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X PEt_ / ' . A »were p r e p a r e d and c h a r a c t e r i z e d for," a s e r i e s o f f o u r t e e n X l i g a n d s .
2 3 3 ' ■
The v a l u e s o f and 3pj._p were o b t a i n e d i n o r d e r t o examine t h e c o r r e l a t i o n o f t h e s e c o u p l i n g s w i t h o t h e r m e a s u r e s o f t h e 2 t r a n s - i n f l u e n c e . I t was found t h a t J „ . - „ c o r r e l a t e d i n a l i n e a r P t - F . 3 f a s h i o n w i t h o t h e r m e a s u r e s o f t h e - ^ t r a n s - i n f l u e n c e , b u t J and ’ P t - F . 3 \ d i d n o t . The l a c k o f a l i n e a r . c o r r e l a t i o n f o r t h e t h r e e bond 2 c o u p l i n g s i s . a s c r i b e d t o a v a r y i n g t h r o u g h s p a c e c o n t r i b u t i o n t o t h o s e c o u p l i n g s . The m a g n i t u d e o f t h e t h r o u g h s p a c e c o u p l i n g d e p e n d s n o t o n l y on t h e d i s t a n c e between t h e p l a t i n u m and f l u o r i n e n u c l e i , b u t a l s o on t h e o r i e n t a t i o n o f thp p l a n e o f t h e p e r f l u o r o v i n y l l i g a n d w i t h r e s p e c t .
t o çhe s q u a r e p l a n e o f l i g a n d s a b o u t p Ta ïi num.
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I I The* compound l i t h i u m o c t a h y d r o p e n t a b o r a t e ( l - ) was p r e p a r e d and shown t o decompose upon re mova l o f s o l v e n t . Dime t h y I b o r o n Bromide
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was r e a c t e d w i t h l-l t hi um o c t a h y d r o p e n t a b o r a t e ( L-) i n e t h e r t o form ^ - d i m e t h y l b o r y l p e n t a b o r a n e ( 9 ) , b u t t h e c o r r e s p o n d i n g
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r e a c t i o n s ‘o f t h e l i t h i u m b o r a t e ( l - ) s a l t w i t h d i e t h y l a l u m i n u m c h l o r i d e and d i m e t h y l t h a l l i u m bromide were u n s u c c e s s f u l . T h i s l a c k o f s u c c e s s was a s c r i b e d , f o r t h e aluminum compound, t o the r a p i d f o r m a t i o n o f t he e t h e r a t e o f d i e t h y l a l u m i n u m bromi de a n d , f o r t h e t h a l l i u m compound, t o
t h e two p h a s e . r e a c t i o n s y s t e m .
A t t e m p t s were made t o p r e p a r e t h e b r i d g e d compounds by t h e
d i r e c t r e a c t i o n o f p e n t a b o r a n e ( 9 ) w i t h i j cri.methy 1 aluminum and i i ) t r i - m e t h y l b o r a n e . The o n l y v o l a t i l e b o r a n e r e a c t i o n p r o d u c t s were t e r m i n a l l y a l k y l a t e d . The r e a c t i o n o f p e , n t a b o r a n e ( 9 ) w i t h t r i m e t h y l a l u m i n u m gave
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■ a h y d r o g e n r i c h r e a c t i o n r e s i d u e o t e m p i r i c a l f o r m u l a AlC^ y The c h e m i c a l n a t u r e o f t h i s r e s i d u e was n o t e l l , u c i d a t e d . » ' f » , S u p e r v i s o r ; D r . G.W. B u s h n e l l The c r y s t a l s t r u c t u r e ' o f b i s ( d i e t h y l a m i n o } d i t h i a b o r e t a n e[(C2h^);^NBsJ 2 -has been d e t e r m i n e d by means o f x - r a y d i f f r a c t i o n . The '
- ■ c r y s t a l s b e l o n g e d t o t he t e t r a g o n a l s y s t e m , s p a ce group P, „ • (No. 9 2 ) .
1 1
The u n i t c e l l d i m e n s i o n s were e s t a b l i s h e d ^ i n i t i a l l y by p h o t q g r a p h i c work and f i n a l l y uy d i f f r a c t o m e t e r m e a s u r e m e n t s , i n t e n s i t i e s o f 373
r e f l e c t i o n s were me as u re d on a f o u r c i r c l e mahual d i f f r a c t o m e t e r and t h e s t r u c t u r e r e f i n q d * t o an R- v a l u e o f ^ 0 9 3 . Thé m o l e c u l a r symmetry i s a p p r o x i m a t e l y 222 (Dg,). '
/. • ; A b s t r a c t . ' * T a b l e ô f c o n t e n t s L i s t o f T a b ] e s L i s t o f F i g u r e s Acknowledgements 1. I n t r o d u c t i o n 1 . 1 . G e n e r a l 1 . 2 . The Tr a n s - i n f l u e n c e 1 . 2 . 1 . T h e o r i e s o f t h e Tr a n s - i n f l u e n c e 1 . 2 . 2 . Measurement o f t h e T r n n s - i n f l u e n c e 1 . 2 . 2 . 1 . X -r a y G r y s c a l l o g r a p h y ^ 1 . 2 . 2 . 2 . V i b r a t i o n a l S p e c t r o s c o p y * 1 . 2 . 2 . 3 . N u c l e a r M a g n e t i c Resonance S p e c t r o s c o p y 1 . 3 . O b j e c t s o f R e s e a r c h 2. E x p e r i m e n t a l ' ' 2 . 1 . G e n e r a l * j 2 . 1 . 1 . C he m i c a l s 2 . 1 . 2 . I n s t r u m e n t s 2 . 2 . P r e p a r a t i o n s 2 . 2 . 1 . T r a n s - h y o r i d o c h l o r o b i s ( t r i e t h y I p h o s p h : p l a t i n u m ( I l ) h y l p h o s p î m î i r ^ ’ 11 X I xilA 20 2 2'
22
22
232 . 2 . 3 . Th'e p r e p a r a t i o n o f t r a n s - p e r f l u o r o v l n y I b r o m o b i s ( t r i e t h y l D h o s p h ' i H e ) p l a i i n u m ( I I ) 27 2 . 2 . 4 . The p r e p a r a t i o n of ■ t r a n s - p e r l ' 3 u o r o v i n y l i o d o b L s ( t r l e t h y l p h o s p h i n e ) p L a t l n u m ( l l ) 28 2 . 2 . 5 . The p r e p a r a t i o n o f t r a n s - p e r f l u o r o v i n y l n i t r l t o b i s ( t r i e t h y l p h o s p h i n e ) p L a t i n u m ( l l ) 28 2 . 2 . 6 . The p r e p a r a t i o n of u f a n s - p c r f l u o r o v i n y l n i t r e t o b i s ( t r i e thy i p h o s p i u ne ) pl a Li n u m( l - l ) 29 2 . 2 . 7 . The p r e p a r a t i o n , of. t r a n s - p e i f l u o r o v i n y l y c y a n o b i s ( t r x e t h y ] p h ü s p h i n e ) p l a t i n u m ( l i ) ' 30 ' 2 . 2 . 8 . The p r e p a r a t i o n o f t r a n s - p e r f . I u o r o v i n y l a ? , i d o b i s ( t r i c t P y l p I i o s p h i ’' ' c ) p l a t i n u m ( î i ) 31 2 . 2 . 9 . The p r e p a r a t i o n o f t r a n s - p e r f l u o r o v i n y l
c a r bony 1 b i s ( t r io t.h. y 1 pho s ph ine ) p 1 à t ir.um ( i l )
'■ p e r c h l o r a t e 32
2 . 2 . 1 0 . The p r e p a r a t i o n o f t r a h n - p c r f l u o r o v i n y l pyr i d y l b i s C t r i e thy Iphospli ine ) p l a t i n u T i ( l l )
p e r c h l o r a t e ' 33
2 . 2 . 1 1 . The p r e p a r a t i o n o f t r a n s - p e r f l u o r o v i n y l t r i s ( t r i e t h y 1 pliosph i n e ) p l a tinum( I I )
^ p e r c h l o r a t e 34 (
2 . 2 . ^ 2 . The p r e p a r a t i o n o f t r a n s - p e r f l u o r o v I n y i t r iph e n y 1 ph os ph i ne b i s ( t r i e t h y I pli Ü s ph ir»e )
p l a t i n u m ( l l ) p e r c h l o r a t e 36
2 . 2 . 1 3 . The p r e p a r a t i o n o f t r a n s - p e r f l u o r o v i n y l t r ' t i e t l i y l p h o s p h i t e b i s C t r i e thy I phos ph ine )
p l a l i n u m ( l l ) p e i c h l o r a t e ' . 37 2 . 2 . 1 4 . The p r e p a r a t i o n of t r a n s - p e r f l u o r o v i n > 1 ' t r i e t h y I p h o s p h i t e b i 6 ( t r i e t h y I p h o s p h i n e ) ’ p l a t i n u m ( l l ) p e r c h y 5 r a t o 38 2.2.1'^». The p r e p a r a t i o n of t r a n s - p e r f l u o r o v i n y l t r i p h e n y I ph os ph i t e b i s ( t r i e thy I ph os ph iu(f) p l a t i n u t n ( i l ) p e r c h l o r a t e . 39
( f r i e t h y i p h o s p h j n e ) p l a t i n u m ( l l ) ' Complexes and Lhe T r f ^ n s - i n f l u e n c e 3 . 1 . P r e p a r a t i o n s , A n a l y s e s and S t e r e o c h e m i s t r y 3 . 2 . The T r a n s - i n f l u e n c e
3 . 2 . 1 . V i b r a t i o n a l S p e c t r a and t h e T r a n s - i n f l u e n c e 3 . 2 . 2 . N u c l e a r M a gn e ti c Res ona nce S p e c t r a and
t h e Tran's- i n f l u e n c e . 3 . 3 . S u g g e s t i o n s f o r F u r t h e r Work « ■ O 4- I n t r o d u c t i o n : B r i d g e S u b s t i t u t i o n i n P e n t a b o r a n e ( 9 ) The C r y s t a l S t r u c t u r e o f B i s ( d i e t h y l a m i n o ) d i t h i a b o r e t a n e ^ 4 . 1 . G e n e r a l * 4 . 2 . N o m e n c l a t u r e 4 . 3 . The B o r a n e 8 4 . 3 . 1 . H i s t o r i c a l <
4 . 3 . 2 . The S t r u c t u r e s o f t he Bora nes 4 . 3 . 3 . Bonding i'n t h e Boranes
4 . 3 . 3 . 1 . G e n e r a l ^ 4 . 3 . 3 . 2 . The T h r e e - C e n t e r Bond 4 . 3 . 4 . P r e p a r a t i o n o f t he Boranes 4 . 3 . 5 . R e a c t i o n s o f t h e Bora nes 4.3.f>'] D e p r o t o n a t i o n o f t h e Bo ra nes 4 . 3 . 7 . B r i d g e S u b s t i t u t i o n in t he Borai^es
4 . 4 . Boron Bonded to Group VA and Group VIA E l e m e n t s 4 . 4 ^ 1. Compound i n v/hi^ch Boron i s Te t r a e o o r d i n a t e
V
-4 . -4 . 2 . Compounds in which Boron i s T r i c o o r d i n a t e 4 . 5 . S p e c t r a l T e c h n i q u e s i n t he S t ud y o f Boron C h e m i s t r y 45 4 5 ■ 50 50 53 »71 73 73 ” \ 77 78 79 79 83 87 89 90 95 ^ 8 99 101 110
/
J4 . 5 . 2 . Mass S p e c t r o s c o p y ' 111
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4 â 5 . 3 . N u c l e a r M a g n e t i c Res ona nce S p e c t r o s c o p y 111. 4 . 6 . S t r u c t u r e D e t e r m i n a t i o n by X - r a y Methods 114 ' 4 . 6 . 1 . G e n e r a l 114. 4 . 6 . 2 . R e c o r d i n g t h e D i f f r a c t i o n P a t t e r n 118 Î1-4 . 6 . 3 . S t r u c t u r e D e t e r m i n a t i o n 121 ■ 4 . 7 . O b j e c t s o f t h e R e s e a r c h ' 131 • « 5.^ E x p e r i m e n t a l ; B r i d g e S u b s t i t u t i o n i n P e n t a b o r a n e ( 9 ) The C r y s t a l S t r u c t u r e o f B i s ( d i e t h y l a m i n o ) d i t h i a b o r e t a n e . 133 & y 5 . 1 . B ri dg e S u b s t i t u t i o n i n P e n t a b o r a n e ( 9 ) 133 ^ 5 , 1 . 1 . C h e m i c a l s , I n s t r u m e n t a t i o n and T e c h n i q u e s 133 ' 5 . 1 . 2 . P r e p a r a t i o n s 134 5% 1 . 2 . 1 . The P r e p a r a t i o n o f D i b o r a n e ( 6 ) • 134 5 . 1 . 2 . 2 . The P r e p a r a t i o n o f P e n t a b o r a n e ( 9 ) 136 5 . 1 . 2 . 3 . L i t h i u m O c t a h y d r o p e n t a b o r a t e ( l - ‘) , • P r e p a r a t i o n and P r o p e r t i e s 140 5 . 1 . 2 . 4 . The P r e p a r a t i o n o f ^ - d i m e t h y I b o r y l p e n t a b o r a n e ( 9 ) 143 5 . 1 . 2 i 5 . The A t t e m p t e d P r e p a r a t i o n of _ ^ - d i m e t h y l a l u m i n u m p e n t a b o r a n e ( 9 ) 145 5 . 1 . 2 . ' . The A t t e m p t e d P r e p a r a t i o n o f ^ / ^ - d i m e t h y l t h a l l i u m p e n t a b o r a n e ( 9 ) 146 . 5 , 1 . 2 . 7 , , The R e a c t i o n P e n t a b o r a r t e ( 9 ) w i t h T r i m e t h y l a l u m i n u m , 150 5 . 1 . 2 . 8 . The R e a c t i o n of P e n t a b o r a n e ( 9 ) w i t h T r i m e t h y l b o r a n e 153 5 . 2 . The S t r u c t u r e o f B i s ( d i e t h y l a m i n o ) d i t h i a b o r e t a n e 155
5 . 2 . 2 . P r e p a r a t i o n s . 156 5 . 2 . 2 . 1 . The P r e p a r a t i o n o f T r i e t h y l a m i n e b o r a n e 156 5 . 2 . 2 . 2 . The P r e p a r a t i o n o f B i s ( d i e t h y l a m i n o ) '' . d i t h i a b o r e t a n e 156 ■ 5 . 2 . 3 . A n a l y s i s o f tVie C r y s t a l S t r u c t u r e o f . B i s C d i e t h y l a m l n o ) d i t h L â b o r e t a n e 160 5 . 2 . 3 . 1 . C r y s t a l Mounting and P h o t o g r a p h i c Work ■ ' 160 5 . 2 . 3 . 2 . D i f f r a c t o m e t r y 162 , 5 . 2 . 3 . 3 . S t r u c t u r e D e t e r m i n a t i o n . 164 6. . D i s c u s s i o n : B ri dge S u b s t i t u t i o n \in P e n , t a b o r a n e ( 9 ) The C r y s t a l S t r u c t u r é o f B i s ( d i e t h y l a m i n o ) d i t h i a b o r e t a n e ' 170 6 . 1 . B r i d g e S u b s t i t u t i o n i n P e n t a b o r a n e ( 9 ) 170 6 . 1 . 1 . P r o p e r t i e s o f l i t h i u m o c t a h y d r o p e n t a b o r a t e ( 1 - ) ; ' J 170 ’ . ^ 6 . 1 . 2 . y W - D i m e t h y l b o r y l p e n t a b o r a n e ( 9 ) || 171 6 . 1 . 3 . A t t e m p t s t o p r e p a r e B r i d g e d Groujj I I I A P e n t a b o r a n e ( 9 ) D e r i v a t i v e s 172 " 6 . 1 . 3 . 1 . The a t t e m p t e d r e a c t i o n o f D i e t h y l aluminum C h l o r i d e w i t h L i t h i u m O c t a h y d r o p e n t a b o r a t e 172 6 . 1 . 3 . 2 . f ^ e a t t e m p t e d r e a c t i o n o f Dimeth. ÿl - t h a I l i u m Bromide w i t h . L i t h i u m O c t a h y d r o p e n t a b o r a t e , 176 6 . 1 . 3 . 3 . The r e a c t i o n s be twee n P e n t a b o r a n e ( 9 ) and 1) T r i m e t h y l a l u m i n u m and <j 2) Tr i p e t h y ^ ^ r a n e 178 6 . 2 . The C r y s t a l S t r u c t u r e o f B i s ( d i e t h y l a m i n o ) d i t h i a b o r e t a n e 181 6 . 2 . 1 . The P r e p a r a t i o n o f B i s ( d i e t h y l a m i n o ) d i t h i a b o r e t a n e 181
B i b l i o g r a p h y _ . 199
A pp en di x I . 206
Ap pe nd ix I I ■ „ ' 218
Appendix I I I . 243
T c b l c I . I I . I I I . IV. V. VI. V I I . V I I I . • IX. X. XI. X I I . X[1II. XIV. XV. 19 F l u o r i n e N u c l e a r Magne ti c Resonance S p e c t r a l P a r a m e t e r s ( F , ) 1 19 P a r a m e t e r s (F^)
F ' l u o r i n e N u c l e a r Magne tic R es on ance S p e c t r a l
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’ 19 '
F l u o r i n e N u c l e a r ' Ma gn e ti c Resonance S p e c t r a l P a r a m e t e r s (F ^)
Observed and L i t e r a t u r e Va lues o f )Jp^ ^ f o r a n i o n i c T r a n s i n f l u e n c e l i g a n d s -Observed and L i t e r a t u r e V a l u e s o f ^ f o r n e u t r a l Trans-r i n f l u e n c e l i g a n d s Observed and L i t e r a t u r e V a l u es o f iJ C=C Page 41 42 43 51 51 53 Ma gn e ti c N u c l e i i n P e r f l u o r o v i n y l p l a t i n . u m ( ] l ) complexes 54 V a r i a t i o n o f C o u p l i n g C o n s t a n t s w i t h T e m p e r a t u r e . C r y s t a l Da ta f o r B i s ( d i e th y lamino )d i L l i i a b o r e t a n e '
F r a c t i o n a l Atomic C o o r d i n a t e s and I s o t r o p i c Thermal P a r a m e t e r s f o r B i s ( d i e t h y l a m i n o ) d ' i i : h i a b o r e t a n e • Bond L en g th s w i t h S t a n d a r d D e v i a t i o n s Bond A n g l e s w i t h S t a n d a r d D e v i a t i o n s P l a n e s i n B i s ( d i e t h y l a m i n o ) d . i t h i a b o r e t a n e ' I n t e r m o l e c u l a r D i s t a n c e s (same l a y e r ) I n t e r m o l e c u l a r D i s t a n c e s ( b e t w ee n l a y e r s ) 70 162 168 189 190 193 195 196
J
d O r b i t a l S p l i t t i n g s i n an O c t a h e d r a l F i e l d I I . I I I . IV. G r i n b e r g ' s P o l a r i z a t i o n Th eo ry Vo, S y r k i t i ' s H y b r i d O r b. i t a J s . VI. V I I . 2 . P t - CF ^ ''®* 3 , 4 t - I l ''=• "j; » ■ P t - C i i . P t - F V l l l .Vu-i,
IX. 2 , P t - F ^.
Pt-CF^ o @ ft-CH_ 3 ' X. % t - F ^ XIa . f e n t a b o r a n e (9 ) «1
Xlb. c i s - 1 ,.2-dime t h y I d i b o r a p e ( 6) X I I . ^ - d i m e t h y l b o r y l p e n t a b o r a n e ( 9 ) X l l l a . B o r a z i n e ' X l l l b . B o r t h i i n X I I I c . D i t h i a b o r e t a n e/
XIV. An I c o s a h e d r o n • XVa. D i b o r a n e ( 6 )^
•* XVb. T e t r a b o r a n e ( l O ) XVc. Hexa/borane(10)( f 4 7 9 10 57 58 65 68 ' 75 75 75 76 76 77 79 80 80 80. XVI,. P e n t a b o r a n e ( 9 ) 81 XVII, Aluminum t r i c h l o r i d e . d i m e t 82 ? X V II I , R e l a t i v e Energy L e v e l s in T h r e e C e n t e r Bond 84 XlXa, b , c . Types of T h r e e C e n t e r Bond ' 85 XXa. T r P b o r a n e ( 9 ) 97 XXb. D _ i m e t h y l a l u m i n u m t r i b o r a n e ( 9 ) . 97 XXI. 1 , 8 , 1 0 , 9 - t r i a z a b o r a d e c a l i n 103 XXII. B | b i s ( t r i m e t h y l s i l y l ) a m i n ( ^ N t r i m e t h y l s i l y l c l o -d i b o r a z a n e ^ 105 X X I I I a . O r t l i o b o r i c a c i d ' 107 r V X X l l I b . Me t a b o r i c a c i d 107 XXIV. P o t a s s i u m m e t a b o r a t e t e t r a h y d r a t e a n i o n 110 »
XXV. ; D i f f r a c t i o n P a t t e r n s R e s u l t i n g from One and Two
D i m e n s i o n a l A r r a y s o f P o i n t S o u r c e s . 116 XXVI. The S t r u c t u r e F a c t o r F and t h e Phase Angle 125 XXVII. The I n d i v i d u a l Atomic S t r u c t u r e F a c t o r s and
t he O v e r a l l S t r u c t u r e F a c t o r • 126
XXVIII. The Heavy Atom S c a t t e r i n g F a c t o r 128
XXIX. A p p a r a t u s Employed in the . P r e p a r a t i o n o f , D i b o r a n e ( 6) 135 XXX. S i l e n t E l e c t r i c D i s c h a r g e A p p a r a t u s 138 XXXI. R e a c t i o n F l a s k employed i n t h e P r e p a r a t i o n o f
L i t h i u m O c t a h y d r o p e n t a b o r a t e ( l - ) 141 XXXII. R e a c t i o n F l a s k Employed i n t he A t t e m p t e d P r e p a r a t i o n
o f ^ - d i m e t h y l t h a l l i u m p e n t a b o j r a n e ( 9 ) 147
P e r f l u o r o v i n y l b i s ( U r i e t : h y l p h o s p h i n G ) p l a t i n u m ( l l ) Complexes
A Not e on For mula e
For t h e p u r p o s e s o f t h i s work t h e f o r m u l a e o ^ s ( t r i e t h y l - p h o s p h i „ e ) p l a t i „ u m ( I I ) complexes c an be c o n s i d e r e d t o be o f two t y p e s ; !)■ Those i n which t h e - t h i r d and. f o u r t h l i g a n d s a r e a n i o n i c (X and Y) a r e g i v e n t he f o r m u l a [ p t X Y ( P E t ^ ) j a n d ,
2) Those i n which t he t h i r d l i g a n d i s a n i o n i c ( x ) and t he f o u r t h n e u t r a l (L) a r e g i v e n the f o r m u l a | p t X L ( P E t ^ ) ^ l
Thus the s e r i e s o f p e r f l u o r o v i n y l b i & r i e t h y l p h o s p h i n e ) p l a t i n u m ( I I ) ' t h e f o u r t h • l i g a n d i s a n i o n i c h a v e ^ e f o r m u l a
. t r a n s . ^ t x ( % ) ( P E t ^ y w h i l e i f t h e f o u r t h l i g a / f T n e u t r a l t h e f o r m u l a i s t r a n s - [ p t ( c ^ F ^ )!.('P R +.
To a v o i d r i p e t l i ^ w h e p - b o t h s e r i e s a r e b e i n g c o n s i d e r e d ■ t o g e t h e r t h e g e n e r a l f o r m u l a t r a n s - ^ t ' & C g P ^ C P E t y J w i l l b e , u s e d . The formulae [ptUCH
3
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) J o r ^ - j ^ t L c K P E t ^ l J s h o u l d be r e a d a s i n d i c a t i n g t h a t 1 c o u l d be e i t h e r a n a n i o n i c o r n e u t r a l ' l i g a n d . When e i t h e r s e r i e s i s d i s c u s s e d s p e c i f i c a l l y t h e s t a n d a r d ' f o r m u l a w i l l be u s e d .I t s h o u l d a l s o be n o t e d t h a t t h e symbols E t and Ph' w i l l be
used for CgHg and
r e sp ec tiv e ly throughout th is work.
( 1) o x i d a t i o n s t a t e s . The g r o u nd s t a t e f o r unbound t r a n s i t i o n m e t a l * atoms o r i o n s c o r r e s p o n d s t o t h a t s t a t e i n which a l l f i v e d o r b i t a l s a r e e n e r g e t i c a l l y d e g e n e r a t e . When a t r a n s i t i o n m e t a l atom o r i o n i s s u r r o u n d e d by l i g a n d s , t h e e n e r g i e s o f t h e d o r b i t a l s on .the m e t ^ a l . a t e i n c r e a s e d due to i n t e r a c t i o n w i t h t h e e l e c t r o n c l o u d s on t h e l i g a n d s . T h e • d e g e n e r a c y o f t h e d o r b i t a l s i s a l s o p a r t i a l l y r emove d. To examine t h i s , c o n s i d e r a t r a n s i t i o n m e t a l i n an o c t a h e d r a l e n v i r o n m e n t , f f t he l i g a n d s a r e p r e s u d t o be l o c a t e d on t h e C a r t e s i a n a x e s , i t can be s e e n t h a t t he ' m e t a l d 2 a n d ' d 2 z X - y 2 o r b i t a l s p o i n t d i r e c t l y a t t h e l i g a n d s , w h i l e t heJ . o J
d , d and d o r b i t a l s a r e d i r e c t e d b et wee n t h e l i g a n d s . Thus the
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i n t e ^ l e c t r o n i c r e p u l s i o n s a r e s t r o n g e s t f o r an e l e c t r o n i n t h e d^2 and d^2 ^2 o r b i t a l s , and the'se o r b i t a l s a r e h i g h e r in e n e r g y t h a n t h e d d and d o r b i t a l s . F i g u r e I - The d 2 and d 2 2 o r b i t a l s a r e
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g xy yz xz a r e r e f e r r e d t o a s t h e L_ o r b i t a l s . The se d e s i g n a t i o n s h a v e . t h e i r 2g . o r i g i n i n g r o u p t h e o r y . ' / ■
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I f . an o c t a h e d r a l l y complexed t r a n s i t i o ^ m e t a 1 p o s s e s s e d e i g h t d e l e c t i o n s s i x o f . t h e s e e l e c t r o n s would occupy t h e t ^ ^ o r b i t a l s w h i l e t h e r e m a i n i n g p a i r o c c u p i e d t h e e o r b i t a l s w i t h p a r a l l e l s p i n s . But i f t he complex were t o ' d i s t o r t i n a t e t r a g o n a l m a n ne r , i e . , t h eEnergy F r e e Ion / / » O c t a h e d r a l F i e l d F i g u r e I d O r b i t a l S p l i t t i n g s in an O c t a h e d r a l F i e l d l i g a n d s oh t h e z moved f a r t h e r from t h e m e ta l, t he e n e r g y o f t he d^2 would drop as'shown in F ig u re I I . i f the t e t r a g o n a l d i s t o r t i o n was g r e a t enouglf t he e l e c t r o n s which had occu p ied t h e e^ o r b i t a l s w i t h p a r a l l e l s p in s would now occupy the lower e n e r g y d^2 o r b i t a l w i t h p a i r e d s p i n s , f t h a s been f ou nd t h a t f o r v e r t l a r g e t e t r a g o n a l , d i s t o r t i o n s , o r t h e l i m i t i n g c a s e o f s q u a r e p l a W c o o r d i n a t i o n , t h e e n e r g y o f t h e d^2 o r b i t a l d r o p s below t h a t o f t h e d^ o r b i t a l . ^ .
The . t r a n s i t i o n m e t a l i o n s which a r e commonly f ou nd t o have square plan ar c o o r d in a t i o n are R h ( l ) , l r ( l ) , P d ( l l ) and A u ( l U ) , a l l
g
o f which are d s p e c i e s . ' Of th e s e P d ( l l ) and P t ( l l ) have r e c e i v e d the most a t t e n t i o n .
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d 2 O c t a h e d r a l F i e l d"41: 44 ^xy' ^yz'
S qua re P l a n a r F i e l d F i g u r e I I .8 O r b i t a l S p l i t t i n g f o r d I o n s i n O c t a h e d r a l and S qu a r e P l a n a r F i e l d s r e a c t i o n . These a r e : ’ 1) O x i d a t i v e a d d i t i o n . T h i s r e a c t i o n c an be s c h e m a t i c a l l y I r e p r e s e n t e d a s +X-Y-(
and examp les a r e ■
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a) t r a n s - f e t l ( C H , ) ( P E t ^ ) j + CH^I ---^‘[pt l ^CCU^) ^(PEt ^) J b) t r a n s - [ i r S K C O ) ( P P h ^ ) ^ ] + --- t^rHgClCCOOCPPh^) ] 2) I n s e r t i o n iii.to m e t a l - h y d r o g e n o r m e t a l - c a r b o n b o n ds . O l e f i n s w i l l i n s e r t i n t o m e t a l - h y d r o g e n bonds a s in '
t r a n s - [ p t I l C l ( P E t ^ ) J + ^ t r a n s - | p t C l ( C ^ H , ) ( F E t ^ ) j and c ar b on monoxide w i l l i n s e r t i n t o m e t a l - c a r b o n bond? a s i n
Of t h e above r e a c t i o n t y p e s ' s u b s t i t u t i o n . r e a c t i o n s have been s t u d i e d m o s t . ^ K i n e t i c i s t s ha ve e xami ned s u b s t i t u t i o n ' a t s q u a r e c o o r d i n a t e P t ( l l ) i n g r e a t d e t a i l ^ I t h a s be en d e m o n s t r a t e d t h a t th6 normal mode o f s u b s t i t u t i o n i s a s s o c i a t i v e , i . e . , a f i v e c o o r d i n a t e
(2 ) ■
i n t e r m e d i a t e i s fo r me d. A number o f f a c t o r s a p p e a r t o have an e f f e c t on the s u b s t i t u t i v e r e a c t i v i t y o f a comp le x. ■ Thesp a r e :
^ 1) The n a t u r e o f t h e e n t e r i n g g r o u p .
2) The n a t u r e o f t h e o t h e r l i g a n d s i n t h e c o m pl e x . ' 3) 'The n a t u r e o f t he l e a v i n g g r o u p .
4 ) The n a t u r e o f t h e r e a c t i o n c e n t e r ,
The f a c t o r s a r e l i s t e d i n o r d e r o f d o m i n a n t e f f e c t . In e q u a t i o n I ' . l we can r e l a t e p o i n t 1) t o t h e n a t u r e o f E> 2) t o t he n a t u r e o f L and X, 3) t o th'e n a t u r e o f A, and 4 ) t o M. I n t h i s work* M ( P t ( l l ) ) i s u n ch a n g e d , a s a r e t h e X l i g a n d s ( ( C y l r ) n P ) . The f a c t o r 2) can be y " / f u r t h e r s u b d i v i d e d i n t o t h e c i s - e f f e e t d e a l i n g w i t h t h e e f f e c t o f X Q * on t h e r e a c t i o n r a t e , and t h e t r a n s - e f f e c t d e a l i n g w i t h t h e e f f e c t o f L. Compared w i t h t h e t r a n s - e f f e e t ‘ t h é c i s - e f f e e t i s q u i t e s m a l l ; i t i s o f i m p o r t a n c e o n l y i n t h o s e - c a s e s i n which t h e li ga nc f t r a n s t o - t h e < ' s u b s t i t u t i o n s i t e h a s ^ v e r y s m a l l t r a n s - e f f e c t . * I n ' d i s c u s s i n g t h e t r a n s - e f f e e t s e p a r a t i o n i n t o two p a r t s i s u s e f u l . T h e s e a r e ground s t a * e e f f e c t s and t r a n s i t i o n s t a t e e f f e c t s .
A Energy
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Ground S t a t e . R e a c t a n t s a -A T r a n s i t i o n S t a t e . F i v e C o o r d i n a t e I n t e r m e d i a t e X-i
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L M '£ + A P r o d u c t s F i g u r e I I I > Energy Pathway f o r S u b s t i t u t i o n R e a c t i o n s i n Sq ua re P l a n a r Complexes To s t u d y t he o v e r a l l t r a n s - e f f e e t k i n e t i c d a t a i s n e c e s s a r y , b u t a s t u d y o f t h e ground s t a t e can be c o n d u c t e d by n o n - k i n e t i c m e t h o d s . 'I n t h e y e a r s s i n c e 1966, wheh the d i v i s i o n between ground s t a t e and a c t i v a t e d s t a t e e f f e c t s was f i r s t s u g g ( | s t e d , c o n s i d e r a b l e d a t a h a v e been c o l l e c t e d r e l a t i n g t o t h e e f f e c t o f t h e l i g a n d L on t h e s t r e n g t h o f t h e bond t r a n s - to i t s e l f i n t h e gro un d s t a t e o f t he m o l e c u l e . T h i s
c o mp l e x e s . / 1 / 2 . The f r a n s - i n f l u e n c e 1 . 2 . 1 . T h e o r i e s o f the T r a n s - i n f l u e n c e The m a j o r p a r t o f t he f o l l o w i n g m a t e r i a l i s from A p p l e t o n ' « iS ^ ( 3 ) (4) e t a l and H a r t l e y . S p e c i f i c r e f e r e n c e s a r e g i v e n t o o t h e r s o u r c e s . ' .
The t r a n s - i n f l u e n c e o f a l i g a n d h a s b een d e f i n e d a s .the
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e x t e n t t o which t h a t l i g a n d weakens a bond t r a n s - t o i t s e l f i n the
( 5 ) ' ' e q u i l i b r i u m s t a t e o f a complex w h e r ea s t h e t r a n s - e f f e c t of the * l i g a n d i s , the e f f e c t the l i g a n d h a s on t h e r a t e o f s u b s t i t u t i o n r e a c t i o n s a t a s i t e t r a n s - t o i t s e l f . The t r a n s - i n f l u e n c e i s t h u s thermodynamic, i n n a t u r e , w h e r e a s t h e t r a n s - e f f e c t i s a k i n e t i c Î , phenomenon. ■ ( 6) G r i n b e r g a d v a n c e d t h e e a r l i e s t t h e o r y o f t h e f o r c e s l e a d i n g t o the t r a n s - i n f l u e n c e . He p o s t u l a t e d t h a t t h e m e t a l , H, i n d u c ed a d i p o l e i n t h e t r a n s -i i n f l u e n c e l i g a n d , L. L i n t u r n ind uc ed a d i p o l e i n M, d i s p l a c i n g e l e c t r o n i c c h a r g e towa rd A, t h e r e b y weak e n i n g t he M-A bond. F i g u r e IV. However, t h i s t h e o r y i s g e n e r a l l y
I
F i g u r e IV G r i n b e r g ' s P o l a r i z a t i o n Theory t h o s e c o mpl exes f o r which t h e t r a n s - i n f l u e n c e i s ^ ^ - r ^ t p r on ou nc e d ( P t ( l l ) ) i s b e l i e v e d to/ be m a i n l y c o v a l e n t . ( 7) S y r k i n p o s t u l a t e d a t h e o r y o f t h e t r a n s - i n f l u e n c e b a s e d on the h y b r i d i z a t i o n of m e t a l s and d o r b i t a l s a s shown i n F i g u r e V. The L-M-A a x i s c an be c o n s i d e r e d t o be a l o n g e i t h e r t h e x a x i s ( s + d ) o r y a x i s ( s - d ) . I f L forms a s t r o n g c o v a l e n t bond w i t h M i t w i l l d e c r e a s e t h e a v a i l a b i l i t y o f the h y b r i d o r b i t a l t o A, w e ak e ni ng t he M-A bond. More r e c e n t l y , t h e o r e t i c a l c a l c u l a t i o n s have b e en c a r r i e d (8) '
o u t w i t h d i f f e r i n g r e s u l t s . Zumdahl and D^ago c a r r i e d o u t
m o l e c u l a r o r b i t a l c a l c u l a t i o n s on a s e r i e s o f c o mpl exes o f P t ( I l ) and t h e i r r e s u l t s s u p p o r t S y r k i n , i . e . , we ake ni ng of t h e M-A bond i s due
s , d 2 2 X - y s + d 2 X - y2 s - d 2 2 x . - y F i g u r e V S y r k i n ' s H y b r i d O r b i t a l s p r i m a r i l y t o t h e w ea ke ni ng o f and ^ 2)"'^ i n t e r a c t i o n s , X —y ( 9 )
However L a n g f o r d and Gray a s c r i b e t h e h i g h t r a n s - i n f l u e n c e of ^ l i g a n d s a s H CH^ and P l y t o t h e . l a r g e o v e r l a p o f t h e s e l i g a n d s w i t h t he PL^^p ^ o r b i t a l , r e d u c i n g t h e a v a i l a b i l i t y o f t h i s o r b i t a l
t o A.
T h e r e h a s been some c o n t r o v e r s y r e g a r d i n g t he r o l e o f TT- b o ndi ng w i t h r e s p e c t t o the t r a n s - i n f l u e n c e . Fo r example t he h i g h t r a n s - e f f e c t of p h o s p h i n e s was a s c r i b e d t o t h e a b i l i t y of t he p h o s p h i n e
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t o remove e l e c t r o n i c c h a r g e from t h e d x z , dyz and dxy o r b i t a l s . * Thus- i f - b o n d i n g l i g a n d s t r a n s - t o t h e p h o s p h i n e would be l e s s s t r o n g l y I &ou%d. However, i t was p o i n t e d o u t t h a t a s t r o n g C T e f f e c t c o u l d q u i t e
a d e q u a t e l y d e s c r i b e t he e f f e c t o f t h e p h o s p h i n e l i g a n d on l i g a n d s t r a n s
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) - ■-t o i -t s e l f . i s now f e l t t h a t ' 1 7 - b o n d i n g i s o f i m p o r t a n c e i n u n d e r s t a n d i n g t h e t r a n s - i n f l u e n c e o n l y i n c a s e s . w h e r e s y n e r g i c ' ^ - b o n d i n g i s n e c e s s a r y t o t h e f o r m a t i o n o f t h e t r bond, i . e . , c omple xes c o n t a i n i n g c a r b o n monoxide o r o l e f i n s . With s y n e r g i c b on d i n g t h e c o n t r i b u t i o n from m e t a l d x z , dyz and dxy o r b i t a l s t o v a c a n t l i g a n d o r b i t a l s h a s an e f f e c t on t h e s t r e n g t h o f t h e m e t a l - l i g a n d <T b on d. j 1 . 2 . 2 . • Measurement o f the Tr a n s - i n f l u e n c e . ^ - \ The t r a n s - i n f l u e n c e h a s been me as u re d by a v a r i e t y o f t e c h n i q u e s o f wÈTch t he most i m p o r t a n t a r e x - r a y c r y s t a l l o g r a p h y , ^ v i b r a t i o n a l s p e c t r o s c o p y and n u c l e a r m a g n e t i c r e s o n a n c e s p e c t r o s c o p y . 1 . 2 , 2 . 1 . X -r ay C r y s t a l l o g r a p h y I • X - r a y c r y s t a l l o g r a p h y a p p e a r s to be an i d e a l way t o me as u re t h e t r a n s - I n f l u e n c e . As t h e t r a n s - i n f l u e n c e o f t h e l i g a n d L i s
changed f o r a s e r i e s o f t r a n s - ^MLAXgj s p e c i e s t h e M-A bond d i s t a n c e s h o u l d c h a n g e . T he re a r e , h ow e v e r , a number o f d i f f i c u l t i e s i n h e r e n t i n t h e method.
I ) A c r y s t a l s t r u c t u r e a n a l y s i s i s r a t h e r mere tinJe -con suming and e x p e n s i v e th an s a y , o b t a i n i n g an i n f r a r e d o r n u c l e a r m a g n e t i c
r e s o n a n c e . ( n . m . r . ) spectrum o f the same compound.
2) D i f f e r e n c e s ï n the M-A bond l e n g t h s f o r a s e r i e s o f P s w i t h c h a n g i n g L are q u i t e s ^ l l and may be o f t he . o r d e r o f m a g n i t u d e o f t h e e x p e r i m e n t a l e r r o r . ' ' .
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3) c r y s t a l i n t e r a c t i o n s can c a u \e s i g n i f i c a n t changes' in bond l e n g t h , i . e . , changing the cong.ter: io h :ca n cause s l i g h t d i f f e r e n c e s in bond le n g th or d i f f e r e n t 'c r y s t a lM n e M o d i f i c a t i o n s o f the same tompound can jhow d i f f e r e n t b on f l e n g t h s .
Ihe q u a l i t y o f the c r y s t a l employed in .the d e te r m in a tio n and the p a r t i c u l a r method .by which the data i s c o l l e c t e d and the
s t r u c t u r e r e f i n e d can cause sm a ll changes' i J t h e s t r u c t u r a l parameters
o b t a in e d . ' \ ■
NO complete data have y e t b e e ^ ^ ^ e d on the changes in the M-a bond le n g th on changing the lig a n d I in a s e r i e s o f complexes — " “ 2- P ^ l b l e to c o n s t r u c t an order o f c î y s
-t a l l o g r a p h i c ^ - i n f l u e n c e from r e l a -t l compounds. T h i s y i e l d s the ord er o f s t r u c t u r a l I m s - W l u e n c e 0 < k H ^ = c l- = C e C O y m c - C O < A s R ' < P R ^ ~ c a r b e n e s V i b r a t i o n a l S p e c t r o s c n n v The V i b r a t i o n a l s t r e t c h i n g m ot ion o f a d i a t o m i c m o l e c u l e A-B c an be a p p r o x i m a t e d by a h a r mo ni c o s c i l W m . . The f r e q u e n c y o f v i b r a t i o n I s g i v e n by p - I i r ? 2 fc y yjL ( 1 . 2 )
where j j i s t he v i b r a t i o n a l f r e q u e n c y , f i s t h e f o r c e c o n s t a n t of À-B bond and JX i s t h e r e d u c e d mass g i v e n by
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/ -'A +
^ ^ The a s s u m p t i o n i s made t h a t f o r a s e r i e s ' o f c omplexes t r a n a -JîlLAX^jyw r e m a i n s unc hange d w i t h c h a n g e s i n L a n d . t h a t t h e f o r c e c o n s t a n t
o f t h e M-A bond i s p r o p o r t i o n a l t o t h e s t r e t c h i n g f r e q u e n c y p . a d e c r e a s e i n t h e s t r e t c h i n g f r e q u e n c y d e n o t e s a weakening o / ^ t h e . bond. The^r-g^^mpt i o n t h a t y t r e m a i n s unchanged d oe s n o t s t r i c t l y h o l d . For e x am pl e , yi f o r t h e P t - C s t r e t c h i n t r a n s - | p t C C ^ F ^ ) < ' C O ) ( P E t ^ ) ^ j i s 6 9 .2 a . m . u . , w h e re as / i f o r t r a n s - [ pt( C^F^) fp(OPh)^J ( P E t ^ ) j i s 73. 2 a . m . u ( The i n c r e a s e i n r e d u c e d mass i n d i c a t e s t h a t t h e f r e q u e n c y o f t he P t- C s t r e t c h w i l l d e c r e a s e from L =" CO t o L = PCOPn)^, i r r e s p e c t i v e i / o f any c h a ng e s i n t r a n s - i n f l u e n c e . A f u r t h e r c o m p l i c a t i o n a r i s e n i n t h a t t h e r e i s a p o s s i b i l i t y o f the M-A v i b r a t i o n c o u p l i n g w i t h ' o t h e r v i b r a t i o n a l modes o f t h e
>
m o l e c u l e . V i b r a t i o n a l c o u p l i n g s a r e n o r m a l l y i g n o r e d i f ^ i s w e l l s e p a r a t e d from o t h a r v i b r a t i o n a l modes which m i g h t c o u p l e .
Cl _ A l s o , d i f f e r e n c e s between s p e c t r a o b t a i n e d from s a m p l e s i n
s o l u t i o n and i n t h e s o l i d s t a t e a r e s omet i mes n o u e d . As i s f ound w i t h ' c r y s t a l l o g r a p h y , c o u n t e r i on c h a n g e s c an a l s o c a u s e s l i g h t s h i f t s i n ' M-A s t r e t c h i n g f r e q u e n c i e s .
Complexes o f t h e t y p e t r a n s - |ptLCIXg] h ave been exami ned i n d e t a i l w i t h r e g a r d t o m e t a l - c h l o r i d e s t r e t c h i n g f r e q u e n c y . I t h a s been ’found t h a t t h i s f r e q u e n c y i s v i r t u a l l y i n d e p e n d e n t o f X, and a p p e a r s a s a s i n g l e band a t a b o u t 300cm The v a l u e of - 1 - 1 c h a n g e s from a h i g h o f .344cm f o r L' = CO t o a low o f 235cm f o r L = GeMe^ w i t h X a s e i t h e r P E t ^ o r PMe^Ph. A t r a n s - i n f l u e n c e s e r i e s ^ f o r some t h i r t y - f i v e l i g a n d s h a s been c o m p i l e d ; t h o s e o f i n t e r e s t t o t h i s wor'. in o r d e r o f i n c r e a s i n g t r a n s - i n f l u e n c e a r e CO^CKpy <P( OPh ) ^cJP (OMe ) 2<PPh_<PE L2<CH“ <C^H^H" .
The s e r i e s o f c omplexes t r a n s - jptHLxJ have a l s o been exami ned i n some, d e t a i l and a t r a n s - i n f l u b n c e s e r i e s a s s e m b l e d f o r some t h i r t y l i g a n d s . A p p r o p r i a t e members o f - t h i s s e r i e s a r e
< c r < B r <P..^<py<I <NO^<CO<P(Ph)^<P(OPh)^ccPEt^<:P(OMe)^<CN". Once a g a i n c h a n g i n g t h e g r o up s c i s - t o t h e h y d r o g e n atom h a s l i t t l e e f f e c t on D i f f i c u l t i e s can a r i s e i n t h a t ' j j ^ ^ ^ a p p e a r s t o be somewhat s o l v e n t d e p e n d e n t , and t he m a g n i t u d e - o f t h e s o l v e n t e f f e c t c h a n g e s with-L. V i b r a t i o n a l c o u p l i n g occ.urs f o r h y d r i d e t r a n s - t o l i g a n d s s uch a s • CN CO and RNC, b u t c o r r e c t e d v a l u e s can be o b t a i n e d by o b s e r v i n g t h e d i f f e r e n c e between p and jj i n a n a l o g o u s c o m p l e x e s . FL-li - )
The c omp le xes t r a n s - | pt L ( C H o ) X j have n o t been s t u d i e d i n a s much d e t a i l a s t h e c h l o r o and h y d r i d o c o m p l e x e s , *but a g a i n a t l e a s t
two t r a n s - i n f l u e n c e s e r i e s b a s e d on' U^ _ can be c o n s t r u c t e d . Th es e
c-r P t - C
s e r i e s a r e CN <l"<NO“< D r" < cr <S CN “<NO” f o r t r a n s - j p t X ( C l U ) ( P E L ^ ) j . . . comple xes and py<C2H^<C0 < p h o s p h i n e < c a r b e n e f o r t r a h s - t ( CH^) L( PMe^Ph) ^ J "
c o m p l e x e s . The p band i s - n o r m a l l y v e r y weak and p o s s i b i l i t i e s
rC-C \
f o r v i b r a t i o n a l c o u p l i n g can o c c u r w i t h s p e c i e s such a s CN and NO». , I n t e r n a l l i g a n d v i b r a t i o n s such a s o r h a v e a l s o been
c o r r e l a t e d w i t h t r a n s - i n f l u e n c e b u t t h e s i t u a t i o n i s much more c omplex. The c o m p l e x i t y i s due t o t h e f a c t t h a t the e f f e c t o f t h e l i g a n d L on
th e back d o n a t i o n t o t h e v a c a n t i T o r b i t a l s o f A m us t be c o n s i d e r e d , a s w e l l a s t he d i r e c t t r a n s - i n f l u e n c e on t h e M-A C b on d . Sys tems such a s t r a n s - jptCl^LCamine)^ h ave been i n v e s t i g a t e d and i t was found t h a t p c o u l d be c o r r e l a t e d w i t h Lj_ „ f o r a s e r i e s o f L.
N-l i • P t - H
1 . 2 . 2 . 3 . N u c l e a r M a g n e t i c R es o na n ce S p e c t r o s c o p y
Chemical s h i f t s h a v e n o t been much employed a m e as u r e of the t r a n s - i n f l u e n c e . The o v e r a l l s h i e l d i n g c o n s t a n t f / i r a n u c l e u s i s composed o f d i a m a g n e t i c and p a r a m a g n e t i c c o n t r i b u t i o n s , The d i a m a g n e t i c c o n t r i b u t i o n A s c o n s i d e r e d t o be s m a l l when t hé
V
c h e m i c a l s h i f t s a r e q u i t e l a r g e , a s i s t h e c a s e w i t h t h e compounds » i n q u e s t i o n . The p a r a m a g n e t i c . c o n t r i b u t i o n t o t h e c h é m i x a l s h i f t o f an atom bonded t o , f o r e x a m p l e , p l a t i n u m a r i s e s from s h i e l d i n g of t he s u b s t i t u e n t by t h e d o r b i t a l s on p l a t i n u m . , T h e r e f o r e , i f t h e atom is^ f a r from t he m e t a l t h e r e s h o u l d be l e s s s h i e l d i n g and c o n s e q u e n t l y a s m a l l e r c h e m i c a l s h i f t . But o t h e r e f f e c t s a t t h e p l a t i n u m n u c l e u s .a s s o c i a t e d w i t h c h a n g i n g L, c o u l d change t h e d o r b i t a l c l o u d on t h e m e t a l , t h u s c h a n g i n g t h e p a r a m a g n e t i c c o n t r i b u t i o n , w i t h o u t any
c hange i n t h e M-A bond. _ ^
T h e r e i s e v i d er j ce t h a t t h e c h e m i c a l s h i f t o f a h y d r o g e n atom bonded t o p l a t i n u m i n t h e s e r i e s ’ |ptHL(PR^)g] d o e s c o r r e l a t e r o u g h l y (1 0) ■ w i t h o t h e r p a r a m e t e r s such a s ^ , b u t i t i s f e l t t h a t , a t t h i s t i m e , t h e r e a r e more d i r e c t methods o f m e a s u r i n g t h e t r a n s - i n f l u e n c e , such a s m e t a l - l i g a n d s t r e t c h i n g v i b r a t i o n s o r n u c l e a r * . m a g n e t i c r e s o n a n c e c o u p l i n g c o n s t a n t s . ^ The s p i n - s p i n c o u p l i n g s in n u c l e a r magneti*b r e s o n a n c e e x p e r i - ' ments a r e t h o u g h t t o be t r a n s m i t t e d from n u c l e u s bo n u c l e u s by t h r e e
me ch a ni s ms . The f i r s t mechanism i n v o l v e s t r a n s m i s s i o n o f s p i n alUgn- • , ment v i a t h e b o n d i n g e l e c t r o n s . T h i s i s t h e F er mi c o n t a c t t e rm and ^
i t i s f r e q u e n t l y c o n s i d e r e d t o be the dominant t e r m . The s ec ond . m e cha ni ^n i n v o l v e s , t h e i n d u c t i o n o f o r b i t a l e l e c t r o n i c c u r r e n t s by t h e n u c l e a r moment p r o d u c i n g m a g n e t i c f i e l d s a t t h e s i t e s o f o t h e r n u c l e i . T h i s p r o c e s s i s t er me d t h e o r b i t a l c o n t r i b u t i o n . The t h i r d , t h e d i p o l e - d ip ol e me char xl s m, i n v o l v e s t h e t r a n s m i s s i o n o f n u c l e a r s p i n s v i a p o l a ^ -z a t i o n - o f t h e - v a l e n c e e l e c t r o n s p i n . Usvfally o n l y t h e F er mi c o n t a c t -- : '
t e r m i s c o n s i d e r e d when c a l c u l a t i n g couplin'g^ c o n s t a n t s . The i n c l u s i o n o f o r b i t a l and d i p o i e - d i p o l e c o n t r i b u t i o n s w i l l be d i s c u s s e d i n 3 . 2 . 2 . The term t h r o u g h s p a c e c o u p l i n g w i l l be a p p l i e d t o t h e s e l a t t e r
con-t r i b u con-t i o n s . T h i s t e r m h a s a l s o been a p p l i e d t o c o u p l i n g s be t we en n u c l e i s e p a r a t e d by many bonds b u t s p a t i a l l y p r o x i m a t e . The l a t t e r u s a g e i s n o t i n t e n d e d h e r e .
y
The m a g n i t u d e o f t h e c o u p l i n g c o n s t a n t between two
d i r e c t l y bound a u c l e i , A and B, c o n s i d e r i n g o n l y the^ Fe rmi c o n t a c t
. t e rm, i s g i v e n i n t h e t r a n s - i n f l u e n c e l i t e r a t u r e ^ y t he p r o p o r t i o n a l i t y y Ïa Vb S ^ ( 0 ) S g ( 0 ) l ' Y Â ( n s ' ) P l ' T É ( n s ) < 4 ^ ^ 1 ^ ^ Ae ( l . i ) ' / _ _ _ • where i s t he v l l u e o f t h e c o u p l i n g c o n s t a p t , and a r e 2 2 t h e g y r o m a g n e t i c r a t i o s o f A and B, S ( 0 ) and S ^ ( 0 ) r e p r e s e n t t h e s ‘ c h a r a c t e r u s ed by e a c h o f t h e A and B a to ms i n t h e i r b ondi ng h y b r i d o r b i t a l s , | ^""'KfiCns) ^ ^ ’ a r c t h e e l e c t r o n d e n s i t i e s - 3 o f t h e n s v a l e n c e o r b i t a l s a t t h e i r r e s p e c t i v e n u c l e i and A e i s a mean t r i p l e t - s i n g l e t e x c i t a t i o n - e n e r g y .
O b v i o u s l y the above e q u a t i o n w i l l n o t a l l o w t h e d i r e c t com p u t a t i o n o f t h e c o u p l i n g c o n s t a n t b u t w i l l a l l o w c o m p a r i s o n o f t h e
* ■ i
r a t i o s of c o u p l i n g c o n s t a n t s f o r re' l. ated t y p e s o f compounds. ,
' . I n a c l o s e l y r e l a t e d s e r i e s o f compounds, e . g . , t r a n s -jPtLAXJ, where o n l y t h e A l i g a n d i s b e i n g changed i t i s n o r m a l l y c o n s i d e r e d t h a t ^ Ae, S ^ ( 0 ) , and i^> change v e r y l i t t l e . Only t he Sp^(O) ' and l " ' | ^ t (6 s ) ^ ^ ^ I ^ t e rm s a r e thought! t o c h a n g e , an<4 t h e change in
2
t h e Sp^(O) term i s t h o u g h t Co be d o m i n a n t . For example f o r t h e com pound c i s - | p t C l ( C I l g ) ( P E t ^ ) ^ j p f o r p h o s p h o r u s t r a n s - t o t h e m e t h y l g r o up i s 1719 Hz w h i l e J f o r p h o s p h o r u s t r a n s - t o t h e c h l o r i d e f s l^t -p ^ 4179 Hz. ' The l a r g e d i f f e r e n c e i n c o u p l i n g c o n s t a n t mu st o r i g i n a t e 2 wltli n d i f f e r e n c e in S p ^ ( O ) , t h é p l a t i n u m s c h a r a c t e r a v a i l a b l e f o r u s e %
i n t;he two P t - P b o n d s , s i n c e j '|Çt.(6s)^*^^ | ^ w oul d, o f n e c e s s i t y , be t h e same f o r b o t h p t - P b o n d s .
Over more t h a n one bond t h e c o u p l i n g " c o n s t a n t J i s A , . . N g i v e n by
A...NOC
i r
JN(ns)(0)
2 3
A e'
( l . (
where a l l symbols have t h e me ani ng s g i v e n a bo ve w i t h t h e e x c e p t i o n of f ( A . . , K ) ' w h i c h r e p r e s e n t s a l l t h e e l e c t r o n i c and s t e r e o c h e m i c a l f a c t o r s c o n c e r n e d in t he t r a n s m i s s i o n o f t h e ' c o u p l i n g fr om A t o N. , *
, T h e r e f o r e , t h e c u r r e n t t h e o r i e s h o l d t h a t i n a s e r i e s o f com pounds t r a n s - [iHLAX^i where A i s b e i n g c h a n g e d , t h e m a g n i t u d e o f ,
--- ■ t Zj ^ ^ P t - L
s h o u l d depend on t h e amount o f Pt-^^ o r b i t a l a v a i l a b l e f o r t h e PL-L bon'd. Li g an ds A w i t h a h i g h t r § n s - i n f l u e n c e would c o n c e n t r a t e PL^^ e l e c t r o n d e n s i t y i n t h e P t - A bond, t h u s d e c r e a s i n g t h e a v a i l a b i l i t y o f t h e P t ^ ^ " o r b i t a l f o r b o n d i n g t o L. T h i s - w e a k e n i n g o f t h e P t - L bond would be
} shown by a d e c r e a s e i n t h e v a l u e of
T r a n s - i n f l u e n c e s e r i e s ba se d on c o u p l i n g o v e r one bond have
1 " 1
been c o mp il e d e m p l o y i n g f o r c omplexes t r a n s - A-Pt-H o r Jpj. p f o r c omple xes t r a n s - A - P t - P . S i m i l a r s e r i e s w i t h c o u p l i n g o v e r two
*
2 2
bonds b as ed on J,, „ i o r complexes t r a n s - A - P t - C H - o r _ f o r
com-Pt- H 3 P t - F
p l e x e s t r a n s - / - P t - C F ^ have a l s o been c o m p i l e d . . T he s e s e r i e s a r e q u i t e s i m i l a r . For e x a m p l e , t h a t f o r compounds o f t h e t y p e t r a n s - jptHAX^]
# ■*
where X=PEt^ o r PMePh^ in o r d e r o f i n c r e a s i n g t r a n s - i n f l u e n c e ( o r d e r
'
(
I
V
o f d e c r e a s i n g i s L <^NO^<Br < C I <SCN < py < C 0 <PPh^<P(OPh)^<PEc^CCNT. \ I t i s a norma l p r a c t i c e i n t h e l i t e r a t u r e to " a t te mp t to c o r r e l a t e t r a n s - i n f l u e n c e s e r i e s m e a s u r e d f o r d i f f e r e n t complexes *o r by d i f f e r e n t me,thods. The c o u p l i n g c o n s t a h t s J are* o f t e n p l o t t e d P t - L
a g a i n s t Tf t he r e s u l t i s a s t r a i g h t l i n e i t i s c o n s i d e r e d t h a t / d o es i n d e e d me as ur e t h e t r a n s - - i n f l u e n c e . • F u r t h e r , „ h as
Iru—L ■ PC—H
been p l o t t e d a g a i n s t ^ from v i b r a t i o n a l s p e c t r a , once a g a i n y i e l d i n g a s t r a i g h t l i n e p l o t . T h i s i n d i c a t e s t h a t t h e two s p e c t r o s c o p i c t e c h n i q u e s a r e m e a s u r i n g t h e same phenomenon,
( 11) ■ ^
R e c e n t l y M a t h e r , P i d c o c k a nd Rapsey d e s c r i b e d a c o r r e l a t i o n
1
be twee n ^ and t h e P t - P bojnd l e n g t h s i n a s e r i e s o f c omp le xes i n which t h e p h o s p h o r u s atom was t r a n s - t o v a r i o u s l i g a n d s . Although^ the c o r r e l a t i o n was n o t l i n e a r t h e r e a p p e a r s t o be a d e f i n i t e r e l a t i o n s h i p . The p l o t s a r e v e r y s i m i l a r i n s h a p e t o C o t t o n ' s bond l e n g t h - b o n d
1 . 3 O b j e c t é o f R e s e a r c h
The o b j e c t o f t h e r e s e a r c h was t o p r e p a r e s e r i e s o f
comp le x es of' t h e t y p e s t r a i l s - [ptXCC^F^)(PEt^) J and t r a n s - [ p t ( C ^ F , ) L ^ ( P E t g )2^ ^ C l O ^ and to d e t e r m i n e i f t h e n . m . r . c o u p l i n g bet.ween p l a t i n u m a n d ' e a c h o f t h e t hr e ' e f l u o r i n e n u c l e i i n t h e p e r f l u o r o v i n y l l i g a n d c o u l d be c o r r e l a t e d w i t h e x i s t i n g m e a s u r e s o f t h e n . m . r . t r a n s - ■ i n f l u e n c e . J Ù
CHAPTER I I
EXPERIMENTAI
P e r f l u o r p v i n y l b i s ( t r i e t h y l p h b s p h i n e ) p l a t i n u m ( l l ) Complexes
2 . 1 . G e n e r a l
2 . 1 . 1 . C h em ic al s d
The t e t r a f l u o r o e t h y l e n e emploÿeS ill' ^t h e p r e p a r a t i o n of t r a n s - ^ e r f l u o r o v l n y l c h l o f o b i s ( t r i e t h y I p h o s p h i n e ) p l a t i n u m ( I l ) was o b t a i n e d from Columbia O r g a n i c Ch em ic al s Co. I t was us ed
w i t h o u t p i ^ i Æ i c a t i o n a f t e r a n i n f r a r e d s p e c t r u m showed o n l y a b s o r p t i o n s due t o t e t r a f l u o r o e t h y l e n e . A l l o t h e r p r e p a r a t i v e c h e m i c a l s employed were r e a g e n t g r a d e . S o l v e n t s were s p e c t r a l g r a d e and were d r i e d o v e r m o l e c u l a r s i e v e , w i t h t h e e x c e p t i o n o f n - p e n t a n e , which was d i s t i l l e d
frpm p h o s p h o r o u s p e n t o x i d e and s t o r e d o v e r s odium.
0
2 . 1 . 2 . I n s t r u m e n t s
I n f r a r e d s p e c t r a were . o b t a i n e d a s N u j o l m u l l ^ between c es ium i o d i d e p l a t e s on a Beckman I . R . 2 0 (louble beam s p e c t r o m e t e r . Cesium i o d i d e r e f e r e n c e p l a t e s were u s e d . S p e c t r a were r u n fr oi \^ 25 0 t o 4000 cm R e p r o d u c i b i l i t y was - 3 cm
1 '
A l l m e l t i n g p o i n t s were o b t a i n e d on a R e i c h e r t h o t s&6 ge
m e l t i n g p o i n t a p p a r a t u s . M e l t i n g p o i n t s were n o t c o r r e c t e ^ The p e r f l u o r o v i n y l coMpounds were a n a l y z e d on a P e r k i n - E l m e r model 240'' c a r b o n - h y d r o g e n ^ n i t r o g e n a n a l y z e r by D.L. M c G i l l i v r a y o f t h e C h e m i s t r y
(Zx
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.
^
D e p a r t m e n t , U n i v e r s i t y o’f V i c t o r i a . The p r o t o n - s p e c t r a o f t h e p e r f l u o r o v i n y l s p e c i e s were o b t a i n e d a t 35 °C i n 0 . 5 cm t h i n w a l l n . m . r . t u b e s on a P e r k i n - E l m e r model R12a s p e c t r o m e t e r . ' The s p e c t r a »were r un a t 60 MHzi.*. A l l s p e c t r a were r u n i n c h l o r o f o r m e x c e p t t h a t o f t r a n s - p e r f l u o r o v l n y l - a z i d o b i s ( t r i e t h y l p h o s p h i n e ) p l a t i n u m ( H ) which was i n s o l u b l e i n c h l o r o f o r m . I t s s p e c t r u m was o b t a i n e d i n
m e t h a n o l . F o r t h o s e compounds which d i d n o t r e s o n a t e n e a r c h l o r o f o r m , t h i s s o l v e n t was employed a s i n t e r n a l , r e f e r e n c e . F o r t h o s e compounds d i s p l a y i n g r e s o n a n c e s n e a r c h l o r o f o r m , i . e . , t h o s e w i t h p h e n y l g r o u p s , d e u t e r o c h l o r o f o r m was u s e d a s s o l v e n t and t e t r a m e t h y l s i l a n e ( T . M . S . ) employed a s i n t e r n a l r e f e r e n c e . The u s e o f T.M.S. was a v o i d e d a s f a r as p o s s i b l e a s i t c a u se d p r e c i p i t a t i o n o f t h e p e r f l u o r o v i n y l s p e c i e s . The f l u o r i n e s p e c t r a were o b t a i n e d on a . V a r i a n model HA.60
I
I . L . S p e c t r o m e t e r a t 5 6 . 4 4 6 MHz. The s o l v e n t s u s e d were a s t h o s e f o r p r o t o n s pe&_r a. The s p e c t r a were r u n a t room t e m p e r a t u r e and in a l l c a s e s L r i c h l o r o f l u o K ^ m e t l i ^ x ^ w a s t h e e x t e r n a l r e f e r e n c e . Due to t he low c o n c e n t r a t i o n o f e a c h f l u o r i n e n u c l e u s , t h e s p e c t r a were c o m p i l e d
'
on a N o r t h e r n S c i e n t i f i c Model NS-560, SAC s e r i e s , time a v e r a g i n g c o m p u t e r . T o t a l s c a n s ‘f o r each n u c l e u s varied,, from 10 s c a n s a t 500
s e c o n d s p e r s c a n t o 200 s c a n s a t 50 s e c o n d s p e r s c a n . - I n g e n e r a l , t he b e s t r e s u l t s were o b t a i n e d w i t h a l a r g e number o f s h o r t s c a n s .
F l u o r i n e n u c l e i were a s s i g n e d l a b e l s as i n d i c a t e d in T a b l e s I , I I and I I I . The s p e c t r u m f o r n u c l e u s I I I was t a k e n t w i c e , once
/
o v e r 1000 Hz t o m e a s u r e P t - F and F-F c o u p l i n g s and once o v e r 250 Hz
i
t o measure P-F c o u p l i n g s .
, . . ■
2 . 2 . L. T r a n s - h y d r i d o c h l o r o b i s ( t r i e t h y 1p h o s p h i n e ) p l a t i n u m ( I I ) T h i s compound was p r e p a r e d by the method o f C h a t t and
(12)
Shaw . C i s - d i c h l o r o b i s ( t r r e t h y I p h o s p h i n e ) p l a t in um( 11) was p r e p a r e d by r e a c t i n g 3 . 7 ml o f t r i e t h y l p h o s p h i n e w i t h 5 . 0 g o f p o t a s s i u m t e t r a c h l o r o p l a t i n a t e ( l l ) ( 1 2 mmol) in I0 0 \ml w a t e r f o r .» ' ' . V f o r t y - f i v e m i n u t e s . To a s s i s t c o n v e r s i o n t o the jbis i s o m e r , t h e m i x t u r e was h e a t e d on "a w a t e r b a t h , w i t h s t i r r i n g , x v n t i l ; t h e f i r s t b l a c k p a r t i c l e s i n d i c a t i n g d e c o m p o s i t i o n a p p e a r e d . The m i x t u r e was c o o l e d , f i l t e r e d , washed w i t h w a t e r and d r i e d u n d e r vacuum. To
com-I
p l e t e c o n v e r s i o n t o t h e c i s i s o m e r , t h e f i l t e r e d m a t e r i a l was b o i l e d i n a n y h d r o u s ' d i e t h y l e t h e r c o n t a i n i n g 0 . 3 â ü t r i e t h y l p h o s p h i n e . The s o l u t i o n was b o i l e d a l m o s t t o d r y n e s s and t h e r e s i d u a l e\|.her t h e n removed u n d e r vacuum. Y i e l d was 4 . 9 g ( 9 , 8 mmol) 81%. The c i s - d i c h l o r o b i s ( t r i e t h y l p h o s p h i n e ) p l a t i n u m ( l l ) was t h e n r e d u c e d by t r e a t ment w i t h 4 . 0 ml h y d r a z i n e h y d r a t e in 100 ml w a t e r . T h i s s o l u t i o n was h e a t e d on a w a t e r b a t h f o r t h i r t y m i n u t e s . A f t e r c o o l i n g , d i l u t e HCl was added u n t i l t he m i x t u r e was a c i d t o n a r r o w r a n g e Li t mu s p a p e r
(pH 6 t o 8^ 5 ) . The p r e c i p i t a t e o f t r a n s - h y d r i d o c h l o r o b i s ( t r i e t h y l -
p h o s p h i n e ) p l a t i n u m ( I I ) was c o l l e c t e d and d r i e d u n d e r vacuum, and r e c r y s t a l l i z e d from p e n t a n e . Y i e l d was 3 . 0 g ( 6 . 4 mmol), 53%, b ase d on KgPbCl^. M e l t i n g p o i n t 82 °C, Pt-H s t r e t c h i n g f r e q u e n c y 2222 cm’'^
n ? 1 ( ' 1 3 ' ) '
2 . 2 . 2 . P r e p a r a t i o n o f t r a n s - p e r f r u o r o v i n y I c h l o r o b i s ( t r i e t h y I p h o s p h i n e ) p l a t i n u m ( I I )
T h i s compound was p r e p a r e d by t h e method o f C l a r k and (14)
Ts ang . T r a n s - h y d r i d o c h 1 e r o b I s ( t r i e t h y l p h o s p h i n e ) p l a t i n u m ( l l )
$
(5 00 mg, 1 . 0 7 mmol) was w ei ghe d i n t o a d r y 250 ml c a p a c i t y p y r e x c a r i u s t u b e . The t u b e was a t t a c h e d t o a vacuum l i n e and e v a c u a t e d . 50 ml o f s p e c t r a l g r a d e b e nz en e was c o n d en s e d i n t o t h e c a r i u s t u b e , f o l l o w e d by 500 mg ( 5 . 0 mmol) t e t r a f l u o r o e t h y l e n e . The tithe was flame s e a l e d and removed to' a p r o t e c t i v e m e t a l t u be which was p l a c e d i n an oven a t 95 f o r t w e n t y - n i n e h o u r s . The c a r i u s t u b e was c o o l e d t o - 1 9 6 °C and o p e n e d . B e nz e ne , u n r e a c t e d t e t r a f l u o r o e t h y l e n e and g a s e o u s r e a c t i o n p r o d u c t s were removed. The s o l i d m a t e r i a l r e m a i n i n g in t he t u be was e x t r a c t e d w i t h warm c y c l o h e x a n e . The c y c l o h e x a n e was removed on a r o t a r y e v a , , o r a t o r and an i n f r a r e d s p e c t r u m o f t h e s o l i d r e m a i n i n g was o b t a i n e d a s a n u j o l m u l l . The a b s e n c e o f a b s o r p t i o n a t 2220 cm ^
i n d i c a t e d t h e r e a c t i o n h a d , g o n e t o c o m p l e t i o n . Two 0=0 d o u b l e bond*
-1
s t r e t c h i n g bands were n o t e d w i t h f r e q u e n c i e s a t 1648 cm due t o
t r a n s - (1- d i f l u o r o m e t h y1- 2 ,2 - d i f l u o r o v i n y l ) c h l o r o b i s ( t r i e t h y l p h o s p h i n e ;
p l a t i n u m ( l l ) and a t 1725 cm ^ .due t o t r a n s - p e r f l u o r o v i n y I c h1e r o b i s
( t r i e t h y l p h o s p h i n e ) p l a t i n u m ( I I ) , c f 1643 cm ^ and 1724 cm ^ These two compounds were s e p a r a t e d on a f l o r i s i l column, 100-200 mesh, 2 . 5 cm i n d i a m e t e r and 60 cm in l e n g t h . C hl or of or - m- pe nt a ne i n a 2 :1 r a t i o was u s ed a s e l u e n t and t h e p e r f l u o r o v i n y l s p e c i e s was t h e f i r s t p r o d u c t o f f the column. Y i e l d 181 mg ( 0 , 3 3 mmol) 32%. The y i e l d o f t r a n s
-( 1- d i f luorome t hy 1-2 ,2- d i f l u o r o v i n y O^duTor o b i s ( t r i e t h y l p h o s p h i n e )
p l a t i n u m ( l l ) was 114 mg ( 0 . 1 9 mmoi) 18%. ^ ___ ^
' . \
• ' A t t em p t s were made t o improve t he y i e l d o f tr ai ps
-p e r f l u o r o v i n y l c h l o r o b i s C t r i e t h y ] -p h o s -p h i n e ) -p l a t i n u m ( I I ) . When t h e r e a c t i o n s o l v e n t , b e n z e n e , was- V i g o r o u s l y d r i e d no r e a c t i o n o c c u r r e d and t h e p a r e n t h y d r i d e was r e c o v e r e d u n c h a n g e d . , Wlien a seven f o l d e x c e s s o f t e t r a f l u o r o e t h y l e n e was employed a t a r e a c t i o n t e m p e r a t u r e
o
o f 110 C f o r f o r t y - e i g h t h o u r s in 50 ml o f c y c l o h e x a n e a s a r e a c t i o n s o l v e n t , t h e y i e l d o f t r a n s - p e r f l u o r o v i n y l c h l o r o b i s ( t r i e t h y l p h o s p h i n e ) p l a t i n u m ( l l ) i n c r e a s e d t o 54.8%.
Wlien t h e above c o n d i t i o n s were u s e d i n c o n j u n c t i o n w i t h a new c a r i u s t u b e y i e l d s r o s e . t o 80.8%. '
C h a r a c t e r i z a t i o n was a s «foll ows. M e l t i n g p o i n t 58-59 °C,
c f . 61 A n a l y s i s . C a l c u l a t e d f o r 3 0 . 6 9 ;
H, 5 . 5 2 . Found: C, 3 0 , 8 9 ; H, 5 . 5 2 .
The i n f r a r e d s p e c t r u m showed Pq_q a t 1725 cm ^ and
Mp^-Ci a t 285 and 305 cm ^ , c f . Pq_q 1724 cm The p r o t o n
n . m . r , s p e c t r u m showed a q u i n t e t ( r e l a t i v e a r e a t h r e e ) a t 6 . 1 6 p . p . m . u p f i e l d from c h l o r o f o r m and a s e p t e t ( r e l a t i v e a r e a two) a t 5 .4 2
'
p . p . m j u p i i e l d from c h l o r o f o r m . F l u o r i n e n . m . r . r e s u l t s a r e shown ^in T a b l e s 1, 1,1 and I I I .
. 2 . 2 . 3 . The p r e p a r a t i o n o f t r a n g - p e r f l u o r o v i n y l b r o m o b i s ( t r i e thy I phos ph i ne ) p l a t i n u n \ ( I I )
T r a n s - p e r f l u o r o v i n y I c h I o r o b i s ( t r i e t h y I p h o s p h i n e )
p l a t i n u n i ( I I ) ( 1 2 5 . 5 mg, 0 . 2 2 9 mmol) and l i t h i u m bromi de ( 4 0 3 . 7 mg, 4 . 4 8 mmol,) were s t i r r e d u n d e r n i t r o g e n in 5 ml a c e t o n e f o r one h o u r .
The a c e t o n e was removed on a r o t a r y e v a p o r a t o r and the
' o '
red-“<^olored r e s i d u e e x t r a c t e d w i t h m e t h y l e n e c h l o r i d e . T h i s p u r p l e c o l o r e d s o l u t i o n was f i l t e r e d t o remove l i t h i u m c h l o r i d e and u n r e a c t e d l i t h i um - b r o m i d e . The m e t h y l e n e c h l o r i d e was removed on a r o t a r y
e v a p o r a t o r . The r e s i d u e was d i s s o l v e d i n m e t h a n o l and c r y s t a l l i z a t i o n $
from t h i s p u r p l e s o l u t- io n was e f f e c t e d by t he a d d i t i o n o f a b o u t 25%
) o
by volume w a t e r and c o o l i n g t o - 2 0 C. O v e r n i g h t a l l t r a c e s o f t he p u r p l e c o l o r d i s a p p e a r e d and d i d n o t r e a p p e a r when t h e c r y s t a l s were r e d i s s o l v e d . The p r o d u c t was o b t a i n e d a s v e r y p a l e y e l l o w c r y s t a l s , ■ y i e l d 110 mg ( 0 . 1 7 9 mmol) 78%. M e l t i n g p o i n t 8 3 - 84 °C, c f . 8 2 - 8 3 A n a l y s i s . C a l c u l a t e d f o r h , 5 . 0 9 , Found: C, 27".98;- H,' 4 . 9 9 . was 1 730 cm ^ . The p r o t o n n . m . r . s p e c t r u m . showed a q u i n t e t ( r e l a t i v e a r e a t h r e e ) a t 6 . 1 7 p . p . m . u p f i e l d from c h l o r o f o r m and a s e p t e t ( r e l a t i v e a r e a two) a t 5 ,2 9 p . p . m . u p f i e l d from chlorofo*-m. F l u o r i n e n . m . r . r e s u l t s a r e shown in T a b l e s I , I I and I _1 .
An u l t r a v i o l e t - v i s i b l e s p e c t r u m c f t he p u ^ p i e m e t h y l e n e c h l o r i d e s o l u t i o n showed a s t r o n g a s y m m e t r i c a b s o r p t i o n a t 238 nye and a much weaker a b s o r p t i o n a t a b o u t 285 i i y t . Molar e x t i n c t i o n c o e f f i c i e n t s were n o t o b t a i n e d .
