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UBC Theses and Dissertations

Crystal and molecular structures of some cyclic phosphonitriles Marsh, Wayne Clifford 1970

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THE CRYSTAL AND MOLECULAR STRUCTURES OF SOME CYCLIC PHOSPHONITRILSS by WAYNE CLIFFORD MARSH B.A.(Hon.), U n i v e r s i t y of Saskatchewan, 196$, M.A., U n i v e r s i t y of Saskatchewan, 1967, A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY i n the Department of Chemistry We accept t h i s t h e s i s as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA June, 1970 \ i i ABSTRACT Supervisor: Professor James Trotter Single c r y s t a l X-ray d i f f r a c t i o n methods have been usee to determine the structures of four c y c l i c phosphoni-t r i l e s : 1 , 1 , 5 , 5-tetrafluoro - 3 , 3 , 7 , 7-tetramethylcyclotetra-phosphenitriie, N^P^F^Me ; 1 , 1 , 3 , 3 , 5 , 5-hexafluoro - 7 , 7-dimethyl-cyclotetraphosphonitrile, N,P,F_-Me0; hexaphenoxycyclotriphos-4 4 ° p h o n i t r i l e , ^NPCdPh^j y, and dodeca(dimethylamino )-cyclchexaphosphonitrilechlorocopper (II) dichlorocuprate (I), NgP^(KKeg )_2^ u^^J +CuCJJ2~« Intensity measurements were made on a Datex automated General E l e c t r i c diffractometer using a s c i n t i l l a t i o n counter; Cu-K ^ . radiati o n being used for the f i r s t three structure determinations and Mo-K radiation f o r the fourth. The structure of N^P^F^Me^ has been determined by Patterson and Fourier methods ana refined by f u l l - m a t r i x least-squares. The molecule i s situated on a axis, and the phosphonitrilic ring has the 'saddle' conformation. Different e l e c t r o n e g a t i v i t i e s of the substituent groups r e s u l t in two d i s t i n c t P-N bond lengths, 1.53 and 1.59 \ explicable in terms of ff -bonding theories. In p r e s e n t i n g t h i s t h e s i s in p a r t i a l f u l f i l m e n t o f the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I a g ree tha t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s tudy . I f u r t h e r 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 c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y purposes may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . It i s u n d e r s t o o d tha t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f C h e m i s t r y  The U n i v e r s i t y o f B r i t i s h Co lumbia Vancouver 8 , Canada Date August 10, 1970 i i i P a t t e r s o n , F o u r i e r , and f u l l - m a t r i x l e a s t - s q u a r e s methods have been used to determine the s t r u c t u r e of N^P^F^Me^. This* molecule i s a l s o s i t u a t e d on a CL, a x i s and has the 'saddle' conformation, but tends s t r o n g l y towards p l a n a r i t y . The most i n t e r e s t i n g f e a t u r e s of the r i n g are four d i s t i n c t P-N bond lengths (1.534, 1.470, 1.532, and 1.437 2 ) , and l a r g e valency angles (145°) at n i t r o g e n , which are e x p l i c a b l e i n terms of f f -bonding t h e o r i e s . The s t r u c t u r e of [NP(GPh) 9l o was determined from Patterson and F o u r i e r syntheses, and refinement of p o s i t i o n a l and thermal parameters of the atoms by block - d i a g o n a l l e a s t -squares. The p h o s p h o n i t r i l i c r i n g i s s l i g h t l y non-planar, o with two ni t r o g e n atoms d i s p l a c e d by 0.15 A i n opposite d i r -e c t i o n s from the plane of the other f o u r (3P and IN) atoms. The conformations of the phenoxy groups are d i f f e r e n t at the three phosphorus atoms, and there are small d e v i a t i o n s among chemic a l l y - e q u i v a l e n t angles; these d i f f e r e n c e s are probably a r e s u l t of i n t r a - and i n t e r m o l e c u i a r s t e r i c e f f e c t s . There are no d i f f e r e n c e s among chemically equivalent bond l e n g t h s , the mean di s t a n c e s being P-N 1.575(2), P-0 1.532(2), 0-C determined by Patt e r s o n , F o u r i e r , and f u l l - m a t r i x l e a s t -squares methods. The s t r u c t u r e i s i o n i c w i t h the c a t i o n and o 1.406 (3) A . The s t r u c t u r e of i v anion each s i t u a t e d on a a x i s . The c a t i o n c o n s i s t s of a Cu(II) bonded to f o u r nitrogens of the p h o s p h o n i t r i i i c r i n g (N-Cu 2 .07 A) and a c h l o r i n e (Cfl-Cu 2.28 2 ) i n a d i s t o r t e d square pyramid. The Cu( 1)0^2 anion i s l i n e a r w i t h a Cu-C£ bond leng t h of 2.11 A*. There are two d i s t i n c t P-N bond lengths i n the p h o s p h o n i t r i i i c r i n g , 1 . 6 2 and 1 . 5 5 A, e x p l i c a b l e by fY -bonding theory. The o v e r a l l shape of the s t r u c t u r e i s determined p r i m a r i l y by s t e r i c e f f e c t s and the d i s t o r t i o n of the p h o s p h o n i t r i i i c r i n g caused by the bonding to copper. V TABLE OF CONTENTS PAGE TITLE PAGE . i ABSTRACT i i TABLE OF CONTENTS v LIST OF TABLES v i i LIST OF FIGURES x ACKNOWLEDGEMENTS . x i i GENERAL INTRODUCTION 1 PART I. THE CRYSTAL AND MOLECULAR STRUCTURES OF 1,1,5,5-TETRAFLUORO-3,3,7,7-TETRAMETHYL-CYCLOTETRAPHOSPHONITRILE AND 1,1,3,3,5,5-HEXAFLUORO-7,7-DIMETHYLCYCLOTETRAPHOSPHO-NITRILE . . . . . 4 1.1 INTRODUCTION , . . . . 5 1.2 THE CRYSTAL AND MOLECULAR STRUCTURE OF 1,1,5,5-TETRAFLUORO-3,3,7,7-TETRAMETHYLCYCLO-TETRAPHOSPHONITRILE 15 1.2.1 Experimental 15 1.2.2 Structure Analysis 16 1.2.3 Discussion 22 1.3 THE CRYSTAL AND MOLECULAR STRUCTURE OF 1,1,3,3,5,5-HEXAFLUORO-7,7-DIMETHYLCYCLO-TETRAPHOSPHONITRILE 32 v i 1.3.1 Experimental 32 1.3.2 Structure Analysis 34 1.3.3 Discussion 44 PART I I . THE STRUCTURE DETERMINATION OF HEXAPHEN-OXYCYCLOTRIPHOSPHONITRILE 49 2.1 INTRODUCTION 50 2.2 EXPERIMENTAL 52 2.3 STRUCTURE ANALYSIS 53 2.4 DISCUSSION 64 PART I I I . THE CRYSTAL AND MOLECULAR STRUCTURE OF D ODECA(DIMETHYLAMINO)CYCLOHEXPH OSPH ONITRILE-CHLOROCOPPER(II) DICHLOROCUPRATE ( I ) . . . 75 3.1 INTRODUCTION. 76 3.2 EXPERIMENTAL 77 3.3 STRUCTURE ANALYSIS 79 3.4 DISCUSSION 88 REFERENCES 100 v i i LIST OF TABLES TABLE PAGE I Structural parameters f o r tetrameric phosphonitriles 10 1»1»5 >5-tetrafluoro -3 .3 . 7 , 7-tetrafluoro- cyclotetraphosphonitrile II E - s t a t i s t i c s f o r N. P, F.Me. 18 4 4 4 4 III Observed and f i n a l calculated structure factors 20 IV F i n a l p o s i t i o n a l parameters with standard deviations and anisotropic thermal para-meters 21 V Bond lengths and valency angles with stan-dard deviations . 24 VI Bond lengths and valency angles i n N.P. F, Me 4 4 4 4 and related molecules 28* 1.1.3 .3 .5 > 5-hexafluoro - 7 , 7-dimethylcyclo- tetraphosphonitrile VII E - s t a t i s t i c s f o r N P F Me, 35 4 4 6 4 VIII Observed and f i n a l calculated structure factors 36 IX F i n a l p o s i t i o n a l parameters with standard deviations and anisotropic thermal parameters 3# v i i i X Bond lengths and valency angles with standard deviations 40 Hexaphenoxycyclotriphosphonitrile XI Structural parameters f o r trimeric phospho-n i t r i l e s 51 XII Observed and f i n a l calculated structure factors . . . 55 XIII F i n a l p o s i t i o n a l and anisotropic thermal parameters with standard deviations f o r the P, N, 0, and C atoms 6 l XIV F i n a l p o s i t i o n a l and is o t r o p i c thermal parameters with standard deviations f o r the H atoms 65 XV Bond lengths and valency angles with stan-dard deviations 66 XVI Bond lengths and angles i n [NP(0Ph)2 ] ^ and related molecules 72 Dodeca(dimethylamino)cyclohexaphosphonitrile- chlorocopper(II) dichlorocuprate(I) XVII Comparison of elemental analyses f o r the postulated and actual formula SO XVIII Measured and f i n a l calculated structure factors 82 XIX F i n a l p o s i t i o n a l and thermal parameters with standard deviations 86 Bond lengths and valency angles with standard deviations X LIST OF.FIGURES FIGURE PAGE 1 Endo- and exocyclic rf -bonding i n phosphonitriles 7 1.1.5,5-tetrafluoro-3,3.7.7-tetrafluorocyclo- tetraphosphonitrile 2 Bond lengths (A*) and valency angles (degrees) i n the phosphonitrilic ring of N P.F Me . . . 23 4 4 4 4 3 The N P F Me molecule, viewed along c* . . . 25 4 4 4 4 ~ 4 Projection of the NP. F. Me. structure down b. 26 4 4 4 4 ~ 5 The N P F Me molecule viewed along c* 4 4 4 4 i l l u s t r a t i n g the thermal e l l i p s o i d s of 0.5 prob a b i l i t y 27 1.1.3.3.5.5-hexafluoro-7,7-dimethylcyclotetra- phosphonitrile 6 Bond lengths {%) and valency angles (degrees) i n the phosphonitrilic r i n g of N.P.F.Me . . . 39 4 4 6 2 7 The N P F Me molecule, viewed along c* . . . 41 4 4 6 2 8 Projection of the N,P F^Me structure down b. 42 4 4 6 2 -9 General view of the N P F Me molecule 4 4 6 2 i l l u s t r a t i n g the thermal e l l i p s o i d s of 0.5 pro b a b i l i t y ( 43 x i 10 ( i ) Deviation of i n d i v i d u a l bond lengths from the mean, and ( i i ) bond-atom polar-i z a b i l i t i e s f o r the N P F,.Me molecule . . . 47 4 > 6 2 Hexaphenoxycyclotriphosphonitrile 11 The fNP(OPh) "1 molecule viewed down b. . 60 2 3 12 Views along the normals to the l o c a l 0P0 planes showing arrangement of the phenoxy groups 63 Dodeca(dimethylamino)cyclohexaphosphonitrile- chlorocopper(II) dichlorocuprate(I) 13 The [ N J P . (NMe ) Cud } +CuCP ~ structure 1 6 6 . 2 1 2 J <• viewed along b . . . 85 14 General view of the N^P.(NMe_) „CuCA + ion. . 91 6 0 2 12 1$ Bond lengths and angles i n the phospho-n i t r i i i c r i n g of the N,P,(NMe ) CuC£ + ion . 94 0 0 2 12 16 The structure of [NP^NMe ) CuC* 1 CuCJl" L 6 6 2 12 J * viewed along b 98 x i i ACKNOWLEDGEMENTS I would l i k e to express my appreciation to Professor Trotter f o r his guidance and assistance through-out my research. I would also l i k e to thank Professor N. Paddock for the c r y s t a l samples of the phosphonitriles and f o r a great deal of very h e l p f u l discussion. The award of a Studentship by the National Research Council of Canada i s also g r a t e f u l l y acknowledged. G E N E R A L I N T R O D U C T I O N 2 X - r a y s w e r e d i s c o v e r e d b y R o e n t g e n i n 1895 a n d w e r e f i r s t u s e d i n a s t r u c t u r e d e t e r m i n a t i o n b y v7. H . B r a g g i n 1913."'' T h e u s e o f X - r a y d i f f r a c t i o n h a s s t e a d i l y i n c r e a s e d s i n c e t h e n b u t i n t h e l a s t f e w y e a r s t h e a v a i l a b i l i t y o f h i g h s p e e d c o m p u t e r s a n a a u t o m a t e d d a t a c o l l e c t i o n e q u i p m e n t h a s r e s u l t e d i n c r y s t a l s t r u c t u r e s o f m u c h g r e a t e r a c c u r a c y b e i n g r e p o r t e d i n u n p r e c e d e n t e d n u m b e r s . T h e b a s i c p r i n c i p l e s o f X - r a y d i f f r a c t i o n , s u c h a s t h e P a t t e r s o n , F o u r i e r , l e a s t -s q u a r e s r e f i n e m e n t m e t h o d s , a n d m o r e r e c e n t l y t h e s o - c a l l e d d i r e c t m e t h o d s , a r e w e l l k n o w n a n d h a v e b e e n r e v i e w e d i n a 2-8 l a r g e n u m b e r o f r e f e r e n c e t e x t s , ~ a n d w i l l n o t b e d i s c u s s e d h e r e . A n y c r y s t a l l o g r a p h i c n o m e n c l a t u r e o r s y m b o l u s e d i n t h e t h e s i s h a s t h e c o n v e n t i o n a l m e a n i n g a s g i v e n i n t h e 9 " I n t e r n a t i o n a l T a b l e s f o r X - R a y C r y s t a l l o g r a p h y . " T h i s t h e s i s i s d i v i d e d i n t o t h r e e m a i n s e c t i o n s a n d c o n s i s t s o f a n a c c o u n t o f t h e s t r u c t u r e d e t e r m i n a t i o n s o f f o u r c y c l i c p h o s p h o n i t r i l e s , a n d a n a t t e m p t t o i n t e r p r e t s o m e o f t h e i r s t r u c t u r a l f e a t u r e s b y m e a n s o f TT - b o n d i n g t h e o r y . P a r t I c o n s i s t s o f a b r i e f r e v i e w o f t h i s b o n d i n g t h e o r y f o r p h o s p h o n i t r i l e s , a r e v i e w o f k n o w n t e t r a m e r i c p h o s p h o n i t r i l e s , a s w e l l a s t h e s t r u c t u r e d e t e r m i n a t i o n s o f t w o r e l a t e d t e t r a -m e r i c p h o s p h o n i t r i l e s ; 1 , 1 , 5 , 5 - t e t r a f l u o r o - 3 , 3 , 7 , 7 - t e t r a m e t h y l -c y c i o t e t r a o h o s p h o n i t r i l e , N , P . F . M e . , a n d 1 , 1 , 3 , 3 , 5 , 5 - h e x a f l u o r o -4 4 4 7 , 7 - d i m e t h y l c y c l o t e t r a p h o s p h o n i t r i l e , Ni¥?i+F£Ne2- ^ n P a r t H 3 t h e s t r u c t u r e d e t e r m i n a t i o n o f a t r i m e r i c p h o s p h o n i t r i l e , h e x a p h e n o x y c y c l o t r i p h o s p h o n i t r i l e , |^ N P ( O P h ) 2 " | -3 > ^ s d e s c r i b e d ; a n d i n p a r t I I I t h e s t r u c t u r e o f a m e t a l - p h o s p h o n i t r i l e c o m -p l e x , d o d e c a ( d i m e t h y l a m i n o j c y c l o h e x a p h o s p h o n i t r i l e c h l o r o c o p p e r ( I I ) d i c h l o r o c u p r a t e ( I ) , | T N 6 P 6 ( N M e 2 ) 1 2 C u C f i J +CuCJc.2~, i s d e s c r i b e d a n d c o m p a r e d w i t h o t h e r m e t a l - p h o s p h o n i t r i l e c o m p l e x e s . T H E C R Y S T A L A N D M O L E C U L A R S T R U C T U R E S O F 1 , 1 , 5 , 5 - T E T R A F L U O R O - 3 , 3 , 7 , 7 - T E T R A M E T K Y L C Y C L O T E T R A P H O S P H O N I T R I L E A N D 1 , 1 , 3 , 3 , 5 , 5 - H S X A F L U O R O - 7 , 7 - D I M E T H Y L C Y C L O T E T R A P H O S P H C N I T R I L E 5 1.1 I N T R O D U C T I O N I n 1834 R o s e ^ a n d L i e b i g a n d W o h l e r " ^ s i m u l t a n e o u s l y -r e p o r t e d : t h e f o r m a t i o n o f a s e r i e s o f p h o s p h o n i t r i l e s , J ^ N P C l ^ ^ y y\* = 3 - 7 , f r o m t h e r e a c t i o n b e t w e e n p h o s p h o r u s p e n t a c h l o r i d e a n d a m m o n i a . A c y c l i c s t r u c t u r e f o r t h e s e c o m -12 13 p o u n d s w a s p r o p o s e d b y S t o k e s , w h i c h X - r a y s t u d i e s o f t h e t e t r a m e r , ^ N P C l ^ j ^ , l a t e r c o n f i r m e d . T h e n a m e p h o s -p h o n i t r i l e w a s d e r i v e d b y a n a l o g y o f t h e h y p o t h e t i c a l m o n o -m e r i c u n i t , X 2 - P ~ ~ " N , t o o r g a n i c n i t r i l e s , R - C _ = N . A n o t h e r n a m e f r e q u e n t l y u s e d i s p h o s p h a z e n e , t h i s n a m e a l s o b e i n g d e r i v e d b y a n a l o g y t o s i m i l a r o r g a n i c c o m p o u n d s : t r i -a z e n e , t e t r a z e n e , e t c . A l a r g e n u m b e r o f r e v i e w s h a v e b e e n p u b l i s h e d s u m m a r i z i n g a g r e a t d e a l o f s t r u c t u r a l a n d c h e m i c a l i n f o r m a t i o n w h i c h h a s b e e n o b t a i n e d s i n c e t h e i n i t i a l 13 X - r a y d i f f r a c t i o n s t u d i e s . I n o r d e r t o h e l p i n t e r p r e t t h e s t r u c t u r a l f e a t u r e s o f t h e c o m p o u n d s d e s c r i b e d l a t e r i n t h e t h e s i s a b r i e f i n t r o -d u c t i o n t o t h e b o n d i n g t h e o r y f o r p h o s p h o n i t r i l e s w i l l b e g i v e n h e r e . T h i s b o n d i n g t h e o r y h a s b e e n d e v e l o p e d p r i m a r i l y b y C r a i g a n d P a d d o c k , a n d h a s b e e n s u m m a r i z e d i n a r e -p a c e n t r e v i e w . F o r c o n v e n i e n c e t h e c o n v e n t i o n s f o r n o m e n -24—28 c l a t u r e a n d o r b i t a l l a b e l l i n g g i v e n b y C r a i g a n d P a d d o c k w i l l b e f o l l o w e d h e r e . T h e p h o s p h o r u s a t o m s m a y b e c o n s i d e r e d o 28 a s p e n t a v a l e n t w i t h a v a l e n c e c o n f i g u r a t i o n (3s)(3p_) (3d). 6 T h e s i g m a b o n d s i n p h o s p h o n i t r i l e s a r e f o r m e d b y o v e r l a p o f s p ^ h y b r i d o r b i t a l s o n n i t r o g e n v / i t h h y b r i d o r b i t a l s o n p h o s -p h o r u s w h i c h a r e a p p r o x i m a t e l y s p ^ , s i n c e t h e p h o s p h o r u s a t o m s a r e f o u r - c o o r d i n a t e , a n d X - r a y a n a l y s i s i n d i c a t e s t h a t t h e y a r e a p p r o x i m a t e l y t e t r a h e d r a l . S i n c e t h e o b s e r v e d b o n d l e n g t h s a r e l e s s t h a n a s i n g l e p h o s p h o r u s - n i t r o g e n b o n d , a s e c o n d a r y TT - s y s t e m m u s t a l s o b e i n v o l v e d i n t h e b o n d i n g . T h i s •IT - b o n d i n g s y s t e m m u s t i n v o l v e t h e 2 p _ o r b i t a l s o n n i t r o g e n , a s w e l l a s t h e 3d o r b i t a l s o n p h o s p h o r u s , s i n c e t h e 3s_ a n d 3p_ o r b i t a l s h a v e b e e n u t i l i z e d i n t h e s i g m a b o n d i n g . F i g u r e 1 i l l u s t r a t e s t h e TT - b o n d i n g s y s t e m i n p h o s p h o n i t r i l e s u s i n g t h e c o n v e n t i o n s o f C r a i g a n d 21 2.L. 2& P a d d o c k . ' t + - ~ ' c o T h e z - a x i s i s c h o s e n p e r p e n d i c u l a r t o t h e l o c a l N P N p l a n e , t h e y _ - a x i s i s i n t h e N P N p l a n e a n d b i s e c t s t h e N - P - N a n g l e , a n d t h e x - a x i s i s o r t h o g o n a l v / i t h r e s p e c t t o t h e o t h e r t w o . T h e r e a r e t w o t y p e s o f TT - b o n d i n g . The f i r s t i n v o l v e s o v e r l a p o f t h e s i n g l y o c c u p i e d n i t r o g e n 2 p _ z o r b i t a l v / i t h a l i n e a r c o m b i n a t i o n o f t h e p h o s p h o r u s 3 _ x z a n d 3d,._ o r b i t a l s c o n t a i n i n g t h e s i n g l e 3d e l e c t r o n . S i n c e — y z — t h e o r b i t a l s i n v o l v e d a r e a n t i s y m m e t r i c w i t h r e s p e c t t o r e -f l e c t i o n i n t h e N P N p l a n e t h i s TT - s y s t e m h a s b e e n d e s i g -n a t e d TT a , a n d i s i l l u s t r a t e d i n F i g u r e l a a n d l b . I n a d d i t i o n t h e r e i s a s e c o n d fT - s y s t e m i n v o l v i n g o v e r l a p b e t w e e n t h e p h o s p h o r u s 3d o o a n d 3 d v „ o r b i t a l s a n d t h e — x * " — y — x y 8 n i t r o g e n s p _ h y b r i d c o n t a i n i n g t h e l o n e p a i r e l e c t r o n s . H e r e t h e o r b i t a l s i n v o l v e d a r e s y m m e t r i c w i t h r e s p e c t t o r e f l e c t i o n i n t h e K P N p l a n e a n d a r e l a b e l l e d IT s . F i g u r e l c a n d I d i l l u s t r a t e t h i s t y p e o f b o n d i n g . F i n a l l y t h e r e i s a t h i r d t y p e o f o v e r l a p w h i c h m a y p e r m i t TV - b o n d i n g t o e x o c y c l i c l i g a n d s o n p h o s p h o r u s . H e r e t h e p r i n c i p a l p h o s p h o r u s o r b i t a l i n v o l v e d i s t h e 3d 2> a s i l l u s t r a t e d i n F i g u r e l e , w i t h t h e 3d a n d 3d v_ p a r t i c i p a t i n g t o a l e s s e r e x t e n t . y ci —"vCZ T h e IT a a n d 1T s s y s t e m s a r e n o t e q u i v a l e n t n o r d o t h e d - o r b i t a l s i n v o l v e d i n t h e m i n t e r a c t w i t h t h e n i t r o g e n 26 £ - o r b i t a l s e q u a l l y . C r a i g a n d P a d d o c k h a v e s h o w n b y m e a n s o f o v e r l a p i n t e g r a l s t h a t i n t h e TT a s y s t e m t h e 3d o r -b i t a l i s t h e p r e d o m i n a n t o n e w h e r e a s i n t h e tr s s y s t e m t h e 3d o o i s t h e m o r e i m p o r t a n t . F u r t h e r m o r e t h e TT a s y s t e m a s a w h o l e p r e d o m i n a t e s , b u t a s t h e r i n g s d e p a r t f r o m p l a n a r i t y t h e i m p o r t a n c e o f t h e ( I s s y s t e m i n c r e a s e s , t h e 26 r e l a t i v e c o n t r i b u t i o n d e p e n d i n g o n t h e c o n f o r m a t i o n . 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 s h o w t h a t t h e u p p e r m o s t o c c u p i e d TT - o r b i t a l i s a l w a y s n o n - d e g e n e r a t e w h e r e a s i t i s d o u b l y d e g e n e r a t e f o r h y d r o c a r b o n s . A s a r e s u l t a n a r o m a t i c n a t u r e f o r c y c l i c p h o s p h o n i t r i l e s i s p r e d i c t e d w h e t h e r t h e y h a v e 4n o r 4n + 2 TT - e l e c t r o n s . T h e n a t u r e o f t h e d e l o c a l i -z a t i o n m u s t d i f f e r f r o m t h a t f o u n d i n t h e a r o m a t i c h y d r o c a r -b o n s , h o w e v e r , d u e t o t h e b o n d p o l a r i t y c a u s e d b y t h e d i f f e r e n t 9 e l e c t r o n e g a t i v i t i e s o f p h o s p h o r u s a n d n i t r o g e n , a n d b e c a u s e o f t h e c h a r a c t e r o f t h e p h o s p h o r u s 3 d - o r b i t a l s . A n a l t e r n a t e a p p r o a c h h a s b e e n p r o p o s e d b y D e w a r 29 e t a l . U n l i k e t h e C r a i g a n d P a d d o c k a p p r o a c h t h i s TT -b o n d i n g s y s t e m i n v o l v e s a n e q u a l p a r t i c i p a t i o n o f t h e p h o s -p h o r u s 3d„„ a n d 3d o r b i t a l s . A p a i r o f l i n e a r c o m b i n a t i o n s r - x z y z i s c o n s t r u c t e d f r o m t h e s e t w o 3 d - o r b i t a l s w h i c h i n t e r a c t s e p a r a t e l y w i t h a d j a c e n t n i t r o g e n 2 ^ o r b i t a l s t o f o r m a s y s t e m o f t h r e e c e n t e r TT - b o n d s . T h e r e s u l t i s a s e r i e s o f ' i s -l a n d s o f e l e c t r o n d e n s i t y ' w h i c h e n c o m p a s s P N P s e g m e n t s a n d , a s a r e s u l t , d o n o t p e r m i t d e l o c a l i z a t i o n a r o u n d t h e r i n g a s a w h o l e . A s w i l l b e d i s c u s s e d l a t e r ( s e c t i o n 1.3.3), h o w e v e r , c e r t a i n e x p e r i m e n t a l o b s e r v a t i o n s c a n o n l y b e e x p l a i n e d i n t e r m s o f a d e l o c a l i z a t i o n o f TT - e l e c t r o n s a r o u n d t h e e n t i r e p h o s p h o n i t r i l i c r i n g . A t t h i s p o i n t s o m e c o m m e n t s h o u l d p e r h a p s b e m a d e o n t h e s i g n i f i c a n t s t r u c t u r a l f e a t u r e s o f t h e t e t r a m e r i c p h o s -p h o n i t r i l e s w h i c h w i l l p r o v i d e a b a s i s f o r t h e d i s c u s s i o n o f t h e s t r u c t u r e s o f N ^ P ^ F ^ M e ^ a n d N ^ P ^ F ^ M e ^ T h e r e s u l t s o f X - r a y s t r u c t u r e a n a l y s e s o f t e t r a -m e r i c p h o s p h o n i t r i l e s a r e c o m p i l e d i n T a b l e I . U n l i k e t h e t r i m e r i c p h o s p h o n i t r i l e s , w h i c h d e v i a t e o n l y s l i g h t l y f r o m p l a n a r i t y ( T a b l e X I a n d s e c t i o n 2.4), t h e t e t r a m e r s a d o p t s e v e r a l d i f f e r e n t c o n f o r m a t i o n s a n a a p l a n a r c o n f i g u r a t i o n i s f o u n d o n l y i n t h e f l u o r i d e . T h e p a r t i c u l a r c o n f o r m a t i o n T A B L E I S t r u c t u r a l p a rameters o f t e t r a m e r i c p h o s p h o n i t r i 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 o f bond l e n g t h s and v a l e n c e a n g l e s i n p a r e n t h e s e s . Compound [ N P M e 2 ] 4 [ N P G 1 2 ] 4 [ N P ( C K e ) 2 ] 4 [ K P C 1 2 ] t N P Ph C I 4 4 4 4 [ HPF_] 4 ( K ) (T) N, P, Ph, (NHMe ), 4 4 4 4 P-N(A) 1.596(3) 1.578(10) 1.57(1) 1.57 1.56(1) 1.57(1) 1.507(17) 1.59(1) P-N-P(degrees) N-P-N(degrees) R i n g C o n f o r m a t i o n R e f e r e n c e 131.9(3) 133.0(6) 131.3(6) 132 133 . 6(8) 137.6 132.4(6) 138.6(6) 147.2(10) 124.6(6) 131.2(6) 119.8(2) 120.1(5) 121.2(5) 122 120.5(7) 120.4(5) 122.7(10) 119.6(5) t u b , 4 tu b , 4 tu b , 4 s a d d l e , 4 c h a i r , 1 c h a i r , 1 p l a n a r c h a i r , T 30 31 32 33 34 35 36 35 i — o 1 1 a d o p t e d i s a r e s u l t o f a c o m p r o m i s e b e t w e e n s t e r i c r e q u i r e -m e n t s a n a t h e r e l a t i v e i m p o r t a n c e o f t h e 1T a a n d TT s b e n d i n g i n t h e p h o s p h o n i t r i i i c r i n g . A s m a y b e s e e n i n T a b l e I t h e r e a r e t h r e e m a i n c o n f o r m a t i o n s w h i c h a r e c o m m o n l y f o u n d i n t h e t e t r a m e r i c p h o s p h o n i t r i l e s . O n e i s t h e ' . t u b ' , w h e r e t h e r i n g a t o m s o c c u r i n p a i r s a l t e r n a t e l y a b o v e a n d b e l o w t h e m e a n p l a n e t h r o u g h t h e r i n g a t o m s r e s u l t i n g i d e a l l y i n S^ s y m m e t r y . T h i s c o n f o r m a t i o n i s s t e r i c a l l y f a v o r a b l e b e c a u s e i t a l l o w s s u b s t i t u e n t s o n t h e p h o s p h o r u s a t o m s t o b e i n a s t a g g e r e d a r r a n g e m e n t . T h e d i h e d r a l a n g l e s i n t h i s c o n f o r m a t i o n w o u l d v a r y a r o u n d t h e r i n g a s t h e a t o m s a l t e r -n a t i v e l y h a v e t h e i r z - a x e s a l i g n e d , w h e n t h e a t o m s a r e o n t h e s a m e s i d e o f t h e m e a n p l a n e , o r m i s m a t c h e d w h e n t h e y a r e n o t . S i n c e t h e t w o 3d o r b i t a l s o n p h o s p h o r u s w h i c h a r e i n v o l v e d i n t h e TT a s y s t e m ( d v „ a n d d ) i n t e r s e c t i n t h e z - a x i s , t h e r e l a t i v e o r i e n t a t i o n s o f t h e l o c a l z - a x e s o n s u c c e s s i v e r i n g a t o m s g i v e s a m e a s u r e o f t h e o v e r l a p o f t h e n i t r o g e n n ^ o r b i t a l s w i t h t h e t v / o d fp o r b i t a l s o n i r — a p h o s p h o r u s . I n o t h e r w o r d s t h e d e g r e e t o w h i c h t h e z - a x e s o n n e i g h b o r i n g r i n g a t o m s a r e a l i g n e d g i v e s a n e s t i m a t e o f 2 1 t h e i m p o r t a n c e o f t h e TT a b o n d i n g s y s t e m . T h e ' s a d d l e ' c o n f o r m a t i o n i s a l s o c o m m o n a n d h e r e t h e p h o s p h o r u s a t o m s a r e i n a p l a n e w i t h s u c c e s s i v e n i t r o g e n a t o m s d e v i a t i n g i n o p p o s i t e d i r e c t i o n s f r o m t h e p l a n e r e s u l t i n g i n D 2 d s y m m e t r y 1 2 i n t h e i d e a l c a s e . T h i s a r r a n g e m e n t r e q u i r e s t h e d i h e d r a l a n g l e s t o b e a p p r o x i m a t e l y e q u a l a r o u n d t h e r i n g r e s u l t i n g i n t h e z - a x e s o n t h e r i n g a t o m s b e i n g e q u a l l y m i s m a t c h e d , t h u s e q u a l i s i n g t h e i n t e r a c t i o n s b e t w e e n s u c c e s s i v e T T - o r b i t a l s . A s t e r i c a l l y u n f a v o r a b l e c h a r a c t e r i s t i c o f t h e ' s a d d l e ' c o n -f o r m a t i o n i s t h a t t h e p h o s p h o r u s s u b s t i t u e n t s a r e n o w e c l i p s e d . T h e r e i s a l s o a ' c h a i r ' f o r m h a v i n g 1 s y m m e t r y i n w h i c h t h e d i h e d r a l a n g l e s b e t w e e n a d j a c e n t r i n g a t o m s a r e l a r g e r t h a n i n t h e ' s a d d l e ' c o n f o r m a t i o n . I n t h i s c o n f o r m a t i o n t h e i m -21 p o r t a n c e o f t h e fT s s y s t e m i s i n c r e a s e d . I t s h o u l d . b e p o i n t e d o u t , h o w e v e r , t h a t t h e t w o s y s t e m s o f T T - b o n d i n g c o m p l e m e n t e a c h o t h e r s i n c e t h e i r p l a n e s o f m a x i m u m o v e r l a p a r e p e r p e n d i c u l a r . A s a r e s u l t d e c r e a s e d o v e r l a p o f t h e TT" a - s y s t e m r e s u l t s i n a n i n c r e a s e i n t h e p a r t i c i p a t i o n o f s - b o n d i n g . T h e r e s u l t s o f a r e c e n t s t r u c t u r e d e t e r m i n a t i o n w o u l d s e e m t o i n d i c a t e t h a t t h e d i s t i n c t i o n b e t w e e n t h e ' s a d d l e a n d ' t u b ' c o n f o r m a t i o n s c a n n o t b e v e r y g r e a t . T h e s t r u c t u r e o f b i s - ( o c t a m e t h y l c y c l o t e t r a p h o ' s p h o n i t r i l i u m ) t e t r a c h l o r o -- - 3 7 c o b a l t a t e ( I i ) c o n t a i n s t w o e i g h t - m e m b e r p h o s p h o n i t r i i i c r i n g s , o n e o f w h i c h a p p r o x i m a t e s a ' t u b ' w h i l e t h e o t h e r a d o p t s t h e ' s a d d l e ' . c o n f o r m a t i o n . T h e r e i s n o i n d i c a t i o n o f a n o v e r a l l p r e f e r e n c e t o w a r d s a s h a p e w h i c h f a v o r s p r e d o m -i n a n t l y fT a o r TV s - b o n d i n g w i t h i n t h e r i n g , t h e d i f f e r e n c e 13 i n c o n f o r m a t i o n m o s t p r o b a b l y b e i n g d u e t o c r y s t a l p a c k i n g . A s w a s m e n t i o n e d e a r l i e r t h e r e e x i s t s t h e p o s s i b i l i t y o f e x o c y c l i c fT - b o n d i n g b e t w e e n p h o s p h o r u s a n d i t s s u b s t i t u -31 33 36* 39 e n t s . T h i s h a s b e e n f o u n d i n s e v e r a l s t r u c t u r e s , ' ' ' 31 b u t t h e t e t r a m e r i c d i m e t h y l a m i d e ^ i s e s p e c i a l l y i n t e r e s t i n g b e c a u s e n o t o n l y a r e t h e e x o c y c l i c P - N b o n d l e n g t h s s h o r t e r t h a n a p u r e s i n g l e b o n d , i n d i c a t i n g t h a t fT - b o n d i n g i s o c c u r r i n g b e t w e e n t h e p h o s p h o r u s a t o m s a n d t h e n i t r o g e n s o f t h e d i m e t h y l a m i n o g r o u p s , b u t o n e d i m e t h y l a m i n o g r o u p o n e a c h p h o s p h o r u s i s o r i e n t e d s o a s t o h a v e g o o d o v e r l a p w i t h t h e n h o s n h o r u s 3d 0 o r b i t a l w h i l e t h e o t h e r g r o u p i s o r i e n t e d t o o v e r l a o w i t h t h e p h o s p h o r u s 3d o r 3d o r b i t a l s . ^ r — x z — y z A n o t h e r f a c t o r w h i c h i s i m p o r t a n t i n t h e b o n d i n g i n p h o s p h o n i t r i l e s i s t h e e l e c t r o n e g a t i v i t y o f t h e s u b s t i t u -e n t s o n p h o s p h o r u s . I t h a s b e e n p o i n t e d o u t t h a t t h e m a i n e f f e c t o f a c h a n g e i n l i g a n d e l e c t r o n e g a t i v i t y i s o n t h e fT - s y s t e m . A s t h e e l e c t r o n e g a t i v i t y i n c r e a s e s t h e l o n e p a i r e l e c t r o n s o n n i t r o g e n a r e d e l o c a l i z e d t o a g r e a t e r e x t e n t t h u s s t r e n g t h e n i n g t h e fT s _ c o m p o n e n t o f t h e b o n d i n g . S i m i l a r l y t h e o v e r l a p o f t h e n i t r o g e n 2p_z o r b i t a l w i t h t h e p h o s p h o r u s 3d o r b i t a l s i s f a c i l i t a t e d r e s u l t i n g i n a s t r o n g e r f T a s y s t e m . C o m p a r i s o n s h a v e b e e n m a d e b e t w e e n v a r i o u s t e t r a m e r i c p h o s p h o n i t r i l e s b u t t h e s e c o m p a r i s o n s h a v e b e e n m a d e b e t w e e n h o m o g e n e o u s l y s u b s t i t u t e d c o m p o u n d s . I t w o u l d 14 b e i n t e r e s t i n g t o e x a m i n e t h e e f f e c t s o n t h e b o n d i n g w h e n l i g a n d s o f d i f f e r e n t e l e c t r o n e g a t i v i t i e s a r e p r e s e n t i n t h e s a m e r i n g . S y s t e m a t i c i n e q u a l i t i e s o c c u r i n t h e P - N b o n d 4 0 l e n g t h s i n t h e s i x - m e m b e r e d r i n g s o f N ^ P ^ C A ^ P h g , I "1 i p N . P _ C j { _ P h , , a n d N 0 P ~ F . P h ~ , a n d t h e s e o b s e r v e d v a r i a t i o n s ; j ^ V J J> 4 a r e a s e x p e c t e d f r o m TT - e l e c t r o n t h e o r y . N o s t r u c -t u r e s o f s u c h i n h o m o g e n e o u s l y g e m i n a l l y s u b s t i t u t e d r i n g s o f l a r g e r s i z e h a v e b e e n r e p o r t e d a l t h o u g h a l t e r n a t i o n o f r i n g b o n d l e n g t h s c a u s e d b y t h e p e r t u r b a t i o n o f t h e TT - s y s t e m b y t h e p r o t o n a t i o n o f a r i n g n i t r o g e n h a s b e e n f o u n d i n t w o 3 7 4 3 o c t a m e t h y l c y c l o t e t r a p h c s p h o n i t r i l i u m i o n s , a n d i n i N ^ P ^ C A ^ ( N H P r ~ ) • H C J Z . A s e r i e s o f g e m i n a l f l u o r o m e t h y l c y c l o -t e t r a p h o s p h o n i t r i l e s w a s p r e p a r e d b y t h e r e a c t i o n o f m e t h y l -l i t h i u m v / i t h o c t a f l u o r c c y c l o t e t r a p h o s p h o n i t r i l e ^ ^ a n d t w o o f t h e s e c o m p o u n d s , 1 , 1 , 5 , 5 - t e t r a f l u o r o - 3 , 3 , 7 , 7 - t e t r a m e t h y l -c y c l o t e t r a p h o s p h o n i t r i l e , N ^ P ^ F ^ M e ^ , a n d 1 , 1 , 3 , 3 , 5 , 5 - h e x a f l u o r o -7 , 7 - d i m e t h y l c y c l o t e t r a p h o s p h o n i t r i l e , N ^ P ^ F ^ M e 2 > w e r e i s o l a t e d f o r c r y s t a l s t r u c t u r e a n a l y s i s . S i n c e t h e s t r u c t u r e s o f N , P , M e r t a n d N . P , F r t a r e k n o w n , t h e a v a i l a b i l i t y o f t h e s e 4 4 o 4 4 o m i x e d m e t h y l - f l u o r i d e t e t r a m e r s a f f o r d e d a n o p p o r t u n i t y t o s t u d y t h e e f f e c t s o n t h e b o n d i n g i n t h e p h o s p h o n i t r i l i c r i n g s , a s w e l l a s o n t h e r i n g c o n f o r m a t i o n s , a s t h e l i g a n d s w e r e g r a d u a l l y c h a n g e d f r o m m e t h y l s t o f l u o r i n e s . 1 5 1.2 THE CRYSTAL AND MOLECULAR STRUCTURE OF 1,1,5,5-TETRAFLUORO-3,3,7,7-TETRAMETHYLCYCLOTETRAPHOSPHOWITRILE 1.2.1 E x p e r i m e n t a l C r y s t a l s o f 1, 1 , 5 , 5 - t e t r a f l u o r o - 3 , 3 , 7 , 7 - t e t r a -m e t h y l c y c l o t e t r a p h o s p h o n i t r i l e a r e c o l o u r l e s s p r i s m s e l o n -gated a l o n g £, w i t h {lio} w e l l d e v e l o p e d and s m a l l e r (00lJ . U n i t - c e l l and space group d a t a were o b t a i n e d f r o m v a r i o u s r o t a t i o n , W e i s s e n b e r g , and p r e c e s s i o n photographs; a c c u r a t e u n i t - c e l l p arameters were o b t a i n e d by a l e a s t - s q u a r e s p r o -c e d u r e ^ a p p l i e d t o 2 0 v a l u e s f o r twenty g e n e r a l r e f l e x i o n s measured on a s p e c t r o g o n i o m e t e r . C r y s t a l Data. — C 4 H 1 2 F 4 W - = 316.1. Mono-c l i n i c , a = 12. 9 1 0 ( 5 ) , b - 9.236(4), £ = 12.329(5) A, = 117.13(3)° ( s t a n d a r d d e v i a t i o n s i n p a r e n t h e s e s ) , U = 1308.3 A^, D = 1.59 ( f l o t a t i o n i n CHBr / C . H j , 2 = 4, _, = 1.604, -m 3 o 6 ~— F(000) = 640. A (Cu-K _ ) = 1.5418 A, M (Cu-K_ ) = 56 cm" . —. —- C\ • Spac? ( r o u p _2/£(Cp^) o r C c ( C ^ ) , from s y s t e m a t i c a b s e n c e s : hk_ when (h + k ) i s odd, h O i when A i s odd. C2/£ from s t r u c t u r e a n a l y s i s . The i n t e n s i t i e s o f a l l r e f l e x i o n s w i t h 2 0 (Cu-K^ ) ^ 120° (minimum i n t e r p l a n a r s p a c i n g , 0.89 A) were measured on a Datex-automated G e n e r a l E l e c t r i c XRD 6 S p e c t r o g o n i o m e t e r , w i t h a s c i n t i l l a t i o n c o u n t e r , a p p r o x i m a t e l y monochromatic Cu-K _ r a d i a t i o n ( N i f i l t e r and p u l s e h e i g h t 1 6 a n a l y z e r ) , a n d a 6 - 2 © s c a n o f t w o d e g r e e s p e r m i n u t e i n 2 O . B a c k g r o u n d c o u n t s f o r 20 s e c o n d s w e r e m a d e a t t h e b e g i n n i n g a n d e n d o f e a c h s c a n . T h e c r y s t a l u s e d h a d a c r o s s s e c t i o n o f 0.2 m m . b y 0.3 m m . a n d a l e n g t h o f 0.5 m m . N o a b s o r p t i o n c o r r e c t i o n s w e r e m a d e . T h e c o m p o u n d i s s l i g h t l y h y g r o s c o p i c , a n d t h e c r y s t a l u s e d w a s s e a l e d i n a L i n d e m a n n g l a s s c a p i l l a r y . L o r e n t z a n d p o l a r i z a t i o n f a c t o r s w e r e a p p l i e d , a n d t h e s t r u c t u r e f a c t o r s w e r e d e r i v e d a s u s u a l . R e f l e x i o n s w h i c h h a d a n e t c o u n t o f l e s s t h a n 3 <s~ a b o v e b a c k g r o u n d , w h e r e <S~ ( I ) i s d e f i n e d b y r 2 ( I ) = 3 + B + (0.05 S ) 2 w h e r e S a n d B a r e t h e s c a n a n d b a c k g r o u n d c o u n t s r e s p e c t i v e l y , w e r e t a k e n a s b e i n g u n o b s e r v e d . T h e s e r e f l e x i o n s w e r e a s -s i g n e d s t r u c t u r e f a c t o r s e q u a l t o t h e m e a s u r e d v a l u e s b u t w e r e e x c l u d e d f r o m t h e r e f i n e m e n t . O f t h e 930 p o s s i b l e r e f l e x i o n s w i t h 2 © ^ 120°, 444 w e r e c l a s s i f i e d a s o b s e r v e d . 1.2.2 S t r u c t u r e A n a l y s i s T o d i f f e r e n t i a t e b e t w e e n t h e t w o p o s s i b l e s p a c e g r o u p s , t h e d a t a w e r e p l a c e d o n a n a b s o l u t e s c a l e u s i n g 4 7 W i l s o n ' s m e t h o d , a n d n o r m a l i z e d s t r u c t u r e a m p l i t u d e s , [ E | , w e r e d e r i v e d . T h i s n o r m a l i z e d s t r u c t u r e f a c t o r i s d e f i n e d b y ^ 17 E ,2 _ 1 4 k * ' 2 -hk£ I n — * j - i where F, , . i s the structure f a c t o r f o r the plane hki, th~ f .(hk£) i s the atomic scattering factor f o r the j atom fo r the scattering angle associated with the plane hk2, N i s the t o t a l number of atoms i n the unit c e l l , and £, ^ i s related to the m u l t i p l i c i t y of the r e f l e x i o n hkfi. The E - s t a t i s t i c s are compared with the t h e o r e t i c a l r e s u l t s f o r 4 9 centric and non-centric d i s t r i b u t i o n s i n Table I I . The choice of C2/£ i s indicated, and t h i s choice was l a t e r to prove correct. The i n t e n s i t i e s of a l l reflexions with A odd were extremely weak, so that i t was expected that the c r y s t a l contained molecules related approximately by t r a n s l a t i o n c/2, The three-dimensional sharpened Patterson function gave the phosphorus positions as: (0, +0.21, z), (0, -0.21, :z), (+0.16, 0, z + 0.16), and (-0.16, 0, z - 0.16), with z = 0 or the two solutions giving i d e n t i c a l P-P vectors. A three-dimensional electron-density map, computed with phases based on the phosphorus atoms, had a f a l s e mirror plane at y_ = 0, but elongations of the light-atom peaks indicated deviations from 2/m molecular symmetry. By the assumption of approximate tetrahedral geometry at the phosphorus atoms 1 8 TABLE I I E - 3 t a t i s t i c s f o r N P,F Me 4 4 4 4 T h e o r e t i c a l Observed Centro. Ifon-Centro. Mean i E 1 0.740 0.798 0.886 Mean | 0.985 1.000 1.000 Mean | 2 E -11 1.094 0.968 0.736 E > 3 (percent) 0.54 0.30 0.01 E > 2 (percent) 7.10 5.00 1.80 S > 1 (percent) 25.27 32.00 37.00 19 two p o s s i b l e s t r u c t u r e s could be d e r i v e d , w i t h molecules of symmetry 1 and 2 r e s p e c t i v e l y , l y i n g on the appropriate sym-metry element i n space group C2/c_. These two s t r u c t u r e s gave equal l y reasonable s t r u c t u r e f a c t o r agreement for^ the 4 even r e f l e x i o n s , but the X - s t r u c t u r e gave very poor agreement f o r the £ odd r e f l e x i o n s , while the 2-structure gave much more encouraging agreement f o r these r e f l e x i o n s , and thus appeared to be c o r r e c t . This s t r u c t u r e was r e f i n e d by f u l l - m a t r i x l e a s t -squares methods, w i t h the s c a t t e r i n g f a c t o r s from the I n t e r -9 n a t i o n a l Tables, and f i n a l weights, w = 0 f o r the unobserved 2 r e f l e x i o n s and w = 1/(7.0 - 0.3 | FQ\ + 0.004 | F.J ) f o r the observed r e f l e x i o n s , the c o e f f i c i e n t s being derived from 2 an a n a l y s i s of w(F - F ) over ranges of | F I . The maximum o ~c -o r a t i o of s h i f t to estimated standard d e v i a t i o n on the f i n a l c y c l e was 0.$, and the f i n a l R was 0.081 f o r the 444 observed r e f l e x i o n s , and 0.153 f o r a l l 930 r e f l e x i o n s . Measured and c a l c u l a t e d s t r u c t u r e f a c t o r s are l i s t e d i n Table I I I . A f i n a l d i f f e r e n c e map, computed w i t h (F - F ) as F o u r i e r —o —c °-3 c o e f f i c i e n t s , showed maximum f l u c t u a t i o n s of + 0.5 e.A . Although there were regions of p o s i t i v e e l e c t r o n d e n s i t y around the carbon atoms, a c o n s i s t e n t set of hydrogen atoms could not be l o c a t e d . F i n a l p o s i t i o n a l and thermal parameters are given i n Table IV. Atoms P ( l ) and P(3) are i n p o s i t i o n s 4(e) of 2 0 T A B L E I I I O b s e r v e d a n d f i n a l c a l c u l a t e d s t r u c t u r e f a c t o r s . U n o b s e r v e d r e f l e x i o n s h a v e a n a s t e r i s k f o l l o w i n g F, 21 TABLE IV Fractional p o s i t i o n a l parameters with estimated standard deviations i n parentheses, and anisotropic thermal parameters °2 2 (A x 1CT). Atom x P ( D P(2) P(3) N(l) N(2) C(l) C(2) F ( l ) F(2) 0 0.1590(2) 0 0.1176(8) 0.0758(11) 0.1801(13) 0.3011(10) 0.0216(8) 0.0708(9) 0.2134(7) 0.0015(7) -0.2132(7) 0.1375(10) -0.1379(13) 0.0461(14) -0.0422(16) 0.3219(13) -0.3240(11) 1/4 0.4104(3) 1/4 0.3237(9) 0.3712(10) 0.5632(12) 0.4234(14) 0.1706(12) 0.2134(9) Atom U -11 U -22 ^33 % 2 *13 U 2 3 P(l) P(2) P(3) N(l) N(2) G(l) C(2) F ( l ) F(2) 4.18 4.35 5-94 4.60 8.08 9.51 5.13 7.53 12.63 4.00 5-54 3.91 4.73 6.25 9.49 10.66 13.67 8.69 8.06 5.02 4.71 7.64 4.34 5.42 10.52 20.30 9.74 0 •0.35 0 •0.56 -0.99 -3.18 3.72 •0.95 5.22 1.10 0.70 0.37 0.96 0.79 3.01 3.67 2.31 2.05 0 0.11 0 1.01 0.50 - 3.40 3.40 10.54 - 1.34 2 2 o, C_2/c_, and the other atoms are i n 8 ( f ) . The thermal vibrations of the substituent atoms, p a r t i c u l a r l y the f l u o r i n e atoms, are f a i r l y large, with root mean square displacements as o high as 0.4 A. Bond lengths and angles pertaining to the r i n g are shown i n Figure 2, while the complete intramolecular bond lengths ana angles, with t h e i r standard deviations, are given i n Table V. A view of the molecule along c* i s shown i n Figure 3 and the molecular packing arrangement viewed along b i n Figure 4- Figure 5 i s a view of the molecule along c* shov/ing the thermal e l l i p s o i d s of 0.5 p r o b a b i l i t y . 1.2.3 Discussion In the N,P F Me molecule, there i s a marked var-4 4 4 4 ia t i o n i n P-N bond lengths around the rin g (Figure 2); the mean P-N bond distance involving the methyl-substituted phos-o phorus atoms i s 1.59(1) A, and the corresponding length f o r o the fluorine-substituted phosphorus atoms i s 1.53(1) A. These bond lengths are not s i g n i f i c a n t l y d i f f e r e n t from the P-N distances of 1.596(3) and 1.51(2) A* found i n d i v i d u a l l y 30 36 i n the parent octamethyl and octafluoro compounds (Table VI). The difference i n P-N bond lengths may be i n t e r -24—28 preted i n terms of TT* -bonding theory. The strongly electronegative f l u o r i n e atoms withdraw electrons from the ring, r e s u l t i n g i n a subsequent transfer of electrons from the adjacent nitrogen atoms into.a tr -bonding system of 23 t h e p h o s p h o n i t r i i i c r i n g o f N . P . F M e . 4 4 4 4 2 4 o TABLE V Bond lengths (A) and valency angles (degrees) with standard deviations i n parentheses. P(1)-K (D P(3)-N(2) P(2)-N(l) P(2)-N(2) 1.54(1) 1.53(1) 1.58(1) 1.60(1) P ( l ) - F ( l ) P(3)-F(2) P(2)-C(l) P(2)-C(2) 1 . 5 K D 1.54(1) 1.82(1) 1.81(1) N(l' )-P(I)-N(l) N(2» )-P(3)-K(2) N(l)-P(2)-N(2) P(l)-N(l)-P ( 2 ) P(2)-K(2)-P(3) F(l» )- P ( l ) - F ( l ) F(2' )-P(3)-F(2) C(l )-P(2)-C(2) 125.8(9) 125-9(10) 117.5(5) 134.6(7) 134.6(8) 97.0(13) 96.4(10) 106.9(7) F(I )-F ( l ' ) F ( 2 ) -F ( 2 M C ( D -C(2)-C ( D -C (2)-P ( l ) - N ( l ) - P ( l ) - N ( l ) P(3 )-N(2) -P(3)-N(2) P(2)-N(l) P(2)-N(l) P(2)-N(2) P(2)-W(2) 105.1(6) 110.1(5) 111.2(6) 104.2(6) 111.4(7) 104.7(7) 104.9(7) 111.1(7) 2 7 28 TKBLE V I o Bond l e n g t h s (A) and v a l e n c y a n g l e s (degrees) i n N P F Me 4 4 4 4 and r e l a t e d m o l e c u l e s . \ P 4 K e 8 30 P - F P - C F-P-N Me-P-N F - P - F Me -P-Me N - F ( F 2 ) - N N-P(Me j-N 119.8(2) 1.805(4) 1.596(3) 104.0(2) P - N - P 131.9(3) 1.51(2) 1.51(2) 100.0(10) 123.0(10) 147.0(10) 1.52(1) 1.81(1) 1.53(1) 1.59(1) 96.7(12) 106.9(7) 125.9(9) 117.5(5)' 134.6(7) 29 the FgP-N bonds, c a u s i n g these bonds t o be s t r o n g e r and s h o r t e r than the Me P-N bonds. The P-F (1.52 A) and P-CH 2 3 (1.81 A) bond l e n g t h s are s i m i l a r to those i n the parent compounds (Table V I ) . With the ex c e p t i o n o f the P-N-P angles a l l the e n d o c y c l i c and e x o c y c l i c bond angles do not d i f f e r s i g n i f i c -a n t l y from those i n the parent compounds (Table V I ) . The P-N-P angle o f 134.6° i s very much s m a l l e r than the angle o f 147° found i n the t e t r a m e r i c f l u o r i d e . In the present compound t h e r e are only h a l f as many f l u o r i n e s , and the indue t i v e e f f e c t s are presumably not as l a r g e as i n (NPF^)^. As a r e s u l t the P-N-P angle i s c l o s e r to the valu e s found i n 21 most of the other t e t r a m e r i c p h o s p h o n i t r i l e s (Table i ) . The p h o s p h o n i t r i l i c r i n g i n the present s t r u c t u r e has the s o - c a l l e d 'saddle' conformation, w i t h the phosphorus atoms on a plane v/ith the n i t r o g e n s a l t e r n a t i n g above and below. The equation of the plane through the f o u r phosphorus atoms i s -0.8370 X ? + 0.5473 = 2.6776, v/here X', Z' are o c o o r d i n a t e s i n A r e f e r r e d to orthogonal axes a, b, and c*, and the displacements o f the n i t r o g e n atoms from t h i s plane are N ( l ) - O.48, N(2) + O.48, N(2 f) - O.48, and N(I') +. O.48 T h i s c o n t r a s t s v/ith the t e t r a m e r i c f l u o r i d e i n which the r i n g 36 i s p l a n a r , and the t e t r a m e r i c methyl compound which has 30 the 'tub' conformation. Considerable a t t e n t i o n has been 3 0 g i v e n t o t h e s h a p e s o f t h e t e t r a m e r i c p h o s p h o n i t r i i i c r i n g s i n a n e f f o r t t o d e d u c e t h e i m p o r t a n c e o f T T - b o n d i n g i n t h e s e 21 c o m p o u n d s . I t i s p o i n t e d o u t t h a t t h e ' t u b ' c o n f o r m a t i o n f o u n d i n t h e o c t a m e t h y l d e r i v a t i v e a l l o w s s t r o n g T T - b o n d i n g , a n d a t t h e s a m e t i m e i s s t e r i c a l l y f a v o u r a b l e a s i t a l l o w s 21 t h e m e t h y l g r o u p s t o b e s t a g g e r e d . T h e p l a n a r i t y o f t h e o c t a f l u o r o c o m p o u n d i s p r o b a b l y a r e s u l t o f t h e s t r o n g i n d u c t i v e i n f l u e n c e o f t h e f l u o r i n e a t o m s , w h i c h p r o d u c e s e x t e n s i v e d e l o c a l i z a t i o n o f t h e n i t r o g e n l o n e p a i r s , a n d o 21,36 r e s u l t s i n a n i n c r e a s e o f t h e P - N - P a n g l e s t o 147 . I n t h e p r e s e n t s t r u c t u r e t h e a d o p t i o n o f t h e ' s a d d l e ' c o n f o r m a t i o n i s p r o b a b l y t h e r e s u l t o f a c o m p r o m i s e b e t w e e n 1T - b o n d i n g a n d s t e r i c r e q u i r e m e n t s . T h e a r r a n g e m e n t o f t h e a t o m s i n t h e ' s a d d l e ' a l l o w s e f f i c i e n t TT - b o n d i n g b e -t w e e n a d j a c e n t p h o s p h o r u s a n d n i t r o g e n a t o m s , b u t a t t h e e x p e n s e o f b r i n g i n g t h e s u b s t i t u e n t s o n t h e p h o s p h o r u s a t o m s i n t o a n e c l i p s e d p o s i t i o n . H o v / e v e r s i n c e t h e v a n d e r i v a a l s r a d i u s " ^ o f f l u o r i n e (1.35 A ] i s m u c h s m a l l e r t h a n t h a t o f o a m e t h y l g r o u p (2.00 A ) t h i s c a u s e s n o s e r i o u s s t e r i c i n t e r -o a c t i o n s . T h e c l o s e s t c r o s s - r i n g c o n t a c t ( 3 . 8 4 A ) i s b e t w e e n C ( l ) a n d F ( l ' ) [ r e l a t e d t o F ( l ) b y t h e C _ 2 a x i s ] a n d i s g r e a t e r t h a n t h e s u m o f t h e v a n d e r W a a l s r a d i i . T h e s h o r t 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 i n v o l v e c o n -t a c t s b e t w e e n m e t h y l g r o u p s a n d f l u o r i n e s a n d c o r r e s p o n d 31 t o v a n c i e r V / a a l s i n t e r a c t i o n s . T h e s h o r t e s t d i s t a n c e i s a o C . . . F c o n t a c t o f 3 . 2 5 A b e t w e e n F ( l ) o f t h e s t a n d a r d m o l e c u l e a n d C ( 2 ) o f t h e m o l e c u l e a t ( i - x , ~ + y _ , i - z). 32 1.3 THE CRYSTAL AND MOLECULAR STRUCTURE OF 1,1,3,3,5,5-KEXAFLUORO-7,7-DIMETHYLCYCLOTSTRAPHOSPHONITRILE 1.3.1 Experimental 1,1,3,3,5,5-Hexafluoro-7,7-dimethylcyclotetraphos-p h o n i t r i l e c r y s t a l l i z e d as colourless fragments, generally elongated along c_. U n i t - c e l l and space group data were deter-mined from various rotation, Vfeissenberg, and precession photo-graphs, and on a spectrogoniometer. No suitable l i q u i d could be found f o r density measurement. Crystal Data — C„H F,N P , M= 321.0. Monoclinic, 6 t> 4 4 a = 9.355 (5 ), b = 12.400(5), c = 11.132(5) A, (2 =113.75(3)° o 3 (standard deviations i n parentheses), U = 1182.0 A , Z = 4, p_c = 1.820. F(000) - 640. A (Cu-K^) = 1.5418 A , u (Cu-K K ) = 65 cm. ^. Space group I2/a (C^, ) or Ia (C^) s _ w _ _ —2h ~s_ from systematic absences: hkJL when (h + k_ + __) i s odd; h0__! when h i s odd. I2/a from structure analysis A great deal of d i f f i c u l t y was encountered i n ob-taining a suitable c r y s t a l f o r analysis. No well-formed crystals were avail a b l e , only fragments which were very hygroscopic. This made preliminary o p t i c a l examination very d i f f i c u l t , and a c r y s t a l which gave suitable photographs was found only a f t e r a large number had been examined. The f a c t that the c r y s t a l s had no recognizable faces, and the necessity 33 o f s e a l i n g t h e m i n g l a s s c a p i l l a r i e s t o p r e v e n t h y d r o l y s i s , m a d e t h e i n i t i a l l i n e - u p v e r y d i f f i c u l t . T h e c r y s t a l f i n a l l y u s e d f o r d a t a c o l l e c t i o n w a s a n i r r e g u l a r f r a g m e n t , w i t h c r o s s -s e c t i o n a p p r o x i m a t e l y 0 . 2 m m . b y 0 . 2 m m . a n d a l e n g t h o f 0 . 5 m m . N o a b s o r p t i o n c o r r e c t i o n w a s m a d e . T h e i n t e n s i t i e s o f a l l r e f l e x i o n s w i t h 2 0 ( G u - K ^ ) ^ 1 2 0 ° ( m i n i m u m i n t e r p l a n a r s p a c i n g 0 . 8 9 2 ) w e r e m e a s u r e d o n a D a t e x - a u t o m a t e d G e n e r a l E l e c t r i c X R D 6 S p e c t r o g o n i o m e t e r w i t h a s c i n t i l l a t i o n c o u n t e r , a p p r o x i m a t e l y m o n o c h r o m a t i c C u - r a d i a t i o n ( N i f i l t e r a n d p u l s e h e i g h t a n a l y z e r ) , a n d a 0 - 2 Q s c a n o f t w o d e g r e e s p e r m i n u t e i n 2 9 • B a c k g r o u n d c o u n t s f o r 2 0 s e c o n d s w e r e m a d e a t t h e b e g i n n i n g a n d e n d o f e a c h s c a n . L o r e n t z a n d p o l a r i z a t i o n f a c t o r s w e r e a p p l i e d a n d t h e s t r u c t u r e f a c t o r s d e r i v e d i n t h e u s u a l m a n n e r . R e f l e x -i o n s w h i c h h a d a n e t c o u n t o f l e s s t h a n 3 s i g m a a b o v e b a c k -g r o u n d , w h e r e c" ( I ) i s d e f i n e d b y 2 2 <r ( I ) = S + B + ( . 0 5 s ) w h e r e S a n d 3 a r e t h e s c a n a n d b a c k g r o u n d c o u n t s r e s p e c t i v e l y , w e r e t a k e n a s b e i n g u n o b s e r v e d . T h e s e r e f l e x i o n s w e r e a s s i g n e d s t r u c t u r e f a c t o r s e q u a l t o t h e m e a s u r e d v a l u e s b u t w e r e e x -c l u d e d f r o m t h e r e f i n e m e n t . O f t h e 8 5 0 i n d e p e n d e n t r e f l e x i o n s 3 4 w i t h 2 0 ^ 1 2 0 ° , 6 2 1 {73%) w e r e c l a s s i f i e d a s o b s e r v e d . 1.3.2 S t r u c t u r e A n a l y s i s T h e d a t a w e r e p l a c e d o n a n a b s o l u t e s c a l e b y 47 49 W i l s o n ' s m e t h o d , a n a t h e E - s t a t i s t i c s ( T a b l e V I I ) s u g -g e s t e d t h e c e n t r i c s p a c e g r o u p , I2/a. T h i s o r i e n t a t i o n w a s u s e d i n p r e f e r e n c e t o t h e c o n v e n t i o n a l C2 / c _ , w h i c h h a d a l a r g e (3 a n g l e (131°). A s i n t h e N P F . M e , s t r u c t u r e , t h e i n t e n s i t i e s o f 4 4 4 4 a l l r e f l e x i o n s w i t h R o d d w e r e e x t r e m e l y w e a k , a n d a t r i a l s t r u c t u r e w a s d e r i v e d i n a s i m i l a r f a s h i o n , o n l y a m o d e l w i t h t h e N , P . F . M e m o l e c u l e s i t u a t e d o n a c r y s t a l l o g r a p h i c C 4 4 6 2 —2 a x i s b e i n g p o s s i b l e i n t h i s c a s e . T h i s s t r u c t u r e w a s r e f i n e d b y f u l l - m a t r i x l e a s t - s q u a r e s m e t h o d s , w i t h t h e s c a t t e r i n g 9 f a c t o r s f r o m t h e I n t e r n a t i o n a l T a b l e s . I s o t r o p i c r e f i n e -m e n t c o n v e r g e d a t R = 0.28, a n d a t h r e e - d i m e n s i o n a l d i f f e r -e n c e s y n t h e s i s i n d i c a t e d a l a r g e a m o u n t o f a n i s o t r o p i c t h e r m a l v i b r a t i o n , p a r t i c u l a r l y f o r t h e f l u o r i n e a t o m s . A n a n a l y s i s 2 o f w ( F - F ) i n r a n g e s o f ( F \ i n d i c a t e d t h a t t h e m o s t o ~ ~ c * —o a p p r o p r i a t e w e i g h t i n g s c h e m e w a s w = 1 f o r t h e o b s e r v e d r e -f l e x i o n s , a n d w = 0 f o r t h e u n o b s e r v e d r e f l e x i o n s . T h r e e a n i s o t r o p i c f u l l - m a t r i x l e a s t s q u a r e s c y c l e s c o m p l e t e d t h e r e f i n e m e n t , t h e f i n a l R b e i n g 0.067 f o r t h e 621 o b s e r v e d r e f l e x i o n s a n d 0.084 f o r a l l 350 r e f l e x i o n s . M e a s u r e d a n d c a l c u l a t e d s t r u c t u r e f a c t o r s a r e l i s t e d i n T a b l e V I I I . A 35 TABLE V I I E - 3 t a t i s t i c s f o r N P.F,Me_ 4 4 o <L T h e o r e t i c a l Observed C e n t r o . N on-centro. Mean 1 E l 0.726 0.798 0.886 Mean \ E | 2 1.043 1.000 1.000 Mean | , s 2 - i | 1.195 0.968 0.736 E > 3 ( p e r c e n t ) 1.53 0.30 0.01 E > 2 ( p e r c e n t ) 7.06 5.00 1.80 E > 1 ( p e r c e n t ) 24.71 32.00 37.00 36 T A B L E VIII Observed and f i n a l calculated structure factors f o r N^P F^Me^. U n o b s e r v e d reflexions have a n asterisk follow-ing 7S ? s 2 }S 2b ? 21 7 20 20 2 21 2b 2 I il s i l- 2k 7 21 27 7 21 22 1 21 2*> ^l 2a 2 72 77. 7 ID f> 2 ?J 7t. 37 f i n a l d i f f e r e n c e map showed maximum f l u c t u a t i o n s of + 0.3 e.A with no c l e a r i n d i c a t i o n of hydrogen atom p o s i t i o n s . F i n a l p o s i t i o n a l and thermal parameters are given i n Table IX. Atoms P ( l ) and P(3) are i n p o s i t i o n s 4(e_) of I2/a: (000; ^  ^ ^) + t n e other atoms are i n 8 ( f ) : (GOO; rj- —) + (x, y_, z_; x, + z ) . Bond lengths and valency angles p e r t a i n i n g to the p h o s p h o n i t r i i i c r i n g are shown sc h e m a t i c a l l y i n Figure 6 and a complete l i s t i n g i s given i n Table X. A view of the molecule down c* i s shown i n Figure 7 and the molecular packing i n the u n i t c e l l viewed down b i n Figure 8. A general view of the molecule i l l u s -t r a t i n g the thermal e l l i p s o i d s of 0.5 p r o b a b i l i t y i s shown i n Figure 9. The thermal parameters (Table V) correspond to a la r g e amount of a n i s o t r o p i c thermal motion, p a r t i c u l a r l y f o r the f l u o r i n e atoms, where the root mean square amplitudes of o v i b r a t i o n are as high as 0 .6 A. (Figure 9) . Since the data were c o l l e c t e d at room temperature (ca. 20°) and the compound o $ 1 melts at 50 , the high thermal v i b r a t i o n i s not s u r p r i s i n g ; nevertheless i t d i d seem necessary to examine whether the observed parameters could i n f a c t be a r e s u l t of d i s o r d e r i n space group I2/a, or of a true symmetry l a . E i t h e r of these p o s s i b i l i t i e s would however r e s u l t i n the observation of an apparent molecular symmetry higher than that to be expected f o r the molecule, whereas the observed bond lengths 33 TABLE IX F i n a l p o s i t i o n a l parameters, w i t h standard d e v i a t i o n s i n o 2 ^ parentheses, and a n i s o t r o p i c thermal parameters (A x 10 ) Atom P ( D F(2) P(3) N ( l ) N(2) F ( l ) F(2) F(3) C ( l ) 0 0.2060(2) 0 0.1261(8) 0.1463(8) 0.0690(7) 0.2455(12) 0.3701(6) 0.0657(10) 0.1734(2) 0.0084(2) -0.1635(2) 0.1177(5) -0.0967(5 ) 0.2548(5) 0.0031(6) 0.0173(5) -0.2508(7) 1/4 0.2340(3 ) 1/4 0.2250(9) 0.2543(9) 0.3549(6) 0.1167(11 0.3259(10 0.3904(8) Atom U U U u 2 3 -11 -22 -33 -12 -13 P ( D 6.98 4.94 10.55 0 3.79 0 P(2) 6.99 6.07 11.03 0.07 7.47 1.63 P(3) 6.31 4.68 18.65 0 3.94 0 N ( l ) 11.52 6.68 25.88 1.51 12.02 2.61 W(2) 8.32 6.28 20.81 -0.37 7.51 -0.12 F ( l ) 16.70 10.94 15.39 -4.32 6.25 -4«46 F(2) 31.64 14.89 38.54 7.60 29.20 7.42 F(3) 7.28 12.91 39.21 -0.74 5.34 1.50 C ( l ) 12.14 8.18 9.07 0.33 3.37 0.80 39 F i g u r e 6. Bond lengths (A) and valency angles (degrees) i n t h e phosphonitrilic r i n g of N. P. F/Me , 40 T A B L E X B o n d l e n g t h s ( A * ) a n d v a l e n c y a n g l e s ( d e g r e e s ) , v / i t h s t a n d a r d d e v i a t i o n s i n p a r e n t h e s e s . P ( l ) - N ( l ) P ( 2 ) - N ( l ) P ( 2 ) - N ( 2 ) P ( 3 ) - N ( 2 ) 1 . 4 8 7 ( 6 ) 1 . 5 3 2 ( 6 ) 1 . 4 7 0 ( 6 ) 1 . 5 8 4 ( 6 ) P ( D - F ( 1 ) P ( 2 ) - F ( 2 ) P ( 2 ) - F ( 3 ) P ( 3 ) - C ( l ) 1 . 4 8 1 ( 5 ) 1 . 4 9 5 ( 8 ) 1 . 4 6 6 ( 6 ) 1 . 7 9 4 ( 8 ) N ( l » ) - P ( l ) - N ( l ) N ( l ) - P ( 2 ) - N ( 2 ) N ( 2 ' ) - P ( 3 ) - N ( 2 ) P ( l ) - N ( l ) - P ( 2 ) P ( 2 ) - N ( 2 ) - P ( 3 ) F ( l ' ) - P ( l ) - F ( l ) F ( 2 ) - P ( 2 ) - F ( 3 ) G ( l ' ) - P ( 3 ) - C ( l ) 1 2 4 . 6 ( 5 ) 1 2 6 . 1 ( 3 ) . 1 1 6 . 9 ( 5 ) 1 4 3 . 3 ( 5 ) 1 4 6 . 7 ( 5 ) 9 4 . 1 ( 5 ) 9 3 . 2 ( 5 ) 1 0 5 . 7 ( 6 ) F ( l ) - P ( l ) - N ( l ) F ( l » ) - P ( l ) - N ( l ) F ( 2 ) - P ( 2 ) - N ( l ) F ( 3 ) - P ( 2 ) - N ( D F ( 2 ) - P ( 2 ) - N ( 2 ) F ( 3 ) - P ( 2 ) - N ( 2 ) C ( l ) - P ( 3 ) - N ( 2 ) C ( I ' ) - P ( 3 ) - K ( 2 ) 1 0 9 . 7 ( 4 ) 1 0 7 . 2 ( 4 ) 1 0 5 . 5 ( 4 ) 1 0 9 . 0 ( 4 ) 1 0 9 . 8 ( 5 ) 1 0 8 . 4 ( 4 ) 1 0 7 . 5 ( 4 ) 1 0 9 . 3 ( 4 ) 43 Figure 9. General view of the N,P.F„Ke„ molecule i l l u s -4 4 o 2 t r a t i n g the thermal e l l i p s o i d s of 0.$ p r o b a b i l i t y . 4 4 a n d v a l e n c y a n g l e s ( F i g u r e 6 a n d T a b l e X ) a n d m o l e c u l a r c o n f o r m a t i o n ( F i g u r e 7 ) c o r r e s p o n d t o m o l e c u l a r s y m m e t r y C . . I t i s l i k e l y t h e n t h a t t h e h i g h t e m p e r a t u r e p a r a m e t e r s a r e a t r u e t h e r m a l e f f e c t . 1 . 3 . 3 D i s c u s s i o n T h e N , P F , H e m o l e c u l e e x h i b i t s f o u r d i s t i n c t P - N 4 4 6 2 b o n d l e n g t h s : I.584, 1 , 4 7 0 , 1 , 5 3 2 , a n d 1 . 4 8 7 ( 6~ = - 0 . 0 0 6 ) o . . . A ( F i g u r e 6 ) . T h i s v a r i a t i o n r e s u l t s f r o m t h e p e r t u r b a t i o n c a u s e d b y t h e d i f f e r i n g e l e c t r o n e g a t i v i t i e s o f t h e s u b s t i t u -2 4 e n t s , a n d m a y b e e x p l a i n e d i n t e r m s o f f T - b o n d i n g t h e o r y . T h e g r e a t e r e l e c t r o n e g a t i v i t y o f t h e f l u o r i n e a t o m s a t P ( 2 ) , c o m p a r e d t o t h e P ( 3 ) m e t h y l g r o u p s ( F i g u r e 6 ) , c a u s e s e l e c -t r o n s t o b e d r a w n f r o m N ( 2 ) i n t o t h e P ( 2 ) - N ( 2 ) TT - b o n d o a n d r e s u l t s i n t h i s P - N b o n d ( 1 . 4 7 0 A ) b e i n g t h e s h o r t e s t i n t h e m o l e c u l e , 0 . 0 4 2 s h o r t e r t h a n t h e b o n d s i n t h e p a r e n t 3 6 o c t a f l u o r o c o m p o u n d , ( N P F ^ ) , a n d t h e s h o r t e s t s o f a r 2 4 f o u n d i n a p h o s p h o n i t r i i i c m o l e c u l e . B e c a u s e o f t h i s a v a i l -a b i l i t y o f t T - e l e c t r o n s f r o m N ( 2 ) t h e d o n a t i o n f r o m N ( l ) t o P ( 2 ) i s l e s s f a v o u r e d a n d t h e r e s u l t i s a n i n c r e a s e i n . . . . o t h e P ( 2 ) - N ( l ) b o n d l e n g t h t o 1 . 5 3 2 A . T h i s i n t u r n e n h a n c e s t h e d o n a t i o n f r o m N ( l ) t o P ( l ) r e s u l t i n g i n a b o n d l e n g t h o o o f 1 . 4 3 7 A w h i c h i s 0 . 0 2 A s h o r t e r t h a n i n ( K P F 0 ) . . T h e o P ( 3 ) - N ( 2 ) b o n d ( 1 . 5 3 4 A ) i s t h e l o n g e s t P - N b o n d i n t h e m o l e -o c u l e , b u t i s a p p a r e n t l y s l i g h t l y s h o r t e r t h a n t h e 1 . 5 9 6 A 45 bond i n t h e p a r e n t o c t a m e t h y l compound. I t might be ex-p e c t e d t h a t the P(3 )-N(2) bond s h o u l d be l o n g e r t h a n i n t h e o c t a m e t h y l compound, because o f t h e f a v o u r e d d o n a t i o n o f N(2) e l e c t r o n s t o P ( 2 ) , but c o u n t e r a c t i n g t h i s tendency i s the g r e a t e r d e l o c a l i z a t i o n o f t h e l o n e p a i r e l e c t r o n s o f a i l t h e n i t r o g e n atoms, because of t h e l a r g e i n d u c t i v e e f f e c t s o f t h e f l u o r i n e s u b s t i t u e n t s . I t appears t h a t t h e net e f f e c t i s a s l i g h t d e c r e a s e i n t h e P ( 3)-N(2) bond d i s -t a nce i n N, P F^ M'e . 4 4 6 2 I t might be noted t h a t t h e bond l e n g t h a l t e r n a t i o n s observed i n N P, F,Ke can not be e x p l a i n e d i n terms o f 6 ^ -4 4 6 2 ^ bond i n a u c t i v e e f f e c t s , w h i c h would produce a g r a d u a l change i n bond l e n g t h around th e r i n g ; 1T -bonding must be i n v o l v e d , and f u r t h e r m o r e must be d e l o c a l i z e d o v er t h e e n t i r e phos-p h o n i t r i l i c r i n g . Thus t h e TT -bonding system p o s t u l a t e d 29 by Dewar which was o u t l i n e d i n s e c t i o n 1.1 does not seem p r o b a b l e . The magnitude o f t h e bond l e n g t h v a r i a t i o n i s s i m -i l a r t o t h a t o b s e r v e d i n r i n g s w h i c h a r e p e r t u r b e d by p r o t o -37,43,44 J . _ _ , n a t i o n a t n i t r o g e n , and i s a t t r i b u t a b l e t o t h e p o l -a r i z a b i l i t y o f t h e TT -bonding system i n p h o s p h o n i t r i l e s , the range of v a r i a t i o n o f bond l e n g t h s b e i n g much g r e a t e r than i n o r g a n i c compounds f o r s i m i l a r changes i n s u b s t i t u e n t . The e f f e c t o f a ft* - i n d u c t i v e p e r t u r b a t i o n a t phosphorus 4 6 has been estimated through the c a l c u l a t i o n of bond-atom 52 — 5/j. p o l a r i z a b i l i t i e s from simple Hiickel theory f o r a de-5 5 l o c a l i z e d Tt -system based on an eight-membered r i n g . They are shown i n Figure 10 , i n comparison v/ith the observed d e v i a t i o n s of i n d i v i d u a l bond lengths from the mean, f o r the four successive d i s t i n c t bonds i n N P F,Me . The cl o s e 4 4 6 2 correspondence i n p a t t e r n seems a d d i t i o n a l evidence f o r 1T - e l e c t r o n d e l o c a l i z a t i o n i n p h o s p h o n i t r i l e s . The mean P-F distance (1.48 A ) and the P-C di s t a n c e o (1 .79 A) are q u i t e s i m i l a r to the lengths i n N,P F Me , and 36 30 ^ 4 4 4 i n the o c t a f l u o r o and octamethyl compounds. The most notable f e a t u r e s of the valency angles are the l a r g e values at the nitrogens (Figure 6 ) , the average o o . . value of 145 approaching the value of 147 found i n (NPF„J . c 4 In the o c t a f l u o r o compound t h i s has been a t t r i b u t e d to the 36 l a r g e i n d u c t i v e e f f e c t s of the f l u o r i n e s , and t h i s i s most l i k e l y the case i n the present s t r u c t u r e as w e l l . The endo-c y c l i c angles at P ( l ) and P(2) are l a r g e r than the c o r r e s -o ponding angle at P(3) by an average of 8 , t h i s being r e -l a t e d to the e x o c y c l i c F-P-F angles at P ( l ) and P(2) being 1 2 ° smaller than the C-P-C angle at P ( 3 ) . The eight-membered p h o s p h o n i t r i l i c r i n g has the 'saddle' conformation (Figure 7 ) , w i t h the f o u r n i t r o g e n atoms a l t e r n a t i n g above and below the plane c o n t a i n i n g the 47 -0.05 J I I 1 1 a b c d Bond F i g u r e 1 0 . ( i ) D e v i a t i o n o f i n d i v i d u a l b o n d l e n g t h s f r o m t h e mean, and ( i i ) b ond-atom p o l a r i z a b i l i t i e s f o r t h e N , P . F , M e m o l e c u l e . 4 4 6 2 4 8 f o u r p h o s p h o r u s a t o m s . T h e e q u a t i o n o f t h e p l a n e i s 0 . 0 3 1 1 X ' + 0 . 9 9 6 7 Z f = 2 . 4 4 3 0 , w h e r e X ' a n d Z ' a r e i n A , r e f e r r e d t o o r t h o g o n a l a x e s a , b , a n d c * . T h e d i s p l a c e m e n t s o f t h e n i t r o g e n a t o m s f r o m t h i s p l a n e a r e : M ( l ) - 0 . 1 $ , e 3 0 N(2) + 0 . 1 5 , N ( 2 ' ) - 0 . 1 5 , a n d N ( l ' ) + 0 . 1 5 A . I t i s u s e f u l t o c o m p a r e t h e r i n g c o n f o r m a t i o n s f o r t h e s e r i e s N . P , M e a , ' 36 4 4 8 N P M e F , I-T P M e F , , a n d N , P , F r , . T h e o c t a m e t h y l c o m p o u n d 4 4 4 V 4 4 2 6' 4 4 8 ' a d o p t s t h e ' t u b ' c o n f o r m a t i o n p r i m a r i l y f o r s t e r i c r e a s o n s . T h e t e t r a m e t h y l t e t r a f l u o r o c o m p o u n d h a s t h e ' s a d d l e 1 c o n f o r -. o m a t i o n w i t h t h e n i t r o g e n s b e i n g a n a v e r a g e o f 0 . 4 8 A o f f t h e p h o s p h o r u s p l a n e . I n t h e p r e s e n t c o m p o u n d t h i s d i s p l a c e -o m e n t i s r e d u c e d t o 0 . 1 5 A , a n d t h e o c t a f l u o r o c o m p o u n d i s p l a n a r . T h u s t h e r e i s a d i r e c t c o r r e l a t i o n b e t w e e n t h e n u m -b e r o f f l u o r i n e s a n d t h e t e n d e n c y t o w a r d s p l a n a r i t y , t h i s a g a i n b e i n g a t t r i b u t a b l e t o t h e l a r g e i n d u c t i v e e f f e c t s o f t h e f l u o r i n e s u b s t i t u e n t s . T h e s h o r t e s t i n t e r m o l e c u l a r d i s t a n c e s i n v o l v e c o n -t a c t s b e t w e e n f l u o r i n e s a n d c o r r e s p o n d t o v a n d e r W a a l s i n t e r -o a c t i o n s . T h e s h o r t e s t d i s t a n c e i s 3-33 A b e t w e e n F ( l ) o f t h e s t a n d a r d m o l e c u l e ( a t x , y_, z) a n d F ( 3 ) o f t h e m o l e c u l e a t ( - £ + x , 2 - i l > 2 j . P A R T I I T H E S T R U C T U R E D E T E R M I N A T I O N O F H E X A P H S N O X Y C Y C L O T R I P H O S P H O N I T R I L E 5 0 2 . 1 I n t r o d u c t i o n T h e s t r u c t u r e s o f t r i m e r i c p h o s p h o n i t r i l e s w h i c h h a v e b e e n r e p o r t e d a r e l i s t e d i n T a b l e X I , a n d a s m a y b e s l i g h t c h a i r o r b o a t c o n f o r m a t i o n s , t h e d e v i a t i o n s f r o m p l a n a r i t y h a v i n g b e e n v a r i o u s l y a s c r i b e d t o i n t r a - a n d i n -t e r m o l e c u l a r s t e r i c e f f e c t s . T h i s r e s e m b l e s t h e s i t u a t i o n i n t h e t e t r a m e r i c c o m p o u n d s ( s e c t i o n 1 . 1 , T a b l e I ) w h e r e , a l t h o u g h s e v e r a l d i f f e r e n t r i n g c o n f o r m a t i o n s h a v e b e e n f o u n d , t h e a d o p t i o n o f a p a r t i c u l a r c o n f o r m a t i o n i s i n f l u e n c e d t o s o m e e x t e n t b y s t e r i c f o r c e s . T h e c r y s t a l a n d m o l e c u l a r s t r u c t u r e o f h e x a p h e n o -x y c y c l o t r i p h o s p h o n i t r i l e , j J ' J P f O P h ) , ^ , w a s u n d e r t a k e n t o c o m p a r e t h e g e o m e t r y w i t h t h e o t h e r h o m o g e n e o u s l y s u b s t i t u t e d t o o b t a i n a c c u r a t e v a l u e s o f t h e m o l e c u l a r d i m e n s i o n s , t o e x a m i n e t h e i n t r a - a n d i n t e r m o l e c u l a r s t e r i c e f f e c t s o f p o s s i b l e e x o c y c l i c TT - b o n d i n g b e t w e e n p h o s p h o r u s a n d o x y g e n a t o m s . p l a c e m e n t o f c h l o r i n e a t o m s o n t h e c o r r e s p o n d i n g c h l o r i d e s e e n o n l y t h e f l u o r i d e 56 i s p l a n a r . T h e o t h e r r i n g s h a v e c y c l o t r i p h o s p h o n i t r i l e s , T h e t r i m e r i c p h e n o x y c o m p o u n d i s p r e p a r e d b y r e -60 b y r e a c t i o n w i t h s o d i u m p h e n o x i d e . N a O P h b e n z e n e T A B L E X I Structural parameters of trimeric phosphonitriles with standard deviations of bond lengths and valence angles i n parentheses. Compound P-N(2) P-N-P(degrees) N-P-N(degrees) Conformation Reference N 3 P 3 F 6 1.56(1) 121(1) 119(1) planar 56 N 3 P 3 C J l 6 1.59(2) 120(1) 120(1) chair 57 N 3 P 3 B r 6 1.58(4) 121(3) 117(2) s l i g h t chair 53 N 3 P 3 P h 6 1.597(6) 122.1(4) 117.8(3) s l i g h t chair 59 N 3 P 3 ° V h 2 1.615(5) 1.555(5) 1.578(5) 122.0(3) 119.2(3) 115-2(2) 119.7(3) s l i g h t chair 40 y 3 c * 2 p \ 1.556(8) 1.609(8) 1.578(8) 121.0(5) 124.9(5) 120.7(4) 115.5(4) s l i g h t boat 41 N P F Ph 3 3 4 2 1.618(5) 1.558(4) 1.539(5) 120.5(2) 115.5(3) 120.6(3) s l i g h t boat 42 N P CJl (NHPr i). •HCA 3 3 2 X 4 1.670(5) 1.56*0(5) 1.560(5) 132.0(4) 125.5(4) 120.0(4) 107.5(4) distorted boat 44 52 2 . 2 E x p e r i m e n t a l C r y s t a l s o f h e x a p h e n o x y c y c l o t r i p h o s p h o n i t r i l e a r e c o l o u r l e s s n e e d l e s e l o n g a t e d a l o n g a . U n i t c e l l a n d s p a c e g r o u p d a t a w e r e o b t a i n e d f r o m v a r i o u s r o t a t i o n , W e i s s e n b e r g , a n d p r e c e s s i o n f i l m s ; a c c u r a t e l a t t i c e p a r a m e t e r s w e r e d e t e r -m i n e d b y a l e a s t - s q u a r e s p r o c e d u r e a p p l i e d t o 2 & v a l u e s f o r t w e n t y - f i v e g e n e r a l r e f l e x i o n s m e a s u r e d o n a s p e c t r o -g o n i o m e t e r . C r y s t a l d a t a . — C _ A H N 0 , P . M = 6 9 3 - 5 8 . — 3D 30 3 6 3 ~ M o n o c l i n i c , a = 1 1 . 1 7 6 ( 4 ) , b = 19.270(3), c = 1 6 . 1 7 1 ( 4 ) A , (3 = 9 2 . 0 7 ( 2 ) ° ( s t a n d a r d d e v i a t i o n s i n p a r e n t h e s e s ) , U = 3 4 8 0 . 2 P, = 1.32 ( f l o t a t i o n i n C H B r / C 6 H 6 ) , ' 2 = 4 , D = 1.323 , F ( 0 0 0 ) = 1440. A ( C u - K * ) = 1.5418 A , ~ £ " - 1 5 M. ( C u - K ft ) = 1 9 . 6 c m . . S p a c e g r o u p P 2 / n ( C ) , f r o m s y s t e m a t i c a b s e n c e s : h O j ? w h e n ( h + j L ) i s o d d , O k O w h e n k i s o d d . T h e i n t e n s i t i e s o f a l l r e f l e x i o n s w i t h 2 0 ( O u - K ^ ) 4- 105° ( m i n i m u m i n t e r p l a n a r s p a c i n g , d = 0.97 A ) w e r e m e a s u r e d o n a D a t e x - a u t o m a t e d G e n e r a l E l e c -t r i c Z R D 6 d i f f r a c t o m e t e r , w i t h a s c i n t i l l a t i o n c o u n t e r , a p p r o x i m a t e l y m o n o c h r o m a t i c C u - K x r a d i a t i o n ( N i f i l t e r a n d p u l s e h e i g h t a n a l y s e r ) , a n d a 0 - 2 0 s c a n a t 2 ° p e r m i n u t e i n 2 0. B a c k g r o u n d c o u n t s o f 2 0 s e c o n d s 53 w e r e m a d e a t t h e b e g i n n i n g a n d e n d o f e a c h s c a n . O f 3883 i n d e p e n d e n t ' r e f l e x i o n s , 2899 (75£>) h a d i n t e n s i t i e s g r e a t e r t h a n 3 < 5 ~ ( I ) a b o v e b a c k g r o u n d , w h e r e 6~ ( I ) i s d e f i n e d b y <r2(i) = s + B + (0.05s) 2 a n d 3 = s c a n c o u n t , B = b a c k g r o u n d c o u n t . T h e o t h e r 984 r e f l e x i o n s w e r e c l a s s i f i e d a s u n o b s e r v e d . A c h e c k r e f l e x -i o n w a s m o n i t o r e d e v e r y s e v e n t y - f i v e r e f l e x i o n s , i t s i n -t e n s i t y v a r y i n g b y a m a x i m u m o f + 1.5/b d u r i n g t h e 168 h o u r s o f d a t a c o l l e c t i o n . L o r e n t z a n d p o l a r i z a t i o n c o r r e c t i o n s w e r e a p p l i e d , a n d t h e s t r u c t u r e a m p l i t u d e s w r e r e d e r i v e d . T h e c r y s t a l h a d l e n g t h 0.52 m m . a n d c r o s s - s e c t i o n 0.21 m m . x 0.19 m m . , a n d n o a b s o r p t i o n c o r r e c t i o n w a s m a d e . 2.3 S t r u c t u r e A n a l y s i s T h e p h o s p h o r u s a t o m p o s i t i o n s w e r e d e t e r m i n e d f r o m a t h r e e - d i m e n s i o n a l s h a r p e n e d P a t t e r s o n f u n c t i o n ; t h e s h a r p e n i n g f u n c t i o n u s e d w a s (2 s i n 2Q ) / ( I + c o s 2Q ). I n t e r p r e t a t i o n o f t h e P a t t e r s o n w a s s i m p l i f i e d b y a s s u m i n g t h a t t h e i n t r a m o l e c u l a r P - P v e c t o r s f o r m a n e a r l y e q u i -l a t e r a l t r i a n g l e o f s i d e 2.85 2 . T h e i n i t i a l d i s c r e p a n c y i n c l u d i n g t h e t h r e e p h o s p h o r u s a t o m s o n l y w a s O.56. T h e 54 r e m a i n i n g f o r t y - f i v e n o n - h y d r o g e n a t o m s w e r e l o c a t e d f r o m t h r e e s u c c e s s i v e e l e c t r o n - d e n s i t y m a p s . T h e d i s c r e p a n c y a t t h i s s t a g e w a s 0.40. a n d a n o v e r a l l s c a l e f a c t o r w e r e r e f i n e d b y b l o c k - d i a g o n a l l e a s t - s q u a r e s m e t h o d s , t h e f u n c t i o n m i n i m i z e d b e i n g ^ ^ ^ ( F Q - F ^ ) , w i t h w t a k e n a s t h e r e c i p r o c a l o f t h e v a r i a n c e i n F, a s d e t e r m i n e d f r o m t h e c o u n t i n g s t a t i s t i c s . 9 T h e s c a t t e r i n g f a c t o r s f r o m t h e i n t e r n a t i o n a l T a b l e s w e r e u s e d . C o n v e r g e n c e w a s r e a c h e d a t R = 0.095 f o r t h e o b s e r v e d r e f l e x i o n s . S i x f u r t h e r c y c l e s v / i t h a n i s o t r o p i c t h e r m a l p a r a m e t e r s r e d u c e d R t o 0 . 0 5 8 . A t t h i s s t a g e a t h r e e - d i m e n s i o n a l d i f f e r e n c e s y n t h e s i s c l e a r l y r e v e a l e d a l l t h i r t y h y d r o g e n a t o m s i n t h e m o l e c u l e , t h e i r e l e c t r o n -d e n s i t y m a x i m a b e i n g a m o n g t h e t h i r t y - s e v e n h i g h e s t p e a k s i n t h e m a p . T h e h y d r o g e n a t o m s w e r e i n c l u d e d i n t h e r e f i n e -m e n t , v / i t h t h e s c a t t e r i n g c u r v e o f S t e w a r t , D a v i d s o n , a n d 6 l S i m p s o n , a n d i s o t r o p i c t h e r m a l p a r a m e t e r s . R e f i n e m e n t w a s c o n t i n u e d u n t i l c o n v e r g e n c e a t R = 0.037 f o r t h e 2 8 9 9 o b s e r v e d r e f l e x i o n s . M e a s u r e d a n d c a l c u l a t e d s t r u c t u r e f a c t o r s a r e l i s t e d i n T a b l e I I I . F i n a l p o s i t i o n a l a n d t h e r m a l p a r a m e t e r s a r e g i v e n f o r t h e p h o s p h o r u s , n i t r o g e n , o x y g e n , a n d c a r b o n a t o m s i n T a b l e XIII, T h e p o s i t i o n a l a n d i s o t r o p i c t h e r m a l p a r a m e t e r s 2 A v i e w o f t h e m o l e c u l e i s s h o w n i n F i g u r e 1 1 . T.-iBLE XXI 55 O b s e r v e d a n a f i n a l c a l c u l a t e d s t r u c t u r e f a c t o r s f o r [NP(0Ph) 2] . U n o b s e r v e d r e f l e x i o n s h a v e a n e g a t i v e F~, 1 8 6 37. 1 38.5 1 B 7 -I.9 0.2 i e e 72.7 72.6 i a 9 19.1 19. 1 1 8 10 12.7 i 8 1 37.3 17.0 l a 12 45.8 46.2 l ft I 3 20.2 19.ft i 4 14 30.0 i 9 - i * 7.0 6.S i •) - i J 24.2 26.0 1 9 -1? 14.0 14.9 1 9 -1 0.0 3.4 1 9 -10 29. 6 28.6 1 9 -9 21.0 20.5 I 1 -8 -2.9 2.3 1 9 -T -4.2 24.8 1 9 -5 12.9 12.7 1 9 -4 B.e> 7.4 1 9 -3 2.5 1 9 -2 49.5 48.3 1 9-1 65.6 19 0 39.9 40.4 1 9 1 22. e"' 21.9 1 9 2 17.8 18.0 1 9 3 6.6 35.B I 9 4 32.5 32.4 1 9 5 37.2 34.3 ._t 9._..6_ .16.3 1 9 7 5.8 4.3~ I 9 8 39.3 37.9 1 9 10 16.3 I 9 11 36.4 36.0 1 9 12 4.4 1 *» 13 . , *.5_ I 9 1<- 16.9 "ia. 2 1 10 -14 -3.9 2.2 I 10 -13 1.1 ID.6 1 10 -1? 1 1.0 1 10-11 0.0 1 10 -10 14.7 14.3 f 10 -9 18.6 ~L9^2~ 1 10 -8 32.2 3.1 1 10 - 1 15.6 15.4 1 10-6 0.0 ?.* I 10-5 15.6 14.2 1 10-4 -2.4 2.8 1 10 -3 45.5 45.1 1 10 -2 3.6 30.9 1 10 -1 5.4 56.6 I 10 0 46. 7 47.2 69.3 70. 8 1 |0 2 25.0 25.7 I 10 3 12.2 110 4 27.9 27.0 1 10 5 41.1 1 10 6 40. 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I 15.6 -3.6 36.0 28.5 18.3 126.8 82.5 70.5 157.7 49.0 2.7 34.2 30. 3 12.B 128.7 85.5 68.7 47.1 TABLE; I I I ( c o n t i n u e d ) 56 continued h k l R, Fc -5.8 20.5 -5.6 -9.5 -3.") -8.9 0.0 13.2 21. a -3.1 72.b 0.0 -2.2 10.6 0.0 1.0 -2.3 19.0 16.5 -•S.3 27.6 61.7 14.2 29.9 0.0 14.R 24.0 0.9 2.0 9.8 2.0" 12.1 13.5 36.X 4.3 27. 1 19.6 21.2 0.0 12.9 -2.3 1.9 28.5 _27.2 10.Fl 69. 1 21.3 73.2 57.4 50.T .. 22-<U n.o 26.8 2.5 6.3 1.2 69.5 2.0 73.8 206.2 108.* 51.0 49.6 5.4 49. 7 32.0 61 .9 76.5 28.9 64.0 62. T 12B. 1 105.7 60.1 7.4 28.2 65.4 6,5 136.2 107.3 79. 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T -7.5_ 14.7 3.0 _6.3 40. t 10.8 27.0 13.2 47.1 5.p. 49.4 3.9 11. 23.8 7.1 18.2 4.0. 1.2 21 .9 48.2 21.5 6.3 _5,3. 15.1 10.0 1.3 31.3 -6.7 32.7 14.0 15.6 48.7 1.8 14.4 15.4 -10.5 10.5 -6.0 _U-4_ 6.9 7.6 3.T 1.8 14.6 50.5 1.7 12.0 15.0 12.1 1.7 5.T 10.0 4.4 10.0 14.6 15.1 -8.1 6.4 11.4 1.5 _-9.4 8.5 -10.1 9.8 15.6 15.8 1.6 13.1 1.0 10.0 -7.0 4.5 10.8 13.0 25.7 -7.3 8.3 9.1 -3.7 . 15.0 0.0 -5.3 -5.5 -3.2 -3.3 34.5 13.6 34.4 6.0 16.1 14.4 -4.5 10.2 -4.4 7.2 43.4 20.3 69.4 31.1 85.8 34.9 24.2 35.8 48.4 46.3 23.7 38.8 2.9 13.5 -10.1 _Z?.3_ 20.6 23.1 21.2 14.1 2.9 2.6 9.0 39. 2_ 41.4 18.9 35^9_ 24.1 36.8 24.1 45.2 " 20.7 39.0 25.1 13.0 6.5 _1.4 20.7 2.1 21.4 13.1 17.5 56.5 25.5 19.6 30.5 _!_7.0_ 59.4 30.4 42.1 -3.6 25.7 15.4 43.8 35.0 21.3 20.1 0.0_ 8.6 -3.2 21.0 13.3 32.6 24.3 5.9 56.0 53.1_ 37.3 28.8 24.2 58.5 16.7 17.5 -6.2 17.7 20.3 -6.4 -6.1 31.5 0.0 21.B -10.2 -7.3 2.1 _r2-8 _ -2.9 35.7 32.2 49.9 8.8 30.4_ 62.2 38. 9 41.2 36.3 63.T _ 80.2 40.9 8.3 27.6 45.T 6.2 14.1 23.5 30.0 20.9 21.4 15.6 12.5 19.8 58.0 25.4 19.4 29.4 _1*-1_ 58.4 28.7 42.1 1.9 24.5 ve*5_ 15.3 4?.8 35.3 20.8 20.8 _ 0.7 5.8" 1.2 2.5 6.0 45.1 16.3 56.3 10.5 1.7 37.1 50-7_ 35628024958615517.8 3.8 17.4 _ 0-2 2.0 38.2 29.2 49.7 7.6 61.3 40.5 39.2 35.3 .14 ,__8.l -14 1.8 -13 13.4 -12 16.6 80.2 _.  8.2. 49.1 -4.7 21.3 21.2 16.1 18.3 12-5_ 4.8 3.4 47.5 25.3 -4.9 6_ -6.7 0.0 -8.9 -5.9 15.3 15.9 -6.7 32.9 -7.1 29.5 23.8 20.6 3.3 2.3 0._2_ 20.4 21.3 25.6 16.7 32.0 47.1 23.8 2.4 28._3 0.7 0.5 8.3 5.9 15.4 14.2 8.8 3.3 16.1 14.2 _13.'>. 4.9 34.6 3.9 0.5 70.0 53 T A B L E X I I ( c o n t i n u e d ) continued h k I F 0 Fc O 43.6 13.8 38.7 43.2 70.1 30.6 55.3 0.0 -3.5 30.4 38.2 33.2 10.3 20.8 -10.7 9.6 22.3 18.7 0.0 9.7 14.5 0.0 -5.7 -8.3 -3.0 12.9 39.5 22.0 8.8 13.7 14.0 16.3 7.5 26.5 21.6 10.6 12.2 48.5 12.3 -3.V 10 -12 22.8 38.3 4.5 70.9 25.3 18.5 21.7 -4.7 41.2 27.0 12.6 8.3 13.4 -5.1 -10.0 20.3 0.0 10. B 41.8 33.1 24.2 0.9 13.5 6.0 33.2 16.9 36.7 2.5 14.3 39.5 23.0 8.4 41.4 17.5 0.0 7.7 15.8 6.9 26. 3 50.8 11.2 6.6 1 1.6 22.4 4.0 9.6 20.8 48.9 19.5 14.0 33.3__ 21.3 -6 .0 17.2 9.5 16.0 _2 l.._9__ 19.5 13.6 1.0 25.6 29.0 13.8 ...33.4 _ 22.1 14.5 9.0 47.6 12~. 3 0.2 35.2 26.1 _-7 1.5.9 14.8 24.3 -3.3 16.2 0.0 -6 .0 25.7 -11.2 29.9 -5.7 38.7 17.5 15.2 39.5 -8 .0 -9.3 22.2 26.6 10.0 38.5 10.1 6.7 8.6 12.8 3.0 22.8 26.3 -4.5 13.4 30.5 12.0 11.0 I I ^ L L 1 3 . 1 _ 0.0 2. -2 .9 2.1 -4.4 3.0 23.8 23.2 31.0 29.3 11.8 11.3 -5.0 5.2 11.4 11.8 65.4 64.7 5.4 6.9 20.1 17.5 18.7 17.8 -2.3 C.9 7.5 -4 .9 29.9 28.1 -6.2 6.0 11.1 11.0 -6.5 5.1 15.4 16.6 -4.2 8.6 15.0 15.0 -9.5 8.8 10.0 9.2 10.9 11.6 30.7 31.5 27.6 26.9 9.9 8.5 5.1 7.0 7.4 4.5 52.7 49.3 29.4 26.0 19.8 19.3 -4 .0 3.1 -4 .7 3.5 14.0 14.0 -2.8 l.T -5 .3 7.0 30.0 31.7 17.0 16.2 26.4 27.5. 13.0 16.2 10.9 11.1 -2 .7 l . l 21.4 20.5 15.0 16.8 -9.3 12.0 38.0 35.9 30.7 30.6 -5.8 5.7 19.6 20.2 9.0 9.3 8.0 6.9 5.7 5.7 9.3 9.8 24.4 25.0 25.9 26.5 61.1 58.0 20.8 20.1 30.0 27.4 5.5 5.9 61.6 61.2 18.0 20.0 15.0 15.3 24.3 24.7 -4.4 l . l 15.6 15.6 0.0 1.7 11.3 10.5 11.4 10.2 12.9 1 3 . Q 8.7 7.6 17.3 18.4 -9.3 5.5 20.2 2C.7 30.5 30.6 35.2 35.5 8.7 8.8 -5.2 4.5 -4.9. 2.0 46.5 48.6 8.3 7.6 41.7 40.9 12.4 12.1 40.2 40.4 35.6 35.9 43.5 41.4 - l . f i 0.5 10.8 10.2 -2.9 0.1 -2 .9 1.6 25.4 27.5 30.6 30.5 18.6 18.4 9.0 9.2 -6.6 8.5 -8.1 8.8 27.8 29.5 23.7 23.2 44.2 44.4 34.R 34.3 0.0 1.5 . 21.4 21.7 11.4 11.2 16.2 17.7 6.7 4.4 62.9 62.0 51.3 50.5 \2.B LU*_ -1.7 4.8 17.4 16.7 40.9 41.5 23.6 23.7 31.1 30.5 24.9 Zl.,3-10.3 8.5 26.3 26.5 25.2 26.1 24.9 25.5 14.5 14.9 P^O USL. 7.4 5.1 13.8 13.4 0.0 0.3 27.3 29.0 -8.4 0.0 51 .1 16.1 28.4 -2.9 6.8 8.7 31 .0 20.2 36.5 21.4 18.3 0.0 12.6 24.4 12. 1 -3.0 20.5 25.0 27.1 19.6 59.3 48.0 -6.4 38.6 -9.7 27.8 1.6 6.6 7.0 29.8 31.8 9.2 21.9 36.3 29.9 21.1 25.1 24.7 11.7 2.5 1.1 46.3 70.0 27.2 28.0 20.7 24.5 26.7 19.4 59.8 46. 1 20.7 35.3 33.4 2.T 12.4 5.0 34.0 27.1 14.1 10.1 31.5 16.9 2.8 20.5 39.6 -7.2 -5.6 10.B 19.2 ,. Z9.3 21.2 12.2 7.6 5.2 11.6 9.0 15.8 49.5 19.8. 42.5 17.1 .13.9 15.7 51.2 38. 8 14.6 6.4 0.0 13.6 9.4 4.7 16.9 24.5 21.9 14.8 4.2 10 63.1 66.8 6 10 -5 14.9 15.7 6 10 -4 44.8 45.0 10 -3 40.8 40.8 6 10 -2 -8.3 6.7 6 10 -1 27.9 27.4 6 10 0 13.6 13.5 10 13.6 10.9 6 10 2 15.8 15.5 6 10 3 39.4 40.2 6 10 4 14.4 13.5 6 10 5 -7.5 4.6 6 10 6 21.7 19.7 6 10 7 20.7 20. 1 10 8 38.9 36.8 10 9 12.5 14.0 6 10 10 20.8 21.5 11 -10 24.8 24.6 11 13.1 13.8 6 11 -8 -6.7 11 13.9 14.6 6 11 14.5 14.9 6 11 -5 -5 .6 5.5 6 11 -4 17.0 16.4 11 -3 12.0 9.4 6 11 -2 1 1 .4 6 11 -1 13.9 13.2 11 0 56. 3 55.4 6 11 1 20.1 22.0 6 11 2 41 .3 40. a 11 3 22.8 24.6 6 11 4 -8.7 5.6 6 11 5 29.5 30. 1 6 11 16.3 14.5 6 11 7 1 1.6 11.5 6 11 8 -8.4 6.7 6 11 9 -4.9 3.6 11 10 11.0 11.5 2 -10 13.3 12.3 6 1? -9 -3.8 4.8 6 12 -8 32.9 32.6 6 12 23.8 23.1 6 12 -6 1?.T 10.7 12 -5 40.5 41.5 6 12 -4 29. 1 30.2 6 12 -3 0.0 3.4 6 12 -2 72.4 73.2 6 12 -1 -4.4 4 . 7 6 12 0 16.1 17.3 12 1 16.7 17.0 12 2 -10.9 9.8 6 12 3 -9.7 9.4 6 12 4 39. 1 39.4 6 12 5 25.5 26.4 6 12 6 34.8 34.9 12 7 19.0 18.4 6 12 8 18.4 18.6 12 9 7.6 6.5 6 13 -9 10.3 10.8 6 13 - a 8.9 9.1 6 13 -7 -1 .9 2.4 6 13 -2.8 4.8 6 13 -5 -5.6 3.4 13 -10.0 10.7 6 1 3 -3 0.0 0.6 6 13 -2 -8.3 7.9 13 -1 -9.8 10.7 13 0 22.8 22.8 6 13 1 -9.6 8.7 13 ? 47.9 47.1 6 13 3 21.3 19.3 13 6. 1 6 13 5 27.3 27.3 6 13 6 -4.6 5.8 6 13 7 -2.1 2.9 6 13 3 -1.7 0.0 6 14 -8 -5.8 7.5 6 14 -7 7.7 6.6 14 -6 -3.6 3.6 6 14 -5 0.0 2.8 14 -4 -6.1 3.5 14 -3 17.0 15.P 6 14 -2 19.2 21.0 6 14 - 1 38.7 39.4 6 14 0 -a .2 8.5 14 25.8 27.2 6 14 2 -3.8 0.3 6 14 3 27.4 28.3 14 4 17.4 18.6 6 14 5 21.6 21.1 6 14 6 -5.3 2.6 6 14 7 21.5 21.5 6 15 -6 8.4 8.1 6 15 -5 -5.3 3.8 6 15 -4 17.6 17.5 6 5 -3 0.0 2.6 6 15 -2 13.2 14.6 6 15 -1 34.6 35.0 6 15 0 -2.7 2.9 15 1 36. 1 35.B 6 15 2 16.5 16.4 6 15 3 46.0 46. 7 6 15 4 M o . 1 10.0 6 15 5 -3.4 1 .3 6 16 -3 .6 0. 1 6 16 -3 17.0 16.6 6 16 -2 9.4 8.1 6 16 8.7 7.1 6 16 0 -6.2 4.5 6 16 10.4 10.0 6 16 2 0.0 2.4 16 3 9.5 tj. e 7 0 -13 10.0 1.2 7 0 -1 1 -3.2 4.2 0 -9 27.4 26.6 0 -7 14.7 14.9 7 0 -5 16.0 15.7 0 -3 13.9 15.2  0 -1 22.1 20.8 7 0 1 13.4 13.8 7 0 3 20.0 19.2 0 5 7.8 8.5 0 7 15.6 17.6 0 9 28.4 28.6 0 1 1 22.3 23.2 -13 0.0 2.2 -12 9.9 9.5 T 1 -11 0.0 0.9 -10 -5.1) 5.7 -9 29.8 28.9 1 -10 30.4 2 -9 -4.4 2 -8 12.3 2 -7 -4.1 2 -6 7.9 2 -5 6.6 4 10 36.1 4 I I -6.0 4 12 14.5 5 -12 18.4 5 -II 20.0 5 -10 27.7 5 -9 23.2 5 -8 -2.4 5 -7 -4 .8 T A B L E X I I ( c o n t i n u e d ) 59 continued h k I F0 F« o -6.0 19.9 10.3 -7.7 14.3 18.0 43.3 16.6 31.3 ?7.2 15.1 19.6 10.7 0.0 58.5 0.0 45.5 13.3 -7.0 I 1.8 45.0 -2.8 16.0 0.0 38.2 21.4 -7.6 21.1 14.5 10.7_ 0.0 2.3 39.5 -4.0 14.3 1 1 .0 18.6 0.0 0.0 2.3 30.8 16.9 27.9 71.6 13.7 30.0 26.5 37.0 -2.9 15.7 9.4 36.5 19.7 15.7 12. 1 0.0 18.3 16. 1 ., . 2.5 10.2 0.9 13.1 17.8 50.9 13.0 30.5 54.9 5.0 20.5 19.5 44. 1 38.0 10.7 16.2 12.0 31.0 28.7 16.6 4.0 13.0 , 20.3 1.0 26.2 1.3 0.0 , 24.6 2.4 20.9 47.7 19.1 -9.1 19.2 27.0 2.2 0.0 23.1 8.9 21.5 43.8 21.4 15.7 -6.9 12.0 12.5 15.7 32.7 21.3 28.1 39.6 2.0 15.6 , 14.4 -5.8 16.8 14,8 20.7 -9.7 3.2 -10.5 20.4 10.7 -5.3 -9.5 14.5 -10.6 1 1.7 11.7 39.0 0.0 21.1 -7.3 12.7 24.0 16.3 15.9 18.1 24.4 21.2 21.5 19.5 27.5 0.3 21.4 43.6 20.0 16. 1 10.0 13.0 16.4 30.6 21.5 28.8 40.5 21.4 14.7, 13.9 10.1 24.8 13.1 5.3 16.7 13.9 19.4 29.7 20.0 26.7 8 10 4 -4.9 5.2 8 10 5 -5.1 7.4 8 10 1.2 9.9 8 10 7 12.1 1.6 8 1 -7 1.0 1.2 -0.8 1.1 8 1 -5 -6.1 4.6 8 16.6 17.8 8 1 -3 25.4 25.3 8 11 -2 1 7. 1 17.7 8 -1 -5.4 2.6 8 0 25.5 26.6 8 11 1 17.5 17.7 8 1 2 0.0 1 .9 8 1 3 16.1 16.5 8 4 0.0 0.9 8 5 23.9 23.4 8 • 6 10.3 10.2 8 -6 -1.7 8 12 -5 8.3 8.5 8 12 -4 13.4 13.4 8 12 -3 15.0 15.4 8 12 -2 15.3 16.2 8 12 -1 -3.2 3.4 8 12 0 -5.3 1.9 a 12 1 1 1.6 1.3 8 12 2 28. B 28.1 8 12 3 15.4 17.0 8 7.6 7.2 8 5 -5.4 5.8 8 13 -4 -3.9 5.6 B 13 -3 9.9 10.5 8 -2 6.8 10.6 9.7 B 0 -0.8 1.7 6 IB.5 18.7 8 1 3 2 9.4 9.2 3 14.3 13.7 8 4 -3.1 3.4 8 14 -1 13.1 12.8 8 0 7.3 S.B 9 ft 7.9 8.9 9 0 -7 46.6 43.9 0 -5 38.0 37.2 0 - 3 31.0 31.0 9 0 - 1 16.7 9 "0 1 42.7 41.5 9 0 3 24.5 24.9 9 0 5 34.4 32.8 9 0 46.4 45.7 9 0 9 -4.5 3.1 9 1 -10 20.7 20.7 9 -9 IB.4 17.6 9 -B IB.2 16.4 9 1 -7 -7.2 1.5 17.0 17.7 9 -5 18.4 19.6 9 34.2 3.3 9 -3 -7.0 10.7 9 -2 25.3 26.4 9 1 14.5 15.5 9 1 0 -4.9 1.5 9 50.2 49.7 9 2 13.3 14.2 3 60.4 60. 7 9 4 20.6 19.0 9 1 5 14.5 14. 1 9 6 5.2 9 7 -7.7 5.0 9 e 35.4 36.3 9 9 9.4 8.5 9 -10 14.0 13.1 9 2 -9 16.9 17.7 2 -8 19.3 20.3 9 2 -0.3 1.7 9 2 -6 14.1 13.6 9 2 -5 14.5 14.0 9 ? -4 16.2 16.9 9 2 -3 -3.1 4.1 9 2 -2 16.0 15.5 9 2 -1 54.5 54.7 9 2 0 41 .2 41.9 9 2 1 0.0 1.3 9 i 2 20.9 20.4 9 2 3 26.6 26.6 9 2 4 25.6 25.9 9 2 6 29. 1 28.8 9 2 7 1 .0 9.4 9 2 a 18.7 19.1 9 7 9 20.9 21.2 9 3 -10 14.4 13.1 9 3 -9 9.7 9.7 9 3 -8 8.8 10.9 9 3 -7 0.0 1.0 3 1 1 .4 14.8 3 -5 -5.5 6.0 9 3 -4 -9.9 7.6 9 3 -3 14.8 1 3. 5 9 3 -2 15.0 15.1 9 3 -1 -9.3 7.0 9 3 0 36.0 35.2 9 1 1 2.6 27.9 9 3 2 52. 3 49.9 9 3 3 -2.5 1. I 3 46.0 51 .0 3 5 18.6 19.6 9 3 6 10.9 9.0 9 3 7 14.7 14.7 9 3 8 26.6 26.1 3 9 23.0 73.4 4 -10 19.3 19.5 9 4 -9 15.3 15.9 -8 14.0 12.9 9 -7 18.1 18.0 9 4 -6 -6.7 6.1 9 4 -5 -5 .1 6.0 9 4 -4 2.9 23.8 4 -3 21.2 21.8 9 4 -2 3.2 32.2 9 4 - 1 15.8 16.0 9 4 ' 0 14.5 12.8 9 4 1 10.4 9 4 2 30.4 29.9 9 4 3 0.0 0.5 9 4 4 -9.5 7.9 9 4 5 16.5 16.2 9 4 6 17.6 16.2 9 4 7 21.0 21.0 4 8 10.7 1.9 9 4 9 7.5 7.1 24.1 50.5 2.7 29.3 13.3 -5.6 -3.6 8.5 12.2. 24.7 0.0 31 .0 13.6. -6.5 26.0 16.7.. -9.3 0.0 0.0 22-<•_ 4.2 32.4 -10.1 32.9 17.5 14.6 2.5 -4.7 16.5 18.7 18.0 -5.0 17.3 18.7 2.4 -5.6 12.7 13.0 6.3 1.5 27.7 0.8 , ,13.5 76.6 19.7 37.7 4.4 18.6 12.5 23.0 36.7 17.4 4.7 16.1 0.7 _ .13 q ? 2.5 5.2 18.4 5.0 14.0 13.0 6.4 10.4 28.2 16.4 18.7 30.5 .. 4.8. 26.7 23.5 14.9 1 1.4 3.2. 16.6 25.2 4.3 -4.5 14.2 -3.4 10.1 13.6 9.9 -6.5 10.9 21.7 13.6 -3.5 0.0 13.0 -5.7 12.3 0.0 13.8 9.0 9.7 -0.8 26.4 -4.4 72.4 10.2 16.0 14.3 6.7 1 .5 0 -3 L5.9 0 -I 9.5 0 1 8.9 0 3 17.7 1 -4 -4.4 1 -3 6.3 2 -3.7 1 19.3 D 13.0 1 17.0 2 -5.0 3 -5.8 4 17.6 3 13.6 I 19.9 1 -2.9 21.1 -6.0 -2.0 1.9 17.6 7.0 -4.4 -4.3 10.4 0.8 5.5 7.0 9.9 2.0 1.6 14.9 1.7 2.7 24.2 17.9 . I S . 2 32. 1 4.2 10. B 2.4 13.5 1.7 8.9 16.6 3.9 3.9 19.3 1.7 18.0 2.7 5.9 17.4 14.7 21.3 1.4 1.6 7.8 21.5 2.3 6.2 15.3 1.3 18.3 6.0 1 0.9 19.5 6 1 TABLE XIII Final p o s i t i o n a l parameters (x 10^) and anisotropic thermal parameters i n the form: exp- 10~ 4(b + £ 3 3 ^ + £12-- + -13--for the P, N, 0, and C atoms, with standard deviations i n parentheses. Atom X Y. P(D 2202(1) 0832(1) 1265(1 P(2) 0546(1) 1622(1) 2049(1 P(3) 2921(1) 2014(1) 2111(1 N(l) 0872(4) 0980(2) 1501(3 N(2) 1601(4) 2084(2) 2410(3 N(3) 3163(4) 1413(2) 1479(3 0(1) 2570(3) 0118(2) 1687(2 0(2) 2251(3) 0622(2) 0325(2 0(3) -0322(3) 2150(2) 1577(2 0(4) -0289(3) 1375(2) 2759(2 0(5) 3414(4) 2725(2) 1769(2 0(6) 3831(4) 1998(2) 2886(2 C(l) 3624(5) -0261(3) 1613(3 C(2) 3625(6) -0899(4) 1979(5 C(3) 4637(7) -1301(4) 1949(6 C(4) 5627(7) -1072(4) 1546(6 C(5) 5606(6) -0433(4) 1181(5 C(6) 4592(6) -0025(3) 1211(4 C(7) 1522(5) 0927(3) -0306(3 C(8) 1569(6) 1626(3 ) -0457(4 G(9) 0842(7) 1886(3) -1093(4 G(10) 0121(6) 1463 (3 ) -1566(4 C ( l l ) 0104(6) 0766(3) -1407(4 C(12) 0805(5) 0439(3) -0772(4 C(13) -1477(5) 1948(3) 1293(3 C(14) -1618(6) 1594(4) 0573(5 C(15) -2802(8) 1420(4) 0317(6 C(16) -3734(7) 1625(5) 0799(7 G(17) -3563(7) 1983(5) 1490(6 C(18) -2414(6) 2152(4) 1760(5 C(19) -0383(5) 0687(3) 3033(4 G(20) -1435(6) 0349(4) 2851(4 G(21) -1554(7) -0334(4) 3173(5 C(22) -0647(8) -0613(4) 3644(5 C(23 ) 0383(8) -0253(5) 3323(5 62 TABLE XIII (cont.) Atom x y_ z G(24) 0520(7) 0406(4) 3514(5) C(25) 3040(6) 2971(3) 0982(4) C(26) 1913(6) 3252(3) 0863(4) C(27) 1601(7) 3521(4) 0088(4) C(23) 2413(3) 3501(4) -0535(4) C(29) 3513(9) 3219(4) -0399(5) C(30) 3848(6) 2949(3) 0361(4) G(3D 3671(5) 1517(3) 3526(4) C(32) 3161(7) 1754(4) 4231(4) C(33) 30H6(8) 1285(5) 4880(5) C(34) 3404(8) 0611(4) 4800(5) C(35) 3916(7) 0390(4) 4096(5) C(36) 4063(6) 0848(3) 3440(4) Atom hi ^22 k33 *12 *13 ^23 P(D 55(1) 18(1) 26(1) 5(1) 8(2) - 2(1) P(2) 61(1) 19(1) 29(1) 8(1) 12(2) - 4(1) P(3) 67(1) 20(1) 3 K D -10(1) - 8(2) 0(1) N(l) 47(4) 20(1) 31(2) - 1(4) 10(5) - 7(3) N(2) 75(5) 23(2) 35(2) - 2(5) - 3(5) -16(3) N(3) 58(4) 20(1) 34(2) - 9(4) 9(5) 0(2) 0(1) 61(3) 20(1) 35(2) 5(4) 16(4) 11(2) 0(2) 75(4) 27(1) 24(2) 28(4) 3(4) - 9(2) 0(3) 62(3) 20(1) 43(2) 10(4) 1(5) 3(3) 0(4) 93(4) 25(1) 39(2) 13(4) 5K5) 1(3) 0(5) 108(4) 22(1) 38(2) -31(4) - 25(5) 8(3) 0(6) 82(4) 27(1) 36(2) -25(4) - 32(4) 7(3) C(l) 66(5) 22(2) 30(2) 17(5) 13(6) 0(4) C(2) 114(7) 32(2) 80(4) 39(7) 62(9) 51(5) C(3) 162(9) 44(3) 125(5) 36(8) 120(12) 90(6) C(4) 133(8) 48(3) 110(5) 89(8) 91(11) 59(7) C(5) 97(7) 41(3) 74(4) 44(7) 71(9) 26(6) C(6) 87(6) 29(2) 55(3) 27(6) 45(8) 15(5) C(7) 64(5) 22(2 ) 26(2) 14(5) 11(6) - 1(4) C(8) 109(7) 20(2) 39(3) -12(6) - 16(8) - 2(4) C(9) 149(8) 22(2) 48(3) 2(7) - 32(9) 8(5) C(10) 118(7) 28(2) 40(3) 11(7) - 29(8) - 1(5) C ( l l ) 95(6) 28(2) 37(3) -13(6) - 13(7) - 6(4) C(12) 88(6) 21(2) 32(3) 0(6) 6(7) 0(4) C(13) 57(5) 25(2) 56(3) 9(6) 8(7) 19(4) 63 TABLE XIII (cont.) Atom b -11 ^22 ^33 b -12 ^13 ^23 C (14) 102(7) 31(2) 67(4) 6(7) - 45(9) -11(5) c [15) 171(10) 39(3) 110(5) 3(9) -121(12) - 7(7) c [16) 85(7) 48(3) 164(8) -17(9) - 43(13) 46(9) c [17) 81(3) 87(5) 125(6) 26(10) 45(12) 60(9) c (18) 78(6) 67(4) 75(4) 55(8) 33(9) 33(7) c [19) 87(6) 25(2) 37(3) 2(6) 43(7) - 2(4) c [20) 103(7) 39(3) 58(4) -16(7) 37(9) - 9(5) G (21) 138(8) 49(3) 83(5) - 5 K 9 ) 63(11) -19(7) C (22) 202(11) 41(3) 84(5) - 7(10) 101(12) 27(6) G (23) 163(10) 50(3) 83(5) 11(10) 10(12) 45(7) G (24) 126(3) 35(2) 57(3) 0(8) 7(9) 27(5) G [25) 106(6) 18(2) 37(3) -19(6) -15(7) 6(4) C [26) 107(7) 24(2) 49(3) 1(7) - 8(8) 1(5) C [27) 150(3) 25(2) 61(4) - 3(7) - 52(10) 15(5) c (28) 205(10) 34(3) 50(4) -40(9) - 32(11) 32(5) C (29) 173(9) 44(3) 56(3) -40(9) 50(9) 37(5) G (30) 113(7) 30(2) 55(3) -22(7) 29(8) 18(5) C ( 3 D 82(6) 29(2) 35(3) -19(6) - 28(7) 9(4) C (32) 126(8) 44(3) 41(3) - 8(8) 12(8) 2(5) C (33) 157(9) 71(4) 47(4) -23(11) 13(10) 17(7) C (34) 173(10) 54(3) 67(4) -47(10) - 53(11) 48(6) C (35) 163(9) 37(3) 63(4) - 8(9) - 68(11) 24(6) C (36) 130(8) 31(2) 47(3) 3(3) - 48(9) - 3(5) 64 a n d f o r t h e h y d r o g e n a t o m s i n T a b l e X I V . B o n d l e n g t h s a n d v a l e n c y a n g l e s a r e g i v e n i n T a b l e X V . 2 . 4 D i s c u s s i o n T h e s i x - m e m b e r e d p h o s p h o n i t r i i i c r i n g i s s l i g h t l y , b u t s i g n i f i c a n t l y , n o n - p l a n a r . T h e e q u a t i o n o f t h e p l a n e t h r o u g h +"he s i x a t o m s o f t h e r i n g i s 0 . 1 3 1 3 X ' - 0 . 5 4 6 7 Y + 0 . 8 2 7 0 Z T = 1 . 1 0 8 7 o w h e r e X ' , Y , Z f a r e c o - o r d i n a t e s i n A r e f e r r e d t o o r t h o -g o n a l a x e s a , b , c * , a n d t h e d i s p l a c e m e n t s o f t h e a t o m s f r o m t h i s p l a n e a r e P ( l ) 0 . 0 1 9 , P ( 2 ) - 0 . 0 1 4 , P ( 3 ) 0 . 0 0 3 , K ( I ) - 0 . 0 2 0 , U(2) 0 . 1 3 2 , a n d K(3) - 0 . 1 6 9 A. The t h r e e phosphorus atoms a n d U{1) a r e t h u s a p p r o x i m a t e l y c o p l a n a r , w i t h N ( 2 ) a n a N ( 3 ) d i s p l a c e d f r o m t h e p l a n e i n o p p o s i t e o d i r e c t i o n s b y a n a v e r a g e o f 0 . 1 5 A ( a b o u t 4 0 CT ) . T h e r i n g t h u s h a s a n a p p r o x i m a t e s y m m e t r y a x i s a l o n g t h e P ( 3 ) • • • N ( 1 ) d i r e c t i o n . O f t h e o t h e r ( P W X ^ ) ^ m o l e c u l e s 56 w h o s e s t r u c t u r e s h a v e b e e n s t u d i e d , t h e f l u o r i d e h a s 57 58 59 a p l a n a r r i n g , b u t the c h l o r o , b r o m o , a n d p h e n y l d e r i v a t i v e s e a c h s h o w s m a l l d e v i a t i o n s o f t h e p h o s p h o n i t -r i i i c r i n g f r o m e x a c t p l a n a r i t y ; t h e r i n g s i n t h e l a t t e r t h r e e c o m p o u n d s e a c h h a v e s l i g h t c h a i r c o n f o r m a t i o n s , t h e 6 5 TABLE XIV 3 F i n a l p o s i t i o n a l (x 10 ) and thermal parameters for the hydrogen atoms, with standard deviations i n parentheses. The atom numbers are those of the carbon atoms to which the hydrogens are bonded. X Z B(A j H(2) 294(6) -110(3) 225(4) 8.3(20 H(3) 468(7) -180(4) 220(5) 11.1(23 H(4) 635(6) -135(4) 155(4) 9.9(21 H(5) 634(7) -025(4) 089(4) 9.3(20 H(6) 461(6) 045(3) 096(4) 7.7(18 H(8) 209(5) 192(3) -017(4) 6.1(16 H(9) 086(6) 238(3 ) -117(4) 7.9(18 H(10) -033(5) 166(3) -202(3) 5.7(15 H ( l l ) -038(5) 045(3) -172(4) 6.5(16 H(12) 080(6) -002(3) -067(4) 6.5(16 H(14) -090(6) 148(4) 025(4) 8.8(20 H(15) -234(7) 122(4) -023(5) 11.3(23 H(l6) -456(8) 148(5) 055(6) 14.1(29 H(17) -421(8) 221(5) 190(5) 14.0(28 H(l8) -221(7) 236(4) 232(5) 10.6(23 H(20) -207(5) 057(3) 249(4) 6.6(16 H(21) -237(8) -048(4) 291(5) 12.7(25 H(22) -071(7) -117(4) 393(5) 11.1(23 H(23) 113(7) -050(4) 418(5) 11.3(23 H(24) 125(6) 069(4) 365(4) 9.5(21 H(26) 139(6) 326(4) 131(4) 8.4(19 H(27) 084(7) 375(4) 001(5) 11.3(23 H(28) 216(6) 366(3) -114(4) 8.3(18 H(29) 415(6) 322(4) -078(4) 8.8(20 H(30) 465(6) 276(3) 050(4) 7.5(18 H(32) 284(6) 225(4) 429(4) 9.8(21 H(33) 254(7) 147(4) 535(5) 11.4(24 H(34) 33K7) 022(4) 533(4) 10.1(22 H(35) 411(7) -016(4) 396(5) 11.9(25 H(36) 451(5) 070(3 ) 292(4) 6.6(16 66 TABLE XV Bond o lengths (A) and valency angles (degrees), with standard deviations i n parentheses. P(l) -N(l) 1.574(4) P(D-0(1) 1.583(4) P(l) -N(3) 1.581(5) P(l)-0(2) 1.576(4) P(2) - N ( D 1.572(5) P(2)-0 3) 1.583(4) P(2) - N ( 2 ) 1.573(5) P(2)-0(4) 1.578(4) P(3) -N(2) 1.574(5) P(3)-0(5) 1.584(4) P(3 ) - N ( 3 ) 1.575(5) P(3)-0(6) 1.585(4) Mean P=N 1.575(2) Mean P-0 1 .582(2) 0(1) - C ( l ) 1.395(7) C-C 1 .33-1 .43 ( * -• = 0.010-0.019), 0(2) -C(7) 1.412(6) mean 1 .37 0(3) -C(13) 1.409(7) 0(4) - C ( 1 9 ) 1.406(7) 0(5) - C ( 2 5 ) 1.407(7) 0(6) -C(31) 1.406(7) Mean o-c 1.406(3 ) N(l) -P(l)-N (3 ) 117 .3(2) 0(1)-P(1)-N(3) 110 .9(2) N(l) -P(2)-N(2) 117 .9(2) 0(2)-P(l)-N (3 ) 110 .2(2) N(2) -P(3)-N(3) 116.6(2) 0(1)-P(1)-N(1) 106 .6(2) 0(2)-P(l)-N(l) 110 .3(2) P(D -N(l)-P(2) 121 .3(3) 0(3 )-P(2)-N(l) 112 .5(2) P(2) -N(2)-P(3) 122 .4(3) 0 (4)-P(2)-N(l) 109.2(2) P(D -N(3)-P(3) 122.1(3) 0 3 )-P(2)-N(2) 104 .6(2) 0(4)-Pl2)-N(2) 110 .9(2) 0(1) -P(l)-0(2) 100.1(2) 0 (5)-PO)-N (2) 112.0(2) 0(3) -P(2)-0(4) 100.1(2) 0(6)-P(3 )-N(2) 109 .9(2) 0(5) -P(3)-0(6) 94.1(2) 0(5)-P(3)-N(3) 109 .8(2) 0(6)-P(3)-N(3) 112.2(2) P( l ) - O d ) - C ( l ) 128 .7(3) mean 118 .4 P(D - 0 ( 2 ) - C ( 7 ) 123.5(3) 0-C-C 115-123, P(2) - 0 ( 3 ) - C ( 1 3 ) 121 .3(4) P(2) -0(4)-C(19) 124.8(4) C-C-C 116-124, P(3) -0(5)-C(25) 120 .8(4) mean 120.0 P(3) -0(6)-C(31) 120.0(4) 67 m a x i m u m d i s p l a c e m e n t s f r o m p l a n a r i t y b e i n g 0 . 0 9 , 0 . 1 4 , 0 a n d 0 . 0 7 A r e s p e c t i v e l y . T h e s e d e v i a t i o n s h a v e b e e n v a r -i o u s l y a s c r i b e d t o i n t r a - a n d i n t e r m o l e c u l a r s t e r i c a r e a l s o r e l a t e d i n p a i r s b y t h e a p p r o x i m a t e C_2 a x i s , b u t t h e p h e n o x y g r o u p s s h o w s i g n i f i c a n t d e v i a t i o n s f r o m a s y m m e t r i c a l a r r a n g e m e n t . F i g u r e 12 s h o w s o r i e n t a t i o n s r e l a t i v e t o t h e l o c a l 0 P 0 p l a n e s . T h e a r r a n g e m e n t s a r e i n f a c t d i f f e r e n t a t t h e t h r e e p h o s p h o r u s a t o m s , s o t h a t i n - c h e c r y s t a l l i n e s t a t e a t l e a s t t h e m o l e c u l e d e v i a t e s f r o m t h e t h r e e - f o l d s y m m e t r y i n d i c a t e d b y t h e c h e m i c a l f o r m u l a t i o n . A t F(3) t h e 0 - C b o n d s a r e b o t h o n t h e s a m e s i d e o f t h e 0 . . . 0 l i n e a s t h e p h o s p h o r u s a t o m , a n d d e v i a t e s l i g h t l y ( c a . 9 ° ) a n d i n o p p o s i t e d i r e c t i o n s f r o m t h e O - P - O p l a n e ( F i g u r e 12). T h i s a r r a n g e m e n t a n d t h e o r i e n t -a t i o n o f t h e p h e n y l r i n g s a t P ( 3 ) a r e s u c h t h a t t h e t w o p h e n o x y g r o u p s a r e r e l a t e d b y t h e a p p r o x i m a t e a x i s o f t h e p h o s p h o n i t r i l e r i n g . A t P ( l ) a n d P ( 2 ) o n e 0 - H b o n d i s o n t h e s a m e s i d e o f t h e 0 . . . 0 l i n e a s t h e p h o s p h o r u s a t o m , a n d t h e o t h e r o n t h e o p p o s i t e s i d e ( F i g u r e 12); i n a d d -i t i o n t h e b o n d s d e v i a t e f r o m t h e 0 P 0 p l a n e s b y s i g n i f i c a n t a m o u n t s ( c a . 25 - 4 5 ° ) , a n a t h e s e d i s p l a c e m e n t s a r e i n t h e s a m e d i r e c t i o n a t P ( 2 ) , a n a i n o p p o s i t e d i r e c t i o n s a t P ( l ) . T h e s e a r r a n g e m e n t s a n d t h e p h e n y l g r o u p o r i e n t a t i o n s a r e e f f e c t s . 56-59 T h e o x y g e n a t o m s o f t h e 68 0(5) 0(6) s h o w i n g a r r a n g e m e n t o f t h e p h e n o x y g r o u p s . T h e d i s p l a c e m e n t s o f t h e f i r s t c a r b o n a t o m o f e a c h p h e n y l r i n g f r o m t h e 0 P 0 p l a n e s a r e g i v e n ( % } . 6 9 s u c h t h a t t h e p h e n o x y g r o u p a t 0 ( 2 ) o n P ( l ) i s r e l a t e d t o t h a t a t 0(4) o n P ( 2 ) b y t h e a p p r o x i m a t e 0 a x i s o f t h e r i n g ( F i g u r e 1 1 ) , b u t t h e 0 ( 1 ) a n d 0 ( 3 ) g r o u p s a r e c o n -s i d e r a b l y d i s p l a c e d f r o m s u c h a n a r r a n g e m e n t . R o t a t i o n o f o n e o r o t h e r o r b o t h o f t h e p h e n o x y g r o u p s a t 0 ( 1 ) a n d 0 ( 3 ) a b o u t t h e P - 0 b o n d s b y a t o t a l o f a b o u t T T / 2 , p l u s s o m e o t h e r m i n o r c o n f o r m a t i o n a l c h a n g e s w o u l d g i v e t h e m o l e c u l e e x a c t s y m m e t r y . T h e b o n d a n g l e s a t p h o s p h o r u s a n d n i t r o g e n ( T a b l e X V ) a l s o s h o w - s i g n i f i c a n t v a r i a t i o n s f r o m t h r e e -f o l d s y m m e t r y , b u t c o n f o r m v e r y c l o s e l y t o s y m m e t r y . T h e m o s t s i g n i f i c a n t f e a t u r e i s t h a t t h e 0 - P ( 3 ) - 0 a n g l e , 9 4 . 1 ( & = 0 . 2 U ) i s 6 U ( a b o u t 2 0 0 " ) s m a l l e r t h a n t h e O - P - 0 a n g l e s a t P ( l ) a n d P ( 2 ) , e a c h o f w h i c h i s 1 0 0 . 1 ° . T h e N - P ( 3 ) - N a n g l e , 1 1 6 . 6 ( 2 ) ° i s 4 ff" s m a l l e r t h a n t h e m e a n o f t h e N - P - N a n g l e s a t P ( l ) a n d P ( 2 ) , 1 1 7 . 6 ° , a l t h o u g h t h i s d i f f e r e n c e i s o f m o r e d o u b t f u l s i g n i f i c a n c e , a s N - P ( 3 ) - N d i f f e r s f r o m N - P ( l ) - N b y o n l y 2 . 5 cr . T h e a n g l e P - N ( l ) - P , 1 2 1 . 3 ( 3 ) ° i s a b o u t 2 . 7 & s m a l l e r t h a n t h e m e a n o f t h e P - N - P a n g l e s a t N ( 2 ) a n d N ( 3 ) . T h e 0 - P - N a n d P - O - C v a r y o v e r s e v e r a l d e g r e e s , a n d t h e d e t a i l e d v a l u e s a r e p r o b -a b l y i n f l u e n c e d b y t h e o r i e n t a t i o n s o f t h e p h e n o x y g r o u p s . I n c o n t r a s t t o t h e d e v i a t i o n s f r o m t h r e e - f o l d s y m m e t r y i n c o n f o r m a t i o n a n d i n v a l e n c y a n g l e s , t h e r e a r e 7 0 no s i g n i f i c a n t differences among chemically-equivalent bond lengths. The P-N bonds are i n the range 1.572 -1.581(5) A , mean 1.575(2) 1 (Table XV); P-0, 1.576 -1.535(4) A , mean 1.582(2) A ; and 0 - C , 1.395 - 1.412(7) A , mean 1.406(3) A . The standard deviations given i n parenth-eses are those from the least-squares equations; the stan-dard deviations obtained from the variations among chemically-equivalent bonds are i n a l l cases smaller, so that the least-squares f s appear to be a reasonable, and i n fact s l i g h t l y pessimistic, estimate of the accuracy of the analysis. The equality of chemically-equivalent bond lengths suggests that there i s no great v a r i a t i o n i n the character of chemically-equivalent bonds, so that the an-gular deviations from three-fold symmetry are probably a result of s t e r i c interactions among the bulky substitu-ent phenoxy groups. Intramolecular s t e r i c e f f e c t s would be expected to result i n minimum energy with three-fold molecular symmetry, so that the very approximate symmetry actu-a l l y observed must be at least partly a resu l t of i n t e r -molecular interactions. There are no unusually short intermolecular distances, and most of the shorter contacts involve the phenoxy groups which are of course on the out-side of the molecule. The shortest distances are two 7 1 0 . . . C c o n t a c t s o f 3 * 4 0 A , b e t w e e n 0 ( 6 ) o f t h e s t a n d a r d m o l e c u l e ( F i g u r e 1 1 a n d T a b l e X I I I ) a n d C ( 1 0 ) o f t h e m o l e -c u l e a t + x, i - y _ , + z), a n d b e t w e e n 0 ( 4 ) , s t a n d a r d a n d 0 ( 2 9 ) , ( - | + x , ~ - y_, | - + z ) . T h e c l o s e s t C . . . C c o n t a c t i s 3 . 4 4 A . I n a d d i t i o n t h e r e a r e s e v e r a l C . . . N o c o n t a c t s , t h e s h o r t e s t b e i n g 3 . 5 4 A b e t w e e n N ( l ) o f t h e s t a n d a r d m o l e c u l e a n d C ( l l ) o f t h e m o l e c u l e a t ( - x , - y_, - z ) -I t i s o f c o u r s e p o s s i b l e t o n o t e t h a t , g i v e n t h e o b s e r v e d c r y s t a l a n d m o l e c u l a r s t r u c t u r e , a n y d i s p l a c e -m e n t s o f p h e n o x y g r o u p s t o w a r d s m o r e s y m m e t r i c a l o r i e n t a -t i o n s w o u l d r e s u l t i n u n a c c e p t a b l y s h o r t i n t r a - o r i n t e r -m o l e c u l a r n o n - b o n d e d c o n t a c t s . T h e o b s e r v e d m o l e c u l a r g e o m e t r y i s p r o b a b l y a d o p t e d t o o p t i m i z e b o t h i n t r a - a n d i n t e r m o l e c u l a r s t e r i c i n t e r a c t i o n s , t h e e n e r g y r e l a t i o n -s h i p s i n v o l v e d o b v i o u s l y b e i n g q u i t e c o m p l e x . T h e d i m e n s i o n s o f t h e m o l e c u l e a r e c o m p a r e d i n T a b l e X V I w i t h t h o s e o f o t h e r s y m m e t r i c a l l y - s u b s t i t u t e d t r i m e r s , ( P N X ^ ) , a n d w i t h m e t h o x y - d e r i v a t i v e s , ^ P N ( 0 M e ) ^ " | n o r e s u l t s f o r o t h e r p h e n o x y c o m p o u n d s b e i n g a v a i l a b l e . O n l y f o r t h e t r i m e r i c p h e n y l d e r i v a t i v e a n d t h e h e x a m e r i c a n d o c t a m e r i c m e t h o x i d e s a r e t h e d i m e n s i o n s d e t e r m i n e d w i t h s u f f i c i e n t a c c u r a c y t o a l l o w m e a n i n g f u l d e t a i l e d c o m p a r i s o n w i t h t h e t r i m e r i c p h e n o x i d e . ( R e c e n t l y t h e T A B L E X V I o _ , Bond lengths (A) and angles (degrees) i n j^NP(OPh)2J ^ and related molecules. PN PNP NPN P0 00 0P0 POC (NPF 2) 3 a 1.56 121 119 - - - -(WPGJ?2 ) 3 b 1.59 120 120 - - - -(NPBr 2) 3 £ 1.58 121 117 - - - -(NPPh 2) 3 d 1.597(6) 1 2 2 . 1 ( 4 ) 117 . 8 ( 3 ) - - - -[NP(OPh) 2| 3 1.575 ( 2 ) 121.9(3) 117 . 3 ( 3 ) 1 . 5 8 2 ( 2 ) 1 .406 (3 ) 98 123 [ N P ( O M e ) 2 J 4 e 1.57 132 120 1.58 1.47 105 120 [ N P ( O M e ) 2 J 6 f 1.567 (3 ) 134.4 (3) 118.6(2) 1 .534 (3) 1.444 103 120 [ N P ( 0 M e ) 2 J a 1.561(5) 1 3 6.7(5) 1 1 6 . 7 ( 4 ) 1.576(5) - 1.440 101 121 a r e f . 56 e re f . 33 b r e f . 57 f r e f . 38 c r e f . 58 r e f . 39 d r e f . 59 73 ( N P B r ) a n d ( N P C S ^ ) s t r u c t u r e s h a v e b e e n r e f i n e d , b u t 6 2 a t t h i s t i m e h a v e n o t y e t a p p e a r e d i n t h e l i t e r a t u r e . ) T h e m e a n P - N b o n d l e n g t h i n J N P ( 0 P h ) 2 } , 1 . 5 7 5 ( 2 ) A , o i s 0 . 0 2 2 A ( 3 . 5 < r ) s h o r t e r t h a n t h e b o n d s i n ( N P P h ) , 0 0 a n d 0 . 0 0 8 A ( 2 . 2 <r ) a n d 0 . 0 1 4 A ( 2 . 6 c ) l o n g e r t h a n t h e b o n d s i n t h e h e x a m e r i c a n d o c t a m e r i c m e t h o x i d e s , r e s p e c -t i v e l y . A l t h o u g h t h e d i f f e r e n c e s a r e b a r e l y s i g n i f i c a n t , t h e y a r e a l l i n t h e d i r e c t i o n s w h i c h w o u l d b e e x p e c t e d f r o m a c o n s i d e r a t i o n o f t h e b o n d i n g . I n t h e t w o t r i m e r s , t h e s h o r t e r P - N b o n d s a r e f o u n d i n t h e p h e n o x y c o m p o u n d , w h i c h h a s t h e m o r e e l e c t r o n e g a t i v e s u b s t i t u e n t s , i n a c c o r d w i t h p r e v i o u s e x p e r i m e n t a l o b s e r v a t i o n s , a n d w i t h t h e o r e -2 4 - 2 8 t i c a l e x p e c t a t i o n s . T h e P H P a n g l e s i n t h e t r i m e r s , o m e a n 1 2 2 , a r e c o n s t r a i n e d b y t h e s i z e o f t h e r i n g , a n d o o t h e l a r g e r a n g l e s , 1 3 4 a n d 1 3 7 , i n t h e m o r e f l e x i b l e l a r g e r r i n g s l e a d t o a n i n c r e a s e i n 1 T - b o n d i n g , a n d t o m o r e p - c h a r a c t e r i n t h e a ' - b o n d s , b o t h o f w h i c h e f f e c t s w o u l d r e s u l t i n t h e o b s e r v e d s h o r t e r P - N b o n d s i n t h e l a r g e r r i n g s . T h e N P N a n g l e s a r e r a t h e r s i m i l a r i n t h e f o u r ' c o m p o u n d s ( T a b l e X V I ) . T h e P - 0 b o n d l e n g t h s a n d t h e P O C a n g l e s a r e v e r y s i m i l a r i n t h e t r i m e r i c p h e n o x i d e a n d t h e h e x a m e r i c a n d o c t a m e r i c m e t h o x i d e s ( T a b l e X V I ) . T h e P - 0 b o n d s ( 1 . 5 8 o a r e a l l a b o u t 0 . 1 3 A s h o r t e r t h a n t h e s i n g l e b o n d d i s t a n c e , s u g g e s t i n g c o n s i d e r a b l e e x o c y c l i c T T " - b o n d i n g , b u t t h e 74 a m o u n t o f T V - b o n d c h a r a c t e r s e e m s t o b e i n s e n s i t i v e t o t h e c o n f o r m a t i o n a l a r r a n g e m e n t s o f t h e p h e n o x y a n d m e -t h c x y g r o u p s , s i n c e n o v a r i a t i o n s o f P - 0 d i s t a n c e a r e f o u n d . o T h e s h o r t e r 0 - C d i s t a n c e s , m e a n 1 . 406(3 ) A , i n t h e p h e n o x y 2 c o m p o u n d a r e p r o b a b l y m a i n l y a r e s u l t o f t h e s p h y d r i d i -3 z a t i o n a t c a r b o n , i n c o n t r a s t t o t h e s p h y d r i d i z a t i o n i n t h e m e t h o x y d e r i v a t i v e s . T h e m e a n 0 F 0 a n d P O C a n g l e s a r e v e r y s i m i l a r i n t h e t h r e e c o m p o u n d s , a l t h o u g h t h e i n d i v i d u a l a n g l e s s h o w v a r i a t i o n s , a s n o t e d a b o v e f o r t h e p h e n o x y d e r i v a t i v e . T h e b o n d d i s t a n c e s a n d v a l e n c y a n g l e s i n t h e p h e n y l r i n g s h a v e b e e n d e t e r m i n e d w i t h l e s s a c c u r a c y , s i n c e t h e c a r b o n a t o m s a r e u n d e r g o i n g l a r g e r t h e r m a l v i b r a t i o n s t h a n t h e a t o m s o f t h e p h o s p h o n i t r i i i c r i n g . T h e m e a s u r e d o o C - G b o n d l e n g t h s v a r y f r o m 1 . 3 3 A t o 1 . 4 3 A ( Cf = 0 . 0 1 0 -o 0 0 . 0 1 9 A ) , t h e m e a n d i s t a n c e b e i n g 1 . 3 7 A . T h e C - H b o n d . o d i s t a n c e s a r e i n t h e r a n g e 0 . 9 3 - 1 . 1 8 A ( u = 0 . 0 6 -. o . o 0 . 0 8 A ; , m e a n 1 . 0 2 A . P A R T I I I T H E C R Y S T A L A N D M O L E C U L A R S T R U C T U R E O F D O D E C A ( D I M E T H Y L A M I N O ) C Y C L 0 H E X A P H O S P H 0 N I T R I L E C H L 0 R 0 C O P P E R ( I I ) D I C H L O R O C U P R A T E ( I ) 76 3.1 I n t r o d u c t i o n Kost o f t h e X - r a y w o r k r e p o r t e d h a s b e e n o n p h o s p h o n i t r i l e s w h i c h a r e h o m o g e n e o u s l y s u b s t i t u t e d , s u c h a s t h e t r i m e r i c p h e n o x y c o m p o u n d d e s c r i b e d i n p a r t I I , a n d m o r e r e c e n t l y on s t r u c t u r e s o f p h o s p h o n i t r i l e s w i t h t w o d i f f e r e n t l i g a n d s , s u c h a s t h e t w o t e t r a m e r i c m e t h y l -f l u o r i n e c o m p o u n d s d e s c r i b e d i n p a r t I . A n o t h e r t y p e o f * 64,65 p h o s p h o n i t r i l e h a s b e e n d e s c r i b e d i n w h i c h a m e t a l a t o m f o r m s a c o m p l e x w i t h a p h o s p h o n i t r i i i c r i n g . O f i n -t e r e s t i s t h e m a n n e r i n w h i c h t h e m e t a l a t o m i s b o n d e d t o t h e p h o s p h o n i t r i l e , a n d t h e e f f e c t t h e m e t a l a t o m h a s o n t h e b o n d i n g w i t h i n t h e r i n g . T h e s t r u c t u r e s o f t w o s u c h m e t a l - p h o s p h o n i t r i l e c o m p l e x e s h a v e r e c e n t l y b e e n r e p o r t e d : o c t a m e t h y l c y c l o t e t r a p h o s p h o n i t r i l i u m t r i c h l o r o c o p p e r ( I I ) , w h i c h c o n t a i n s a p r o t o n a n d a C u C J ^ g r o u p c o v a l e n t l y b o n d e d t o o p p o s i t e n i t r o g e n a t o m s o f a n e i g h t - m e m b e r e o p h o s p h o n i -t r i i i c r i n g , a n d b i s - ( o c t a m e t h y l c y c l o t e t r a p h o s p h o n i t r i l i u r n ) 3 7 t e t r a c h l o r o c o b a l t a t e ( I I ) , a n i o n i c s t r u c t u r e c o n t a i n i n g 2-t w o p r o t o n a t e d p h o s p h o n i t r i i i c r i n g s a n d a C o C X i o n . 4 I n b o t h t h e s e s t r u c t u r e s t h e T T - s y s t e m i n t h e p h o s p h o n i -t r i i i c r i n g i s p e r t u r b e d by t h e r e m o v a l o f n i t r o g e n l o n e p a i r s o f e l e c t r o n s by a p r o t o n i n t h e c o b a l t c o m p l e x , o r by a p r o t o n a n a a c o p p e r i n t h e c o p p e r c o m p l e x . I n b o t h s t r u c t u r e s t h e e f f e c t o n t h e b o n d l e n g t h s i n t h e p h o s p h o n i -24-28 t r i l i c r i n g s i s t h a t p r e d i c t e d by r f - b o n d i n g t h e o r y . 77 A new copper-phosphonitrile complex has been prepared by the reaction of dodeca(dimethylamino)cyclohexa-phosphonitrile with anhydrous cupric chloride i n methyl ethyl nn< 67 66 ketone i n an analagous manner to the preparation of the [(NPMe„) h i CuCi complex. Evaporation of the r e s u l t -2 4 J 3 ing solution yielded bright orange c r y s t a l s of the copper-phosphonitrile complex. I n i t i a l chemical analysis sug-gested the formula [ N P U M e ^ J 6»2CuC^ 2, but the X-ray structure analysis has established the formula as f N.P (NMe ) CuCJl 1 +CuC& ~. L 6 6 2 12 J 2 This structure determination was undertaken to compare the manner i n which the copper i s bonded to the ri n g , and the e f f e c t i t has on the ' TT-system i n the rin g , with the two previously reported structures. 3.2 Experimental Crystals of ^N^P^ (NMe j^CuCJ!, "j + G u C ^ 2 ~ a r e bright orange plates with (101*) developed, elongated along b. U n i t - c e l l and space-group data were determined from various ro t a t i o n , vVeissenberg, and precession photographs, and on a spectrogoniometer. Crystal Data. C 2 4 H 7 2 G V U 2 N 1 8 P 6 ' ~ = 1 0 3 2 5 monoclinic, a = 19.352(8), b = 8.690(6), c = 14.069(7) A, o (2 =91.04(4) (standard deviations i n parentheses), 78 U = 23c-5.6 , D = 1.45 ( f l o t a t i o n i n CKBr, /C AH. ), Z = 2, ~ — m 3 ^ o — ™~ , v o D = 1.450, F(000) = 1082. Mo-K ^ r a d i a t i o n , A = 0.7107 A, ~x -1 ~ — — J- 2 4 =13.5 cm. . Space group P n ( C s ) o r P2/n ( C ^ ) , from s y s t e m a t i c a b s e n c e s : hp 4. when (h+J?) i s odd; P2/n from s t r u c t u r e a n a l y s i s . The i n t e n s i t i e s o f a l l r e f l e x i o n s w i t h 2 & (Mo-K ^ ) ^. 40° (minimum i n t e r p l a n a r s p a c i n g , 1.04 A ) were measured on a Datex-autcmated G e n e r a l E l e c t r i c XiiD 6 S p e c t r o g o n i o m e t e r , w i t h a s c i n t i l l a t i o n c o u n t e r , approxim-a t e l y monochromatic Mo-K ^ r a d i a t i o n (Zr f i l t e r and p u l s e -h e i g h t a n a l y s e r ) , and a 8-2 0 scan a t a scan speed o f f o u r degrees per minute i n 2 9. Background c o u n t s f o r t e n seconds were made a t t h e b e g i n n i n g and end o f each scan. The s t a n d a r d d e v i a t i o n o f an i n t e n s i t y , I , was c a l -c u l a t e d from the e x p r e s s i o n <5^(1) = S + B + (O.C5S) 2 where 3 and 3 are the scan ana background c o u n t s , and r e -f l e x i o n s w i t h I < 2 <T* ( I ) were c l a s s i f i e d as unobserved; these r e f l e x i o n s were a s s i g n e d s t r u c t u r e f a c t o r s e q u a l t o t h e i r measured v a l u e s , but v/ere e x c l u d e d from t h e r e f i n e -ment. Of 2300 r e f l e x i o n s w i t h 2 Q ^ 40°, 1103 (48'/*) were c l a s s i f i e d as o b s e r v e d . The c r y s t a l used was a t h i n 7 9 p l a t e , w i t h l e n g t h 0 . 2 8 mm. p a r a l l e l t o b , a n d c r o s s - s e c t i o n 0.10 x 0.03 H o a b s o r p t i o n c o r r e c t i o n w a s m a d e . 3•3 S t r u c t u r e A n a l y s i s I n i t i a l e l e m e n t a l a n a l y s i s ( T a b l e X V I I ) s u g -g e s t e d t h a t t h e compound c o n t a i n e d two c o p p e r a t o m s , f o u r c h l o r i n e a t o m s , and t h e p h o s p h o n i t r i l e . The c a l c u l a t e d d e n s i t y o f 1.50 g.cm. "* a g r e e d a p p r o x i m a t e l y w i t h t h e rnea-~ 3 s u r e a v a l u e o f 1.4-5 g . c m . , a n a t h i s f o r m u l a t i o n was a c -c e p t e d i n i t i a l l y . The t h r e e - d i m e n s i o n a l P a t t e r s o n f u n c t i o n s u g g e s t e d t h a t t h e s p a c e - g r o u p was P 2 / n , v / i t h t h e two c o p -per atoms s i t u a t e d cn s e p a r a t e a x e s , and w i t h t h e p h o s -p h o r u s atoms a r f - n d one o f t h e c o p p e r a t o m s . T h e Cu-Cj? v e c t o r s i n d i c a t e d t h e p r e s e n c e o f Cu-CJ? b o n u s b o t h a l o n g and p e r p e n d i c u l a r t o a x e s , w h i c h s u g g e s t e u t h e p o s s i b l e z-p r e s e n c e o f a uuGJ, i o n . In o r d e r n o t t o b i a s t h e a n a l y s i s h o wever t h e f i r s t e l e c t r o n - d e n s i t y map was p h a s e d o n l y on the c o p p e r and p h o s p h o r u s a t o m s . T h i s mar; r e v e a l e d a l l o f t h e atoms o f t h e p h o s p h o n i t r i l e , v / i t h a c o p p e r a t o m , C u ( 2 ) , i n t h e c e n t r e o f t h e r i n g ; t h e map a l s o s h o w e d t h e p r e s e n c e o f o n l y t h r e e c h l o r i n e a t o m s , one b o n d e d t o C u ( 2 ) , ana two b o n a e d t o C u ( I ) . T h i s s t r u c t u r e was r e f i n e d , i n i -t i a l l y b y b l o c k - d i a g o n a l , and f i n a l l y b y f u l l - m a t r i x l e a s t -s q u a r e s p r o c e d u r e s . The s c a t t e r i n g f a c t o r s f r o m t h e I n t e r -9 n a t i o n a l T a b l e s were u s e d , ana t h e f u n c t i o n m i n i m i z e d 80 TABLE XVII Comparison of elemental analyses f o r the postulated and actual formula f o r the complex. Element Cu CJP P N C H I n i t i a l 11.40 12.99 23.52 27.33 6.78 Analysis {%) Fi n a l 12.33 10.24 13.22 24.15 28.18 6.86 Element Cu CX P N C H Theoretical Composition [N 6P 6 (NMe2 ) 1 2 J . 2CuCi 2 (NMe2 ) 1 2 • CuClJ * CuC* 2" 11.90 13.28 17.41 23.61 26.99 6.81 12.31 10.30 18.00 24.43 27.92 7.04 81 was > w(F -F ) , w i t h w t a k e n as t h e r e c i p r o c a l o f t h e — —o —c — v a r i a n c e i n F, as d e t e r m i n e d from the c o u n t i n g s t a t i s t i c s . I s o t r o p i c r e f i n e m e n t w i t h a n i s o t r o p i c t h e r m a l parameters f o r the copper, phosphorus, and c h l o r i n e atoms gave a f i n a l R o f 0.083. Measured and c a l c u l a t e d s t r u c t u r e f a c t o r s a r e l i s t e d i n Table X V I I I . A f i n a l d i f f e r e n c e map had maximum f l u c t u a t i o n s o-3 o i j u.5 e . A . Many o f the peaks were i n r e a s o n a b l e pos-i t i o n s f o r m e t h y l group hydrogen atoms, but no a t t e m p t was made t o i n c l u d e t h e s e atoms i n t h e a n a l y s i s . There were no f e a t u r e s on t h e map t o i n d i c a t e t h e presence o f a f o u r t h c h l o r i n e atom, so t h a t p r e p a r a t i o n o f t h e compound must i n -v o l v e r e d u c t i o n o f one o f the C u ( I I ) atoms to C u ( I ) . The s t r u c t u r e o f t h e compound i s shown i n F i g u r e 13; c h e m i c a l and s t r u c t u r a l c o n s i d e r a t i o n s (see D i s c u s s i o n } i n d i c a t e t h a t the o u ( I I ) atom i s bonded t o the p h o s p h o n i t r i i i c r i n g , so t h a t the compound i s N • P / - ( N M e ) C u X x G H \ Cu^CiL"". F i n a l L o o 2 12 J 2 p o s i t i o n a l and t h e r m a l parameters are g i v e n i r ; Table XIX. The o n l y s l i g h t l y u n u s u a l f e a t u r e i s a h i g h t h e r m a l m o t i o n f o r t h e CuCfl,. g r o u p i n g , w i t h t h e r.m.s. d i s p l a c e m e n t f o r CJJ.-] ) b e i n g n e a r l y 0.5 A i n t h e b - d i r e c t i o n , t h a t i s a t r i g h t a n g l e s t o t h e Cu~C£ bend. A l t h o u g h i t i s not u n r e a s o n a b l e t h a t t h e i s o l a t e d CuC$ 2 does undergo t h e s e l a r g e t h e r m a l v i b r a t i o n s , i t seemed d u r i n g the course of the a n a l y s i s TKBLE X V I I I M e a s u r e d and f i n a l c a l c u l a t e d s t r u c t u r e f a c t o r s . U n o b s e r v e d r e f l e x i o n s h a v e a n e g a t i v e F . l l 7 -15.J? ?l-lr> A. ? "-Q., , iq.ao 2 4 5 i i -7 **.7* L 6 -a o.o 4.30 i t, -5 ]<..«() h k I F„ F£ 0 ^ 116.65 115.71 0 10 -?<J.6L il.Z" fc5.51 8 2 -*.!2 in . ; ?2.?3 50.04 18.95 83 T A B L E X V X I X ( c o n t i n u e d ) 8 4 TABLE XVIII ( c o n t i n u e d ) 86 T A B L E X I I °2 F i n a l p o s i t i o n a l ( f r a c t i o n a l ) a n d t h e r m a l p a r a m e t e r s (B i n A ; o2 2, U ^ j i n A x 10 ) , w i t h s t a n d a r d d e v i a t i o n s i n p a r e n t h e s e s . S p a c e - g r o u p P 2 / n ( ( £ . ); C u ( l ) i n 2 ( e ) : + ( f , y , f ) ; < d n ~ A A -C u ( 2 ) a n d C * ( 2 ) i n 2 ( f ) : + ( f ; y , ~ ) ; o t h e r a t o m s i n 4 ( g J : + ( x , y _ , z ; ^ - x , y _ , i - z ) A t o m X B N ( l ) 0.7349(10) 0.2326(23) 0.3907(14) 2.79(50) N (2 ) 0.6561(9) 0.3145(24) 0.2657(13) 2.63(45) N(3) 0.6426(9) 0.3858(22) 0.0838(12) 1.94(43) N(4) 0.6503(11) 0.4852(24) 0.4220(15) 2.65(50) N(5) 0.6036(12) 0.2090(28) 0.4357(16) 3.95(53) N(6) 0.5703(12) 0.5487(28) 0.1951(15) 4.15(57) N(7) 0.5380(12) 0.2546(26) 0.1850(16) 4.18(59) N ( 3 ) 0.7223(10) 0.3687(24) -0.0568(14) 2.71(47) N(9) 0.6603(11) 0.1095(24) 0.0122(14) 3.07(49) C ( l ) 0.6876(13 ) 0.6103(30) 0.3765(18) 2.89(61) C ( 2 ) 0.6302(15 ) 0.5259(34) 0.5195(20) 4.30(73) C ( 3 ) 0.5315(14) 0.2543(28) 0.4335(18) 3.57(70) C ( 4 ) 0.6164(14) 0.0464(34) 0.4499(19) 3.27(65) C ( 5 ) 0.5162(13 ) 0.5720(31) 0.2645(18) 3.16(64) C(6) 0.5992(16) 0.6367(40) 0.1478(22) 5.95(35) 0(7) 0.4784(15) 0.2979(36) 0.1153(20) 4.94(71) C ( 8 ) 0.5456(14) 0.0908(33 ) 0.1974(19) 3.61(69) C ( 9 ) 0.6881(17) 0.5038(37) -0.0968(22) 5.61(87) 0(10) 0.7596(15) 0.2690(34) -0.1260(21) 4.75(77) C ( l l ) 0.6001(17) 0.1175(38) -0.0564(23) 6.09(36) C(12) 0.6951(15) -0.0413(34) 0.0080(20) 3.97(72) A t o m X y . z C u ( l ) 1/4 0.1417(7) 1/4 Cu(2) 3 A 0.1937(6) 1/4 C X ( 1 ) 0.1490(5) 0.1427(16) 0.2005(7) 01(2) 3/4 -0.0684(12) 1/4 P ( l ) 0.6599(3) 0.3138(9) 0.3793(5) P ( 2 ) 0.6045(4) 0.3763(9) 0.1833(5) P ( 3 ) 0.6974(4) 0.2778(9) 0.0413(5) 37 T A B L E X I X (cont.} Atom hi 11 -22 3^3 hz %3 ^23 Cu(l) 10.38 8.03 4.76 0 0.89 0 Cu(2) 1.36 3.37 2.20 0 -0.33 0 C*d) 8.64 22.96 7.30 2.46 -0.05 -0.23 CA(2) 9.60 1.14 5.30 0 -I.64 0 P ( D 1.91 3.03 3.02 0.78 -0.11 0.04 P(2) 2.65 2.33 3.49 0.07 -0.56 0.01 P(3) 2.62 3.60 1.69 -0.12 -1.03 0.47 88 t h a t t h e l a r g e v i b r a t i o n s might r e a l l y r e p r e s e n t d i s o r d e r o f t h e C$(1) p o s i t i o n . However, r e f i n e m e n t o f two h a l f -c h l o r i n e a t o m s , d i s p l a c e d a l o n g b, converged t o the mean p o s i t i o n , so t h a t t h e l a r g e t h e r m a l v i b r a t i o n ooes appear t o oe H r f i a i e 1 1 e c t . Bond d i s t a n c e s and v a l e n c y a n g l e s a r e g i v e n i n i'abi e i.X. 3 • /»• D i s c u s s i o n The compound s t u d i e d i n the p r e s e n t X-ray a n a l y -s i s was o b t a i n e d by r e a c t i o n o f N .F . (UKe ) . w i t h CuCJfc 6 o 2 1-c 2 i n m e t h y l e t h y l k e t o n e . The X-ray r e s u l t s i n d i c a t e t h a t t h e f o r m u l a u n i t c o n t a i n s t h e p h o s p h o n i t r i l e w i t h the add-i t i o n c f two copper arid t h r e e c h l o r i n e atoms, so t h a t h a l f o f the- copper i n the complex must have been reduced t o C u ( I ) . The p r e p a r a t i o n was r e p e a t e d , and a c a r e f u l elemen-t a l a n a l y s i s (Table X V I I ) o f the p r o d u c t was i n agreement w i t h t h r e e c h l o r i n e atoms per f o r m u l a u n i t T h e magnetic s u s c e p t i b i l i t y was measured, and a l t h o u g h i t i s d i f f i c u l t t o make an a c c u r a t e d i a m a g n e t i c c o r r e c t i o n f o r a substance o f t h i s c o m p l e x i t y , the r e s u l t s were i n agreement w i t h one C u ( I I ) atom per f o r m u l a u n i t . The presence o f C u ( I I ) and C u ( I ) ' i n the complex 6 6 was c o n f i r m e d by t h e f o l l o w i n g s e r i e s o f r e a c t i o n s , c a r r i e d o u t i n a c e t o r i i t r i i e , i n which r e d u c t i o n was not t o be e x p e c t e d : 8 9 T A B L E XX o Bond lengths (A) and valency angles (degrees), with standard deviations i n parentheses. Cu(2 )-N(l) C u ( 2 ) - N ( 2 ) Cu(2)-Cl(2j 2.03(2 2.11(2 2.28(1 Cu(l)-CA(1) 2.06(1) [2.11(1) corrected f o r l i b r a t i o n ] N(l)-P(l) 1 .62(2) N 4) -G (1) 1.46(3) N ( l)-P (3 f ) 1.65(2) N< 4) -C ( 2 ) 1.48(3) N(2)-P ( l ) 1.60(2) N [5) -C (3) 1.45(3) N(2)-P(2) 1.61(2) N \5) -G (4) 1.45(3) N(3)-P(2) 1.53(2) N [6) -C (5) 1.46(3) N ( 3)-P ( 3 ) 1.57(2) N 6) -C (6) 1.49(3) P ( l ) - N ( 4 ) 1.62(2) N [7) -C (7) 1.55(3) P ( l ) - N ( 5 ) 1.64(2) N 7) -C (3) 1.44(3) P ( 2 ) - N ( 6 ) 1.65(2) N 8) -C (9) 1.46(3) P ( 2 ) - N ( 7 ) 1.67(2) N iS) -C (10) 1.50(3) P(3)-N(8) 1.67(2) N| [9) -C (ID 1.50(3) P(3)-N(9) 1.68(2) N 9) -C (12) 1.47(3) N(2)-Cu(2)-N(l) 71.2(7) N [1) -P (1)-N(2) 97.2(10 N(2)-Cu(2)-N(l» ) 99.1(8) N (1) -P (D-N(4) 118.2(11 N(2)-Cu(2)-N(2» ) 120 .5(11) N [1) -p (1)-N(5) 108.2(12 N(l ) - C u ( 2 ) - N ( l ' ) 160 .9(12) N [ 2 ) -p (1)-N(4) 111.3(11 Cl(2 )-Cu(2)-N(2) 119.8(5) N 2 ) -p (D-N(5) 117 .9(11 CA(2 )-Cu(2)-N(l) 99.6(6) N i4) -P (1)-N(5) 104 .5(12 CA(1)-CU (1 ) -CJI (1» ) 179 .5(9) N (2) -p (2)-N(3) 110 .0(10 N 2) -p (2)-N(6) 118 .5(12 N 2) -P (2)-N(7) 104 .3(11 P ( l)-N ( l)-P (3 ' ) 130 .7(13) N [3) -p (2)-N(6) 103.8(12 P ( l J-MliJ-Gui2) 96.9(10) N -p (2)-N(7) 115-5(12 P ( 3 T ) - N ( D - C u ( 2 ) 118 .4(11) N [6) -p ( 2 ) - N ( 7 ) 105.2(12 P(l)-N(2)-P(2) 137.6(13) N (3) -p (3)-N( lM 115 .4(10 P(l)-N(2)-Cu(2) 94 .5(9) N (3) -p (3)-N(8) .106.0(11 P(2)-N(2)-Cu(2) 127 .9(11) N (3) -p (3)-N(9) 109.6(11 P(2 ) - N ( 3)-P ( 3 ) 132 .4(13) N (1* )-P(3)-N(8) 110.7(10 N (1' )-P(3)-N(9) 105.3 (11 N IB) -P(3)-N(9) 109.8(10 C-N-G 111-118, mean 114 P-N-C 114-127, mean 120 9 0 ( i ) p h o s p h o n i t r i l e w i t h c o p p e r ( I I ) c h l o r i d e g a v e a c r y s t a l l i n e s o l i d , w h i c h w a s d i f f e r e n t i n a p p e a r a n c e f r o m t h e m a t e r i a l p r o d u c e d i n m e t h y l e t h y l k e t o n e , a n d w h i c h g i v e s a t i s f a c t o r y e l e -m e n t a l a n a l y s i s f o r N ^ P ^ ( N M e „ ) , r • C u „ C X . ; o b 2 It 2 4 ( i i ) p h o s p h o n i t r i l e w i t h c o p p e r ( I ) c h l o r i d e g a v e a p o o r l y - d e f i n e d s o l i d ; ( i i i ) p h o s p h o n i t r i l e w i t h a n e q u i m o l a r m i x t u r e o f c u p r i c a n d c u p r o u s c h l o r i d e s g a v e a c r y s t a l l i n e s o l i d , i d e n t i c a l w i t h t h a t p r e v i o u s l y u s e d i n t h e X - r a y a n a l y s i s , a s i n d i c a t e d b y e l e m e n t a l a n a l y s i s , a n d b y V / e i s s e n b e r g a n d p r e c e s s i o n p h o t o g r a p h s . I t r e m a i n e d o n l y t o d e c i d e w h i c h o f t h e c o p p e r a t o m s i n t h e c o m p o u n d i s C u ( I ) . S i n c e n o f i v e - c o o r d i n a t e d c o m p o u n d s o f C u ( I ) h a v e b e e n r e p o r t e d , a n d s i n c e a n i o n i c s t r u c t u r e r a t h e r t h a n a s i m p l e C u C J ^ a d d u c t s e e m s m o r e r e a s o n a b l e , i t i s l i k e l y t h a t t h e G u ( I I ) a t o m i s b o n d e d t o t h e p h o s p h o n i t r i i i c r i n g , a n d t h a t t h e c o m p o u n d i s [ I] P , ( N K e ) C u ^ C j ? ~\ + C u ^ C X ~ , d o d e c a ( d i m e t h y l a m i n o ) -L 6 o 2 1 2 J 2 c y c l o h e x a p h o s p h o n i t r i l e c h l o r o c o p p e r ( I I ) d i c h l o r o c u p r a t e ( I ) . T h e c u p r i c c o p p e r a t o m , C u ( 2 ) i n F i g u r e 1 3 , i s c o o r d i n a t e d t o f o u r n i t r o g e n a t o m s o f t h e p h o s p h o n i t r i i i c r i n g , a n d t o a c h l o r i n e a t o m ( F i g u r e 1 4 ) - T h e f i v e f o l d 2.28 F i g u r e 1 4 . G e n e r a l v i e w o f t h e N 6 ? 6 ( N M e 2 ^ 2 C u C * i o n , s h o w i n g t h e c o p p e r ( I I ) a t o m c o o r d i n a t i o n ( N M e 2 g r o u p s o m i t t e d f o r c l a r i t y ) . 92 c o o r d i n a t i o n i s p r o b a b l y b e s t d e s c r i b e d as a d i s t o r t e d square pyramid, w i t h the c h l o r i n e atom i n the a p i c a l p o s -i t i o n , a l t h o u g h an a l t e r n a t i v e and e q u a l l y s a t i s f a c t o r y d e s c r i p t i o n i s as a d i s t o r t e d t r i g o n a l b i p y r a m i d , w i t h } and i-i{1' ) i n a x i a l p o s i t i o n s ( F i g u r e 1 4 ) . O t h e r com-pounds w i t h f i v e - c o o r d i n a t e C u ( I I ) i n s i m i l a r c o n f i g u r a t i o n s have been r e p o r t e d , e.g. d i m e t h y i g l y o x i m a t o c o p p e r ( I I ) . o The Cu (2 )-C£.bond d i s t a n c e , 2.28(1) A (Table XX and F i g u r e 1 4 ) , i s s i m i l a r t o the l e n g t h found i n v a r i o u s C u ( I I ) corn-o 69 pounds, e.g. 2.28 A i n CuC*2*2H 0 } 2.22 - 2.26 A i n £(NrMe^) Hj CuCS^.^ The s m a l l d i f f e r e n c e b e t w e e n the two ^ o Cu(2 )-N bond d i s t a n c e s , 2.03(2) and 2.11 (2 ) A, may b e s i g -n i f i c a n t , and t h e d i f f e r e n c e i s not s u r p r i s i n g , s i n c e s t e r i c e f f e c t s d o u b t l e s s p l a y a p a r t i n d e t e r m i n i n g t h e e x a c t c o n f i g u r a t i o n a t Cu(2 ); the Cu(2 ) - N l e n g t h s a r e s i m i l a r t o those i n r e l a t e d compounds, e.g. 2.04(2) A i n £ ( I J F M e 0 )^HJCuCA The c u p r o u s copper atom, C u ( l ) i n F i g u r e 13, i s i n the l i n e a r a n i o n C u C X . T h i s a n i o n has been d e t e c t e d i n s o l u t i o n , ^  but i t s occurrence, i n the s o l i d s t a t e h a s not p r e v i o u s l y been d e f i n i t e l y e s t a b l i s h e d . The Cu — CJZ bona l e n g t h , c a l c u l a t e d from the f i n a l a t omic c o o r d i n a t e s , o i s 2,06(1 ) A ; c o r r e c t i o n f o r t h e r m a l l i b r a t i o n , assuming 72 a r i d i n g m o d e l , i n c r e a s e s t h i s d i s t a n c e t o a f i n a l v a l u e o of 2.11(1) i i . Few o t h e r r e l i a b l e v a l u e s a r e a v a i l a b l e 93 f o r comparison. The Cu-Cft d i s t a n c e i s g i v e n as 2.16 ± o *Z 3 C.015 ft i n the CuCJJ t r i m e r , ' where the C*-Cu~C4 a n g l e O 1L i s about 150 . The sum o f the c o v a l e n t r a d i i ' ^ o f c h l o r i n e ( 0 . 9 9 A ) a n a o f C u ( I ) i n a l i n e a r c o o r d i n a t i o n (1.18 A) o i s 2.17 A. The observed d i s t a n c e i n the p r e s e n t s t r u c t u r e i s s l i g h t l y l e s s t h a n t h e s e v a l u e s . The r e l a t e d i o n s AgCfi,,", AuCJ?2~? and nutsr,," have been found i n the s o l i a s t a t e , and a l l a r e l i n e a r . F o r AgGJ^" and AuC8 0~ t h e sum o f t h e c o v a l -o ent r a d i i a r e 2.38 and 2.33 A, r e s p e c t i v e l y , and the measured 75 Ag-CJt and Au-Cfc d i s t a n c e s , a r e , w i t h i n r a t h e r wide l i m i t s o.t e r r o r , 2.36 and ^ .31 A r e s p e c t i v e l y . f o r the more a c c u r -„ • 9 a t e l y measured AuBr, , tne c o v a l e n t r a d i u s sum i s 2.45 A, 2 76 o and the measured Au-3r d i s t a n c e i s 2.35(1) A. The bond-i n g s i t u a t i o n i n Cudft^" i s o b v i o u s l y v e r y s i m i l a r to t h a t i n t h e s e r e l a t e d i o n s . There a r e two d i s t i n c t t y p e s o f P-N bond d i s t a n c e i n the p h o s p h o n i t r i i i c r i n g (Table XX and F i g u r e 1 5 ) . The P-N bend l e n g t h s i n v o l v i n g n i t r o g e n atoms w h i c h a r e bonded to copper a r e i n the range 1.60 - 1.65(2) A ( F i g u r e 1 5 ) , mean 1.62 these d i s t a n c e s a r e c l o s e t o t h e l e n g t h s o f s i m i l a r bonds, 1.63(2) A, i n [(NPMe 0) h i CuCS The L 2 4 J 3 P-N bond d i s t a n c e s i n v o l v i n g N ( 3 ) , w h i c h i s not bonded t o o o copper, a r e .1.53 and 1.57(2) A , mean 1.55 A, s i m i l a r t o o 77 the bono l e n g t h , 1.56(1) A, i n t h e p a r e n t N,P,(NMe_) , . b o 2 12 95 These bend l e n g t h d i f f e r e n c e s can he i n t e r p r e t e d i n terms 24-28 o i f T -oonaing t h e o r y . The l o n e - p a i r e l e c t r o n s o f a n i t r o g e n atom w h i c h i s bonded t o copper a r e u t i l i z e d i n t h e Cu-N bona, and a r e th u s removed from the P - N ft -bonding _ 24-28 system. A second T T-system i s s t i l l o p e r a t i v e , o ana'the net r e s u l t i s a P - N bona l e n g t h o f 1.62 A a t th o s e n i t r o g e n atoms bonded t o co p p e r , a d i s t a n c e i n t e r m e d i a t e 053 between a s i n g l e bond l e n g t h of 1.77 A ana a normal l e n g t h .0 77 o f I . 5 0 A i n N P { N k e j 6 6 2 12 The v a l e n c y a n g l e s i n t h e r i n g (Table XX and 77 F i g u r e 15 i d i f f e r g r e a t l y from t h o s e i n t \ L P , ( N M e ~ ) ^ „ 6 b 2 12 and i n o t h e r p h o s p h o n i t r i l e s , and the u n u s u a l a n g l e s i n the p r e s e n t compound are d i r e c t l y a t t r i b u t a b l e t o the d i s -t o r t i o n o f t h e p h o s p h o n i t r i i i c r i n g caused by t h e bonding t o the copper atom. The d i f f e r e n c e s a r e most pronounced a t P ( l ) , where t h e N(1 )~P(1 ) - N ( 2 ). a n g l e o f 97.2° i s the s m a l l e s t e n d o c y c l i c a n g l e a t phosphorus wh i c h has been r e -p o r t e d i n a p h o s p h o n i t r i i i c compound. The c o r r e s p o n d i n g a n g l e s a t P(2} ana P ( 3 ) , 110.0° and 115.4° r e s p e c t i v e l y , o 77 a r e a l s o s m a l l e r than the 120 an g l e found i n i \ L - P , ( N R e ) , _ , 0 0 2 12 2.1 and i n o t h e r p h o s p h o n i t r i l e s . The average P - N - P a n g l e o o i n the r i n g , 134 , i s much s m a l l e r t h a n the a n g l e o f 147.5 found i n the p a r e n t N ^ P , ( N M e „ ) e a l l she, 77 6 " 6 ' 2 ' 1 2 * The e x o c y c l i c P-N bond d i s t a n c e s (Table XX) o 63 r t e r t h a n the P-N s i n g l e - b o n d l e n g t h o i 1.77 A , 96 ana t h i s s u g g e s t s the e x i s t e n c e o f e x o c y c l i c P-N ; 1T-bond-i n g , u t i l i z i n g n i t r o g e n p_TT o r b i t a l s . C o n s i s t e n t v / i t h t h i s i n d i c a t i o n of f f - b o n d i n g , t h e dimet h y l a r a i n o groups ar e a l l not f a r from p l a n a r , the sums o f the v a l e n c e a n g l e s a t the n i t r o g e n atoms v a r y i n g from 3 4 4 ° a t N(9) t o 360° a t N ( 6 ) . The e x o c y c l i c P-N d i s t a n c e s a t P ( l ) , 1.62(2) and o o 1.64(2) A, mean 1 . 6 3 ( 1 ) A, a r e . s l i g h t l y s h o r t e r t h a n t h o s e 0 o a t P(2 ) and P (3 ), 1.65 - 1.68(2) A, mean 1 . 6 7 ( 1 ) A. A l -though the d i f f e r e n c e i s b a r e l y s i g n i f i c a n t , i t i s i n the expected d i r e c t i o n , s i n c e w i t h d r a w a l o f t h e l o n e - p a i r e l e c -t r o n s a t i'J(l) ana N(2) by t h e copper atom s h o u l d enhance d o n a t i o n from K(4) and N(5 ) t o P ( l ) ( F i g u r e 1 3 ) , and r e s u l t i n g r e a t e r e x o c y c l i c TT-bonding ana hence s h o r t e r exo-c y c l i c p-K bonds a t P ( l ) . The C-N bond l e n g t h s i n t h e di m e t h y l a m i n o groups o are i n the range 1.45(3) to 1.55(3) A (Table X X ) , the mean o d i s t a n c e o f I.48 A not d i f f e r i n g s i g n i f i c a n t l y from the v a l u e o f I.46 t\ found i n N,P^ ( M e ) . . . 6 6 2 12 S t e r i c e f f e c t s must p l a y an i m p o r t a n t p a r t i n d e t e r m i n i n g the e x a c t c o n f o r m a t i o n o f t h e p h o s p h o n i t r i l i c r i n g , and the d e t a i l s o f t h e C u ( I I ) c o o r d i n a t i o n i n t h e p r e -sent s t r u c t u r e . The copper c o n f i g u r a t i o n c o u l d be made more n e a r l y square p y r a m i d a l , and t h e e n d o c y c l i c N-P-N a n g l e a t P ( l ) c o u l d be i n c r e a s e d t o a more normal v a l u e , by b r i n g -i n g P ( l ) ana P ( i ' ) c l o s e r t o g e t h e r . T h i s would however 97 cause increased s t e r i c interactions between NMe^ groups. The conformation of the phosphonitrilic r i n g (Figure 14) bears l i t t l e resemblance to those of known p h o s p h o n i t r i l i c structures. The r i n g can be regarded as being derived from a completely planar arrangement, which i s folded about the N(1)...N(1') d i r e c t i o n to give two approximately planar o sections at a dihedral angle of 129 (Figure 14). The packing of the ions i n the unit c e l l i s shown in Figure 16. The shorter i n t e r i o n i c distances involve contacts between methyl groups, and between methyl groups and chlorine atoms. The shortest CH^ CI distance i s 3.54 A* between C£(2) of the standard formula unit at (:*> Y.> £) a n d ^(1) °f t n e i ° n a t (^J Y__l> £ ) • Theise are several CH OH contacts l e s s than the sum of the van 3 , o v50 o der Waals r a d i i (40 A) , the shortest being 3.50 A between 3 i ° C(10) at (x, y_, z) and C(10) at (~-x, y_, - ~ z ) , and 3.61 A between C(6) at (x, y_, z) and C(12) at (x, l+y_, z). These are not to be considered unduly compressed, however, since CH •"•CH- contacts of l e s s than 4.0 % are not uncommon 3 3 o ' 7 3 and contacts as small as 3.13 A have been reported. V/ith non-rotating methyl groups these need not involve unreasonably small H****H distances. This i s the- t h i r d metal-phosphonitrile complex whose structure has been elucidated, and a l l three are of dif f e r e n t types. [(NFMe ) H + 1 CoC* 2 ~ i s an ionic 2 4 ^ 2 4 99 37 compound, i n which the cobalt atom i s not d i r e c t l y bonded CuCiJ group with the copper atom covalently bonded to one 43 nitrogen of the ring; and the structure described above i s i o n i c and has a copper bonded to four nitrogen atoms of a phosphonitriiic r i n g . There i s no apparent explanation for t h i s variety of metal-phosphonitrile complexes, thus making t h i s a f i e l d where further work would be very p r o f i t a b l e . to the phosphonitriiic ring ; REFERENCES 101 1. W . L . B r a g g , P r o c . 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