - protons- on 2  the  siloxyphosphine.  3-1-3. P r e p a r a t i o n of the S o l u b l e Complexes. Phosphine complexes of Rh(I)  are g e n e r a l l y prepared  by  l i g a n d exchange  methods where the s q u a r e - p l a n a r  symmetry around the m e t a l atom i n the  s t a r t i n g compounds i s p r e s e r v e d  i n the product.  and  In t h i s work the  c h l o r o s i l y l p h o s p h i n e complexes of g e n e r a l formulae  siloxy-  (NBD)RhPC£,  P R h ( C 0 ) C £ , P R h C £ and P^Rt^Ci,, were s y n t h e s i z e d u s i n g these w e l l 2  3  e s t a b l i s h e d procedures.  Norbornadienechlorophosphinerhodium complexes  -94-  a r e prepared  80  i n a r e a c t i o n between s t o i c h e o m e t r i c  (NBD) Rh C£ and v a r i o u s 2  2  2  II  ci  ^ R /  / The  ligands  (eq. ( 8 ) ) .  IK  \  h  \ /  ci  ,||  2L  ) +  /  amounts o f  R/  2 (  V\  v  product o f t h i s b r i d g e - s p l i t t i n g r e a c t i o n c o n t a i n s  (8)  t h e new l i g a n d  L and C£ i n c i s p o s i t i o n s . In the p r e p a r a t i o n  o f t h e w e l l known V a l l a r i n o complex, .[(C^E^)^P] -  68 Rh(C0)C£  and i t s analogues  c o n t a i n i n g o t h e r phosphines, t h e  s t a r t i n g m a t e r i a l used i s (CO) Rh C£ 4  OC  /  OC  Here  CI  2  2  (eq. ( 9 ) )  CO  \ r /  \ /  \  CI  CO  L + AL —>  2  CO  \  /  /  CI  <> 9  \  JL  L  t h e r e a c t i o n p r o d u c t j5 i s o f t r a n s - c o n f i g u r a t i o n and t h e analogues  of t h e W i l k i n s o n  81 complex [ (C^H^J^P]^RhCJl  a s i m i l a r b r i d g e - s p l i t t i n g reaction using  82 can be p r e p a r e d  (C^H^) Rh C£ 4  2  2  in  as t h e s t a r t i n g  compound ( e q . ( 1 0 ) ) .  Rh  Rh  When t h e l i g a n d / e t h y l e n e bridge  82 i s retained  +  6L  complex r a t i o (eq. (11)).  »  2  Rh  ( 1 0 )  i s m a i n t a i n e d a t 4:1 t h e c h l o r i n e  -95-  Rh / \  Rh \  /  + Ul —>  Rh / \  Rh /  \  S i n c e t h e new phosphine l i g a n d s used i n t h i s work a r e r e l a t i v e l y bulky  t h e i r c o o r d i n a t i n g p r o p e r t i e s were t e s t e d by f i r s t a t t e m p t i n g t h e  s y n t h e s i s o f { [ ( C H ^ S i - O - ] (CH ) S i - ( C H ^ - P ( C ^ ) } R h ( N B D ) C £ 2  F.  3  2  complex,  When t h i s was s u c c e s s f u l l y a c c o m p l i s h e d s i l o x y - and c h l o r o s i l y l p h o s p h i n e  complexes {[(CH ) Si-0-] (CH )Si-(CH ) -P(C H ) } Rh(CO)C£,  G,  [C£ Si-(CH ) -P(C H ) ] Rh(CO)C£,  K,  3  3  3  2  2  3  2  6  2  5  2  6  5  2  2  2  {[CH ) Si-0-] (CH )Si-(CH ) -P(C H ) } RhC£,  H,  [C£ Si-(CH ) -P(C H ) ] RhC£,  L,  [C£ Si-(CH ) -P(C H ) ] RhC£,  M,  3  3  2  3  2  3  2  3  2  2  6  g  5  6  5  2  2  6  5  2  3  3  2  3  { [ ( C H ) S i - 0 - ] ( C H ) S i - ( C H ) - P ( C H ) > Rh C£ 3  and  3  2  3  2  2  f i  5  2  4  2  J,  2  [C£ Si-(CH ) -P(C H ) ] Rh C£ , 3  2  were s y n t h e s i z e d The  6  5  according  2  4  2  N  2  t o t h e e q u a t i o n s ( 9 ) , ( 1 0 ) , and ( 1 1 ) .  c h l o r o s i l y l p h o s p h i n e complexes thus formed a r e t h e p r e c u r s o r s f o r  the p o l y m e r i c prototype  2  s i l o x a n e complexes.  The s i l o x y p h o s p h i n e  study models f o r t h e i r p o l y m e r i c  complexes s e r v e as  counterparts.  I t i s found t h a t t h e c h l o r o s i l y l p h o s p h i n e complexes become i n s o l u b l e a f t er e v a p o r a t i o n  of the r e a c t i o n solvent.  s m a l l degree o f p o l y m e r i z a t i o n  T h i s i s most l i k e l y due t o a  i n t h e presence o f t r a c e s o f m o i s t u r e .  C o n s e q u e n t l y , i n o r d e r t h a t t h e NMR s p e c t r a c o u l d be r e c o r d e d i m m e d i a t e l y a f t e r formation  o f t h e complexes, t h e p r e p a r a t i o n s  i n deuterobenzene.  have t o be c a r r i e d out  -96-  The  Siloxyphosphine  The  i d e n t i t y of the products  1  Complexes was  confirmed  by m i c r o a n a l y s i s , mass,  31 H NMR,  P NMR,  and  IR s p e c t r a .  r e s u l t s f o r complexes F and the complexes H and  G and  The m i c r o a n a l y t i c a l C, H, r e s u l t s f o r C, H,  J agree w e l l w i t h  peaks i n the mass s p e c t r a of the f i r s t  two  compounds, F and  the p r e d i c t e d m o l e c u l a r  than M .  The mass s p e c t r a c o u l d not be r e c o r d e d  t h e i r high molecular The  weights  P and  the c a l c u l a t e d v a l u e s .  well with +  CI,  and  weight, w i t h no m/e  CI  Fh f o r The  G,  parent  correspond  peaks at v a l u e s  f o r H and  J because of  (>1300).  s i l i c o n - m e t h y l r e g i o n of a l l the 4  NMR  spectra i s potentially  the most i n f o r m a t i v e as to the c o o r d i n a t i o n s t a t e around the m e t a l s i n c e the chemical to S i - C H  3  and  s h i f t s and  Si(CH ) 3  Si-^l^^-P^gH^^* In the  3  centre  the r e l a t i v e i n t e n s i t i e s of the peaks  m o i e t i e s of the f r e e l i g a n d  B, may  [(CH ) Si-0-] (CH )3  3  2  3  s h i f t s and  the a r e a  of the s i l c o n - m e t h y l peaks i s the same as i n the f r e e phosphine.  Si-CH  3  from those  ( s t r u c t u r e _9); the peaks are s h i f t e d  of the f r e e phosphine by 0.06  and  and  Si(CH )  The  p a t t e r n changes f o r the t r i s p h o s p h i n e and  complexes.  3  3  trans-  slightly  ppm  f o r the  resonances r e s p e c t i v e l y .  Complex J has  s t r u c t u r e 10, hence i t s 4 of the f r e e l i g a n d .  0,07  ratio  This i s  a l s o found i n the spectrum of the c a r b o n y l complex G where the two  downfield  due  a l t e r on c o o r d i n a t i o n .  (NBD)PRhCA complex F the c h e m i c a l  phosphlnes a r e e q u i v a l e n t  higher  f o u r e q u i v a l e n t phosphines as i n d i c a t e d by NMR  Instead  methyl r e g i o n at 0.126.  tetraphosphine  The  the  p a t t e r n should a l s o l o o k s i m i l a r to t h a t o n l y one  singlet  i s observed i n the  a r e a of the peak accounts f o r a l l 42  siliconprotons  -97-  i n the Si-CH^ and SiCCH^)^ groups.  I n the t r i s p h o s p h i n e complex H the  two phosphines t r a n s t o each o t h e r a r e c h e m i c a l l y i n e q u i v a l e n t t o the one  t r a n s t o C£ as can be seen i n the s t r u c t u r e 9_. For a l l the  methyl-  phosphine and - a r s i n e R h ( I I I ) complexes RhP^X^ of m e r - c o n f i g u r a t i o n ( s t r u c t u r e 11) two s e t s of s i g n a l s of r e l a t i v e i n t e n s i t y 2:1 due  to  X  two d i f f e r e n t t y p e s of phosphines a r e a l s o expected two  f o r the P^RhCJl complex.  s i n g l e t s a t 0.18  and  typical The  83  Similarly this i s  s i l i c o n - m e t h y l r e g i o n has  0.076 of r e l a t i v e i n t e n s i t i e s 2:1.  However,  as i n complex J , t h e r e i s no d i f f e r e n c e i n the c h e m i c a l s h i f t s of Si-CH  3  and  Si(CH ) 3  3  the  protons.  The p h e n y l r e g i o n of the "*"H NMR  s p e c t r a of the complexes G, H,  J c o n t a i n s two d i s t i n c t m u l t i p l e t s w h i c h a r e s e p a r a t e d by 0.6-0.8 and have r e l a t i v e i n t e n s i t i e s between 1:2 complexes t h e a r o m a t i c resonances due  and  2:3.  and  ppm,  I n some i r i d i u m  t o the t r i p h e n y l p h o s p h i n e l i g a n d s  a l s o show a s i m i l a r p a t t e r n w h i c h has been a t t r i b u t e d t o a d i f f e r e n t s h i e l d i n g of o r t h o phenyl p r o t o n s ^ ^ ' ^ ^ protons.  The  "4i NMR  compared w i t h meta and  para  p a t t e r n i n the complexes s y n t h e s i z e d i n t h i s work  can a l s o be a t t r i b u t e d t o a s i m i l a r phenomenon, a l t h o u g h i t i s d i f f i c u l t t o account f o r r e l a t i v e a r e a s d i f f e r e n t from a 2:3  ratio.  I n the spectrum  of complex F a l l the peaks due t o the c o o r d i n a t e d s i l o x y p h o s p h i n e are  -98-  s h i f t e d s l i g h t l y downfield  r e l a t i v e to the f r e e l i g a n d , but  i s the same as f o r the f r e e phosphine. 1  on the b a s i s of the r e p o r t e d Although the  1  H NMR  peaks due 86  spectrum  s p e c t r a present  s p e c t r a c o n f i r m the m o l e c u l a r by s t r u c t u r e s 7-10.  H NMR  The  to NBD  of  pattern  are  assigned  (NBD)Rh[P(C,H ) ]C£. C  Q  b _> J  s l i g h t ambiguities  31 P  the  NMR  s t r u c t u r e s of the complexes as i n d i c a t e d  A l l t h r e e complexes F, G, and  J c o n t a i n phosphines  which a r e c h e m i c a l l y e q u i v a l e n t and which g i v e r i s e to one Rh-P  the  c o u p l i n g i n each case.  doublet  due  o  Carbonylchlorobis(triphenylphosphine)-  87 rhodium has been r e p o r t e d  to show a d o u b l e t  to 80% H P 0 , J(Rh-P)=124 Hz.  Both the NBD  3  4  the s i l o x y p h o s p h i n e ppm  show d o u b l e t s  w i t h J(Rh-P) of 171.6  of the doublet  and  124.6  i n the spectrum of  and  at -29.5 CO  ppm  relative  complexes c o n t a i n i n g  i n t h i s r e g i o n , at -31.45 and Hz r e s p e c t i v e l y .  The  -29.65  chemical  shift  [ ( p - C H ^ - C g H ^ ^ P ^ R t ^ C ^ complex changes  82 considerably  to -49.5  ppm  w i t h J(Rh-P) of 196  Hz.  analogue f o l l o w s the same t r e n d by showing a doublet J(Rh-P) i s 196.5  Hz. 88  I t i s known  The  siloxyphosphine  at -47.02 ppm  89 '  t h a t J(M-P) v a l u e s  phorus atom i s t r a n s to a l i g a n d w i t h low such as h a l i d e s , than when i n f l u e n c e , such as PR^,  H,  are l a r g e r when the phos-  trans-influencing properties,  i t i s t r a n s to a l i g a n d of h i g h e r or CO.  trans-  T h i s i s seen i n the present  where the phosphines which a r e t r a n s to CI i n the t e t r a p h o s p h i n e J have h i g h e r J(Rh-P) v a l u e s where the two The  where  t r i s p h o s p h i n e compound H has  two  other. i n e q u i v a l e n t types of phosphines  groups of peaks of d i f f e r e n t  d i f f e r e n t J(Rh-P) v a l u e s .  compound  than i s found i n the c a r b o n y l complex G  phosphines a r e t r a n s to each  which g i v e r i s e to two  results  chemical  shifts  and  Thus c h l o r o t r i s ( t r i p h e n y l p h o s p h i n e ) r h o d i u m shows  -99-  a double  doublet a t -32.2  ppm  and a double  t r i p l e t a t -48.9  ppm  82 where J(Rh-P) are 146  and  192 Hz r e s p e c t i v e l y  .The  double  doublet  i s a t t r i b u t e d to the phosphines t r a n s to each o t h e r and the triplet  to the phosphine t r a n s to Ci.  H the same t r e n d i s f o l l o w e d . triplet  at lower  J(Rh-P)=188 Hz, a double  The  f i e l d . - 4 4 . 9 7 ppm than the two  double  In the s i l o x y p h o s p h i n e complex  phosphine t r a n s to CI g i v e s a and  has a h i g h e r c o u p l i n g c o n s t a n t ,  phosphines t r a n s to each o t h e r  doublet a t -29.75 ppm  double  and have J(Rh-P) of 140  Hz.  which g i v e The  J(P-P)  v a l u e s f o r the s i l o x y p h o s p h i n e complexes a r e v e r y s i m i l a r , 39 Hz, QO  those f o r the W i l k i n s o n complex [(C,H )^P]„RhC£ , 37.5 Hz. 0 5 3 3 J(Rh-P) c o u p l i n g c o n s t a n t s are of the magnitude expected from C  d i s c u s s i o n i n the p r e v i o u s  to  The the  paragraph.  31 The  P NMR  and -29.92 ppm  s p e c t r a of G and H c o n t a i n a s i n g l e peak a t -29.44  respectively.  The  presence  of a s i n g l e t r a t h e r than a  doublet  i n d i c a t e s t h a t the phosphorus atom i s not bound to rhodium. The 79 chemical s h i f t s of phosphine oxides a r e known to be c o n s i d e r a b l y d o w n f i e l d from those of the c o r r e s p o n d i n g phosphines. For example the 31  P NMR  s i g n a l due  to (p-CH^CgH^) P i s o b s e r v e d  r e l a t i v e to 80% H P0. whereas t h a t of 3 4 o  ppm.  The  8?  at +6.8  9  3  p o s i t i o n of the s i n g l e t  ppm  (p-CH„-C,H.)„P=0 o c c u r s a t 3 6 4 3  i n the s p e c t r a of the  ppm  which s t r o n g l y suggests  t h a t some o x i d e i s p r e s e n t as an i m p u r i t y .  f o r the f r e e phosphine This  by the mass spectrum of the c a r b o n y l complex G which shows  a parent peak c o r r e s p o n d i n g the sample probe i s heated to  ppm  aforementioned  complexes i s around -30  i s confirmed  compared w i t h +9.14  -23.7  the probe the presence  to the m o l e c u l a r weight of the complex when to 300°C.  However, when no heat  i s applied  of a substance w i t h a parent peak at m/e  450 i s  -100-  observed. oxide  T h i s v a l u e corresponds  to the m o l e c u l a r weight of the phosphine  [(CH ) SiO] (CH )Si-(CH ) ~P(C H 3  3  2  3  2  I t has been f o u n d  2  ) 0.  f i  t h a t (C,H ) P=0 i s produced i n the  9 0 , 9 1  c  b j  r e a c t i o n s of [ ( C g H ^ ] RhC£,  o  j  [ ( C H ) P ] R h C £ , and [ ( C ^ ) P ] R h ( C 0 ) C £ 6  5  3  4  2  2  3  2  31 with molecular  oxygen. S i n c e n e i t h e r  P NMR nor t h e mass s p e c t r a o f the  f r e e s i l o x y p h o s p h i n e B i n d i c a t e the presence  o f the phosphine oxide i t  i s p o s t u l a t e d t h a t t h e oxide i s formed from t h e phosphine and t r a c e s of molecular  oxygen d u r i n g the p r e p a r a t i o n o f the complexes.  i s c a t a l y z e d by some i n t e r m e d i a t e rhodium s p e c i e s p r e s e n t  The r e a c t i o n i n the r e a c t i o n  mixture. The IR c a r b o n y l s t r e t c h i n g frequency i n t h e V a l l a r i n o complex, [(C,H.)„P]„Rh(C0)C£, v a r i e s between 1960 and 1970 cm" depending upon b _) j z 92 —1 the s o l v e n t used . A s i n g l e s t r o n g band a t 1968 cm i n the 1  spectrum of compound G i n d i c a t e s the presence  of one type o f c a r b o n y l  group i n t h e m o l e c u l e w i t h an environment s i m i l a r t o t h a t i n the t r i p h e n y l phosphine complex. The  f a r IR s p e c t r a of t h e W i l k i n s o n complex, [ (C,H..) _P] „RhC£, and  [ (CgH,-) P] R h C £ 3  4  2  2  show  93  D  _> J  J  —1 a medium i n t e n s i t y band a t 296 and 303 cm  r e s p e c t i v e l y , a t t r i b u t e d t o Rh-C£ s t r e t c h i n g f r e q u e n c i e s .  The s i l o x y -  phosphine analogues show medium-weak peaks a t 260 and 255 cm  1  respectively.  C h l o r o s i l y l p h o s p h i n e Complexes The rhodium  spectroscopic results f o r carbonylchlorobis(chlorosilylphosphine)K, p a r a l l e l  • those f o r the s i l o x y p h o s p h i n e analogue.  c a r b o n y l s t r e t c h i n g frequency  a t 1970 cm  1  ( i n C^D^) i s almost -1  w i t h t h a t o f the s i l o x y p h o s p h i n e complex G a t 1968 cm  The IR  identical 31  .  The  P NMR  chemical s h i f t and the J(Rh-P) v a l u e s a r e a l s o v e r y s i m i l a r ; -30,00 ppm  -101-  F i g u r e 38.  P NMR spectrum of the product m i x t u r e o b t a i n e d i n the p r e p a r a t i o n of [ C J ^ S i - ( C H ) ~ P ( C ^ ) ] R h C l , L. 2  2  2  3  -102-  and  J(Rh-P)=127.5 Hz  peak a s s i g n a b l e of the two  compared w i t h -29.65 ppm  to a phosphine o x i d e i s observed.  downfield  m u l t i p l e t s i n the 4  s u g g e s t s , as f o r the s i l o x y p h o s p h i n e the ortho  protons.  The  case f o r the other  NMR  relative  spectrum are 2:3  m i c r o a n a l y t i c a l d a t a f o r C, H,  intensities which  CI,  P,  The mass spectrum, as  and  s e n s i t i v i t y of the  The m i c r o a n a l y t i c a l r e s u l t s (C, H, c h l o r o s i l y l p h o s p h i n e complexes L, M,  and  CI,  Rh  i s the  c h l o r o s i l y l p h o s p h i n e complexes, c o u l d not be  because of h i g h m o i s t u r e / a i r  NMR  The  No  analogue, d i f f e r e n t s h i e l d i n g of  agree w e l l w i t h the c a l c u l a t e d v a l u e s .  values.  and*J(Rh-P)=124.6 Hz.  recorded  compound.  P,  and  Rh)  f o r the  other  N agree w e l l w i t h the c a l c u l a t e d  However, t h i s i s r a t h e r meaningless i n view of the f a c t  s p e c t r a show t h a t a m i x t u r e of compounds i s produced.  The  that  the  number  and  the amount of s i d e p r o d u c t s can be decreased i f the r e a c t i o n v e s s e l s  are  p r e t r e a t e d w i t h CA^Si-CH^.This d e a c t i v a t e s - t h e  glass  surface.  Thus i t i s l i k e l y  to the Rh(I)  groups on the  t h a t the i m p u r i t i e s are produced by  h y d r o l y s i s , p o s s i b l y followed HC£  f r e e OH  the  partial  by an o x i d a t i v e a d d i t i o n of the l i b e r a t e d  centres. 31  As  an example, the  the attempted p r e p a r a t i o n It contains constants 40 Hz.  P NMR of  a double t r i p l e t  J(Rh-P) of 186.8  spectrum of the p r o d u c t s o b t a i n e d  [ C & S i - ( C H ) - P ( C H ) ] R h C £ i s shown i n F i g . 3 8 . 3  1 and  and  140.4  2  6  5  2  a double doublet Hz  There are f o u r m u l t i p l e t s , 3 and  3  2, w i t h  r e s p e c t i v e l y and 4 and  3' and  4'  dt p a t t e r n , and  and  a double d o u b l e t .  show a g r e a t e r  (They have a v e r y  coupling  J(P-P) about ( b u r i e d under  the b i g peaks) which c o u l d p o s s i b l y c o n s i s t of at l e a s t one a double t r i p l e t  during  other  set of  d e f i n i t e dd  i n t e n s i t y i n the spectrum of the  batch  and  -103-  prepared i n u n p r e t r e a t e d g l a s s w a r e ) .  The p r i n c i p l e s e t s 1 and 2 a r e  p r o b a b l y due t o t h e r e q u i r e d complex [CJl^Si-(CE^) ~P(C^H,-)^\^RhCA  since  2  t h i s p a t t e r n i s t o be expected an analogous  f o r t h e square p l a n a r s t r u c t u r e .  However,  p a t t e r n would a l s o be expected from t h e HC£ adducts  which  94 95 have been r e p o r t e d  '  t o e x i s t i n two o f t h e p o s s i b l e i s o m e r i c  forms, 12_ and 13.  H  P  P X  The 4  12  NMR spectrum o f t h e same product m i x t u r e which g i v e s t h e  31 P NMR spectrum  i n F i g . 38 shows t h a t t h e h y d r i d o complex i s a minor  product and o f t h e two p o s s i b l e s t r u c t u r e s t h e complex has t h e s t r u c t u r e 12.  The h i g h - f i e l d 4  NMR spectrum has an u n r e s o l v e d m u l t i p l e t a t  -146  whose s p e c t r a l w i d t h i s about 65 Hz. T h i s m u l t i p l e t c o l l a p s e s t o a d o u b l e t , J(Rh-P)=10 Hz, on phosphorus d e c o u p l i n g which i n d i c a t e s t h e presence o f o n l y one o f t h e two p o s s i b l e HC£ adducts. 95 s t r u c t u r e L2 and 13 can be d i f f e r e n t i a t e d  Compounds o f  by t h e i r J(P-H) v a l u e s ,  12 h a v i n g s m a l l e r v a l u e s ( c a . 10-20 Hz) than 13 ( c a . 200 H z ) .  Thus on  the b a s i s o f t h e s p e c t r a l w i d t h o f t h e h y d r i d e p r o t o n m u l t i p l e t s t r u c t u r e 12_ can be a s s i g n e d f o r t h e i m p u r i t y .  (65 Hz)  The r e l a t i v e a r e a s o f  the - C ^ - C ^ - s i g n a l s t o t h a t o f t h e h y d r i d e peak i s f a r g r e a t e r ( c a . 33:1)  than 12:1 (expected f o r t h e pure 1:1 HC£ adduct) which  indicates  -104-  that  i t i s the HC£ The  adduct which i s present  presence of the HC£  i n s m a l l e r amounts.  adduct i s a l s o seen i n the IR  spectrum 96  where t h e r e i s a band a s s i g n a b l e to a Rh-H at and  2095 cm 260  cm  \  \  and  s t r e t c h i n g frequency  two weak bands i n the v(Rh-C£) r e g i o n , a t  S i n c e the M-C£  i n f l u e n c e d by the n a t u r e  97 '  280  s t r e t c h i n g frequencies are s t r o n g l y 93 98 99  of the l i g a n d t r a n s to c h l o r i n e  '  '  but  o n l y s l i g h t l y a f f e c t e d by c i s l i g a n d s , a m i x t u r e of a P R h C £ complex 3  and  i t s HC£  adduct ]_2_ c o u l d c o n t a i n two,  v(Rh-C£) bands. P would be v e r y  The  f r e q u e n c i e s due  r a t h e r than the expected  to Rh-C£ s t r e t c h e s f o r C£ t r a n s to  s i m i l a r or the same f o r the two  t r a n s to H i n the P^RhHC^ complex should a s l i g h t l y lower f r e q u e n c y the v(Rh-C£) at 260 v(Rh-C£) at 280 P R h C £ and  cm  P RhHC£  3  3  The  cm 1  1  1 0 0  .^  i s assigned  compounds.  The  chlorine  g i v e r i s e to another band a t  Considering  v  i s assigned  three  the above argument  to C£ t r a n s to H,  and  the degenerate  to C£ t r a n s to P i n both the  complexes,  2 <  s p e c t r a of the products  obtained  i n the p r e p a r a t i o n of M  N a l s o i n d i c a t e t h a t a m i x t u r e of compounds i s produced.  and  In the attempted  p r e p a r a t i o n of M the d e s i r e d complex [ C £ S i - ( C H ) - P ( C H ) ] R h C £ i s the 3  main product  as i n d i c a t e d by the NMR  presence of v(Rh-H) and  No Instead  adduct w i t h  g  6  5  2  s p e c t r a of the product  v(Rh-C£) IR bands as w e l l as h y d r i d e  ( s p e c t r a l w i d t h c a . 70 Hz) a l s o an HC£  2  show t h a t the major i m p u r i t y  3  mixture.  The  "'"H NMR  peaks  i s most  likely  the c o n f i g u r a t i o n 12.  one major product  i s obtained  i n the attempted syntheses of  a number of compounds i s produced i n r o u g h l y 31 i n d i c a t e d by the r e l a t i v e i n t e n s i t i e s of the P NMR  N.  the same y i e l d s  as  peaks.  by  Judging  -105-  the presence and  of h y d r i d e peaks i n the """H NMR  v(Rh-C£) .  spectrum and by v(Rh-H)  IR bands some HC£ a d d u c t ( s ) a r e formed.  no l i t e r a t u r e r e p o r t s a r e known f o r HCJl adducts and  Unfortunately  of T^Rh^Ci^ complexes  the data o b t a i n e d i n t h i s work do not g i v e c o n c l u s i v e  as to the n a t u r e of such s p e c i e s .  The h i g h - f i e l d  c o n t a i n s a m u l t i p l e t at about -146  and a double  of r e l a t i v e i n t e n s i t i e s 1:4. (c a. 40 Hz)  and  The  NMR  spectrum  t r i p l e t a t -15.726,  s m a l l s p e c t r a l width  the s m a l l J(P-H) v a l u e of the dt  evidence  of the m u l t i p l e t  (18 Hz)  indicate that  both the d i f f e r e n t types of rhodium h y d r i d e protons a r e c i s to P. However, no d e f i n i t e s t r u c t u r e can be a s s i g n e d to the p r o d u c t s of  this  reaction.  3-2.  Syntheses of the P o l y m e r i c  merize  Complexes  The o b j e c t i v e of the next stage i n the s y n t h e t i c work was  to p o l y -  the c h l o r o s i l y l p h o s p h i n e complexes i n such a way  chemical  environment around the metal  t h a t the  c e n t r e would not be changed and  would have good p h y s i c a l p r o p e r t i e s such as h i g h p o r o s i t y and and  thermal  stability.  the  product  mechanical  As mentioned b e f o r e , the range of p h y s i c o -  c h e m i c a l a n a l y t i c a l t e c h n i q u e s which can be a p p l i e d to o b t a i n u s e f u l i n f o r m a t i o n about i n s o l u b l e s o l i d s i s v e r y l i m i t e d .  In the case of  the  polymers s y n t h e s i z e d i n t h i s study the o n l y r e a d i l y a v a i l a b l e  techniques  f o r c h a r a c t e r i z a t i o n were IR s p e c t r o s c o p y  Unlike  and m i c r o a n a l y s i s .  c h l o r o t r i s p h o s p h i n e r h o d i u m and d i - y - c h l o r o t e t r a k i s p h o s p h i n e d i r h o d i u m the complex [ C £ S i - ( C H ) - P ( C H ) ] R h ( C O ) C £ c o n t a i n s a v e r y convenient 3  2  2  6  5  2  2  d e t e c t a b l e , b u i l t - i n probe i n the form of the c a r b o n y l group. s t r e t c h i n g frequency  The  IR C=0  i s v e r y s e n s i t i v e to changes i n the environment of  -106-  the c e n t r a l m e t a l atom.  For e x a m p l e ^ ' v ( C = 0 )  {Rh(C0)C£[P(C„H )(C,H )„]„} o c c u r s at 1955-1960 cm" I D b o l l c  f o r trans-  9  1  C  f o r trans-{Rh(C0)CJl [P(C H ) ( C H ) ] > . 3  2  5  6  5  2  and at 2107  cm"  1  A l s o the c a r b o n y l s t r e t c h i n g  2  103 frequency changes  upon o x i d a t i v e a d d i t i o n of HBr to t r a n s -  { R h ( C 0 ) B r [ P ( C , H ) ] } from 1980 to 2055 o 5 3 I c  o  o  cm" , 1  Because of such v(C=0) s e n s i t i v i t y a few p o l y m e r i z a t i o n t e c h n i q u e s were t r i e d out w i t h [C£-Si-(CH„)-P(C,H )„]„Rh(C0)C£ and those which gave a 3 / 6 5 I I C  polymer of the d e s i r e d p h y s i c a l and c h e m i c a l p r o p e r t i e s were then used l a t e r f o r the p o l y m e r i z a t i o n of o t h e r macrocomplexes.  3-2-1.  D i f f e r e n t Methods of P o l y m e r i z a t i o n of [ C ^ S i - ( C H Q ~P (C^H^) Q ] ~ 2  2  Rh(C0)C£. H y d r o l y s i s of c h l o r o s i l a n e s to h y d r o x y s i l a n e s i s f o l l o w e d t a n e o u s l y by p o l y c o n d e n s a t i o n w i t h the e l i m i n a t i o n of water.  instan-  As d i s c u s s e d  i n S e c t i o n 1-2, the n a t u r e of the s i l o x y p o l y m e r i c products depends on the p r o p e r t i e s of the s t a r t i n g c h l o r o s i l a n e s and on the r e a c t i o n c o n d i t i o n s . Three d i f f e r e n t polymerizing  i n t e r f a c i a l p o l y c o n d e n s a t i o n t e c h n i q u e s used i n  [ C £ S i - ( C H ) ~ P ( C ^ ) ] Rh(C0)C£ g i v e p r o d u c t s w i t h 3  2  factory properties.  2  In a l l  2  2  the t h r e e methods the s t a r t i n g  satis-  chlorosilyl-  phosphine complex d i s s o l v e d i n the minimum amount of benzene i s i n t r o d u c e d i n t o the h y d r o l y z i n g medium.  The r e a c t i o n should proceed a c c o r d i n g to  eq. (12);  D+HpO  [C£ Si-(CH ) -P(C H ) ] Rh(C0)C£ 3  2  2  6  5  2  2  2)-H 0 >  { [ O ^ S i - ( C H ) ~P ( C ^ ) ] Rh2  2  2  2  (C0)C£)  (12)  In two methods which i n v o l v e b a s e - c a t a l y z e d p r o c e s s e s the h y d r o l y z i n g medium c o n s i s t of water i n a v e r y l a r g e excess. and KOH(aq).  The bases used a r e N ( C H ^ ) 2  No s o l u b l e low-molecular weight polymers a r e produced s i n c e  3  -107-  the f i l t r a t e  a f t e r the i n i t i a l polymer p r e c i p i t a t i o n as w e l l as  the  f u r t h e r washings are a l l c o l o u r l e s s . Both of the p r o d u c t s e x h i b i t a strong  IR band at 1965  1970  i n the s t a r t i n g c h l o r o s i l y l p h o s p h i n e complex can be  cm  1  cm  \  The  buted to the d i f f e r e n c e i n the  small s h i f t  from the v(C=0) at attri-  IR sample d i s p e r s i o n media ( N u j o l  vs.  C,D, s o l u t i o n ) and/or to the remote i n f l u e n c e of the S i - O - S i v s . o D — groups of the  ligands.  When pure water i s used as the h y d r o l y z i n g medium the i s extremely v i g o r o u s .  mixed w i t h dioxane i s found to be a good h y d r o l y z i n g medium. proportion  of dioxane to water i s 4:1  products.  The  (v/v)  and  s t r e t c h i n g frequency at 1965 i s not  cm  1  The  The m i c r o a n a l y t i c a l d a t a  i t s IR  i n d i c a t e s t h a t the environment of  (C,H,P, and  Rh)  C  f o r the polymer P  o  Since  centres  a f f e c t e d i t seems t h a t the excess of c h l o r i n e d e t e c t e d  obtained calculated  However, the  (12.3%) i s more than t w i c e t h a t p r e d i c t e d .  v i r t u a l l y unchanged IR v(C=0) shows t h a t the Rh(I)  i s due  the  polymerization.  the f o r m u l a {[0. ,_Si-(CH„)„-P(C,H )_] Rh(C0)C£} . 3/2 2 2 6 5 2 2 x  content found  evolved.  carbonyl  by h y d r o l y s i s i n water/dioxane m i x t u r e agree w e l l w i t h the v a l u e s for  optimal  g i v e s h i g h - m o l e c u l a r weight  i n good y i e l d and  a l t e r e d i n the p r o c e s s of  solvent  method water  r e a c t i o n i s e f f e c t i v e l y a c i d - c a t a l y z e d s i n c e HCJi i s  i n s o l u b l e polymer P i s o b t a i n e d  metal centre  reaction  D i l u t i n g the water w i t h some other m i s c i b l e  p e r m i t s more c o n t r o l ; i n the t h i r d s u c c e s s f u l p o l y m e r i z a t i o n  The  Si-C&  by  Ci  the  remain  un-  microanalysis  to t h r e e p o s s i b l e f a c t o r s : (a) some i n t e r f e r e n c e from  other  element(s) i n the a n a l y t i c a l measurements, (b) incomplete h y d r o l y s i s of the S±-Ci m o i e t i e s ,  and/or  (c) a d s o r p t i o n  of evolved  HC&  onto the polymer.  -108-  I n t e r f e r e n c e from S i has to be c o n s i d e r e d i n p o s s i b i l i t y T o t a l CI  content i n the polymer P i s determined  i n the f o l l o w i n g  The sample i s burnt i n an oxygen f l a s k i n the presence of an (NaOH and  .  Then the excess of H^O^  (a).  i s d e s t r o y e d by  way.  absorbent  boiling  2+ and the phosphorus i s removed by p r e c i p i t a t i o n w i t h Ca or  phosphite).  acetone, bility  Then the s o l u t i o n , a c i d i f i e d  is titrated  w i t h HNO^  (as phosphate and d i l u t e d  w i t h AgNO^(aq). There i s the c o m p l i c a t i n g p o s s i -  of f o r m a t i o n o f sodium s i l i c a t e s  ( d u r i n g the f i r s t  stages of the  procedure) which can subsequently c o p r e c i p i t a t e w i t h AgC£ as silicates.  with  A l l silver  s i l i c a t e s are known to have v e r y low  U n f o r t u n a t e l y s e l e c t i v e removal  of s i l i c a t e s  i s not  silver solubility ^ 1  possible,  S i n c e the h i g h CSL content i s found  i n the a n a l y t i c a l method d e s c r i b e d . o n l y f o r the p o l y m e r i c complexes  (see a l s o s e c t i o n 3-2-3) and not f o r  the s o l u b l e ones i t i s concluded  t h a t the S i i n t e r f e r e n c e i s most l i k e l y  imposed by the p o l y m e r i c n a t u r e of the s i l o x a n e network.  Unfortunately  no standard compound i s a v a i l a b l e to prove the above t h e s i s . T r i a l and (b) and  error c a l c u l a t i o n s f o r p o s s i b l e products r e s u l t i n g  (c) i n d i c a t e t h a t the c h l o r i n e content found f o r the p o l y m e r i c  c a r b o n y l complex P (12.3%) may {[0  3 / 2  correspond w i t h two  Si-(CH ) -P(C H ) ] Rh(CO)C£.(HC£) 2  and/or { [ 0  9 / 8  2  6  (C£  3 / 4  5  2  2  1  5  >  2  6  5  2  2  formulae:  x  )Si-(CH ) -P(C H ) ] Rh(CO)C£} . 2  possible  x  The C, P, and  v a l u e s f o r these formulae are d i f f e r e n t from those f o r the o r i g i n a l formula P, { [ 0 ,„Si-(CH„)„-P(C,H )J_Rh(C0)C£} , b e i n g low by about 5/2 2 2 o D 2 2 x o  1, and  from  C  1 p e r c e n t r e s p e c t i v e l y , and  C£ c o n t e n t .  Rh  3-4,  thus are s e n s i t i v e to the changes i n  S i n c e the percentage of C, P, and Rh found agrees w e l l w i t h  -109-  the formula P i t seems u n l i k e l y t h a t a r e a l i n c r e a s e i n CH content i s encountered.  In some o t h e r polymers  d i s c u s s e d i n the f o l l o w i n g  problems w i t h C a n a l y s i s a r e e x p e r i e n c e d . v a l u e s found a r e always  sections,  However, i n those cases the  lower than those expected.  Thus i t i s concluded  t h a t the f o r m a t i o n of not o n l y {[0» , Si-(CH„)„-P(C,H )„]„Rh(C0)C£.(HC£), } 3/1 1 1 D D I I 1.5 0  and  {[0 ^ (C£ g  2  3 / 4  C  r  X  ) S i - ( C H ) - P ( C H ) ] R h ( C O ) C £ } , but a l s o of the HCJl 2  2  6  5  2  2  x  o x i d a t i v e a d d i t i o n p r o d u c t , { [ O ^ S i - (CH ) ~ P ( C ^ ) ] R h ( C O ) H C £ ) 2  2  2  2  2  x  is  unlikely. P o l y m e r i z a t i o n of C J l ^ S i - ( C H ) ~ P ( C ^ H ^ ) 2  2  2  a l o n e c a r r i e d out i n the  same manner as t h a t of the c a r b o n y l complex y i e l d s a p o l y m e r i c product w i t h C£ content 9.2%  which i s h i g h e r than expected  {0„ Si-(CH ) -P(C,H ) } j / l l l b j l ' x . / 0  0  0  r  0  .  (0%) f o r  T h i s i n d i c a t e s t h a t the h i g h CI  percentage  i s not n e c e s s a r i l y due t o the r e a c t i o n of HC£ w i t h Rh(I) c e n t r e s . I t can be concluded on the b a s i s of the above d i s c u s s i o n factor is  that  (a) i . e . the i n t e r f e r e n c e from o t h e r e l e m e n t ( s ) , p r o b a b l y S i ,  most l i k e l y r e s p o n s i b l e f o r the h i g h C£ content found f o r the  p o l y m e r i c complex P, a l t h o u g h some degree of c o m p l e t e l y excluded.  (b) and  (c) cannot  I t s h o u l d be s t r e s s e d t h a t no R h ( I I I ) HC£  i s p r e s e n t i n the polymer s i n c e no Rh-H  and no changed C=0  IR  be adduct  stretching  f r e q u e n c i e s a r e observed.  3-2-2.  D i f f e r e n t Methods of P o l y m e r i z a t i o n of  [CJ^Si-(CH ) ~P(CgH^ ] RhC&.  A s e r i e s of homo- and c o p o l y m e r i c complexes was  2  2  2  3  synthesized using  the t h r e e s a t i s f a c t o r y p o l y m e r i z a t i o n methods d e s c r i b e d above.  S i n c e the  macrocomplexes were to be used as h y d r o g e n a t i o n c a t a l y s t s i t was important to  establish their stability  to hydrogen.  I t has p r e v i o u s l y been e s t a b l i s h e d  -110-  by EM s t u d i e s  26  t h a t t h e darkening of t h e s i l i c a - s u p p o r t e d  phinerhodium(I) of  complexes d u r i n g h y d r o g e n a t i o n r e a c t i o n s i s a r e s u l t  r e d u c t i o n o f Rh(I)  crystallites.  trisphos-  to.Rh(O) w i t h the subsequent  f o r m a t i o n o f metal  T h e r e f o r e , any n o t i c a b l e darkening o f t h e s i l o x y p o l y m e r  exposed t o hydrogen was taken t o be an i n d i c a t i o n of the same p r o c e s s and,  i f t h i s happened, the p o l y m e r i z a t i o n technique by which t h e  polymer was o b t a i n e d was n o t s t u d i e d f u r t h e r . When t h e c h l o r o s i l y l p h o s p h i n e complex i s h y d r o l y t i c a l l y  polymerized  and copolymerized w i t h CA^Si-CH^ i n d i f f e r e n t p r o p o r t i o n s t h e r e a c t i o n proceeds  a c c o r d i n g t o t h e g e n e r a l e q u a t i o n (13).  D+H 0 2)-H 0 2  [ C £ S i - ( C H ) - P ( C H ) ] R h C J l + mCJ^Si-QL^ 3  2  2  6  5  2  3  (13) >  {[0  3 / 2  Si-(CH ) -P(C H ) ] RhC£.(0 2  2  6  5  2  m=0-200; x=large,  3  3 / 2  Si-CH ) } 3  m  unspecified.  T a b l e I shows t h e r e s u l t s o b t a i n e d w i t h t h e polymers catalyzed, N(C H^) , hydrolysis. 2  prepared by base-  The h y d r o l y z i n g medium i s pure water  3  i n a l a r g e excess.  x  Most o f t h e p r o d u c t s a r e u n s t a b l e t o hydrogen as  judged by t h e d a r k e n i n g of t h e polymer.  The r e a c t i o n of t h e W i l k i n s o n  complex, [ ( C ^ H ^ ) P ] R h C £ , and i t s analogues w i t h hydrogen i n v o l v e s 3  3  f o r m a l o x i d a t i v e a d d i t i o n t o Rh(I)  thereby forming  Rh(III)  . 81,82,105,106 species  RhP C£ + H 3  2  >  RhH P C£ 2  (14)  3  S i n c e t h e darkening o f t h e polymer i s accompanied by t h e hydrogen which i s g r e a t e r than c a l c u l a t e d  f o r one m o l e c u l e o f H  2  uptake  per atom of  -111-  Rh(I)  t h i s r e i n f o r c e s the i d e a that d e c o m p o s i t i o n t o m e t a l l i c rhodium  takes p l a c e .  The r e s u l t s a r e not always reproduceable as i s found f o r  example i n t h e complex o f formula w i t h m=100. the hydrogen uptake i s almost 1:1 and t h e r e sample from another p r e p a r a t i o n  F o r one p r e p a r a t i o n  batch  i s no d i s c o l o u r a t i o n y e t a  b a t c h of t h e same complex darkens and  the hydrogen uptake i s more than p r e d i c t e d .  The l a r g e l y  negative  r e s u l t s and t h e i n c o n s i s t e n c i e s observed l e a d t o t h e abandonment of this polymerization  t e c h n i q u e as a v i a b l e method.  In a s i m i l a r method KOH(aq) i s used as t h e c a t a l y t i c base. r e s u l t s obtained  f o r these polymers a r e summarized i n T a b l e I I .  The Again,  most of t h e p r o d u c t s darken upon exposure t o hydrogen and consume more hydrogen than t h a t c a l c u l a t e d on t h e b a s i s of one YL^ per Rh atom. T h i s polymerization  t e c h n i q u e was a l s o r e j e c t e d .  When t h e h y d r o l y z i n g medium c o n s i s t s of water d i l u t e d w i t h  solvents  53 of e l e c t r o n .donating p r o p e r t i e s  ,  DMF or dioxane without t h e a d d i t i o n  of base o r a c i d c a t a l y s t , polymers a r e obtained  whose p r o p e r t i e s a r e  summarized i n T a b l e I I I . Although n e i t h e r of t h e two p r o d u c t s by p o l y m e r i z a t i o n  i n t h e DMF/water m i x t u r e decompose t o m e t a l l i c rhodium  the amount o f hydrogen consumed i s v e r y eq.  (14) t h a t o n l y v e r y  The  s m a l l extent  s m a l l which i n d i c a t e s i n view of  few m e t a l l i c c e n t r e s  are available for reaction.  of hydrogen r e a c t i o n i s a l s o i n d i c a t e d by t h e f a c t  the o r i g i n a l orange c o l o u r , become y e l l o w ,  obtained  c h a r a c t e r i s t i c o f Rh(I)  t y p i c a l f o r Rh(III)  that  s p e c i e s , does not  species.  When a water/dioxane m i x t u r e i s used as t h e h y d r o l y z i n g p r o d u c t s have s a t i s f a c t o r y p r o p e r t i e s .  medium t h e  As can be seen i n T a b l e  III .  none o f t h e polymers darken upon exposure to hydrogen, a l l o f them change  -112-  c o l o u r from orange t o y e l l o w , and the amount of hydrogen consumed does not exceed the maximum expected v a l u e .  The  general trend i s that  amount of hydrogen taken up i n c r e a s e s w i t h the c o n t e n t m e r i c component O ^ ^ S i C H ^ . o n l y 0.27  When m=0  of the  The  copoly-  the observed hydrogen uptake i s  of the a n t i c i p a t e d amount; f o r m=50 i t i s 0.75;  m=200 i t i s 100%.  the  and when  s y n t h e s i s of the polymer w i t h m=100 was  repeated  but the hydrogen u p t a k e v a l u e s v a r y over a wide range (Table I I I ) .  This  l e a d s t o a b e l i e f t h a t e i t h e r the r e a c t i o n i s not reproduceable or t h a t p o s s i b l y the c o n t e n t  of p a r t l y s o l u b l e polymers of lower m o l e c u l a r  d i f f e r s from one p r e p a r a t i o n b a t c h t o another.  weights  D i f f e r e n t contents  of  these compounds would g r e a t l y a f f e c t the r e a c t i v i t y of the macrocomplex towards hydrogen. I n o r d e r t o ensure t h a t the f i n a l product polymers o n l y , the product (1:4 v/v) m i x t u r e  then S o x h l e t e x t r a c t e d w i t h  I t i s found t h a t the r e s u l t s o b t a i n e d  d i f f e r e n t b a t c h e s of the same macracomplexes prepared reproduceable (Table I V ) .  high-molecular  o b t a i n e d by the h y d r o l y s i s i n w a t e r / d i o x a n e  i s s e p a r a t e d , d r i e d , and  d i c h l o r o m e t h a n e f o r 24h.  c o n s i s t s of  with  i n t h i s way  are  Both the homo- and the copolymers change  t h e i r c o l o u r upon exposure t o hydrogen from s t r o n g orange t o l i g h t orange, and do not show any s i g n s of d e c o m p o s i t i o n  t o m e t a l l i c rhodium.  The amount of hydrogen consumed i n c r e a s e s w i t h i n c r e a s e d c o n t e n t copolymeric  of  the  component O ^ ^ S i C H ^ .  T h i s p r o c e d u r e was  t h e r e f o r e adopted f o r the p r e p a r a t i o n of a l l  the p o l y m e r i c c h l o r o ( s i l o x y p h o s p h i n e ) r h o d i u m  complexes.  -113-  3-2-3.  Homopolymerization of Phosphine Complexes  Copolymerization with  o f Rh(I) and t h e i r  Cl^Si-CH^.  Apart from t h e polymers d e s c r i b e d i n t h e p r e v i o u s s e c t i o n a l l other p o l y m e r i c complexes d e s c r i b e d i n t h i s work were s y n t h e s i z e d by h y d r o l y s i s i n a water/dioxane (1:4 v/v) m i x t u r e f o l l o w e d by S o x h l e t e x t r a c t i o n w i t h dichloromethane.  Only i n one case does t h e method  to produce an i n s o l u b l e polymer.  T h i s i s t h e polymer produced from  [C£ (CH )Si-(CH ) -P(C H ) ] RhC£, 2  3  2  2  6  with dichloromethane.  5  2  3  which d i s s o l v e s upon e x t r a c t i o n  The lower c r o s s - l i n k e d  produced by h y d r o l y s i s of S i C &  fail  s t r u c t u r e o f t h e polymer  groups p r o b a b l y accounts f o r t h i s  2  solubility. Four types of i n s o l u b l e s o l i d p o l y m e r i c complexes were s y n t h e s i z e d successfully.  {[0  3 / 2  T h e i r g e n e r a l formulae can be w r i t t e n as f o l l o w s :  Si-(CH ) -P(C H ) ]3RhC£.(0 2  n  6  5  2  3 / 2  Si-CH ) } m  x  n=2  ;  m=0,75,150,200 ;  R  n=8  ;  m=0,100  R  ;  3 / 2  Si-(CH ) -P(C H ) ]  {[0  3 / 2  Si-(CH ) -P(C H ) ] Rh C£ .(O,  2  2  2  6  2  6  5  5  m=0,200  2  2  3 > 7  4  RhC£>  2  2  ;  2-0,75,150,200.  8  {[0  In a l l  3  x  ;  / 2  -0,100.  S  Si-CH ) } 3  m  x  T  2-0,200.  t h e complexes x i s p r o b a b l y v e r y l a r g e but i t i s undetermined.  The macrocomplexes  were examined by m i c r o a n a l y s i s , mp d e t e r m i n a t i o n and  f a r IR s p e c t r o s c o p y .  -114Th e m i c r o a n a l y t i c a l d a t a which were o b t a i n e d a r e f a r from adequate f o r p r o v i n g the p r e d i c t e d formulae  o f t h e polymers but when  combined w i t h t h e IR evidence they g i v e a good i n d i c a t i o n as t o the i d e n t i t y of the macrocomplexes.  The o x i d a t i o n s t a t e o f rhodium seems  to be ( I ) i n t h e p o l y m e r i c complexes and v e r y l i t t l e  i f any R h ( I I I )  products o f HC£ o x i d a t i v e a d d i t i o n t o rhodium(I) a r e p r e s e n t . The homopolymeric complexes show weak broad bands i n t h e v(Rh-CA) r e g i o n , a t 285 cm at  290 cm  1  -1  w i t h a shoulder a t 255. cm  w i t h a shoulder a t 265 cm  1  -1  2—U  (I^.Q) •  the r e g i o n t y p i c a l f o r v(Rh-H) around 2100 cm . 1  intrinsically  (R  and R ) and o—U  There i s no peak i n The combination  o f the  s m a l l i n t e n s i t y of these peaks t o g e t h e r w i t h t h e h i g h  " d i l u t i o n " o f the complex by O ^ ^ S i - C H ^ i n the copolymers i s the cause of  t h e absence o f v(Rh-CJl)  (and v(Rh-H)) i n t h e IR s p e c t r a of t h e  copolymers. I t was noted  t h a t i n the course o f the polymer p r e p a r a t i o n the  yellow colour ( c h a r a c t e r i s t i c of Rh(III)) of the o r i g i n a l  precipitate  changes t o orange ( c h a r a c t e r i s t i c o f R h ( I ) ) f o r the homopolymers and darker y e l l o w f o r the copolymers ( d i l u t i o n by c o l o u r l e s s  O^^Si-CH^  moieties). The C£ content found f o r a l l the homopolymers and f o r some c o p o l y mers (R _y^) i s h i g h e r than expected. 2  The S i content found  i s i n good  agreement w i t h the c a l c u l a t e d v a l u e s f o r the polymers t e s t e d . the v a l u e s f o r P and Rh found and ^2-200'' ^ i s lower  o r  a  1  1  t  *  i e  o  t  n  e  r  So a r e  i n t h e homopolymers and copolymers  copolymers t h e percentage  ^-75  of P, Rh, and C£  than the a c c u r a c y of the d e t e r m i n a t i o n hence these elements were  not a n a l y z e d .  The carbon content  i n a l l the copolymers and T _ Q i s found 2  -115-  as p r e d i c t e d but  i t i s low i n a l l the other homopolymers.  S i n c e no  c o r r e l a t i o n i s found between the h i g h CI and low C v a l u e s i n the s e r i e s of polymers i t i s concluded  by analogy w i t h polymer P t h a t  the h i g h C% v a l u e s are most l i k e l y due analytical  to S i i n t e r f e r e n c e i n the  procedure.  In view of the above d i s c u s s i o n h i g h e r emphasis must be put the IR r e s u l t s and  on  the c o l o u r of the products which i n d i c a t e t h a t  the homopolymers do not c o n t a i n R h ( I I I ) p r o d u c t s r e s u l t i n g from oxidative addition.  HC£  T h i s c o n c l u s i o n can a l s o be e x t r a p o l a t e d to the  copolymers. As mentioned b e f o r e the carbon content R„  o J  Z—U  R  D  o—0  and  S i s lower  analytical method  1 0 7  than expected  i n the homopolymers  i n s p i t e of an  improved  which g i v e s much b e t t e r r e s u l t s than  the  108 standard a n a l y t i c a l procedures  .  The  improvement p r o v i d e s a  method of e l i m i n a t i n g the f o r m a t i o n of s i l i c o n  c a r b i d e which would  to low carbon v a l u e s c a l c u l a t e d on the b a s i s of CO^  lead  e v o l v e d . There i s  a p o s s i b i l i t y t h a t h i g h e r c r o s s - l i n k e d p o l y m e r i c networks promote s i l i c o n carbide formation.  As d i s c u s s e d i n the p r e v i o u s s e c t i o n  a c c e s s i b i l i t y of Rh c e n t r e s t o hydrogen i s lower and  i n c r e a s e s w i t h the 0^^S±-CE^ content  the  f o r the homopolymers  i n the copolymer. I f t h i s i s  taken as an i n d i c a t i o n of the " t i g h t n e s s " or the degree of c r o s s l i n k i n g of the network (see a l s o s e c t i o n s 4-1-1 why it  the carbon i s lower  and  4-2)  i t may  explain  content found f o r the copolymers i s as c a l c u l a t e d  although  f o r the homopolymers.  An i n t e r e s t i n g t r e n d i n the v a l u e s f o r the decomposition of the polymers i s seen i n the d a t a i n T a b l e  V.  points  -116-  T a b l e V.  Decomposition p o i n t s o f t h e p o l y m e r i c complexes  R n-m  Polymer  , S, and T„ z-m  Decomp. p o i n t °C  R  2-0  R  8-0  220-230 185-195  S  260-265  T  220-230  2-0  R  2-75  R  2-150  R  2-200  R  8-100  T  2-200  255-265 255-265 255-265 250-260 270-280  None o f the polymers a c t u a l l y melt; they a l l decompose over a range of about 10°C l e a v i n g e i t h e r b l a c k or grey r e s i d u e s . mers decompose a t temperatures 30-50°C copolymers. and R  Z—ZUU  F o r example R _o 2  a t 255-265°C.  A l l t h e homopoly-  lower than the c o r r e s p o n d i n g  decomposes a t 220-230°C  The homopolymer R„  n  o—U  whereas R^_^^, ^ - 1 5 0 '  w i t h 8-carbon  ligands  decomposes a t t h e lowest temperature whereas the copolymer w i t h an excess o f t h e phosphine, S, i s almost as s t a b l e as ^-^uo the h i g h e s t decomposition temperature o f a l l . decompose a t r o u g h l y the same temperature  w  n  ^  c  n  n  a  s  A l l the o t h e r copolymers  ( c a . 260°C) r e g a r d l e s s of t h e i r  -117-  c o m p o s i t i o n , and a l l lower than S and 2-200* T  The a n a l y t i c a l r e s u l t s o b t a i n e d g i v e o n l y an i n c o m p l e t e i n d i c a t i o n o f t h e i d e n t i t y of t h e macrocomplexes produced.  Therefore,  i n t h e c o u r s e o f t h i s study a number o f experiments were c a r r i e d out i n o r d e r t o c h a r a c t e r i z e them more f u l l y by means of t h e i r c h e m i c a l reactivity. t h i s work.  These experiments a r e d e a l t w i t h i n t h e next c h a p t e r o f  -118-  CHAPTER 4  Reactions  o f t h e Complexes w i t h H^, CO, and HCft(g).  The c h e m i c a l i d e n t i t y o f compounds can o f t e n be e s t a b l i s h e d by i n d i r e c t methods f o r example by c h e c k i n g c e r t a i n reagents.  t h e i r r e a c t i v i t y towards  Both [ (C,H ),,P] „RhC£ and [ (C H..)„P] .Rh„C£ and C  £  0  t h e i r analogues undergo a v a r i e t y o f o x i d a t i v e a d d i t i o n r e a c t i o n s . Hydrogen adds o x i d a t i v e l y t o t h e d i - p - c h l o r o t e t r a k i s p h o s p h i n e d i r h o d i u m , and t o t h e c h l o r o t r i s p h o s p h x n e r h o d i u m  CI  P  CI  Rh + H / \ P P  0  2  P  •  CI  /* \ / \ CI  ^  P  P R  P  • , 81,82,105,106 complexes  Rh / | \ P p H  z=>  ( 1 5 )  P  CI  / \ P  /\\ I CI  v  +  82  2  P  ?  •35.  \  H (16)  H  P  Two o f t h e p o s s i b l e s t r u c t u r e s o f t h e ECU adducts o f t h e c h l o r o t r i s p h o s uu J i u • 94-97,100 phinerhodium complexes have been p r e v i o u s l y r e p o r t e d and were J  d i s c u s s e d i n S e c t i o n 3-1-3 o f t h i s work.  .CI  Pv Rh  P r  -  P • HCl<I±  P r  H v  Rh  P  1  CI  •  P  12  CI  P.  .CI  H  Rh  P  1  U7)  CI P  13  -119-  The  above r e a c t i o n s a l l o w a d i s t i n c t i o n to be made between Rh(I) and  Rh(III)  s p e c i e s s i n c e the l a t t e r do not undergo o x i d a t i v e a d d i t i o n to  rhodium. Both the complexes P^RhCJl and P ^ R l ^ C ^ r e a c t w i t h species.  The r e a c t i v i t y of [(C^H^)^P]^RhCA i s probably  P RhC£ formation 2  be  in solution^ ' 1  1 0 9  .  electron-donor  due t o t h e ease o f  The r e a c t i o n w i t h CO i s r e p o r t e d ^  1  to  irreversible.  P^  /P Rh^ C£ ^ P  +  X  P /CO C O — " ^ R h C£ ^P  +P  (18)  X  16 In the case o f d i - u - c h l o r o t e t r a k i s p h o s p h i n e d i r h o d i u m  complexes a b r i d g e -  82 s p l i t t i n g r e a c t i o n takes p l a c e and  i n the presence of donors such as C ^4  CO (eq 19) , y i e l d i n g a product  equation  (18).  2  w i t h the same s t r u c t u r e 1_6 as shown i n  Carbon monoxide has been r e p o r t e d to d i s p l a c e  phosphines i n ( F ^ ^ R t ^ C ^  a l l four  g i v i n g (CO^Rt^CJ^.  Rh p/  1 1 0  ^cr^  Rh ^P  +  2C0 ^  2  (19)  RK  C£^  ^P  16 Both the model complexes and the p o l y m e r i c to r e a c t i o n s (15) - (19) and the r e s u l t s o b t a i n e d compounds were compared.  analogues were s u b j e c t e d  f o r the two groups o f  Because of the h i g h s o l u b i l i t y o f the model  complexes even i n s o l v e n t vapours q u a n t i t a t i v e uptake measurements u s i n g the gas uptake apparatus c o u l d not be made. followed s p e c t r o s c o p i c a l l y .  The r e a c t i o n s were t h e r e f o r e  -120-  4-1.  Reactions with  4-1-1.  H^.  R e a c t i o n s of P^RhCA Complexes . The r e a c t i o n of t h e s o l u b l e complex H was f o l l o w e d w i t h IR,  1  31 H NMR,  and  P NMR  s p e c t r o s c o p y . The m o l e c u l a r s t r u c t u r e lb_ has  been a s s i g n e d t o the hydrogen adduct of [ (C^H^^PJ^RhCJi and  CU  'Pa  Rh  p/  I \u  81 82 i t s analogues  '  around 2050 cm  1  .  They show a broad medium i n t e n s i t y v(Rh-H) peak  w i t h a broad s h o u l d e r a t a f r e q u e n c y about 50 cm  g r e a t e r than t h e main peak.  1  The s o l u b l e s i l o x y p h o s p h i n e compound  o b t a i n e d i n t h e r e a c t i o n o f H w i t h hydrogen shows a s i m i l a r peak a t 2075 cm  1  w i t h a s h o u l d e r a t 2160 cm \  The h i g h - f i e l d 4  NMR  spectrum  of the adduct of t h e W i l k i n s o n complex c o n t a i n s t h r e e p e a k s ^ - ^ ^ 8  - 9 , -11, and -286 w i t h r e l a t i v e i n t e n s i t i e s 1:1:2. of peaks, a t -8.5, -10.1 and -17.9 s i l o x y p h o s p h i n e compound.  f  around  An analogous p a t t e r n  6 r e s p e c t i v e l y , i s observed f o r t h e  Upon p a r t i a l phosphorus d e c o u p l i n g the two  s m a l l e r peaks c o l l a p s e i n t o one m u l t i p l e t and the b i g one i n t o a d o u b l e t ; the r a t i o of t h e i r i n t e g r a t e d a r e a s b e i n g 1:1. The  3 1  P  NMR  spectrum of (Ph P) RhH C£ c o n t a i n s 3  3  2  d o u b l e t of -48.92 ppm due t o the phosphorus P f u r t h e r u p f i e l d a t -32.21 ppm due t o P^.  a  1 0 6  a double  and a d o u b l e t r i p l e t  An analogous spectrum i s found  f o r the s i l o x y p h o s p h i n e hydrogen adduct w i t h a double d o u b l e t a t -41.03 ppm  -121-  and a double t r i p l e t  at -20.17 ppm,  w i t h a l l the c o u p l i n g c o n s t a n t s  c o n s i d e r a b l y s m a l l e r than those f o r the t r i p h e n y l p h o s p h i n e complex. The  s i n g l e t due  spectrum  to s i l o x y p h o s p h i n e oxide which i s observed  of the s t a r t i n g complex i s a l s o noted  The h y d r o g e n a t i o n  i n the  i n t h a t of the  product.  p r o c e s s , as f o r the W i l k i n s o n complex, i s  c o m p l e t e l y r e v e r s i b l e . Upon removal of the s o l v e n t i n vacuo a l l the IR and NMR  s p e c t r a l f e a t u r e s due  to the h y d r i d e s p e c i e s d i s a p p e a r  the p a t t e r n t y p i c a l of the s t a r t i n g P^RhCJi r e a p p e a r s .  The  and  recovered  complex can s u c c e s s f u l l y be rehydrogenated, as i n d i c a t e d by the s p e c t r a . The p o l y m e r i c R^-rj  a n <  * 2-75  i n a t o l u e n e suspension and the amount of toluene.  c o m  Plexes  i n the s o l i d  w  e  r  exposed to H  e  state.  2  both  Data i n F i g . 5 show  uptake v s . time f o r the r e a c t i o n c a r r i e d out i n  A f t e r 33h the homopolymer consumes 11.5%  56% of the The  R  and  the copolymer  as compared w i t h the amounts c a l c u l a t e d f o r 1:1  uptake.  f a c t t h a t the homopolymer consumes l e s s hydrogen (per c a l c u l a t e d  number of rhodium atoms) may bility  be a r e f l e c t i o n of the degree  of a c c e s s i -  of rhodium atoms which i s a r e s u l t of the degree of  and d i l u t i o n w i t h O ^ ^ S i - C H ^ m o i e t i e s .  cross-linking  However, the IR s p e c t r a of a l l  the hydrogenated  p r o d u c t s show no v(Rh-H) peaks i n the expected r e g i o n ,  2050-2150 cm  There a r e two  p o s s i b l e reasons  f o r t h i s . One  h i g h i n s t a b i l i t y of the h y d r i d o s p e c i e s which c o u l d r e v e r t s t a r t i n g compound d u r i n g the IR m u l l p r e p a r a t i o n i n a N The other i s the i n t r i n s i c a l l y  2  i s the  to the  atmosphere.  s m a l l i n t e n s i t y of the v(Rh-H) IR  a b s o r p t i o n combined w i t h the s m a l l amount of H  2  uptake by the homopolyme  A d d i t i o n a l l y t h e r e i s the problem of the " d i l u t i o n " by O ^ ^ S i - C H ^ f o r t h copolymer.  -122(a)  2 3  -123-  4-1-2. R e a c t i o n of P^Rh^CJ^ Complex, J . The compounds ( A r P ) R h C A ( A r = C H , p = C H - ( C H ) a r e r e p o r t e d t o 3  4  2  2  6  5  3  6  4  g i v e o n l y one complex 15 on r e a c t i o n w i t h hydrogen.  P P  CI  H  \ / \ Rh  P  Rh  / \ / CI  /  \  H  15  P 82  T h i s s t r u c t u r e has been e s t a b l i s h e d by e x t e n s i v e IR and NMR of  the p - t o l y l p h o s p h i n e complex.  band about 2115 cm  -1  .  studies  The IR spectrum shows a broad  The p r o t o n decoupled  31  P NMR  spectrum c o n s i s t s  of two d o u b l e t s , J(Rh-P)=195 and 118 Hz, and the h i g h - f i e l d H 1  spectrum has a d o u b l e t (J(Rh-H)=22 The  31  P and the h i g h - f i e l d  NMR  Hz) of t r i p l e t s J(P-H)=17 Hz. 1 H NMR  complex J a r e shown i n F i g . 39a and 39b.  s p e c t r a of the H  2  adduct of  The f o u r resonances 1-4 i n  31 the  P NMR  spectrum can be a s s i g n e d t o the two d o u b l e t s of a s p e c i e s  w i t h t h e same s t r u c t u r e as 15_. I t i s not i m m e d i a t e l y c l e a r , however, w h i c h peaks b e l o n g t o which d o u b l e t s .  The f o r m a t i o n of such a h y d r i d o  s p e c i e s i s however c o n f i r m e d by the double t r i p l e t a_ and b_ i n the h i g h f i e l d H NMR X  spectrum a t -20.16, J(Rh-H)=24 Hz and J(P-H)=16 Hz, which  c o l l a p s e s t o a d o u b l e t on phosphorus d e c o u p l i n g . In v i e w o f the i n f o r m a t i o n a v a i l a b l e i n the e x i s t i n g  literature  31 p o s s i b l e assignments f o r the o t h e r  P NMR  peaks p r e s e n t  a d i f f i c u l t y , when compared w i t h the peaks i n the 4  NMR  somewhat of spectrum.  The  -124-  31  four  P NMR  peaks of lower i n t e n s i t y ,  of peaks 1-4  5-8,  c o u l d p o s s i b l y be a s s i g n e d  Rh /  which l o o k l i k e a shadow  t o an isomer 1_7 of the complex 15.  Rh \  /  P  I  \  I  CI  17  P  H  Such a s t r u c t u r e a l s o c a l l s f o r a d o u b l e t r i p l e t i n the "*"H NMR  spectrum.  Only one  t r i p l e t c was  high-field  observed at -19.86; t h e r e i s  the p o s s i b i l i t y t h a t i t s " t w i n " t r i p l e t i s b u r i e d under the l a r g e peaks of the double t r i p l e t a-b_.  However, so f a r no t r a n s i t i o n  m e t a l complex  w i t h two H atoms t r a n s to each o t h e r has been r e p o r t e d . The  peaks 5 and  the s t a r t i n g  6  siloxy-complex  11 have the same c h e m i c a l siloxy  show the same f r e q u e n c y as the d o u b l e t  P ^ R h ^ C J l and  9 i s due  the c h e m i c a l  two  s m a l l m u l t i p l e t s 10 of t r i p l e t s of  s h i f t s of 7,3,8, and  t o the s i l o x y p h o s p h i n e  oxide.  The  and  the  4 a r e the same as  peaks of the same P Rhl^Cfc complex.  s m a l l m u l t i p l e t s e^ and d_ a t -16.1 doublet  The  s h i f t s as the d o u b l e t  those of the double d o u b l e t singlet,  P^RT^CJ^-  of  NMR  The  contains  small two  and -17.86 each of w h i c h forms a  p a t t e r n on p a r t i a l phosphorus d e c o u p l i n g .  The  one a t -17.86  i s i d e n t i f i e d as the l a r g e peak o f the t h r e e i n the P^Rhi^CJi spectrum. The  s m a l l m u l t i p l e t a t .-16.26 cannot be  assigned.  A l t h o u g h a p r e c i s e assignment of a l l the complexes formed cannot be u n e q u i v o c a b l y made, the s p e c t r a show t h a t complex 1_5 i s the main p r o d u c t of h y d r o g e n a t i o n of complex J .  The  h y d r o g e n a t i o n of J i s  -125-  r e v e r s i b l e , s i m i l a r to H.  4-2.  Reactions with  CO.  As shown by e q u a t i o n s  (18) and  (19) b o t h P,jRhCJt- and P^Rt^CJ^  (P=P(C,H )„, P(p-CH -C,H.) ) r e a c t w i t h CO g i v i n g t r a n s C  complexes o n l y . between  P Rh(C0)C£  0  o  The same p r o d u c t s a r e o b t a i n e d i n the r e a c t i o n  ( C O ^ R t ^ C J ^ .and t h e phosphines (eq.9).  F o r some c h e l a t i n g  . . . , • ^ • rt - u ,102,111 phosphxnes, complexes wxth a c i s c o n f i g u r a t i o n have been r e p o r t e d The v(C=0) of R h ( C 0 ) C A [ ( C H ) P - ( C H ) - P ( C H ) ] w i t h a 6  5  2  2  2  c i s c o n f i g u r a t i o n i s h i g h e r , a t 2010 cm  6  -1  5  2  _ -1 , than v(C=0), a t c a . 1960 cm ,  of the d i m e r i c complexes (Rh(CO)C£[(C,H )_P-(CH„) -P(C,H )„]}„ C  o 5 z  C  D  z n  j  z  (n=l,3,4)  z  i n which P atoms of the b r i d g i n g phosphines a r e t r a n s t o each e t h e r . When (CO) R h C £ r e a c t s w i t h e i t h e r s o l u b l e or p o l y m e r i c phosphines w i t h a 4 z z 31 112 113 P:Rh r a t i o of 1:1, c i s - d i c a r b o n y l complexes a r e formed ' ' , 0  0  t h e i r IR s p e c t r a show two v(C=0) bands i n the 2000 cm  1  region.  The IR s p e c t r a of the s o l u t i o n s of both the s o l u b l e  siloxyphosphine  complexes H and J exposed to, CO c o n t a i n a s t r o n g band a t 1965 cm  1  which  i s i d e n t i c a l w i t h the v(C=0) of complex G, t r a n s - { [ ( C H ^ S i - O - J ^ C l L j ) S i (CH ) -P(C H ) } Rh(CO)C£, 2  2  6  5  2  2  s y n t h e s i z e d a c c o r d i n g to e q . ( 9 ) .  The  3 1  P  NMR  spectrum of the product o b t a i n e d from J i s i d e n t i c a l w i t h t h a t of G, e x h i b i t i n g a d o u b l e t a t -29.81 ppm w i t h J(Rh-P)=124.7 at -30.00 ppm  Hz.  A small  i s due t o a s m a l l amount of the phosphine o x i d e .  singlet  However,  the o x i d e i s not a product of the r e a c t i o n w i t h CO s i n c e i t i s a l s o present i n the s t a r t i n g complex J . 31 The  P NMR  spectrum of the s o l u t i o n c o n t a i n i n g complex H w i t h  shows a v e r y broad i n t e n s e m u l t i p l e t from -30 to -3 ppm  CO  (plus the s i l o x y -  -126-  phosphine o x i d e s i n g l e t expected  at -29.94 ppm) i n s t e a d of t h e d o u b l e t a t -29.81  f o r t h e t r a n s -P2Rh(C0)C£ complex and the s i n g l e t a t +9.14 due  to t h e d i s p l a c e d phosphine.  The spectrum  r e c o r d e d i n deuteroacetone a t  -60°C has a s i m i l a r m u l t i p l e t but s h i f t e d d o w n f i e l d .  The p r o t o n NMR  s i g n a l s a t 35°C a r e a l s o broad w i t h no s e p a r a t e s e t of peaks f o r t h e complex and t h e f r e e phosphine.  The broadening  of the s i g n a l s i s most  l i k e l y due to l i g a n d exchange between t h e new c a r b o n y l complex formed and  the r e l e a s e d f r e e  phosphine.  When c a r b o n y l complex G and f r e e phosphine B a r e mixed i n a 1:1 molar 31 r a t i o the  P NMR spectrum  of the s o l u t i o n shows a broad m u l t i p l e t  to -3 ppm) and t h e s i l o x y p h o s p h i n e o x i d e s i n g l e t a t -29.41 ppm. result  (-20  This  thus c o n f i r m s the p o s t u l a t e d l i g a n d exchange between t h e c a r b o n y l  complex and t h e f r e e d i s p l a c e d phosphine i n the r e a c t i o n d i s c u s s e d above. In t h e case of t h e p o l y m e r i c complexes t h e IR s p e c t r a of a l l these a f t e r t h e r e a c t i o n w i t h CO c o n t a i n a s t r o n g peak around 1965-1970 cm The  Q and t h e copolymer R^ y^ a l s o show  c h l o r i n e - b r i d g e d homopolymer  a medium to weak peak a t 2080 cm \ s t r o n g peak a t 1995 cm  1  and R^ y^ e x h i b i t s a d d i t i o n a l l y a  (Tables V and V I ) .  When the r e a c t i o n w i t h CO  i s c a r r i e d out i n the absence o f any s o l v e n t the product o b t a i n e d R  \  from  Q a l s o e x h i b i t s a medium i n t e n s i t y peak a t 2080 cm . 1  2  The a b s o r p t i o n a t 1965 cm  1  i s a t the same frequency  as found  f o r t h e p o l y m e r i c c a r b o n y l complex P s y n t h e s i z e d from t r a n s - [ C ^ ^ S i - ( C ^ ) ^ ~ P ( C , H ) „ ] R h ( C 0 ) C £ . Hence i t i s assumed t h a t a l l the polymers R„ R ,  o  C  D  ZZ o  z - U  0  n  o-U  R"2 yi-, and T2 Q form a t r a n s c a r b o n y l complex w i t h s t r u c t u r e 16_ (same as 8 ) . As mentioned b e f o r e , the C=0 s t r e t c h i n g frequency  f o r the carbonyl  complex w i t h c i s c o n f i g u r a t i o n i s h i g h e r than t h a t f o r t h e t r a n s compounds.  -127-  The  f r e q u e n c i e s of both the bands a t 2080 and  v(C=0) f o r the trans-(CO)P RhC£ products  (1965  2  of the two  c o u l d be a t t r i b u t e d  1995  cm  cm" )  are higher  than  and hence e i t h e r  1  to the more unusual  1  c i s configuration,  the p o s s i b i l i t y b e i n g t h a t the p o l y m e r i c l i g a n d s a c t as c h e l a t e s . The p r o b a b i l i t y of the 2080 cm"  1  band b e i n g due  to  g r e a t e r because, as d i s c u s s e d below, the 1995 due  cm  band i s more l i k e l y  1  2  1995  cm  1  band appears  of the r e a c t i o n of R^_j^ 2  2  t o the cis-(CO) PRhC£ s p e c i e s . The  R _^^  cis-(C0)P RhC£ i s  w i t h CO.  absorbs more CO than any  o n l y i n the spectrum  of the  product  At the same time, as seen i n T a b l e  other polymer t e s t e d .  Formation  of some  c i s - b i s c a r b o n y l c h l o r o ( p h o s p h i n e ) r h o d i u m p r o b a b l y takes p l a c e and  thus  ;  the apparent  100%  a b s o r p t i o n , c o u n t i n g one molecule  atom, i s i n f a c t probably lower when c o u n t i n g 2:1 centres.  v(C=0)  2  cm  of CO per rhodium  f o r some rhodium  The cis-(CO) PRhC£ complexes e x h i b i t two  t h e r e f o r e another band a p a r t from t h a t a t 1995  the 1965  I t i s p o s s i b l e t h a t i t has a frequency cm  1  or 2080 c m  -1  bands and  i s expected.  1  However, no f o u r t h v(C=0) band i s p r e s e n t i n the spectrum product.  V,  of  this  coincident with  peaks, a l r e a d y a s s i g n e d to the  either  (C0)P RhC£ 2  species. The CO uptake d a t a i n T a b l e s V and VI show a wide v a r i a t i o n which probably r e f l e c t s the a c c e s s i b i l i t y of Rh(I) The degree of a c c e s s i b i l i t y ,  c e n t r e s i n the polymers t e s t e d .  as mentioned b e f o r e  l i k e l y a r e s u l t of the degree of c r o s s - l i n k i n g . a r e p r o b a b l y due blocked.  ( s e c t i o n 4-1-1), i s most The  low v a l u e s  observed  to the f a c t t h a t some metal c e n t r e s a r e p h y s i c a l l y  The h i g h CO uptake i n case of R  2  ^  may  a l s o be the r e s u l t  i n c r e a s e d a c c e s s i b i l i t y of rhodium c e n t r e s by " d i l u t i o n " w i t h  of  O^^Si-CH^  -128-  moieties.  Some p r i o r o x i d a t i o n t o R h ( I I I ) would a l s o r e s u l t  uptake v a l u e s but t h i s seems l e s s l i k e l y  4-3.  i n low  3-2-3).  (Section  Reactions with HC£(g). As d i s c u s s e d e a r l i e r  (Section 3 - 1 - 3 )  HC£ adds o x i d a t i v e l y t o  both c h l o r o t r i s p h o s p h i n e r h o d i u m and d i - u - c h l o r o t e t r a k i s p h o s p h i n e d i r h o d i u m complexes. P RhH C&. 3  2  2200 cm" region.  1  There a r e two p o s s i b l e s t r u c t u r e s 1_2 and J-3_ f o r t h e product Isomer jL2 e x h i b i t s an IR v(Rh-H) b a n d and two v(Rh-Cfc) b a n d s  '  9 5  '  1 0 0  '  '  9 7  around 2 1 0 0 -  i n t h e 2 2 5 - 2 9 0 cm"  1 0 1  1  The Rh-H s t r e t c h e s i n t h e isomer 13_ g i v e r i s e t o peaks a t  lower f r e q u e n c i e s 95  —1 1 9 6 0 - 1 9 9 0 cm .  95 97  '  o n l y one band '"'" cm \  9 4  9 6  00  The v(Rh-C£) r e g i o n shows  a t a frequency h i g h e r than t h a t f o r 1_2, 3 2 0 - 3 3 0  c h a r a c t e r i s t i c o f CI t r a n s t o CI. Upon r e a c t i o n w i t h HC£(g) both s o l u b l e s i l o x y p h o s p h i n e complexes  H and J g i v e s o l i d p r o d u c t s i n s o l u b l e i n common s o l v e n t s hence t h e a n a l y s e s were r e s t r i c t e d  t o IR and m i c r o a n a l y s e s .  The p r e s e n c e o f two v(Rh-C£) bands  ( 2 7 3 and 253 cm ) and t h e  p o s i t i o n of t h e v(Rh-H) band w e l l above 2000 cm  1  1  ( 2 1 1 0 cm ) suggest 1  f o r m a t i o n o f an adduct of s t r u c t u r e 1_2 i n t h e r e a c t i o n o f t r i s p h o s p h i n e complex H w i t h HC£.  The product of the r e a c t i o n w i t h t h e t e t r a p h o s p h i n e  complex a l s o shows two IR v(Rh-C£) bands a t 2 5 5 and 2 7 5 cm v(Rh-H) a t 2 1 0 0 cm  1  1  and one  but i t s s t r u c t u r e cannot be determined on the  b a s i s of these d a t a . The a d d i t i o n o f HC£ i s p a r t l y r e v e r s i b l e f o r both t h e adducts and upon pumping  the HG£(g) o f f , the peaks due t o t h e Rh-H and Rh-C£  s t r e t c h i n g f r e q u e n c i e s d i m i n i s h and the y e l l o w c o l o u r o f t h e adducts  -129-  ( c h a r a c t e r i s t i c of Rh(III)) The  formation  changes to orange ( c h a r a c t e r i s t i c o f Rh(I)) .  of an i n s o l u b l e s o l i d  i n the r e a c t i o n between  the s o l u b l e complexes H and J and HC£(g) was r a t h e r unexpected.  The  mechanism of the a c i d - c a t a l y z e d r e d i s t r i b u t i o n of s i l o x a n e l i n k a g e s i s not w e l l understood,but anhydrous or c o n c e n t r a t e d j ^„ , , _,47,48,114,115 and HC£ have been r e p o r t e d TT  The  r e v e r s a l of t h i s p r o c e s s ,  , , , to break s i l o x a n e bonds.  i n v o l v i n g new p a r t n e r s , l e a d s t o t h e  r e d i s t r i b u t i o n of the siloxane l i n k a g e s . takes  a c i d s such as H^SO^  A s i m i l a r process most  p l a c e i n t h e r e a c t i o n o f the s i l o x y p h o s p h i n e  The h i g h H and CZ m i c r o a n a l y t i c a l v a l u e s explained The  i n terms of HC£ c h e m i s o r p t i o n explanation of formation  likely  complexes w i t h  found f o r t h e products  HC£(g)  may be  t o the s u r f a c e o f the s o l i d .  o f an i n s o l u b l e s o l i d  from H and J  upon exposure t o HC£(g) i n terms o f s i l o x a n e l i n k a g e rearrangement and polymerization  i s supported  v i n y l s i l o x a n e forms an  by the f a c t t h a t  i n s o l u b l e g e l when t r e a t e d w i t h  Exposure of the p o l y m e r i c at 25°C g i v e s products  l,l,l,3,5,5,5-heptamethyl-3-  complexes R^-O  a n c  * 2-75 R  HC£(g). t  o  ^^^s)  w i t h no v(Rh-H) o r v(Rh-C£) peaks c h a r a c t e r i s t i c  of an HC£ adduct, although  a c o n s i d e r a b l e i n c r e a s e i n the weight of t h e  samples i s observed, up t o a 2:1 r a t i o o f HC£ per rhodium atom.  Such IR  r e s u l t s i n d i c a t e t h a t l i t t l e o r no HC£ r e a c t s w i t h  the Rh(I)  However, t h e p o s s i b i l i t y e x i s t s t h a t , as e x p l a i n e d  f o r the r e a c t i o n w i t h  hydrogen, a b s o r p t i o n s  due to an adduct a r e too weak i n i n t e n s i t y  ( a c c e s s i b i l i t y of rhodium c e n t r e s a n d " d i l u t i o n " b y observed.  centres.  The s t r o n g c h e m i s o r p t i o n  by the h i g h m i c r o a n a l y t i c a l v a l u e s  Q^/2 ^i-CH^)  of HC& t o the m a t r i x f o r H and CI.  s t r o n g and n o t e a s i l y r e v e r s e d by pumping a t 25°C.  t  o  ^  e  i s indicated  The c h e m i s o r p t i o n When s o l i d  seems  polymer  -130w h i c h has been exposed t o HC£(g) i s added t o t o l u e n e a t 60°C gas evolution occurs.  T h i s i s p r o b a b l y due t o r e v e r s i b l e c h e m i s o r p t i o n  perhaps a i d e d by s w e l l i n g of t h e polymer network.  -131-  CHAPTER 5 C a t a l y t i c Hydrogenation of O l e f i n s  The mechanism of o l e f i n hydrogenation catalyzed by Wilkinson complex [(C,H ) P]„RhC£ has been postulated C  0  O J J  81  to be as o u t l i n e d i n the  J  r e a c t i o n scheme (20) and (21)  RhC£(PPh„)„  > RhC£(PPh )„ + PPh.  g  RhC£(PPh ) + H 3  2  ^  2  H RhC£(PPh ) 2  3  K olefin H  RhC£(PPh ) (olefin)  2  More recent studies i n d i c a t e  (21)  RhC£(PPh ) + p a r a f f i n  2  v i a the "hydride" path.  2  *1 olefin  2  3  (20)  Q  3  lift  2  that the r e a c t i o n more l i k e l y proceeds  The high c a t a l y t i c a c t i v i t y of (Ph P) RhC£ i s 3  due to the extreme r e a c t i v i t y of complex 1_8_.  3  The a v a i l a b i l i t y of which 105  i s affected by the e q u i l i b r i u m (22) which l i e s f a r 2RhC£(PPh ) — ^ — > 3  2  Rh C£ (PPh ) 2  2  3  to the r i g h t  In the presence of hydrogen the i n t e r c e p t i o n of 18^ by H of the tetraphosphine  complex.  (22)  4  2  precludes  formation  The dimer i t s e l f i s described as a good  on hydrogenation c a t a l y s t  but with l i t t l e s u b s t a n t i a t i o n .  A wide range  of studies have been done on the Wilkinson complex whose very high c a t a l y t i c e f f i c i e n c y i s comparable with that of Raney n i c k e l . Quantitative studies of the hydrogenation of some o l e f i n s with [(C,H )„P] RhC£ have shown the dependence of the r e a c t i o n rate on substrate C  0  -132-  and  c a t a l y s t concentrations^temperature,  r a t e law  can be  expressed as  where [S] and  2  c a t a l y s t concentrations,  i n s o l u t i o n and  r a t e constants  r e a c t i o n rates increase with and  K [S]  [C] a r e the o l e f i n and  e q u i l i b r i u m and  The  0  [P][S][C]  1+K^P] +  the hydrogen c o n c e n t r a t i o n  pressure "'"'^"'"'.  follows:  ..kU Rate  and  K^,  K^,  f o r the r e a c t i o n s  increased  and  -are  (20)-(21).  concentration  [P] i s  The  of both  olefin  c a t a l y s t as w e l l as w i t h an i n c r e a s e of hydrogen p r e s s u r e  r e a c t i o n temperature. s o l u t i o n s and  i t was  These r e a c t i o n s were c a r r i e d out  the  and  the  i n benzene  found that the a d d i t i o n of p o l a r c o s o l v e n t s  as a l c o h o l s speeds up  the r e a c t i o n r a t e s u b s t a n t i a l l y .  are hydrogenated more r a p i d l y than i n t e r n a l and  such  Terminal  cyclic olefins;  olefins the  rate  118 decreases f o r the c y c l i c ones w i t h  increasing ring  size  S i m i l a r dependence o f the r e a c t i o n r a t e s on the above mentioned f a c t o r s has  been found f o r analogues of the W i l k i n s o n  on p o l y s t y r e n e  and  on s i l i c a ^ > 1 1 9 , 1 2 0 ^ 2  ^  n  are hydrogenated more r a p i d l y than i n t e r n a l and  g  e  n  e  r  a  complex supported i  terminal  cyclic olefins,  here the s i z e of the o l e f i n v s the pore s i z e of the support important r o l e a l s o . access  Larger  olefins although  plays  an  o l e f i n s , are l e s s r e a c t i v e because t h e i r  to the a c t i v e c a t a l y t i c s i t e s i s r e s t r i c t e d by  the pore  size.  As found f o r [ (C^B.^)^P] ^RhCA h y d r o g e n a t i o n of t e r m i n a l o l e f i n s by 120 121 supported c a t a l y s t s i s accompanied by  isomerization  '  .  the  Polymer-  s w e l l i n g p r o p e r t i e s of p o l a r s o l v e n t s have an a d d i t i o n a l p o s i t i v e i n f l u e n c e on the r e a c t i o n r a t e s .  Reaction  rates also increase with  increased  -133-  temperatures the s i l i c a U  A-  2  but h i g h e r temperatures  supported  (100°C) have been found  to decompose  [ ! ^ - 0 - S i - ( C H ) - P ( C H ) ] R h C £ complex to m e t a l l i c 2  2  6  5  2  3  6  rhodxum  9 It  i s claimed  '•  t h a t the a c t i v i t y of a supported  Wilkinson  complex should be h i g h e r than t h a t of the c o r r e s p o n d i n g s o l u b l e [ ( C g H ^ ) P ] R h C £ complex. 3  3  The a c t i v i t y of the c a t a l y s t i s dependent  the phosphine d i s s o c i a t i o n e q u i l i b r i u m  (eq 20) and  i n a polymeric  system  the r e a s s o c i a t i o n of the phosphine w i t h the rhodium c e n t r e i s l e s s than i n the s o l u b l e s p e c i e s where an o l e f i n has to compete 122 mobile phosphine f o r the f r e e c o o r d i n a t i o n s i t e supported of  .  on  likely  w i t h the  free  However, i n the  c a t a l y s t s some of the m e t a l c e n t r e s are i n s i d e the s m a l l pores  the polymer which makes them e i t h e r c o m p l e t e l y s u b s t r a t e - i n a c c e s s i b l e  or  e l s e the d i f f u s i o n of the s u b s t r a t e s to the a c t i v e s i t e s becomes a r a t e 3 119 determining f a c t o r ' . The comparison of r e a c t i o n r a t e s and t u r n o v e r 123 124 37 numbers ' shows, w i t h one e x c e p t i o n , t h a t the a c t i v i t y of the W i l k i n s o n type complexes supported  on v a r i o u s polymers i s f a r i n f e r i o r  t h a t of the s o l u b l e [ ( C g H ^ P ] R h C £ 3  3  V a r i o u s polymer supported  to  complex.  Rh(I)  systems can be r e c y c l e d but  no  p a t t e r n of the m a i n t a i n e d l e v e l of a c t i v i t y has been noted. Some c a t a l y s t s . . . . . 37,125,1-2-6decrease i n t h e i r a c t i v i t y to v a r i o u s degrees on r e c y c l i n g J  . • , -, , o t h e r s r e t a i n i t at the same l e v e l in  some cases the a c t i v i t y of the c a t a l y s t  first to  • i_ r i n the f i r s t  cycle  3 6 12 ' ' .  Silica  supported  r i 12,37,126 few c y c l e s  increases s l i g h t l y after  systems have been r e p o r t e d  m a i n t a i n t h e i r a c t i v i t y over c_a. 70h p e r i o d under continuous  32  and the '  127  flow  conditions. The  e f f e c t of the l e n g t h of the a n c h o r i n g "arms" of phosphines  has  -134-  28 77 been s t u d i e d and i t has been shown  '  that i n general,,complexes  with  longer "arms" a r e c a t a l y t i c a l l y more a c t i v e than those w i t h s h o r t ones, and can be r e c y c l e d more times.  One i r r e g u l a r i t y  i n t h i s p a t t e r n has  been found f o r the h y d r o f o r m y l a t i o n r e a c t i o n by s i l i c a  supported Rh(I)  28 complex  .  A f t e r attachment  of [(C_H 0)„Si-(CH„) -P(C,H )„]Rh(C0D)C£ z D 3 z n fa _> z (n=2,8) to s i l i c a the complex w i t h the c h a i n i s more a c t i v e than t h e one w i t h the C c h a i n . The EPR s t u d i e s of p o l y s a c c h a r i d e supported o 128 129 c  c  0  n i t r o x i d e s have shown freedom  '  t h a t l o n g e r spacer "arms" g i v e more  o f m o b i l i t y to the anchored  s i t e s and the s p e c t r a become s i m i l a r to  t h a t of the s p e c i e s i n a s o l u t i o n ; t h e extended makes t h e anchored  d i s t a n c e from the support  s i t e s l e s s s e n s i t i v e to the geometry of the s u p p o r t .  The i n c r e a s e o f the spacer "arms" beyond a c e r t a i n l e n g t h ( e q u i v a l e n t t o a C chain) causes no f u r t h e r change, o D  Homogeneous c a t a l y s t s prepared v a r i o u s phosphines,  the l e f t .  [(olefin) RhC£] 2  a  n  2  d  0  J  P/Rh r a t i o i s 2; w i t h added phosphine, 5 118 '  from  i n c l u d i n g P(C,H,.) , e x h i b i t h i g h e s t a c t i v i t y when  fa  decreases  in situ  J  the a c t i v i t y of t h e c a t a l y s t  p r o b a b l y because of t h e s h i f t  A s i m i l a r t r e n d i s observed  of e q u i l i b r i u m  f o r the supported  On a d d i t i o n of e i t h e r s o l u b l e o r p o l y m e r i c phosphine  (20) t o 130  complexes  to the supported  complexes of t h e P^RhCA type the c a t a l y s t ' s a c t i v i t y decreases c o n s i d e r i-i 12,37 ably I t has been shown t h a t h i g h e r P/Rh r a t i o s , on t h e o t h e r hand, have a s t a b i l i z i n g around  the metal  e f f e c t on the supported c a t a l y s t s .  c e n t r e caused by the r i g i d i t y  Steric  strain  of the p o l y m e r i c l i g a n d s  6 '131 133 —  is believed rhodium.  '  _  t o be r e s p o n s i b l e f o r decomposition  Complexes of the type { [ R h ( N B D ) p o l y P ( C H ) ] > &  5  2  2  +  to m e t a l l i c  i n which rhodium-  -135-  content higher  i s v a r i e d do n o t decompose t o the metal (7.8-31 v s . 2.7-4.4).  of complexes w i t h t h e l e a s t  when the P/R.h r a t i o i s  T h i s i s e x p l a i n e d i n terms o f f o r m a t i o n s t r a i n e d c o n f i g u r a t i o n when a g r e a t e r c h o i c e  of l i g a n d s i s p o s s i b l e (higher P c o n t e n t ) .  I t i s p o s s i b l e that  polymer-imposed s t r a i n causes c l e a v a g e of Rh-P bonds. i s thought  3?  such  The l a t t e r  effect  to be r e s p o n s i b l e f o r rhodium e l u t i o n from a m a t r i x  The r e s u l t s o f r e c e n t s t u d i e s of h y d r o f o r m y l a t i o n w i t h (poly-P)C£ suggest  32  cis-RMCO^  -  t h a t the s h i f t s i n e q u i l i b r i u m between phosphine,  carbonyl,hydrido phosphine, and h y d r i d o c a r b o n y l complexes ( s o l u b l e and anchored) o f d i f f e r e n t  s t a b i l i t i e s a r e r e s p o n s i b l e f o r rhodium  elution  from the r e s i n A h i g h metal P^RhBr  1 3 5  l o a d i n g of the supported  systems P^RhC^ ' 5  and' Cp T i C i ! ^ " ^ l e a d s t o f o r m a t i o n of d i m e r i c s p e c i e s .  r e s u l t of i t , a c t i v i t y o f the c a t a l y t i c s p e c i e s d e c r e a s e s .  As a  F o r example  s p e c i f i c a c t i v i t y o f the c a t a l y s t s s y n t h e s i z e d from R l ^ C ^ ( C ^ H ^ ) ^ phosphinated  and  p o l y s t y r e n e polymers decreases w i t h i n c r e a s i n g rhodium 9  content  i n t h e polymer  .  X-ray a b s o r p t i o n s t u d i e s show t h a t  i s o l a t i o n i n P^RhBr supported contents  site  on a styrene-DVB copolymer w i t h h i g h e r DVB  (20%) r e s u l t s i n g r e a t l y reduced  i s o l a t i o n i n CP2T1C&2 supported  P^Rl^Br dimer f o r m a t i o n .  Site  on h i g h l y - c r o s s l i n k e d polymers a l s o  formation of dimeric species r e s u l t i n g  prevents  i n a s u b s t a n t i a l i n c r e a s e of i t s  c a t a l y t i c a c t i v i t y as compared w i t h the s o l u b l e complex. A l l o f these r e s u l t s a l l o w some p r e d i c t i o n s to be made w i t h to the c a t a l y t i c behaviour  o f the p o l y m e r i c  siloxyphosphine  s y n t h e s i z e d i n t h i s work.  T h e i r a c t i v i t y i s expected  regard  complexes  t o be lower  than  t h a t o f t h e s o l u b l e s i l o x y p h o s p h i n e model analogues w i t h the copolymers  -136-  showing h i g h e r o v e r a l l a c t i v i t y than the homopolymers. with C  The  complexes  spacer "arms" should be more a c t i v e than those w i t h C  D  o  "arms".  0  Z  The macrocomplex S, w i t h an excess of the phosphine,  ^RhC£ should  be  l e s s a c t i v e but more s t a b l e than P^RhCA. As mentioned b e f o r e no a c t u a l study has been r e p o r t e d on c a t a l y t i c a c t i v i t y of P^Rt^CA,,  D  u  the  i t s f o r m a t i o n on supports i n the  t  p r e p a r a t i o n of the W i l k i n s o n c a t a l y s t bound to phosphine polymer  has  136 been documented is  .  I t has been i m p l i e d t h a t the a c t i v i t y of P ^ R t ^ C ^  lower than t h a t of P^RhC^  be expected 5-1.  solution  i n  1 1  ^  and  f o r the p o l y m e r i c s i l o x y p h o s p h i n e  Hydrogenation The two  analogues.  of Styrene w i t h the S o l u b l e S i l o x y p h o s p h i n e  new  3  2  3  2  2  6  5  2  and  3  { [ (CH ) Si-0-] ( C H ) S i - ( C H ) ~ P ( C ^ ) > R h C £ 3  3  2  3  2  2  2  4  H and J , were t e s t e d as to t h e i r a b i l i t y styrene.  The  Complexes.  s o l u b l e s i l o x y p h o s p h i n e complexes  {[(CH ) Si-0-] (CH )Si-(CH ) -P(C H ) } RhC£ 3  the same p a t t e r n can  results plotted  2  2  to c a t a l y z e h y d r o g e n a t i o n  of  i n F i g . 6 show t h a t both the complexes  a r e e f f e c t i v e c a t a l y s t s , the r e a c t i o n r a t e b e i n g h i g h e r f o r the t r i s p h o s p h i n e complex H than f o r the t e t r a p h o s p h i n e one J .  As w i l l be seen l a t e r , com-  p a r a b l e r a t e s are o b t a i n e d when u s i n g the p o l y m e r i c analogues c o n c e n t r a t i o n s of both o l e f i n and creased by a f a c t o r of  5-2. { [0  Hydrogenation 3 / 2  2  (per rhodium c e n t e r s ) a r e i n -  10.  of O l e f i n s w i t h P o l y m e r i c Complex  Si-(CH ) -P(C H ) ] RhC£. 2  catalyst  6  5  o n l y i f the  2  3  A s e r i e s of experiments  ( 3/2 0  was  S 1 C  R  2  V75 }  x  c a r r i e d out w i t h the p o l y m e r i c  catalyst  -137-  "*"  no  r  d  e  r  t o  determine t h e i n f l u e n c e o f f a c t o r s such as s u b s t r a t e  and c a t a l y s t c o n c e n t r a t i o n s , t e m p e r a t u r e , s o l v e n t , and n a t u r e o f t h e o l e f i n on t h e r e a c t i o n r a t e s .  T h i s s e r i e s o f experiments was a l s o done  i n t h e b e l i e f t h a t t h e r e s u l t s would be o f v a l u e i n c h o o s i n g t h e most c o n v e n i e n t e x p e r i m e n t a l c o n d i t i o n s f o r f u r t h e r work w i t h t h i s and o t h e r polymers.  5-2-1.  V a r i a t i o n of O l e f i n s . A range o f o l e f i n s was hydrogenated  a t atmospheric pressure u s i n g  a c o n s t a n t amount o f t h e c a t a l y s t and benzene as a s o l v e n t ( T a b l e V I I ) . The r e a c t i o n was stopped a f t e r 23h and y i e l d s o f p r o d u c t s determined w i t h GLC.  Cyclohexene, s t y r e n e , 1-heptene, and 1-octene were chosen as r e -  p r e s e n t a t i v e s o f i n t e r n a l and p r i m a r y o l e f i n s .  The f i r s t  two do n o t  a l l o w i s o m e r i z a t i o n whereas t h e l a t t e r two do. The r e s u l t s o b t a i n e d f o r t h e s e o l e f i n s were expected t o p a r a l l e l those w h i c h have been r e p o r t e d f o r s i m i l a r supported c a t a l y s t s .  For 120  example 1-pentene y i e l d s n-pentane and c i s - and t r a n s - 2 - p e n t e n e 120 1-heptene y i e l d s n-heptane and 2- and 3-heptenes  and  i n various pro-  p o r t i o n s when hydrogenated w i t h p o l y s t y r e n e and s i l i c a s u p p o r t e d W i l k i n s o n type c a t a l y s t s .  H y d r o g e n a t i o n r a t e s f o r s t y r e n e a r e n o t much l o w e r t h a n T-20 t h o s e o f 1-pentene . Although i n general i n t e r n a l o l e f i n s a r e _ . - _ , . , 26,81,120 , . , hydrogenated s l o w e r than t h e t e r m i n a l ones j i t has been r e p o r t e d t h a t when e t h a n o l i s used as a s o l v e n t h y d r o g e n a t i o n o f c y c l o h e x e n e proceeds f a s t e r than t h a t f o r s t y r e n e . In  t h i s work r e d u c t i o n o f c y c l o h e x e n e , f o l l o w i n g t h e g e n e r a l t r e n d  expected o f i n t e r n a l o l e f i n s , proceeds a t a r a t e s l o w e r than f o r any o f t h e p r i m a r y o l e f i n s , t h e c o n v e r s i o n a f t e r 23h b e i n g about t e n t i m e s lower than  -138-  t h a t of t h e other  substrates.  to the same e x t e n t .  A l l t h r e e primary o l e f i n s a r e hydrogenated  However, both 1-heptene and 1-octene g i v e  products  composed of a ^ a . 1:1 m i x t u r e o f the p a r a f f i n and the u n s a t u r a t e d Styrene,  although  more b u l k y ,  isomers.  r e a c t s t o the same extent g i v i n g : s o l e l y  ethylbenzene.  5-2-2.  V a r i a t i o n of Solvent. Suspensions o f R^  exposed to hydrogen.  i n v a r i o u s s o l v e n t s c o n t a i n i n g s t y r e n e were  The hydrogen uptake was not monitored and o n l y  c o l o u r changes of the c a t a l y s t were noted  (Table V I I I ) . Only when benzene  or t o l u e n e a r e used as s o l v e n t s does the c o l o u r o f the polymer remain orange.  A d d i t i o n o f p o l a r c o s o l v e n t s , t r i e t h y l a m i n e and e t h a n o l ,  the polymer t o change i t s c o l o u r from orange t o grey; polymer t u r n s b l a c k immediately upon a d d i t i o n . or t r i e t h y l a m i n e has not been r e p o r t e d The  darkening  causes  i n pure e t h a n o l the  T h i s e f f e c t of e t h a n o l  previously.  o f the polymer i s assumed t o be due t o the r e d u c t i o n  of Rh(I) t o m e t a l l i c Rh(0).Thus t r i e t h y l a m i n e and e t h a n o l were not used as s o l v e n t s i n f u r t h e r s t u d i e s o f o l e f i n hydrogenation siloxyphosphine  Rh(I)  w i t h the p o l y m e r i c  complexes.  5-2-3. V a r i a t i o n of Temperature. As mentioned b e f o r e , temperature.  hydrogenation  rates increase with  increased  F o r example w h i l e o n l y t r a c e s of i s o p r e n e a r e hydrogenated 26  at 50° w i t h a s i l i c a  supported  P^RhCA c a t a l y s t  the y i e l d s  increase  to 11% when t h e temperature i s r a i s e d t o 80°C. The  r a t e of styrene hydrogenation  i n t o l u e n e as a s o l v e n t e x h i b i t s  s i m i l a r tendency as seen i n F i g . 7 where an i n c r e a s e from 35° t o 60°C causes the r e a c t i o n r a t e to i n c r e a s e by about a f a c t o r o f two.  -139-  5-2-4. V a r i a t i o n of C o n c e n t r a t i o n s  of O l e f i n and C a t a l y s t .  As was d e s c r i b e d f o r the s o l u b l e and p o l y m e r i c mentioned e a r l i e r ,  the h y d r o g e n a t i o n  amount  8 1  1  -j^ i n c r e a s e s w i t h  rate using  increased concentration of o l e f i n .  systems ' "^  The r a t e of h y d r o g e n a t i o n  of a g i v e n  of s t y r e n e a l s o i n c r e a s e s as the amount of the p o l y m e r i c  c a t a l y s t i n a constant The  s o l u t i o n volume i s i n c r e a s e d  ( F i g , . 8 and 9 ) .  r e s u l t s shown i n F i g . 8 show t h a t the degree o f c o n v e r s i o n i n  a g i v e n time i n c r e a s e s w i t h an i n c r e a s e o f s t y r e n e c o n c e n t r a t i o n but the dependence i s not l i n e a r . lower styrene/Rh  ratios  This effect  i s much more pronounced f o r the  (7.5 v s . 75) than f o r h i g h e r  (75 v s . 250).  When d e a l i n g w i t h heterogeneous c a t a l y s t s the term " c o n c e n t r a t i o n " i s not s t r i c t l y  a p p r o p r i a t e but i n s t e a d the amounts o f the c a t a l y s t i n  g i v e n s o l u t i o n volumes should be s p e c i f i e d . The r e s u l t s p l o t t e d i n F i g . 9 show t h a t the degree o f s t y r e n e r e d u c t i o n a f t e r a g i v e n time a l s o i n c r e a s e s w i t h t h e amount o f the c a t a l y s t i n t r o d u c e d . However, u n l i k e t h e r e s u l t s for  increasing o l e f i n concentrations  catalyst  ( F i g . 8 ) , as the amount o f t h e  i s i n c r e a s e d the degree o f c o n v e r s i o n i n a g i v e n time becomes  g r e a t e r than expected  for a linear  relationship.  S i n c e the degree o f c o n v e r s i o n r a t h e r than r e a c t i o n r a t e i s b e i n g measured the term "order o f r e a c t i o n " i s not s t r i c t l y for  l a c k of a b e t t e r t e r m i n o l o g y  c o n v e r s i o n i s lower than " f i r s t and  higher  than " f i r s t  a p p l i c a b l e . However,  i t can be s t a t e d t h a t t h e degree o f order" with regard to styrene  concentration  o r d e r " w i t h r e g a r d t o the amount o f t h e c a t a l y s t  introduced.  5-3.  Hydrogenation o f Styrene w i t h the Polymeric The  Complexes.  r e s u l t s of the experiments d i s c u s s e d i n the p r e v i o u s  sections  -140-  ( S e c t i o n s 5-2)  a l l o w the c h o i c e of the most convenient  c o n d i t i o n s f o r use i n f u r t h e r s t u d i e s .  Styrene was  experimental  chosen  as  the  r e f e r e n c e o l e f i n because of the convenient h y d r o g e n a t i o n r a t e  and  f o r m a t i o n of o n l y one p r o d u c t , ethylbenzene. Of the two benzene and  t o l u e n e , the former was  chosen  suitable solvents  f o r the reason t h a t i t s  v a l u e i n GLC does not c o i n c i d e w i t h e i t h e r t h a t of s t y r e n e or benzene. of  ethyl-  The r e a c t i o n c o n d i t i o n s were s t a n d a r d i z e d i n the whole s e r i e s  experiments;  the s o l u t i o n volume was  runs c o u l d be monitored the temperature  was  3 mL  and  i n order t h a t a  few  c o n c u r r e n t l y over a convenient p e r i o d of  maintained  at 35°.  time  The amount of s t y r e n e was  0.319g  -2 (3.0 mmol), and  the amount of each c a t a l y s t was  on the number of Rh atoms). n a t u r e of the c a t a l y s t  always 3.0x10  mmol  The o n l y d i f f e r e n c e between runs was  introduced.  In t h i s way  i t was  ensured  f a c t o r s o t h e r than the i n t r i n s i c p r o p e r t i e s of the p o l y m e r i c i t s e l f would i n f l u e n c e the course of each i n d i v i d u a l  g a r d l e s s of the f a c t t h a t they a r e homo- or copolymers  no  relative  cycle.  Re-  a l l the c h l o r o -  t r i s p h o s p h i n e r h o d i u m complexes are c o n s i d e r a b l y more a c t i v e  r a t e s do not d i f f e r v e r y much but a f t e r about  that  reaction.  a c t i v i t i e s of d i f f e r e n t p o l y m e r i c c a t a l y s t s i n t h e i r f i r s t  d i - y - c h l o r o t e t r a p h o s p h i n e d i r h o d i u m ones.  the  catalyst  The d a t a p r e s e n t e d i n F i g . 10 p r e s e n t a p i c t u r e of the  than the  (based  The  catalysts  initial  reaction  40% c o n v e r s i o n has been  a c h i e v e d the dimers' curves depart from those of the t r i s p h o s p h i n e complexes. With the e x c e p t i o n of R  0  which e x h i b i t s s l i g h t anomalous behaviour which  o—U w i l l be d i s c u s s e d l a t e r , t h e h y d r o g e n a t i o n w i t h the homo- and t r i s p h o s p h i n e compounds proceeds v e r y f a s t t o c o m p l e t i o n without r e a c h i n g a p l a t e a u .  The degrees  copolymeric  ( F i g . 10,  15-18)  of c o n v e r s i o n when the t e t r a p h o s p h i n e  -141-  complexes a r e employed in  the case of the  ( F i g . 10)  copolymer T2_2QQ-  of the s o l u b l e complexes trisphosphine  start declining particularly T h i s p a t t e r n of a c t i v i t y  t e t r a p h o s p h i n e complex J ,  r e l a t i v e a c t i v i t y of the s o l u b l e complexes b e i n g than the p o l y m e r i c ones.  The  On  trisphosphine  d a t a p l o t t e d i n F i g s . 11-14  complexes which were not ( i-8-  H)  F  as  ones, i n the  show the d e a c t i v a t i o n p a t t e r n of  one  but  i n the  i t gradually  i t reaches a n e g l i g i b l e l e v e l i n the  Judging by  of the  some e l u t i o n  none i n the initial  first  three.  Therefore  t h r e e runs i s not Homopolymer Rg_Q  ( F i g . 12)  in  the f i r s t  in  the second a n d ' t h i r d  low  the  fifth  (Table  run. IX)  i n the f o u r t h c y c l e  there  but the  loss.  shows s l i g h t l y anomalous b e h a v i o u r  trissiloxyphosphine catalysts.  is relatively  in  to  the d e a c t i v a t i o n i n at l e a s t  caused by m e t a l  compared w i t h a l l the o t h e r run  s o l u t i o n a f t e r the r e a c t i o n  of rhodium from the polymer  the  second c y c l e almost  loses  always  Macrocomplex  subsequent runs u n t i l  is  higher  corresponding c y c l e s .  c o p o l y m e r i z e d w i t h CJ^Si-CH^.  i n the f i r s t  the c o l o u r  Its  activity  but most i n t e r e s t i n g l y i t i n c r e a s e s  ones. I n i t i a l l y  i t was  thought t h a t  d i f f u s i o n b a r r i e r which causes such b e h a v i o u r but  i t is a  preconditioning  the  polymer i n benzene s u s p e n s i o n , under an atmosphere of hydrogen, and the absence of s t y r e n e makes o n l y a s l i g h t the in  first  cycle.  the f i r s t  for  the  t e t r a p h o s p h i n e compounds a r e  maintains i t s a c t i v i t y  the same extent  considerably  that  r e c y c l i n g a l l the c a t a l y s t s show d e c r e a s e  the a c t i v i t i e s of the  lower than those of the  follows  ( F i g . 6) where the r e a c t i o n r a t e s a r e h i g h e r  complex H than f o r the  i n a c t i v i t y but  quickly  d i f f e r e n c e to the r a t e i n  T h i s c a t a l y s t can be used s i x times; the l o s s of  f o u r c y c l e s i s not  in  activity  caused by rhodium l o s s s i n c e e l u t i o n i s  -142-  n o t i c e d o n l y a f t e r the l a s t  two  runs.  c a t a l y t i c a c t i v i t y a f t e r the f i r s t  S i m i l a r cases of an i n c r e a s e d  c y c l e f o r RhCA^ supported  12  +  hinated s i l i c a styrene^  on phosp-  and  (Rh(NBD)[poly-P(C^K^) ]}  supported  2  on p o l y -  have been r e p o r t e d . Tetraphosphine  only twice.  The  complex T _ Q 2  ( F i g . 13) can be used  effectively  c o n v e r s i o n which i s r e l a t i v e l y slow i n the f i r s t  d i m i n i s h e s i n the second, and  i n the t h i r d one  i s practically  Rhodium e l u t i o n i s n o t i c e d o n l y a f t e r the f i r s t complete d e a c t i v a t i o n a f t e r the second  run  zero.  run t h e r e f o r e the  one must be due  almost  to some o t h e r  factor(s). C o p o l y m e r i z a t i o n of the t r i s p h o s p h i n e complexes w i t h CA^Si-CH^ a l s o h e l p s m a i n t a i n the a c t i v i t y . the polymers were used in  For the  series  f i v e times, w i t h the copolymers b e i n g more a c t i v e  the l a s t run than the homopolymer.  The d e a c t i v a t i o n p a t t e r n changes  g r a d u a l l y w i t h the i n c r e a s i n g content of 0^/2 homopolymeric 2_o  ^i-CH^.  A c t i v i t y of the  decreases g r a d u a l l y i n every subsequent c y c l e whereas  R  the copolymers m a i n t a i n h i g h a c t i v i t y drop of a c t i v i t y  ( F i g s . 11, 15-17) a l l  i n more c y c l e s . T h i s i s then f o l l o w e d by a  i n subsequent c y c l e s .  The l a r g e r the 0^/2  the l o n g e r the c a t a l y s t r e t a i n s i t s h i g h a c t i v i t y .  ^i-CH^  content  There i s some rhodium  e l u t i o n n o t i c e d f o r a l l t h r e e copolymers i n the t h i r d c y c l e , none i n the f o u r t h , o n l y to become s t r o n g i n the f i f t h c o r r e l a t i o n between the d e a c t i v a t i o n and In  the rhodium  There i s no  distinct  elution.  c o n t r a s t , the d i f f e r e n c e i n the d e a c t i v a t i o n p a t t e r n of  homo- ( F i g . 13) and T^_Q  run.  and ^2-200  1 s  n  the copolymeric o  t  large.  ( F i g . 19) t e t r a p h o s p h i n e  T h e i r a c t i v i t y decreases  v e r y low l e v e l f o r the copolymer and almost  the  complexes,  g r a d u a l l y to a  zero f o r the homo i n t h r e e  -143-  F i g u r e 40.  Schematic r e p r e s e n t a t i o n of pores w i t h i n the p o l y m e r i c m a t r i x of t h e complexes (a) R2-0 8-0> 0>) 2-75,150,200 8-100-  R  a n d  R  a n d  R  a n d  -144-  consecutive  c y c l e s , always b e i n g  than the t r i s p h o s p h i n e  f o r the d e a c t i v a t i o n p a t t e r n o f the  t r i s p h o s p h i n e macrocomplexes and the f a c t  t h a t t h e a c t i v i t y o f the t e t r a p h o s p h i n e than t h a t o f the t r i s p h o s p h i n e The and  compounds i s always lower  i s schematically depicted  [?2RhC£]2 e x e m p l i f i e d  by eq (22) should  depend on the d i s t a n c e between the rhodium c e n t r e s . network appears t o be r i g i d .  complex metal c e n t r e s a r e probably ( F i g . 40a).  copolymeric  species.  c l o s e t o each other w i t h i n a pore  i n most cases a r e  from each other by 0^^S±-CR^ m o i e t i e s i s hindered.  s e p a r a t i o n o f rhodium c e n t r e s copolymerization  ( F i g . 40b) and thus  I t i s a l s o found t h a t t h e  i n the d i m e r i c  with Ci^Si-CH^  On the other  can prevent the d i m e r i z a t i o n o f the  Here t h e rhodium c e n t r e s  the d i m e r i z a t i o n process  The s i l o x a n e  I n the homopolymeric phosphine  Hence the d i m e r i z a t i o n can e a s i l y occur.  hand the r i g i d i t y of the m a t r i x  separated  i n F i g . 40.  e q u i l i b r i u m between the c a t a l y t i c a l l y a c t i v e s p e c i e s P2RhC£  the l e s s a c t i v e dimer  polymeric  runs  complexes.  A possible explanation homo- and copolymeric  lower i n the c o r r e s p o n d i n g  P^Rt^CJ^ complexes by  does n o t improve the a c t i v i t y and  r e c y c l a b i l i t y of the complex. The  above r e s u l t s seem t o i n d i c a t e t h a t the d i m e r i z a t i o n t o  P ^ R l ^ C ^ i s one o f the reasons f o r d e a c t i v a t i o n o f the t r i s p h o s p h i n e macrocomplexes P^RhCA, whose o v e r a l l a c t i v i t y depends on the s e r i e s of r e a c t i o n e q u i l i b r i a  (23), analogous t o (16),  (20) and ( 2 1 ) .  -145-  P — Rh CI  P\  P —RhCl  Rh  / Cl\ ci ^  x  p/  ^p-  Rh  \p-1  (23)  I  p  ^RhH CI 2  P  H  CI  :RK  2^P-  Rh  Cl  The s t a b i l i t y o f the c a t a l y s t S w i t h the f o r m u l a { [ O ^ ^ S i P(C,H,.) ], RhC£} i s g r e a t l y improved as compared w i t h R o .> 2 J • / x 0  7  mentioned e a r l i e r  t h e i n c r e a s e d P/Rh  ratio  and R  2—(J  w i t h S i s lower even i n the f i r s t r u n than t h a t of t h e 2  ( F i g . 14).  Due  . As o—0  hydrogenation  tetraphosphine  t o t h e r i g i d i t y of t h e p o l y m e r i c network  t h e e x t r a phosphines (over t h e s t o i c h i o m e t r i c 3:1 relatively  (CH^-  i n f l u e n c e s a d v e r s e l y the  a c t i v i t y of the c a t a l y s t and indeed the a c t i v i t y f o r s t y r e n e  complex T^ QQ  D  \P-  of P/Rh  r a t i o ) are  c l o s e t o the rhodium atoms as r o u g h l y shown i n F i g . 41.  -146-  F i g . 41.  Schematic r e p r e s e n t a t i o n  of a pore w i t h i n the p o l y m e r i c  m a t r i x of the complex S, { [ 0 y S i - ( C H ) - P ( C H ) ] 3  The p r o x i m i t y equilibrium  2  2  2  6  5  2  3  -?  R h c  ^ x  of t h e phosphines w i t h i n a pore s h i f t s the d i s s o c i a t i o n (20)  RhCAP, «c  ^  RhCJIP. + P  (20)  -147-  to the l e f t  thereby p r o h i b i t i n g the f o r m a t i o n of the a c t i v e  bisphosphine  s p e c i e s and d e c r e a s i n g the chances of the o l e f i n competing f o r the coordination s i t e .  On the other hand the presence  l i g a n d s has a p o s i t i v e e f f e c t . first  two  c y c l e s decreases  at l e a s t two more c y c l e s .  Although  and  s t a y s at t h i s l e v e l i n  the e x t r a phosphines  i n the f i r s t  a steady l e v e l i n the subsequent runs. phosphines  additional  The a c t i v i t y which i s the same i n the  i n the t h i r d one  lower the c a t a l y s t ' s a c t i v i t y  of the  c y c l e s they h e l p to m a i n t a i n i t  Due  the c o m p e t i t i o n of e q u i l i b r i u m  i n the polymer  to the p r o x i m i t y of  (20) w i t h  free  (22) somehow prevents  the f o r m a t i o n of l e s s a c t i v e d i m e r i c s p e c i e s P ^ R l ^ C ^ No rhodium e l u t i o n at any phosphines  time  (Table IX) suggests  w i t h i n the polymer have a s t a b i l i z i n g  e f f e c t on the complex.  This result  i s s i m i l a r to those o b t a i n e d f o r the p o l y m e r i c  7(.C^B.^)^]}  where h i g h e r P/Rh  metal  The r i g i d i t y  +  .-  complex by imposing result  t h a t the e x t r a  {Rh(NBD)[poly-  r a t i o s seem to prevent decomposition  to the  of the p o l y m e r i c backbone d e s t a b i l i z e s the macro-  s t e r i c s t r a i n on the m e t a l c e n t r e .  This i n turn  may  i n d i s s o c i a t i o n of the l i g a n d s f o l l o w e d e v e n t u a l l y by e l u t i o n of  the m e t a l , p r o b a b l y i n the form of some s o l v a t e d polymer's network.  The  s p e c i e s , from  c a t a l y s t w i t h the h i g h e r P/Rh  ratio,  the  S, i s  more s t a b l e ; here the d i s s o c i a t e d l i g a n d s can be r e p l a c e d by o t h e r s i n the v i c i n i t y of the m e t a l The  atom and  thus p r e v e n t i n g the e l u t i o n .  f a c t t h a t a l l the polymers d e a c t i v a t e to d i f f e r e n t  degrees  upon r e c y c l i n g , i n c l u d i n g the t e t r a p h o s p h i n e complexes, i n d i c a t e s t h a t f a c t o r s other than d i m e r i z a t i o n of P^RhCJi and rhodium e l u t i o n from m a t r i x p l a y a r o l e i n the d e a c t i v a t i o n p r o c e s s .  Complex 2-0 R  ^  o r  the e  x  a  m  P l  e  i s oxygen s e n s i t i v e and when exposed to a i r between c y c l e s ( F i g . 20) l o s e s  -148-  its activity rapidly.  I t i s p o s s i b l e that i n s p i t e o f g r e a t  precautions  taken the polymers come i n t o c o n t a c t w i t h t r a c e s o f oxygen, when handled between c y c l e s , and a r e d e a c t i v a t e d t h i s way.  S i n c e upon r e c y c l i n g the  s u r f a c e a r e a o f the c a t a l y s t s i n c r e a s e s , as i n d i c a t e d by EM micrographs ( F i g s . 33-37 and S e c t i o n 5-5.), oxygen has p r o b a b l y m e t a l c e n t r e s and thus can " p o i s o n "  e a s i e r access to  the c a t a l y s t e a s i e r .  M i g r a t i o n o f a c t i v e m e t a l c e n t r e s on t h e s u r f a c e o f t h e polymer 6 12 A and/or a change of n a t u r e  o f the a c t i v e s p e c i e s have been suggested '  as b e i n g p o s s i b l y r e s p o n s i b l e f o r the change i n the p r o p e r t i e s of t h e supported  phosphine rhodium c a t a l y s t s .  A s i m i l a r phenomenon i s  p o s s i b l e i n t h e c a s e o f t h e s i l o x y p h o s p h i n e macrocomplexes where t h e s t r a i n around the m e t a l c e n t r e imposed by the r i g i d d i s s o c i a t i o n of some l i g a n d s w i t h still  l i g a n d s may cause  the subsequent f o r m a t i o n  of some o t h e r ,  attached  t o the polymer, but l e s s a c t i v e s p e c i e s . 137 On the o t h e r hand i t has been r e p o r t e d . that i n the c a t i o n i c 2+ s p e c i e s {Rh^[1,2-bis(diphenylphosphino)ethane] } each Rh atom i s bonded to two P atoms and through t h e symmetrical  II-arene c o o r d i n a t i o n t o a  phenyl r i n g o f the l i g a n d ; each Rh atom m a i n t a i n i n g  thus an " 1 8 - e l e c t r o n  138 valence  shell"  the p o l y m e r i c  .  By a n a l o g y , t h e p o s s i b i l i t y o f t h e d e a c t i v a t i o n o f  c a t a l y s t s i n t h e hydrogenation  c o o r d i n a t i o n v i a the aromatic  of s t y r e n e due t o t h e s t y r e n e  r i n g was c o n s i d e r e d .  Since the phenyl r i n g  i s a 6 - e l e c t r o n donor i t would have t o d i s p l a c e o t h e r "18-"  or " 1 6 - e l e c t r o n r u l e " c o u l d be p r e s e r v e d .  l i g a n d s so t h a t the  The c a t a l y t i c  of such a newly formed complex would be c o n s i d e r a b l y d i f f e r e n t of the s t a r t i n g phosphine complex.  activity from t h a t  -149-  T h i s may be checked by changing s t y r e n e t o cyclohexene hydrogenation  s u b s t r a t e and so e l i m i n a t i n g the p o s s i b i l i t y o f II-arene  c o o r d i n a t i o n t o Rh(I). F i g . 30 shows t h a t w i t h cyclohexene of  as t h e  the polymeric  c a t a l y s t R^-O decreases  the a c t i v i t y  on r e c y c l i n g a l s o .  In a f a s h i o n  s i m i l a r t o r e s u l t s o b t a i n e d w i t h ^ - 7 5 e a r l i e r i - the course o f t h i s work n  ( s e c t i o n 5-2-1) the degrees of c o n v e r s i o n w i t h than f o r s t y r e n e .  No rhodium e l u t i o n  a  r  i s observed.  e  a  ^-  s o m  u  c  lower  n  What i s most r e l e v a n t  i s the f a c t t h a t a n o t i c e a b l e d e a c t i v a t i o n of the c a t a l y s t takes p l a c e when going from the f i r s t styrene. to  c y c l e t o the second, i n f a c t even more so than f o r  T h i s i n d i c a t e s t h a t even i f t h e r e i s any s t y r e n e c o o r d i n a t i o n  Rh(I) i t i s not t h e main cause o f d e a c t i v a t i o n o f the c a t a l y s t . The  e f f e c t o f the l e n g t h o f the spacer "arm" between the m e t a l  atom and t h e m a t r i x d i s c u s s e d e a r l i e r i n t h i s chapter the p o l y m e r i c  siloxyphosphine  pronounced when R  z—U  and R  o—0  complexes  R n  _ ; the e f f e c t i s p a r t i c u l a r l y m  a r e compared.  Complex R  a c t i v i t y over a g r e a t e r number of c y c l e s than R^-O though rhodium e l u t i o n takes p l a c e f o r Rg_Q i a c t i v i t y i n the s i x t h c y c l e i s s t i l l  i s also noticed i n  n  o—0  maintains i t s  ^ i g s 11 and 12).  Even  t h e l a s t two runs t h e  g r e a t e r than t h a t o f R _ Q  i  n  2  the  fifth. The presence of l o n g e r C  Q  chains i n R  _ as compared w i t h C„ c h a i n s z  o—U  o  i n R^ Q r e s u l t s most l i k e l y i n a s p r e a d i n g  of the a c t i v e rhodium  centres  f u r t h e r apart thus p r e v e n t i n g d i m e r i z a t i o n and i n t u r n a l l o w i n g t h e c a t a l y s t to  be a c t i v e over a l a r g e r number of c y c l e s than 2 _ Q ' R  b e f o r e , t h e e f f e c t of longer spacer  A l s o , as mentioned  "arms" i s such t h a t the anchored  sites  which g a i n more freedom of m o b i l i t y behave more l i k e s p e c i e s s o l u b l e i n solution.  The s o l u b l e s i l o x y p h o s p h i n e  complex H i s found  t o be more a c t i v e  -150-  than any  of the p o l y m e r i c  siloxyphosphine  t h e r e f o r e p o s s i b l e t h a t the f a c t ( C chain) o  It i s  t h a t the o v e r a l l l i f e t i m e of  i s l o n g e r than t h a t of R„ _. (C„ c h a i n ) z—U z  0  similar  complexes s t u d i e d .  Rg_Q  i s i n f l u e n c e d by  factor(s). The  a c t i v i t y of the copolymer R  ( F i g . 18)  i s higher  i n the  o—1UU first  two  c y c l e s than  the a c t i v i t y of R  c  _ ( F i g . 12).  However,  on  o—U  subsequent r e c y c l i n g t h a t of R„ „. o—U may  be  5-4.  The  explained  the a c t i v i t y of R  phenomenon i s not w e l l understood  i n terms of some changes w i t h i n the  Hydrogenation of Styrene  Complex R^  d e c l i n e s more r a p i d l y  g  and  Cyclohexene w i t h  and  at t h i s p o i n t  polymer.  the  Polymeric  i n S o l u t i o n s of D i f f e r e n t Volumes.  An unusual phenomenon i s observed s o l u t i o n volumes d i f f e r e n t  when r e a c t i o n s are run  from the standard  3 mL  w i t h other  with  p r e v i o u s l y used. T h i s  i s most e v i d e n t f o r the homopolymeric t r i s p h o s p h i n e complex but observed  than  i s also  polymers.  Data p l o t t e d i n F i g . 21 show t h a t the degrees of c o n v e r s i o n s t y r e n e over  the r e a c t i o n time-span a r e d i f f e r e n t  volumes when u s i n g R _ The  ,. a l t h o u g h  for different  of  solution  a l l the c o n c e n t r a t i o n s a r e the same.  degree of c o n v e r s i o n a t a g i v e n time i s s m a l l e r f o r l a r g e r volumes  in  the f i r s t  c y c l e . In the second c y c l e the d i f f e r e n c e between two  of  volumes 3 and  6 mL  is negligible  ( F i g . 22).  Finally  i n the  third  c y c l e the degrees of c o n v e r s i o n are s m a l l e r f o r the s o l u t i o n w i t h s m a l l e r volume  the  ( F i g . 23).  Polymer S shows a s i m i l a r smaller extent.  runs  The  tendency  ( F i g s . 24-26) but  to a much  degrees of c o n v e r s i o n of s t y r e n e at a g i v e n  time  -151-  are  v e r y s i m i l a r w i t h d i f f e r e n t volumes but i n a l l t h r e e c y c l e s the runs  w i t h l a r g e r volume g i v e s l i g h t l y lower c o n v e r s i o n s than those w i t h s m a l l e r volumes. The s i t u a t i o n i s s i m i l a r f o r the d i m e r i c copolymer i n h y d r o g e n a t i o n of s t y r e n e ( F i g s . 27-29).  In the f i r s t  ^QQ when used  c y c l e the d i f f -  erence between the 3 and 6 mL volume runs i s e v i d e n t , as f o r R^-rj' run  g i v i n g a g r e a t e r c o n v e r s i o n s than the 6 mL  one.  t l i e  In the second and  c y c l e s the percentage c o n v e r s i o n are i d e n t i c a l over the r e a c t i o n time  third span  r e g a r d l e s s of the s o l u t i o n ' s volume. F i g u r e s 31 and 32 show t h a t when cyclohexene i s hydrogenated R  2-0  t  '  i e  d  e  8  r  e  e  s  with  °f c o n v e r s i o n over a g i v e n time p e r i o d do not v a r y v e r y  much w i t h d i f f e r e n t  s o l u t i o n volumes.  Here the t r e n d both i n the  first  and the second c y c l e i s such t h a t i n runs of l a r g e r s o l u t i o n volumes the degrees of c o n v e r s i o n are s l i g h t l y h i g h e r than i n those w i t h s m a l l e r volumes. The t r e n d i s o p p o s i t e to t h a t observed f o r s t y r e n e . These r e s u l t s a r e q u i t e r e p r o d u c e a b l e b u t t h e r e i s no nor any apparent l o g i c a l p a t t e r n .  Increased s t i r r i n g  regularity  speed of a  suspen-  37  s i o n of supported phosphine rhodium result But  c a t a l y s t has been r e p o r t e d  i n h i g h e r a c t i v i t y of the c a t a l y s t  to  (expressed i n t u r n o v e r numbers).  i n t h i s work v a r i a t i o n of s t i r r i n g r a t e does not have any  influence.  The observed changes of the degrees of c o n v e r s i o n over a g i v e n time, w i t h different the  s o l u t i o n volumes i s most l i k e l y caused by some p r o c e s s e s a f f e c t i n g  p o l y m e r i c network r a t h e r than the a c t i v e m e t a l c e n t r e s .  However, no  s u i t a b l e e x p l a n a t i o n of the observed phenomenon has y e t been found. 5-5.  E l e c t r o n Microscope Studies . I t has been e s t a b l i s h e d by EM s t u d i e s  26  t h a t the d a r k e n i n g of  -152-  the s i l i c a - s u p p o r t e d t r i s p h o s p h i n e r h o d i u m ( I ) complexes  during  hydro-  g e n a t i o n r e a c t i o n s i s a r e s u l t of r e d u c t i o n of Rh(I) to Rh° w i t h the subsequent Two  f o r m a t i o n of rhodium m e t a l  samples  microscope. One was  of the polymer  R 2  -75 -  crystallites. w e r e  examined w i t h the e l e c t r o n  the f r e s h l y prepared c a t a l y s t and the o t h e r was  the c a t a l y s t from the same b a t c h which had been used i n the hydrog e n a t i o n of s t y r e n e i n a benzene/ethanol The c a t a l y s t changed reaction.  i t s c o l o u r from orange to l i g h t grey d u r i n g  As d i s c u s s e d i n S e c t i o n 3-2-2  Rh° metal c l u s t e r f o r m a t i o n and i t was from X-ray and/or  (1:1 v/v) s o l v e n t m i x t u r e . the  the d a r k e n i n g i s a t t r i b u t e d to  hoped t h a t t h i s c o u l d be  established  secondary image EM m i c r o g r a p h s .  The power of the a p p l i e d e l e c t r o n beam had t o be m a i n t a i n e d at a low l e v e l so t h a t the e l e c t r o n s  themselves would not reduce the Rh(I)  s p e c i e s to Rh(0) At the same time maximum m a g n i f i c a t i o n was Attempts  required.  to o b t a i n secondary image micrographs of c r o s s - s e c t i o n s o f the  p o l y m e r i c beads a t h i g h e r beam power and at a m a g n i f i c a t i o n f a c t o r proved to be u n s u c c e s s f u l due to s t r o n g  900  discharges.  Rhodium d i s t r i b u t i o n , as observed on the X-ray m i c r o g r a p h s , of the polymer used i n h y d r o g e n a t i o n was  not d i f f e r e n t  from t h a t of the  f r e s h s p e c i e s and d i d not i n d i c a t e f o r m a t i o n of m e t a l c l u s t e r s ; a t the maximum m a g n i f i c a t i o n a c h i e v e d (11,200 f o l d ) the r e s o l u t i o n was 0.1  about  pm. The secondary image micrographs of the polymer  s u r f a c e , shown  i n F i g s . 33-37, do not r e v e a l any m e t a l l i c rhodium c l u s t e r f o r m a t i o n e i t h e r , but they g i v e i n t e r e s t i n g of the polymer.  i n f o r m a t i o n as to the p h y s i c a l n a t u r e  A c o n s i d e r a b l e d i f f e r e n c e between the appearance of  -153-  the new  c a t a l y s t and  seen i n F i g s . 33 and  a f t e r i t has been used i n hydrogenation 34.  The  f r e s h l y prepared  r e l a t i v e l y smooth g l o b u l e s c l u s t e r e d t o g e t h e r  ruptures.  T h i s c o u l d be due  i n bigger  course  and  effects.  (a)  The  stirred vigorously  thus i t s s u r f a c e c o u l d be damaged m e c h a n i c a l l y ,  (b) In  the  of the r e a c t i o n hydrogen d i f f u s e s i n s i d e the polymer's pores  remains t h e r e i n the form of e i t h e r a Rh h y d r i d e gas.  conglomerates.  i t shows s i g n s of  to two  polymer i s suspended i n the r e a c t i o n s o l u t i o n and f o r 23h;  be  polymer c o n s i s t s of  A f t e r the c a t a l y s t has been used i n hydrogenation deep c r a c k s and  can  A f t e r the r e a c t i o n i s t e r m i n a t e d d r i e d by  evacuation.  The  complex or as hydrogen  the polymer i s f i l t e r e d , washed,  r a p i d removal of a c o n s i d e r a b l e amount of  gas adsorbed i n s i d e the polymer c o u l d cause r u p t u r e of the beads. c r a t e r s seen i n F i g . 35b  I n t h e l e f t bottom c o r n e r o f t h i s photo-  graph t h e r e are s u r f a c e c r a c k s which c o u l d be the i n i t i a l  At h i g h e r m a g n i f i c a t i o n s  any  s i g n s of c r a c k i n g .  (>1100) and h i g h e r beam powers ( F i g . 36)  c r o s s - s e c t i o n can be  (>11,200)(Fig. 37)  seen i n the same polymer.  s m a l l p i e c e s of The  the  shape.  rectangular  X-ray images do  i n c r e a s e d c o n c e n t r a t i o n of rhodium atoms along At t h i s stage no  In  t h e r e a r e numerous h o l e s of r e c t a n g u l a r  At even h i g h e r m a g n i f i c a t i o n s  cavities.  of  of the s t r u c t u r e of the used polymer can be seen.  s u r f a c e of the open c r a c k s  show any  stages  S i m i l a r m a g n i f i c a t i o n of a bead of the f r e s h polymer  shows a v e r y uneven s u r f a c e but without  another aspect  Little  c o u l d p o s s i b l y form by the r u p t u r e of lumps  from the s u r f a c e o f t h e beads.  such a r u p t u r e .  and  the edges of  not the  e x p l a n a t i o n as to the cause of t h i s phenomenon  has been found. Unfortunately  the attempt to prove, u s i n g EM,  t h a t darkening  the polymer i s r e l a t e d to m e t a l l i c rhodium c l u s t e r f o r m a t i o n  of  f a i l e d . Most  -154-  l i k e l y d i f f e r e n t and s p e c i f i c i n s t r u m e n t a l c o n d i t i o n s a r e r e q u i r e d t o d e t e c t t h e presence of s m a l l m e t a l l i c c r y s t a l l i t e s .  However, a v e r y  i n t e r e s t i n g i n s i g h t has been gained w i t h r e g a r d t o the p h y s i c a l s t r u c t u r e of the polymer and the e f f e c t o f h a n d l i n g and u s i n g i t i n t h e hydrogenation r e a c t i o n .  -155CONCLUSIONS The  s y n t h e s i s of p o l y s i l o x y p h o s p h i n e complexes of rhodium(I)  was  a c h i e v e d by h y d r o l y s i s of the c h l o r o s i l y l p h o s p h i n e r h o d i u m p r e c u r s o r s . The p r o c e s s of h y d r o l y t i c p o l y c o n d e n s a t i o n ment around the c e n t r a l metal mainly,  does not change the e n v i r o n -  atom; the macrocomplexes produced c o n t a i n  i f not e x c l u s i v e l y , rhodium(I) s p e c i e s of the p r e d i c t e d  T h i s i s concluded  on the b a s i s of the m i c r o a n a l y t i c a l and  the r e a c t i v i t y of the non-carbonyl  formulae.  IR d a t a ,  complexes towards hydrogen and  and carbon  monoxide. All  the complexes which do not c o n t a i n a c a r b o n y l group a r e  r e c y c l a b l e c a t a l y s t s i n hydrogenation a c t i v i t y decreases to be caused  by:  upon r e c y c l i n g .  of s t y r e n e and  cyclohexene,  effective but  The d e a c t i v a t i o n of the c a t a l y s t s seems  (a) d i m e r i z a t i o n to d i - u - c h l o r o t e t r a p h o s p h i n e s p e c i e s i n  the case of the t r i s p h o s p h i n e complexes;  (b) " p o i s o n i n g " of the  catalysts  by t r a c e s of oxygen; (c) e l u t i o n of rhodium from the m a t r i x ; and/or other changes i n the nature of the o r i g i n a l c a t a l y t i c s p e c i e s . it  i s p o s s i b l e t h a t some of the d e a c t i v a t i o n i s caused  (d)  However,  by p h y s i c a l changes  i n the p o l y m e r i c m a t r i x of the c a t a l y s t s which occur e i t h e r d u r i n g hydrogenation  their  the  r e a c t i o n or i n the h a n d l i n g between c y c l e s .  C o p o l y m e r i z a t i o n of t r i s p h o s p h i n e complexes w i t h CA^Si-CH^ r e s u l t s i n maintaining high a c t i v i t y to metal  c e n t r e i s o l a t i o n thereby p r e v e n t i n g d i m e r i z a t i o n .  w i t h an excess and  due  Copolymerization  of a phosphine p r e v e n t s rhodium e l u t i o n from the m a t r i x  results i n maintaining  lowers  i n more c y c l e s , which i s b e l i e v e d to be  i t a t a steady l e v e l upon r e c y c l i n g ,  the c a t a l y s t ' s i n i t i a l a c t i v i t y .  between the backbone and  the metal  E x t e n s i o n of the spacer  "arm"  c e n t r e from a two-carbon to an  e i g h t - c a r b o n c h a i n g i v e s a c a t a l y s t w i t h an o v e r a l l l o n g e r t h i s i s a l s o most l i k e l y  although  the r e s u l t of b e t t e r s e p a r a t i o n of  lifetime; the  -156-  active  sites. The  r e s u l t s show t h a t i n order  to extend the l i f e - t i m e of  these  a i r - s e n s i t i v e c a t a l y s t s the polymers have to be handled i n such a as to ensure more r i g o r o u s e x c l u s i o n of oxygen. flow process  Probably a  continuous-  w i t h an e x c l u s i o n of t r a c e s of oxygen from the  s o l u t i o n feed-stock  olefin  would be more s u c c e s s f u l i n t h i s r e s p e c t  r e c y c l i n g the c a t a l y s t a f t e r i n d i v i d u a l h y d r o g e n a t i o n runs. l i f e - t i m e of a c a t a l y s t w i t h P/Rh>3 and w i t h C  spacer  0  way  than Also,  the  "arms" would  o probably  be c o n s i d e r a b l y  out t h a t l a r g e P/Rh  increased.  However, i t should  r a t i o s would c o n s i d e r a b l y  lower the  be  pointed  catalytic  activity. Unfortunately,  i n s p i t e of e x p e c t a t i o n s ,  not  enough  c o u l d be garnered about the a c t u a l n a t u r e of the p o l y m e r i c to permit d e l i b e r a t e improvements.  information catalysts  I t i s recommended t h a t the  m e r i z a t i o n procedure be more s t a n d a r d i z e d  by u s i n g  either  or s y r i n g e pumps f o r i n t r o d u c i n g the s o l u t i o n of the phosphine complexes i n t o the h y d r o l y z i n g medium.  poly-  peristiltic  chlorosilyl-  T h i s would  improve  the r e p r o d u o e a b i l i t y of the p r o p e r t i e s of the polymers produced. 31 "Magic a n g l e " being  considered  P NMR  s p e c t r a of the s o l i d polymers, which i s  at the moment, i f s u c c e s s f u l , c o u l d g i v e  information  as to the a c t u a l geometry of the l i g a n d s around the rhodium atoms. X-ray absorption  f i n e s t r u c t u r e (EXAFS) s p e c t r o s c o p i c r e s u l t s would  a b l e to c o n f i r m  be  i f d i m e r i z a t i o n of t r i s p h o s p h i n e s p e c i e s i s one  of  the  causes f o r d e a c t i v a t i o n of the c a t a l y s t s . D e t e r m i n a t i o n of s w e l l a b i l i t y of the polymers and i s a l s o recommended.  Further  the pore  e l e c t r o n microscope s t u d i e s may  size  reveal  more d e t a i l s as to the i n f l u e n c e of f a c t o r s such as pore shape and  size  -157-  as w e l l as the r o l e , i f any, o f t h e r e c t a n g u l a r c a v i t i e s on the c a t a l y t i c b e h a v i o u r o f t h e macrocomplexes.  observed,  -158-  Bibliography 1)  R.H.  Grubbs, Chemtech, 512  2)  D. Commereuc and G. M a r t i n o , Rev. I n s t . F r . P e t r . , and r e f e r e n c e s  3)  F.R.  Hartley  4)  therein. 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