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The chemical characteristics of transition-metal organometallic nitrosyl complexes Nurse, Charles Richmond 1983

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THE CHEMICAL CHARACTERISTICS OF TRANSITION-METAL ORGANOMETALLIC NITROSYL COMPLEXES by CHARLES RICHMOND NURSE B.A., (HONOURS), OXFORD UNIVERSITY, 1978 A THESIS SUBMITTED IN PARTIAL FULFILMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY in THE FACULTY OF GRADUATE STUDIES DEPARTMENT OF CHEMISTRY We accept t h i s t h e s i s as conforming to the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA MAY 1983 © CHARLES RICHMOND NURSE, 1983 In p r e s e n t i n g t h i s t h e s i s i n p a r t i a l f u l f i l m e n t of the requirements f o r an advanced degree a t the U n i v e r s i t y o f B r i t i s h Columbia, I agree t h a t the L i b r a r y s h a l l make 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 study. 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 copying of t h i s t h e s i s f o r s c h o l a r l y purposes may be granted by the head o f my department or by h i s or her r e p r e s e n t a t i v e s . I t i s understood t h a t copying or 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 allowed without my w r i t t e n p e r m i s s i o n . Department of >— rV6-»»V\ i The U n i v e r s i t y of B r i t i s h Columbia 1956 Main Mall Vancouver, Canada V6T 1Y3 Date )E-6 (3/81) ABSTRACT The r e a c t i o n s of ( T? 5 - C 5 H 5 )Cr (CO) 2 (NO) with halogens r e s u l t i n e i t h e r ( T? 5 - C 5 H 5 )Cr (NO) 2X (X=C1 or Br) or [ ( T ? 5 - C 5 H 5 )Cr (NO) I ] 2 . Fu r t h e r treatment of the iodo-complex with excess I 2 or NO leads to the formation of ( T J 5 - C 5 H 5 )Cr (NO) 2 I • T h i s complex a l s o r e s u l t s from thermal decomposition of the dimeric iodo—complex. Reaction of ( 77 5 — C 5 H 5 )Cr (CO) (NO) (PPh 3) with halogens, or cleavage of the i o d i d e b r i d g e s i n [ (T? 5-C 5H 5 )Cr (NO) I ] 2 with Lewis bases, r e s u l t s i n a s e r i e s of s t a b l e paramagnetic complexes, ( T 7 S - C S H 5 )Cr (NO)LX (L=Lewis b a s e X = h a l i d e ) . In a d d i t i o n , the r e a c t i o n s of halogens with (175 —C 5Me 5)M(CO) 2 (NO) (M=Cr, Mo and W) are d e s c r i b e d . Reaction of [ ( r j 5 — C 5 H 5 )W(NO) I 2 ] 2 with t h a l l i u m or sodium c y c l o p e n t a d i e n i d e r e s u l t s i n the e l e c t r o n — r i c h complexes (C SH 5) 2W(NO)X (X=I or 77 1-C 5H 5). The f l u x i o n a l behaviour and instantaneous molecular s t r u c t u r e s of these complexes are d i s c u s s e d . Reduction of [ (T? 5-C 5H 5 )Mo(NO)1 2 ] 2 with Na/Hg i n the presence of n o n — c y c l i c conjugated dienes produces ( T } S - C 5 H 5 )Mo(NO) (7 ] a - d i e n e ) ; the diene i s c o o r d i n a t e d i n the ra r e s — t r a n s conformation. An unusual s o l v e n t c o n t r o l i s observed i n the r e a c t i o n of (C 5H 5) 2Mo(NO)I with the s i l v e r (I) s a l t s , AgBF, or AgSbF 6. In CH 3CN, s a l t s of the [(C 5H 5) 2Mo(NO)(CH 3CN)]* c a t i o n are formed i n high y i e l d , while i n aqueous acetone the t r i m e t a l l i c s p e c i e s , [ {(7? 5-C 5H 5 )Mo(NO) (OH)} 30]Y (Y=BF, of S b F 6 ) , r e s u l t . In CH 2C1 2, a no n - c o o r d i n a t i n g s o l v e n t , the i n s o l u b l e adducts, (C 5H 5) 2Mo(NO)I.AgY (Y=BF 0 or S b F 6 ) , p r e c i p i t a t e i n high y i e l d , the o r g a n o m e t a l l i c r e a c t a n t presumably f u n c t i o n i n g as a " s o f t " Lewis base. Reaction of (C5H5) 2Mo(NO)I with AICI3 e f f e c t s h a l i d e a b s t r a c t i o n to give the unsolvated c a t i o n , [ ( 7 j 5-C 5H s) 2Mo(NO) ] *. A d d i t i o n of the str o n g a c i d s HBF„.OMe 2 or HPF 6(aq) to a CH 2C1 2 s o l u t i o n of (^-CgHaMe) 3Mn 3 (NO), O ) r e s u l t s i n the r e v e r s i b l e formation of the novel hydroxyimido complexes, [ ( 7 j 5-C 5H 4Me) 3Mn 3 (NO) 3 (NOH) ]Y (2a, Y=BF„; 2b, Y=PF 6). F u r t h e r treatment with a c i d induces r e d u c t i o n of the N-0 bond to giv e [(n 5-C 5H aMe) 3Mn 3(NO) 3(NH)]Y (3a, Y=BF«; 3b, Y=PF 6). X-ray c r y s t a l l o g r a p h i c a n a l y ses of 2a and 3b have been performed i n order to c h a r a c t e r i s e the novel (M 3-N0H) and (M 3—NH) groups. The t r i m e t a l l i c imido complex i s a l s o one of the products of the r e a c t i o n of [ (17 S—C 5H„Me)Mn (CO) (NO) ] 2 with HBF,.OMe2. In a d d i t i o n , the new amido complex, [ (7j5—CsH(,Me) 2Mn 2 (NO) 2 (CO) (NH 2) ]BPh a, can be i s o l a t e d from the r e a c t i o n mixture a f t e r treatment w i t h aqueous NaBPh,. i v Table Of Contents ABSTRACT i i Table Of Contents i v L i s t Of F i g u r e s v i i i L i s t Of Tables ix L i s t Of Schemes x i A b b r e v i a t i o n s And S t y l i s t i c Notes x i i Acknowledgements x i v CHAPTER ONE: INTRODUCTION 1 ( i ) NO As An Environmental Hazard 1 (a) Photochemical Smog 2 (b) A c i d Rain 7 ( i i ) Abatement And C o n t r o l Of NOx Emissions 10 ( i i i ) The Reaction Of NO With T r a n s i t i o n Metal Complexes 12 (a) Simple Adduct Formation 13 (b) S u b s t i t u t i o n 13 (c) Reductive N i t r o s y l a t i o n 14 ( i v ) The Bonding And R e a c t i v i t y Of T r a n s i t i o n Metal N i t r o s y l Complexes 14 (a) Terminal, L i n e a r M-NO Bonds 15 (b) Terminal, Bent M-NO Bonds 17 (c) B r i d g i n g NO Linkages 18 (v) A Comparison Of N i t r o s y l And Carbonyl Chemistry 20 V (a) Hydride Complexes 21 (b) A l k y l Complexes 21 ( v i ) O b j e c t i v e s Of T h i s Study 25 CHAPTER TWO: THE REACTIONS OF HALOGENS WITH (r? 5 - C 5 R 5 )M(CO) (NO)L (M=Cr, R=H OR Me, L=CO OR PPh 3; M=Mo OR W, R=Me, L=CO) 27 ( i ) I n t r o d u c t i o n 27 ( i i ) R e s u l t s And D i s c u s s i o n 29 (a) Reactions Of (T? 5-C 5H 5 )Cr (CO) 2 (NO) With Halogens 29 (b) Reactions Of ( T J 5 — C 5 H 5 ) C r (CO) (NO) (PPh 3) With Halogens 41 (c) Reactions Of (rj 5 —C 5 Me 5 ) M (CO) 2 (NO) (M=Cr,Mo Or W) With Halogens 49 ( i i i ) Experimental S e c t i o n 58 CHAPTER THREE: SYNTHESIS AND CHARACTERISATION OF NEW CYCLOPENTADIENYL AND DIENE COMPLEXES DERIVED FROM [ ( T ? 5 - C 5 H 5 ) M ( N O ) I 2 ] 2 (M=MO OR W) 72 ( i ) I n t r o d u c t i o n 72 ( i i ) R e s u l t s And D i s c u s s i o n 73 (a) Reaction Of [ ( T? 5 - C 5 H 5 )W(NO) 1 2 ] 2 W i t h M ( C 5 H 5 ) (M=Na or T l ) 73 (b) S y n t h e s i s And C h a r a c t e r i s a t i o n Of ( T ? 5 - C 5 H 5 )Mo(NO) (rj"-diene) 78 ( i i i ) Experimental S e c t i o n 86 CHAPTER FOUR: SOLVENT CONTROL OF THE REACTIONS OF v i DICYCLOPENTADIENYLIODONITROSYLMOLYBDENUM WITH SOME SILVER (I) SALTS 90 ( i ) I n t r o d u c t i o n 90 ( i i ) R e s u l t s And D i s c u s s i o n 91 (a) Reaction Of S i l v e r (I) S a l t s With (C 5H 5) 2Mo(NO)I In A c e t o n i t r i l e 91 (b) In Aqueous Acetone 95 (c) In Dichloromethane 100 (d) Reaction Of A1C1 3 With (C 5H 5) 2Mo(NO)I In CH 2C1 2 106 ( i i i ) Experimental S e c t i o n 109 CHAPTER FIVE: ELECTROPHILE—INDUCED REDUCTION OF COORDINATED NITROGEN MONOXIDE. SEQUENTIAL CONVERSION OF A M 3-NO GROUP TO M3-NOH AND M3-NH LIGANDS 116 ( i ) I n t r o d u c t i o n 116 ( i i ) R e s u l t s And D i s c u s s i o n 118 ( i i i ) Experimental S e c t i o n 131 CHAPTER SIX: ELECTROPHILE-INDUCED REDUCTION OF COORDINATED NITROGEN MONOXIDE. CONVERSION OF A M 2~NO GROUP TO A M 2-NH 2 LIGAND .. 136 ( i ) I n t r o d u c t i o n 136 ( i i ) R e s u l t s And D i s c u s s i o n 138 ( i i i ) Experimental S e c t i o n 148 EPILOGUE 152 BIBLIOGRAPHY 154 APPENDIX 1 168 V I 1 APPENDIX 2 180 v i i i L i s t Of F i g u r e s 1.1 D a i l y V a r i a t i o n Of NO, N0 2 And 0 3 C o n c e n t r a t i o n s In Los Angeles, J u l y 1 9, 1965 4 1.2 A Comparison Of (a) A T y p i c a l Los Angeles Smog And (b) A Simulated Smog I n i t i a l l y C o n t a i n i n g Propylene And NO 6 2.1 E l e c t r o n Paramagnetic Resonance Spectra (X—Band) Of D i l u t e Toluene S o l u t i o n s Of (a) ( T? 5—C 5H 5 )Cr (NO) (PPh 3 )C1 And (b) ( V - C 5 H 5 )Cr (NO) (PPh 3 ) l . 45 2.2 I n f r a — r e d S p e c t r a l Changes Accompanying The Reaction Of (TJ 5—C 5Me 5 )Cr (CO) 2 (NO) With 0.5 E q u i v a l e n t s Of I 2 51 3.1 80 MHz 1H—NMR Spectra Of (C 5H 5) 3W(NO) In The Temperature Range -95°C -> 27°C 76 3.2 P o s s i b l e Molecular S t r u c t u r e s For The Complexes ( C 5 H 5 ) 2M(NO)X 78 3.3 400MHz 1H—NMR Spectrum Of ( T ? 5 - C 5 H 5 )Mo(NO) ( 7 ? 4 - s - t r a n s - C 5 H 8 ) ]_ ( v i n y l Region) .. 83 4.1 80MHz 1H-NMR Spectra Of [(C 5H 5) 2Mo(NO)(CH 3CN)]SbF 6 93 5.1 S t e r e o s c o p i c Views Of 2a And 3b 120 5.2 Mol e c u l a r S t r u c t u r e Of 2a 121 5.3 Mol e c u l a r S t r u c t u r e Of 3b 122 5.4 1H—NMR Spectrum Of 3a In CD 2C1 2 126 i x L i s t Of Tables 1.1 Sources Of Scandinavian A c i d Rain 8 2.1 Low-Resolution Mass S p e c t r a l Data For [ ( r ? 5 - C 5 H 5 ) C r ( N O ) l ] 2 36 2.2 Magnetic S u s c e p t i b i l i t y Data 37 2.3 Low-Resolution Mass S p e c t r a l Data For [ (T? 5-C 5H 5)Cr(NO) (OMe) ] 2 39 2.4 E l e c t r o n Paramagnetic Resonance Data 44 2.5 Low—Resolution Mass S p e c t r a l Data For (T7 5-C 5H 5 )Cr(NO) (PPh 3 )X (X=Cl,Br,l) 46 2.6 Low—Resolution Mass S p e c t r a l Data For ( 7 ? 5 —C 5H 5 )Cr (NO) {P(OPh) 3 } I 47 2.7 A Comparison Of The N i t r o s y l - S t r e t c h i n g Frequencies Of The New ( T? 5 - C 5 H 5 )Cr (NO)LX With The Analagous 18— e l e c t r o n Manganese Complexes 48 2.8 IR And 1H—NMR S p e c t r a l Data For The New Pen t a m e t h y l c y c l o p e n t a d i e n y l Complexes 54 2.9 13C-NMR S p e c t r a l Data For The New Pent a m e t h y l c y c l o p e n t a d i e n y l Complexes 55 3.1 1H—NMR Chemical S h i f t Data (6 In CDC1 3) For The New Diene Complexes 84 3.2 Proton-proton Coupling Constants ( i n Hz) For The New Diene Complexes 85 4.1 N i t r o s y l S t r e t c h i n g Frequencies Of Some Molybdenum And Tungsten Complexes 102 5.1 S p e c t r o s c o p i c P r o p e r t i e s Of The New Hydroxyimido And Imido Complexes. 124 x i L i s t Of Schemes 2.1 32 4.1 96 4.2 99 4.3 105 5.1 128 5.2 130 5.3 131 6.1 139 x i i A b b r e v i a t i o n s And S t y l i s t i c Notes In g e n e r a l , the a b b r e v i a t i o n s used i n t h i s t h e s i s are those recommmended i n "Handbook f o r Authors of Papers i n American Chemical S o c i e t y P u b l i c a t i o n s " , p u b l i s h e d by the American Chemical S o c i e t y . F i g u r e s , T a b l e s , Schemes and Equations are numbered (x, y ) , where x re p r e s e n t s the Chapter and y r e s e t s to 1 at the beginning of each Chapter. B i b l i o g r a p h i c r e f e r e n c e s are i n d i c a t e d by [xx] i n the running t e x t ; f o o t n o t e s are represented by s u p e r s c r i p t s . In a d d i t i o n , the f o l l o w i n g a b b r e v i a t i o n s are a l s o used:— A Angstrom (10" 1 0 m) a<N> e l e c t r o n / n u c l e u s h y p e r f i n e c o u p l i n g constant (N=coupled nucleus) B Base BM Bohr Magnetons bpy 2 , 2 ' — b i p y r i d i n e Cp (r? 5-C 5H 5) Cp" ( 7? 5-C 5Me 5) dec decomposed dmpe 1,2—bis(dimethylphosphino)ethane dppe 1,2—bis(diphenylphosphino)ethane E Main Group element E, Half—wave p o t e n t i a l X I 11 Anodic peak p o t e n t i a l g—value of the unpaired e l e c t r o n gauss I n t e r - n u c l e a r c o u p l i n g constant between n u c l e i X and Y 2 — e l e c t r o n donor l i g a n d a mixture of n i t r o g e n oxides organic a l k y l group s a t u r a t e d calomel e l e c t r o d e 2 , 6 - b i s ( 2 ' - p y r i d y l ) p y r i d i n e T e t r a h y d r o f u r a n h a l i d e The e t a — nomenclature i n d i c a t e s the number of atoms (x) i n the l i g a n d which are w i t h i n bonding d i s t a n c e of the metal atom The mu— nomenclature i n d i c a t e s the number of metal atoms (x) w i t h i n bonding d i s t a n c e of the l i g a n d chemical s h i f t d o w n f i e l d from t e r a m e t h y l s i l a n e i n f r a r e d s t r e t c h i n g a b s o r p t i o n molar magnetic s u s c e p t i b i l i t y e f f e c t i v e magnetic moment wavelength molar c o n d u c t i v i t y ohms. x i v Acknowledgements I wish to thank the f a c u l t y and t e c h n i c a l s t a f f of the chemistry department f o r t h e i r " expert a s s i s t a n c e and advic e throughout t h i s study. In p a r t i c u l a r , I wish to acknowledge Mr. P. Borda, Dr. S. J . R e t t i g , and the members of my S t e e r i n g Commitee; Drs. M. Fryzuk, R. Stewart and J . T r o t t e r . The d i l i g e n t p r o o f — r e a d i n g of B. Wassink and A. D. Hunter i s a l s o g r e a t l y a p p r e c i a t e d . I am indebted to the members of the group, both past and present, f o r p r o v i d i n g a ple a s a n t atmosphere f o r work and e s p e c i a l l y , I thank A l l e n D. Hunter and David T. M a r t i n , whose wit and d e d i c a t i o n to e x c e l l e n c e was a constant source of encouragement! F i n a n c i a l a s s i s t a n c e from the U n i v e r s i t y of B r i t i s h Columbia, i n the form of a U n i v e r s i t y Graduate F e l l o w s h i p i s g r a t e f u l l y acknowledged. F i n a l l y , I wish to express my g r a t i t u d e to Dr. P. Legzdins f o r h i s guidance, support and constant enthusiasm, without which the completion of t h i s work would not have been p o s s i b l e . "Experiments are the only means of knowledge at our d i s p o s a l . The r e s t i s poetry, i m a g i n a t i o n . " MAX PLANCK 1 CHAPTER ONE INTRODUCTION The p r i n c i p a l impetus f o r the c u r r e n t i n t e r e s t i n the c h a r a c t e r i s t i c chemistry of c o o r d i n a t e d n i t r o g e n monoxide, NO, d e r i v e s from the widespread occurrence of oxides of n i t r o g e n (NOx) as an environmental hazard produced i n many combustion processes [ 1 ] . Previous s t u d i e s had been s t i m u l a t e d by the f a c t that NO i s only a proton and an e l e c t r o n removed from CO [ 2 ] . However, r e c e n t l y there has been a s h i f t i n emphasis away from these comparative s t u d i e s of n i t r o s y l and c a r b o n y l complexes, towards the p o s s i b l e use of t r a n s i t i o n — m e t a l complexes i n the e f f e c t i v e removal of NO from exhaust gases, and co n v e r s i o n i n t o l e s s harmful and p o t e n t i a l l y more u s e f u l p r o d u c t s . ( i ) NO As An Environmental Hazard In 1975, 24.4 m i l l i o n tons of n i t r o g e n oxides (NOx) were produced i n the U.S. from f o s s i l f u e l combustion p r o c e s s e s . In a d d i t i o n , a f u r t h e r 2.1 m i l l i o n tons o r i g i n a t e d from Canadian sources [ 3 ] , The major sources of 2 these emissions are v e h i c l e exhausts, e l e c t r i c power p l a n t s and i n d u s t r i a l b o i l e r s . At the e l e v a t e d temperatures r e q u i r e d f o r these processes, n i t r o g e n and oxygen r e a c t to produce NO which i s then converted • i n t o N0 2 by a e r i a l o x i d a t i o n i n the atmosphere. N 2 + o 2 > 2NO ...(1.1) 2N0 + 0 2 > 2N0 2 ...(1.2) The r e l e a s e d n i t r o g e n oxides (NO + N0 2), commonly r e f e r r e d to as NOx , are i n v o l v e d i n the formation of two environmental problems:— a) photochemical smog, and b) a c i d r a i n . (a) Photochemical Smog One of the most d i s c o m f o r t i n g f e a t u r e s of l i f e i n urban areas of i n d u s t r i a l i s e d n a t i o n s i s the frequent presence of smog, the prime example being the South Coast A i r Basin i n C a l i f o r n i a [ 4 ] . Smog i s c h a r a c t e r i s e d by a r e l a t i v e l y high l e v e l of oxidants i n the atmosphere, which i r r i t a t e the eyes and t h r o a t and aggravate r e s p i r a t o r y problems. These oxi d a n t s i n c l u d e ozone ( 0 3 ) , n i t r o g e n d i o x i d e (N0 2), hydrogen peroxide ( H 2 0 2 ) and p e r o x y a c y l n i t r a t e s (RC0 3N0 2). 3 While the exact nature of the photochemical r e a c t i o n s i n v o l v e d i n smog formation has not yet been completely determined, i t has been demonstrated that the most important r e a c t i o n sequence i s the s o — c a l l e d n i t r o g e n d i o x i d e p h o t o l y t i c c y c l e [ 5 ] . N0 2 + hv(<0.38Mm) > NO + 0 ...(1.3) 0 + 0 2 + M > 0 3 + M ...(1.4) 0 3 + NO > N0 2 + 0 2 ...(1.5) However, t h i s simple model does not account f o r the h i g h c o n c e n t r a t i o n s of 0 3 observed ( F i g u r e 1.1). A n a l y s i s of the s t e a d y - s t a t e k i n e t i c s r e q u i r e s that [N0 2]/[NO] must be 10 or g r e a t e r , but the observed r a t i o emitted i s t y p i c a l l y about 0.05 [ 5 ] . Hence, the l a r g e q u a n t i t i e s of ozone and n i t r o g e n d i o x i d e observed can be e x p l a i n e d only i f a d d i t i o n a l mechanisms f o r the o x i d a t i o n of NO to N0 2 . can be e s t a b l i s h e d . Two such mechanisms have been c i t e d which l e a d to i n c r e a s e d N0 2 and 0 3 c o n c e n t r a t i o n s [ 6 , 7 ] . Both i n v o l v e atomic oxygen as an i n i t i a t o r , the s u b s t r a t e being e i t h e r unsaturated organic compounds or water. The important steps in the mechanisms are given below:— 4 Fi g u r e 1.1 D a i l y V a r i a t i o n Of NO, NQ 2 And Q 3 C o n c e n t r a t i o n s  In Los Angeles, J u l y 19, 1965. (a) 0 + o l e f i n > R« + RCO* ...(1.6) 0 3 + o l e f i n > RCHO + R0- + RCO- ...(1.7) R. + o 2 > ROO- ...(1.8) RCO- + 0 2 > RC0 3- ...(1.9) ROO- + NO > RO- + N0 2 ...(1.10) 5 RC0 3- + N0 2 > RC0 3N0 2 (1.11) (b) 0 + H 20 > 20H- ...(1.12) OH- + 0 3 > H0 2• + 0 2 ...(1.13) OH- + CO •> C0 2 + H- ...(1.14) H0 2- + NO > N0 2 + OH- ...(1.15) Even with i n c l u s i o n of these two mechanisms, the s i t u a t i o n i s s t i l l o v e r s i m p l i f i e d . However, a comparison of average c o n c e n t r a t i o n s of p o l l u t a n t s i n a t y p i c a l Los Angeles smog, with a simulated smog which i n i t i a l l y c o n t a i n e d propylene and NO (Figure 1.2) i n d i c a t e s that i n c l u s i o n of processes which i n v o l v e hydrocarbons g i v e s a good q u a l i t a t i v e match to the observed s i t u a t i o n [ 5 ] , In summary, photochemical smog i n v o l v e s the i n i t i a l p h o t o d i s s o c i a t i o n of N0 2 to produce atomic oxygen. Chain r e a c t i o n s , i n v o l v i n g molecular oxygen, water vapour and unsaturated organic s u b s t r a t e s l e a d to a r a p i d b u i l d u p i n atmospheric o x i d a n t s . As a r e s u l t , the r e d u c t i o n of smog e f f e c t s w i l l r e q u i r e a s u b s t a n t i a l r e d u c t i o n i n the ammount of NOx emitted. 6 F i g u r e 1.2 A Comparison Of (a) A T y p i c a l Los Angeles Smog  And (b) A Simulated Smog I n i t i a l l y C o n t a i n i n g  Propylene And NO. (a) Hydrocarbons / \ ^ N . Aldehydes / Ozone NO 6 8 10 12 AM 2 4 6 P.M. (b) 0 50 100 150 200 250 Irradiation time, minutes 7 (b) A c i d Rain A c i d r a i n w i l l probably be the most p o l i t i c a l l y emotive environmental issue to face the i n d u s t r i a l i s e d n a t i o n s d u r i n g the next 2—3 decades. U n l i k e photochemical smog which i s l o c a l i n nature , the problem i s i n t e r n a t i o n a l i n scope. For i n s t a n c e , i t has been claimed that only 17% of the a c i d r a i n which f a l l s on the l a k e s and mountains of Scandinavia a c t u a l l y o r i g i n a t e s from Scandinavian sources, the m a j o r i t y of i t being c a r r i e d by the p r e v a i l i n g winds from the i n d u s t r i a l h e a r t l a n d of Europe [8] (Table 1.1). A s i m i l a r s i t u a t i o n e x i s t s i n N. America where i t has been estimated that 50% of the a c i d r a i n f a l l i n g on Northern O n t a r i o o r i g i n a t e s from the U.S. [ 8 ] . Of course, the p o l l u t i n g c o u n t r i e s tend to d i s p u t e these r e s u l t s , and i t i s evident that much work s t i l l needs to be done to determine the exact causes and nature of a c i d r a i n . I t i s p r e s e n t l y thought that a c i d r a i n i s formed i n the r a i n c l o u d s , by a combination of o x i d a t i o n and h y d r o l y s i s of S0 2 and NOx [ 5 , 7 ] . These gases are produced from i n d u s t r i a l p r o c e s s e s , as w e l l as from n a t u r a l sources, such as volcanoes and e l e c t r i c a l storms. 4N0 2 + 2H 20 + 0 2 > 4HN03 ...(1.16) 3N0 2 + H 20 > 2HN03 + NO ...(1.17) 8 Table 1.1 Sources Of Scandinavian A c i d Rain Country % C o n t r i b u t i o n Sweden/Norway 1 7% U.K. 11% E. Germany 9% W. Germany 8% Poland 6% U.S.S.R. 5% Czechoslovakia 4% France 4% Denmark 3% F i n l a n d 2% Belgium 1% Hungary 1% I t a l y 1% Netherlands 1% Yugo s l a v i a 1% Unknown 27% N0 2 + -OH > HN0 3 ...(1.18) S0 2 + H 20 > H 2S0 3 ...(1.19) H 2S0 3 + [0] > H 2SO« ...(1.20) where [0] = OH, 0 3, 0H 2, or H 2 0 2 . It has been estimated that i n the e a s t e r n s t a t e s and p r o v i n c e s ^70% of the a c i d r a i n r e s u l t s from sulphur d i o x i d e emissions produced by non-ferrous smelters and c o a l — b u r n i n g power s t a t i o n s [ 9 ] . In the west, however, the a c i d i t y of the 9 r a i n i s almost e n t i r e l y due to n i t r i c a c i d . Since the n i t r o g e n oxides are p a r t of the n a t u r a l n i t r o g e n c y c l e i t has a l s o been claimed that a d i s t i n c t i o n can be made between harmful S0 2 emissions and b e n e f i c i a l NOx. However, i t i s the i n c r e a s e d a c i d i t y of the r a i n and not the nature of the anions which seems to have the most profound e f f e c t on the environment. "Pure" r a i n has a pH of 5.6 due to d i s s o l u t i o n of carbon d i o x i d e . Over the l a s t 10—15 years an i n c r e a s i n g area of N. America and Northern Europe has experienced a c i d i c r a i n f a l l with pH's i n the range 4.0-4.5. The most a c i d i c r a i n f a l l ever recorded had a pH of 1.5 ( i . e . , =*10,000 times more a c i d i c than "pure" r a i n [ 3 ] ) . The e f f e c t of t h i s a c i d i c r a i n f a l l on the environment depends on a number of f a c t o r s , which i n c l u d e the b u f f e r i n g c a p a c i t y and m i n e r a l content of the s o i l . N e u t r a l i s a t i o n of the r a i n leaches out the metal ions from the s o i l s . T h i s has two important consequences:— f i r s t , elements which are n u t r i e n t s (e.g. Ca, Mg) are removed from the s o i l [10] and second, t o x i c elements such as aluminum, manganese and mercury which are normally f i x e d as harmless i n s o l u b l e compounds are m o b i l i s e d and d i s s o l v e d as l e t h a l s u l p h a t e s and n i t r a t e s [ 1 1 ] . Many l a k e s and r i v e r s i n a f f e c t e d areas no longer support a q u a t i c l i f e due to the high c o n c e n t r a t i o n s of t o x i c metals and the g e n e r a l high a c i d i t y . 10 A c i d r a i n i s a l s o very c o r r o s i v e . For inst a n c e , the i n c r e a s e d a c i d i t y of the r a i n i s causing an e s c a l a t i o n of c o r r o s i o n of car bodies as w e l l as e r o s i o n of stone s t r u c t u r e s ; those c o n s t r u c t e d of limestone being p a r t i c u l a r l y s u s c e p t i b l e [12]. Furthermore , the higher a c i d i t y of domestic tap water i s causing concern , as t h i s produces an i n c r e a s e i n t o x i c copper l e v e l s [10]. To summarise, the i n c r e a s i n g a c i d i t y of g l o b a l p r e c i p i t a t i o n i s having grave environmental consequences, which can only be a l l e v i a t e d by a r e d u c t i o n i n the S0 2 and NOx emis s i o n s . ( i i ) Abatement And C o n t r o l Of NOx Emissions Present methods f o r the r e d u c t i o n of NOx emissions can be c a t e g o r i s e d a c c o r d i n g to two c l a s s i f i c a t i o n s : — a) abatement, i . e . r e d u c t i o n of the amount of NOx produced by modifying the combustion process, and b) c o n t r o l — removal of the NOx produced by v a r i o u s c a t a l y t i c and n o n — c a t a l y t i c p r o c e s s e s . While improvements i n the design of the burner and furnace have been made they have, i n g e n e r a l , r e s u l t e d i n a r e d u c t i o n i n the e f f i c i e n c y of combustion. On the other hand, the methods p r e s e n t l y employed to remove the NOx are e i t h e r somewhat i n e f f i c i e n t or very expensive. For i n s t a n c e , the most common process - Exxon's Thermal "Denox" - i n v o l v e s 11 the gas phase r e a c t i o n 4NH3 + 4NO + 0 2 > 4N 2 + 6H 20 ...(1.21) in the combustion zone. The drawbacks of t h i s process are the low NOx removal (<70%) and the l a r g e amount of expensive NH 3 r e q u i r e d [13]. Recently, some success i n e f f e c t i n g the removal of NOx using homogeneous c a t a l y s t s has been r e p o r t e d , [14-16]. The o v e r a l l process i n v o l v e s the r e a c t i o n between carbon monoxide and n i t r o g e n monoxide to g i v e the much l e s s t o x i c gases, carbon d i o x i d e and d i n i t r o g e n monoxide. CO + 2NO > C0 2 + N 20 ...(1.22) The c a t a l y s t systems s t u d i e d were a c i d i c aqueous or e t h a n o l i c s o l u t i o n s of P d C l 2 [14], C u C l 2 [14], R h C l 3 [15] and [Rh(CO) 2C1 2 ]" [15,16]. While these processes have been s u c c e s s f u l i n removing n i t r o g e n monoxide from exhaust gases to v a r y i n g degrees, the emphasis of most of the work has been to accomplish the co n v e r s i o n of NO i n t o l e s s noxious products, p r i n c i p a l l y N 2 and to a l e s s e r extent N 20. However, both of these products are q u i t e n o n — r e a c t i v e , and f u r t h e r expensive t r a n s f o r m a t i o n s must be e f f e c t e d i n order to convert the n i t r o g e n i n t o important chemicals such as f e r t i l i z e r s . An 12 a l t e r n a t i v e approach , which m e r i t s i n v e s t i g a t i o n , i s to convert the NO d i r e c t l y i n t o more u s e f u l s p e c i e s . T h i s approach, i f s u c c e s s f u l , would not only l e a d to a r e d u c t i o n of NOx emissions but may a l s o pay f o r i t s e l f from the s a l e s of the products thus obtained. The f i r s t s tep i n the s t r a t e g y i n v o l v e s t r a p p i n g of the n i t r o g e n monoxide on an e l e c t r o n — r i c h t r a n s i t ion—metal c e n t r e to form a n i t r o s y l complex. Once obtained, the r e a c t i v i t y of the c o o r d i n a t e d n i t r o s y l l i g a n d may be e x p l o i t e d to o b t a i n the d e s i r e d o b j e c t i v e . At present, ample precedent e x i s t s i n the l i t e r a t u r e [17] f o r the f i r s t s t e p, while the r e a c t i v i t y of c o o r d i n a t e d NO i n c o o r d i n a t i o n complexes has been s t u d i e d [18,19]. However, i n most of these complexes, the NO l i g a n d s are a t t a c h e d to t r a n s i t i o n metals i n high, r a t h e r than low, formal o x i d a t i o n s t a t e s . ( i i i ) The Reaction Of NO With T r a n s i t i o n Metal Complexes I t has been e s t a b l i s h e d that NO r e a c t s with a p p r o p r i a t e t r a n s i t i o n metal complexes to e f f e c t 3 p r i n c i p a l types of t r a n s f o r m a t i o n s [ 1 7 ] : — a) simple adduct formation b) s u b s t i t u t i o n , and c) r e d u c t i v e n i t r o s y l a t i o n . 1 3 (a) Simple Adduct Format ion T h i s type of r e a c t i o n occurs when the t r a n s i t i o n — m e t a l complex i s e i t h e r a 15— or 17—electron s p e c i e s , l a c k i n g one or three e l e c t r o n s from the i n e r t gas c o n f i g u r a t i o n [20-22] e.g. C r ( N R 2 ) 3 + NO > Cr( N O ) ( N R 2 ) 3 ...(1.23) C o C l 2 L 2 + NO > C o ( N O ) C l 2 L 2 ...(1.24) C r ( O P P h 3 ) 2 X 2 + NO > C r ( N O ) 2 ( O P P h 3 ) 2 X 2 ...(1.25) (b) S u b s t i t u t i o n Reaction of n i t r o g e n monoxide with many c o o r d i n a t i v e l y s a t u r a t e d t r a n s i t i o n metal complexes r e s u l t s i n the s u b s t i t u t i o n of l i g a n d ( s ) capable of donating 3n e l e c t r o n s to the metal c e n t r e [23-26] e.g. Cr ( C O ) 6 + 4N0 + hv > Cr(NO)„ + 6CO ...(1.26) [ ( 7 ? 5 - C 5 H 5 ) V ( C O ) 3 C N ] - + NO > ( T ? 5 - C 5 H 5 )V(NO) 2 (CO) + 2CO + CN- ...(1.27) 14 [ ( 7 ? s - C 5 H 5 ) C r ( C O ) 3 ] 2 + 2N0 > 2 ( T? 5 - C 5 H s )Cr (CO) 2 (NO) + 2CO ...(1.28) 2 ( T J 5 - C 5 H 5 )Co(CO) 2 + 2NO > [ ( r j 5 - C 5 H 5 )Co(NO) ] 2 + 4CO ...(1.29) (c) Reductive N i t r o s y l a t i o n Many t r a n s i t i o n metal h a l i d e s are reduced by NO gas, the o x i d i s e d product i n these r e a c t i o n s u s u a l l y being N0C1 [27-29]. e.g. MoCl 5 + 5NO > [Mo(NO) 2Cl 2] + 3NOC1 ...(1.30) ( 7 j 3 - C 3 H 5 ) F e ( C O ) 2 L C l + 2NO > (JJ 3—C 3H 5)Fe(CO) (NO)L + NOC1 ...(1.31) 2 C o C l 2 + 6NO + 2B + 2ROH > [ C o ( N O ) 2 C l ] 2 + 2BH + + 2C1" + 2RONO ...(1.32) ( i v ) The Bonding And R e a c t i v i t y Of T r a n s i t i o n Metal N i t r o s y l  Complexes Once i n c o r p o r a t e d i n t o the t r a n s i t i o n metal's c o o r d i n a t i o n sphere, the n i t r o s y l l i g a n d can engage i n one 15 of three p r i n c i p a l bonding modes, a l l of which i n v o l v e m e t a l — t o — n i t r o g e n r a t h e r than M—ON i n t e r a c t i o n s [ 1 9 ] : — a) t e r m i n a l , l i n e a r M—NO groups, b) t e r m i n a l , bent M—NO groups c) b r i d g i n g NO groups. I t i s here that one n o t i c e s the f i r s t d i f f e r e n c e between NO and CO as a l i g a n d , s i n c e carbon monoxide does not f u n c t i o n i n the bent mode. (a) T erminal, L i n e a r M-NO Bonds T h i s i s the most common type of M—NO bonding, p a r t i c u l a r l y i n o r g a n o m e t a l l i c complexes. In t h i s type of bonding the NO group f u n c t i o n s as a 3 — e l e c t r o n donor ( i . e . f o r m a l l y NO*). The l i n e a r mode, as shown i n resonance s t r u c t u r e s (a) and (b) , 2- + + - + M—N=0 « * M=N=0. (a) (b) p a r a l l e l s d i r e c t l y CO c o o r d i n a t i o n i n v o l v i n g a s y n e r g i c c o u p l i n g c o u p l i n g of a and it components [30]. As with c a r b o n y l c o o r d i n a t i o n , the degree of m e t a l — t o — l i g a n d 7T—backbonding i s i n f l u e n c e d by the complex charge, metal o x i d a t i o n s t a t e or the nature of a n c i l l a r y l i g a n d s . 16 Resonance s t r u c t u r e s (a) and (b) above represent two extremes of the continuum and t h i s formalism i l l u s t r a t e s how the degree of backbonding i n f l u e n c e s the n i t r o s y l s t r e t c h i n g frequency, P(NO), of the complex. When r e l a t i v e l y l i t t l e e l e c t r o n d e n s i t y i s t r a n s f e r r e d to the n i t r o s y l by t h i s i n t e r a c t i o n , as evidenced by a v(NO) > 1880cm" 1, the n i t r o s y l e x h i b i t s NO* c h a r a c t e r and i s a c t i v a t e d towards n u c l e o p h i l i c a t t a c k at n i t r o g e n [31] e.g. [ l r C l 3 ( N O ) ( P P h 3 ) 2 ] + + O E f > I r C l 3 ( N ( O ) O E t ) ( P P h 3 ) 2 ...(1.33) On the other hand, s p e c i e s having p a r t i c u l a r l y low valu e s of »>(NO) may be expected to be l i a b l e t o a t t a c k by e l e c t r o p h i l e s , p a r t i c u l a r l y at the 0 atom. For i n s t a n c e , i t has been shown that Lewis A c i d s such as A1C1 3, SnClj, ,TiCl« and ( T J 5 - C 5 H s ) 3Ln form i s o n i t r o s y l l i n k a g e s with ( T ? 5 - C 5 H 5 )M(CO) 2 (NO) (M=Cr,Mo,W). [32,33]. M-NO + EX n > M-NO->EXh ...(1.34) 17 (b) T e rminal, Bent M-NO Bonds T h i s type of bonding i s r e l a t i v e l y common f o r l a t e t r a n s i t i o n — m e t a l n i t r o s y l c o o r d i n a t i o n complexes, but i s rar e i n o r g a n o m e t a l l i c n i t r o s y l s . In t h i s type of bonding the NO group f u n c t i o n s as a 1—electron donor ( f o r m a l l y NO"), i . e . The bond angle i s t y p i c a l l y 120° ( i . e . the n i t r o g e n i s e s s e n t i a l l y s p 2 / h y b r i d i s e d ) , but there are many complexes (bent) and 180° ( l i n e a r ) . S t r u c t u r a l s t u d i e s of n i t r o s y l s of t h i s type have a l s o shown that the bent NO l i g a n d i n v a r i a b l y occurs at the a p i c a l p o s i t i o n of a square based pyramid or a d i s t o r t e d octahedron [34]'. Since the n i t r o g e n atom possesses a nonbonding p a i r of e l e c t r o n s , the charge a f f i n i t y of the n i t r o g e n atom has been i n v e r t e d from that found i n l i n e a r n i t r o s y l s . Whereas, the l i n e a r n i t r o s y l undergoes n u c l e o p h i l i c a t t a c k at N ( p r o v i d i n g i-(NO) i s high enough), the bent n i t r o s y l r e a c t s with e l e c t r o p h i l e s [35] e.g. M—N which have M—N—O bond angles i n t e r m e d i a t e between 120° 18 O s C l ( C O ) ( N O ) ( PPh 3 ) 2 + HC1 > O s C l 2 ( C O ) ( H N O ) ( P P h 3 ) 2 ...(1.35) (c) B r i d g i n g NO Linkages The b r i d g i n g mode of NO c o o r d i n a t i o n i s r e l a t i v e l y r a r e . I t occurs i n a few b i — and t r i — m e t a l l i c c y c l o p e n t a d i e n y l d e r i v a t i v e s and i n a few mixed c a r b o n y l n i t r o s y l c l u s t e r s , e.g. [ ( r ? 5 - C 5 H 5 )Cr (NO) 2 ] 2 [36], ( T ? 5 - C 5 H 5 ) 3Mn 3 (NO) , • [37], [ ( TJ 5 — C 5 H 5 )Fe (NO) ] 2 [38] and H 3Os,(CO), 2(NO) [39]. B r i d g i n g NO l i n k a g e s can be c l a s s i f i e d i n 3 c a t e g o r i e s : — (a) d o u b l y — b r i d g i n g (M2—NO) supported by a M—M bond e.g. O (b) d o u b l y — b r i d g i n g (ju 2— NO) unsupported by a M—M bond e.g. 19 (c) t r i p l y - b r i d g i n g (M 3-NO) e.g. o O Mn = (C5H5)Mn The oxygen atom i n a l l types of b r i d g i n g NO groups i s b a s i c , the order of i n c r e a s i n g b a s i c i t y being ( 1x3— NO) =* (n2—NO) < t e r m i n a l NO [40], S u r p r i s i n g l y , t h i s order i s the reverse of tha t found f o r c a r b o n y l complexes [41]. The n i t r o g e n atom i n b r i d g i n g systems should be a c t i v a t e d towards n u c l e o p h i l i c 1The t h r e e hydrogen atoms were not l o c a t e d i n the s t r u c t u r e d e t e r m i n a t i o n . 20 a t t a c k , and i n f a c t t h i s has been demonstrated i n the r e a c t i o n of t-BuLi with [ ( T} 5-C 5H 5 )Cr (NO) 2 ] 2 1 which g i v e s the complex a f t e r h y d r o l y s i s [42]. S i m i l a r l y , the r e a c t i o n of the chromium complex with Na[A1H 2(OCH 2CH 2OCH 3) 2] r e s u l t s i n the formation of ( T ? 5 — C 5 H 5 ) 2 C r 2 (NO) 3 (NH 2) and ( T } 5 - C 5 H 5 ) 2 C r 2 (NO) 2 (NH 2) 2 i n low to moderate y i e l d s [43]. (v) A Comparison Of N i t r o s y l And Carbonyl Chemistry U n f o r t u n a t e l y , due to the r e l a t i v e underdevelopment of n i t r o s y l chemistry compared to c a r b o n y l chemistry, a complete comparison of the two i s not p o s s i b l e . However, i n recent y e a r s , a few s i g n i f i c a n t d i f f e r e n c e s i n t h e i r chemistry have been d i s c o v e r e d . 21 (a) Hydride Complexes A c h a r a c t e r i s t i c p r o p e r t y of car b o n y l h y d r i d e s i s t h e i r Lowry—Bronsted a c i d i t y . Most of these h y d r i d e s r e a c t with bases to produce c a r b o n y l anions [44] e.g. H 3 R e 3 ( C O ) 1 2 + KOH > K[H 2 R e 3 ( C O ) , 2 ] + H 20 ...(1.36) The only n i t r o s y l hydride to be s t u d i e d i n any d e t a i l ; ( r j 5 - C 5 H 5 )W(NO) 2H, i s , however, not a c i d i c but h y d r i d i c i n behaviour [45]. T h i s i s s u r p r i s i n g i n view of the f a c t t h a t NO i s c o n s i d e r e d to be a b e t t e r it—acid than CO. In a d d i t i o n , while most c a r b o n y l h y d r i d e s have very high f i e l d chemical s h i f t s i n t h e i r 1H—NMR s p e c t r a , ( 77 5-C 5H 5 )W(NO) 2H resonates d o w n f i e l d from TMS (62—3 depending on s o l v e n t ) . Without f u r t h e r examples, however, no d e f i n i t i v e c o n c l u s i o n on the g e n e r a l i t y of t h i s behaviour can be made. (b) A l k y l Complexes A common f e a t u r e of a l k y l c a r b o n y l complexes i s a l k y l m i g r a t i o n (or c a r b o n y l i n s e r t i o n ) r e s u l t i n g i n the formation of an a c y l complex [46], For example, alkylpentacarbonylmanganese complexes rearrange i n the presence of l i g a n d s such as CO, PR 3, NR3 or X" as shown i n equation (1.37). 22 (OC) 5MnR + L > (OC)„(L)Mn(COR) ...(1.37) D e t a i l e d s t u d i e s on t h i s system suggest that the r e a c t i o n occurs v i a i n i t i a l a l k y l m i g r a t i o n . In a subsequent step, the c o o r d i n a t i v e l y unsaturated a c y l takes up an e x t e r n a l l i g a n d i n the s i t e l e f t vacant by the m i g r a t i n g a l k y l group. (OC)«Mn—CO -> (OC) aMn—C + L (OC) uMn—C ,R . . (1 .38) An analogous r e a c t i o n f o r a l k y l n i t r o s y l complexes would l e a d to an a l k y l n i t r o s o s p e c i e s . To date, however, only one example of such a r e a c t i o n has been completely c h a r a c t e r i s e d , although there are s e v e r a l r e a c t i o n s , which probably i n c l u d e such a step [47], ^NO ( r j 5 - C 5 H 5 ) C o ^ + PPh 3 R ^ P P h 3 -> ( r j 5 - C 5 H 5 ) C o ...(1.39) ^N=0 R Again, the proposed mechanism i s i n i t i a l a l k y l m i g r a t i o n to g i v e the c o o r d i n a t i v e l y u n s a t u r a t e d a l k y l n i t r o s o complex 23 which i s then trapped by the phosphine l i g a n d . A d i r e c t comparison of the p r o p e n s i t y of c a r b o n y l and n i t r o s y l a l k y l s to undergo a l k y l m i g r a t i o n can be obtained from the r e a c t i o n s of the i s o e l e c t r o n i c complexes ( T } 5 - C 5 H 5 )Cr (NO) 2Me and ( r j 5 — C 5 H 5 )Fe(CO) 2Me with PPh 3 (equations 1.40 andl.41) [48,49]. ( T ? 5 - C 5 H 5 )Fe(CO) 2Me + PPh 3 > ( T J 5 - C 5 H 5 )Fe (CO) (PPh 3) (COMe) ...(1.40) ( r j 5 — C 5 H 5 )Cr (NO) 2Me + PPh 3 > N/R ...(1.41) On the other hand both of the a l k y l complexes i n s e r t S0 2 a f f o r d i n g the S-sulphinate M-S0 2R (equation 1.42) [50]. ( T J 5 - C 5 H 5 )M(LO) 2Me + S0 2 > ( T J 5 - C 5 H 5 )M(LO) 2S0 2Me ...(1.42) (M=Fe, L=C; M=Cr, L=N) However, i n t h i s case, the mechanism i s thought to be e l e c t r o p h i l i c cleavage of the M—C bond by a t t a c k of the e l e c t r o p h i l i c S0 2 molecule at the a l k y l carbon. The f a c t t h a t (7j 5 —C 5 H 5 ) C r (NO) 2 Me i s amongst the most r e a c t i v e a l k y l s to S0 2 i n s e r t i o n suggests t h a t the a l k y l carbon i s f a i r l y n u c l e o p h i l i e . Thus the reason f o r i t s i n e r t n e s s to a l k y l m i g r a t i o n probably i s that the NO l i g a n d i s not e l e c t r o p h i l i c enough r a t h e r than a lack of n u c l e o p h i l i c i t y 24 at the carbon atom. T h i s c o n c l u s i o n i s not s u r p r i s i n g i n view of the charge s e p a r a t i o n i n the f r e e l i g a n d s (CO and NO), which may be determined by c o n s i d e r i n g the e l e c t r o n e g a t i v i t i e s of C, N and 0 [51] or more r i g o u r o u s l y by ab i n i t i o molecular o r b i t a l c a l c u l a t i o n s [2,52]. F u r t h e r chemical evidence, which confirms t h i s c o n c l u s i o n can be found i n the r e a c t i o n of [ (7j 5 —C 5 H 5) Re (CO) (NO)L]BF„ with hydride reagents. Depending on the c o n d i t i o n s and reagents employed, the f o l l o w i n g products may be i s o l a t e d :- (TJ 5— C 5 H 5 )Re(CHO) (NO)L, ( T J 5 - C 5 H 5 )Re(CH 2OH) (NO)L or ( T? 5 - C 5 H 5 )Re (CH 3 ) (NO)L (L=CO,PPh 3) [53] e.g. ( TJ5 —C 5H 5 )Re (CO) 2 (NO) + NaBH«/H 20 > ( TJ 5—C 5H 5 )Re (CO) (NO) (CHO) . . . ( 1 .43) + 2NaBH<,/H20 > ( T? 5 —C 5 H 5 ) Re (CO) (NO) (CH 2 OH) . . . ( 1 .44) + NaBH u/THF > ( T ? 5 - C 5 H 5 )Re(CO) (NO) ( C H 3 ) ... .....( 1 .45) A l l of the products r e s u l t from i n i t i a l r e a c t i o n at. the ca r b o n y l r a t h e r than the n i t r o s y l l i g a n d . The general c o n c l u s i o n to be drawn from these o b s e r v a t i o n s i s that a c o o r d i n a t e d n i t r o s y l i s l e s s r e a c t i v e 25 towards n u c l e o p h i l e s than a c o o r d i n a t e d carbon monoxide l i g a n d . In a d d i t i o n , i t may a l s o u niquely i n f l u e n c e the c h a r a c t e r i s t i c chemistry of other l i g a n d s present i n the c o o r d i n a t i o n sphere. ( v i ) O b j e c t i v e s Of T h i s Study The o b j e c t i v e s of t h i s study are t w o — f o l d , i n l i n e with the two main d i r e c t i o n s of study i n t r a n s i t ion—metal n i t r o s y l chemistry o u t l i n e d above, ( i . e . to i n v e s t i g a t e the e f f e c t of the NO l i g a n d on the chemistry of other l i g a n d s i n the c o o r d i n a t i o n sphere and to i n v e s t i g a t e r e a c t i o n s which might l e a d to a t t a c k at the c o o r d i n a t e d NO l i g a n d ) . In p a r t i c u l a r , Chapter 2 and Chapter 3 d e a l with the p r e p a r a t i o n and d e r i v a t i v e chemistry of some c y c l o p e n t a d i e n y l h a l o n i t r o s y l d e r i v a t i v e s of the Group VIA metals prepared by the r e a c t i o n of ( 77 5-C 5R 5 )M(CO) (NO)L (M=Cr, Mo, W; R=H, Me; L=CO, PPh 3) with halogens. Chapter 4 p r e s e n t s a d e t a i l e d study of one p a r t i c u l a r r e a c t i o n , that of (C 5H 5)M(NO)I with s i l v e r s a l t s , i n which the s o l v e n t has a pronounced i n f l u e n c e on the outcome of the t r a n s f o r m a t i o n s . Chapters 5 and 6 d e s c r i b e the r e s u l t s of the r e a c t i o n s Of ( TJ 5—C 5HftMe ) 3Mn 3 (NO) a and [ ( TJ5 —C 5 H„R)Mn(CO) (NO) ] 2 (R=H or CH 3) with the strong p r o t o n i c a c i d s HBF„.OMe 2 and HPF 6(aq). The major o r g a n o m e t a l l i c products of these r e a c t i o n s are 26 imido (NH) or amido (NH 2) complexes and r e s u l t from e l e c t r o p h i l e — i n d u c e d r e d u c t i o n of c o o r d i n a t e d n i t r o g e n monoxide. / 27 CHAPTER TWO THE REACTIONS OF HALOGENS WITH ( T? 5-C 5R 5 )M(CO) (NO)L (M=Cr,  R=H OR Me, L=CO OR PPh 3; M=Mo OR W, R=Me, L=CO) ( i ) I n t r o d u c t i o n T r a n s i t i o n — m e t a l o r g a n o m e t a l l i c h a l i d e s are very convenient s t a r t i n g m a t e r i a l s f o r the s y n t h e s i s of a wide v a r i e t y of c a t i o n i c , n e u t r a l , and a n i o n i c complexes [44]. For i n s t a n c e , d u r i n g previous work from t h i s l a b o r a t o r y , the c h a r a c t e r i s t i c chemistry of the c h l o r o n i t r o s y l compounds ( T ? 5 - C 5 H 5 )M(NO) 2C1 (M=Cr, Mo, W) was e x p l o i t e d to prepare some novel o r g a n o m e t a l l i c n i t r o s y l complexes, [45,54,55] i . e . ( 7 ? 5 - C 5 H 5 ) C r ( N O ) 2 C l + Zn/Hg > [ ( T? 5 - C 5 H 5 )Cr (NO) 2 ] 2 ...(2.1) ( 7? 5-C 5H 5)Cr(NO) 2C1 + H" > [ ( TJ 5—C 5H 5 )Cr (NO) 2 ] 2 ...(2.2) (r? 5-C 5H 5 )M(NO) 2C1 + H" > ( T J 5 - C 5 H 5 )M(NO) 2 H ...(2.3) M=Mo,W 28 ( T J 5 - C 5 H 5 )M(NO) 2C1 + R 3A1 > ( T J 5 - C 5 H 5 ) M ( N O ) 2 R . . . ( 2 . 4 ) R = a l k y l or a r y l ( r ? 5 - C 5 H 5 )W(NO) 2C1 + AgBF, > [ (775 —C 5 H 5 ) W (NO) 2]BF a . . . ( 2 . 5 ) [ (rj 5-C 5H 5)W(NO) 2]BF f l + L > [ ( 7? 5-C 5H 5 )W(NO) 2L]BF„ . . . ( 2 . 6 ) L=PPh 3, C 8H L F L, (r? 5-C 5H 5)W(NO) 2H The products i s o l a t e d from the r e a c t i o n s ( 2 . 1 ) — ( 2 . 6 ) are p a r t i c u l a r l y i n t e r e s t i n g s i n c e t h e i r chemical p r o p e r t i e s d i f f e r markedly from those d i s p l a y e d by t h e i r c a r b o n y l analogues (see Chapter 1, ( i v ) ) [ 4 5 , 5 4 - 5 6 ] . In a s i m i l a r v e i n , the s y n t h e s i s of [ (7? 5 —C 5H 5)W(NO)1 2 ] 2 by the treatment of (rj 5-C 5H 5)W(CO) 2 (NO) with i o d i n e was d e s c r i b e d [ 5 7 ] . T h i s i o d o n i t r o s y l complex l i k e i t s molybdenum congener, a l s o proved to be a u s e f u l p r e c u r s o r to a v a r i e t y of new o r g a n o m e t a l l i c species [ 4 3 , 5 7 - 6 1 ] e.g. [ ( T ? 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 + 2L > 2 ( T ? 5 - C 5 H 5 ) W ( N O ) ( L ) I 2 . . . ( 2 . 7 ) L=PPh 3, P(OPh) 3, SbPh 3 29 [ ( T ? 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 + S n ( C 3 H 5 ) A > 2(TJ 5-C 5H 5)W(NO) ( T J 5 - C 3 H 5 ) I ... (2.8) [ ( T J 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 + H" > [ (TJ 5-C 5H 5)W(NO) ( H ) l ] 2 ...(2.9) [ (TJ 5-C 5H 5)W(NO) ( H ) l ] 2 + 2P(OPh) 3 > 2(T? 5-C 5H 5)W(NO) {P(OPh) 3 } ( H ) I ... (2. 10) With a view towards extending t h i s l a t t e r chemistry to encompass the chromium—containing analogues, i t was decided to i n v e s t i g a t e the f e a s a b i l i t y of p r e p a r i n g the r e q u i s i t e p r e c u r s o r s by the r e a c t i o n s of halogens with ( T J 5 - C 5 R 5 )Cr (CO) (NO)L (R=H or Me, L=CO or PP h 3 ) . T h i s chapter presents the complete r e s u l t s of these s t u d i e s . In a d d i t i o n , the r e a c t i o n s of the r e c e n t l y s y n t h e s i s e d (rj 5-C 5Me 5 )M(CO) 2 (NO) (M=Mo, W) [62] with i o d i n e are d e s c r i b e d . ( i i ) R e s u l t s And D i s c u s s i o n (a) Reactions Of (T? 5—C SH 5 )Cr (CO), (NO) With Halogens The products r e s u l t i n g from the treatment of ( TJ5 — C 5 H 5 ) C r (CO) 2 (NO) with halogens do not resemble those produced by the congeneric molydenum and tungsten compounds. 30 The a d d i t i o n of halogens to the l a t t e r compounds in 1:1 s t o i c h i o m e t r y r e s u l t s i n the p r o d u c t i o n o f the halogen-bridged dimers, [ ( T J 5 - C 5 H 5 )M(NO)X 2 ] 2 (M=Mo, X=C1 [63], Br [63], I [58,63] ; M=W, X=I [57] ), which can be i s o l a t e d i n good y i e l d s , i . e . 2 ( TJ 5 — C 5 H 5 )M(CO) 2 (NO) + 2X 2 > [ ( T? 5 - C 5 H 5 )M(NO)X 2 ] 2 + 4CO ...(2.11) M=Mo or W; X=C1, Br, I. In c o n t r a s t , p r e v i o u s work in these l a b o r a t o r i e s has e s t a b l i s h e d that the r e a c t i o n of ( T J 5 - C 5 H 5 )Cr (CO) 2 (NO) with C l 2 a f f o r d s ( T? 5 - C 5 H 5 )Cr (NO) 2C1 as the only n i t r o s y l — c o n t a i n i n g product [64]. The s i m i l a r r e a c t i o n with bromine has been performed and found to r e s u l t i n the r a p i d formation of the analagous ( TJ 5 — C 5 H 5 )Cr (NO) 2 B r . In n e i t h e r case has s p e c t r o s c o p i c evidence been obtained f o r the formation of any intermediate c a r b o n y l — n i t r o s y l or n i t r o s y l complex. I n t e r e s t i n g l y , however, treatment of ( TJ 5 —C 5 H 5 ) C r (CO) 2 (NO) with i o d i n e i n a 2:1 molar r a t i o gives r i s e to the new dimeric complex, [ ( TJ 5—C 5H 5 )Cr (NO) I ] 2 , i n e x c e l l e n t y i e l d s , i . e . 31 2 (7 j 5 —C 5H 5 )Cr (CO) 2 (NO) + I 2 > [ (T? 5-C 5H 5 )Cr(NO)l ] 2 + 4CO ...(2.12) T h i s s t o i c h i o m e t r y of r e a c t a n t s i s e s s e n t i a l f o r the formation of the d i m e r i c product i n optimum y i e l d s s i n c e the dimer r e a c t s f u r t h e r with excess I 2 to y i e l d ( r j 5 — C 5 H 5 ) C r (NO) 21 as the u l t i m a t e n i t r o s y l — c o n t a i n i n g s p e c i e s . A more d e t a i l e d a n a l y s i s of these t r a n s f o r m a t i o n s can be e f f e c t e d by c a r e f u l m o nitoring of t h e i r progress by IR spectroscopy. Thus, upon the a d d i t i o n of 0.5 e q u i v a l e n t s of s o l i d i o d i n e to a CH 2C1 2 s o l u t i o n c o n t a i n i n g 1 e q u i v a l e n t of ( r j 5 - C 5 H 5 )Cr (CO) 2 (NO) , the c h a r a c t e r i s t i c a b s o r p t i o n s of the o r g a n o m e t a l l i c r e a c t a n t ( i . e . J>(CO) = 2020, 1945 cm" 1; v(NO)=1680cm"1) disappear r a p i d l y , and three new absorbances appear i n the c a r b o n y l — n i t r o s y l r e g i o n of the spectrum ( i . e . *>(CO)=2096cm" 1 ; »>(NO) = 1706, 1673 cm" 1). The c a r b o n y l and higher energy n i t r o s y l a b s o r p t i o n s then g r a d u a l l y d i m i n i s h i n i n t e n s i t y , u n t i l a f t e r 10 mins only the 1673 cm - 1 band due to [ ( T J 5 - C 5 H 5 )Cr (NO)I ] 2 remains. A l t e r n a t i v e l y , i f an excess of I 2 i s added to the o r i g i n a l d i c a r b o n y l n i t r o s y l r e a c t a n t , the i n i t i a l IR s p e c t r a l changes are as d e s c r i b e d i n the preceding paragraph f o r the s t o i c h i o m e t r i c r e a c t i o n . However, a new n i t r o s y l a b s o r p t i o n at 1745 cm - 1 appears before the bands at 2096 and 1706 cm - 1 have completely vanished, and i t a t t a i n s maximum i n t e n s i t y a f t e r ^2hrs. Concomitantly a b s o r p t i o n s at 1817 and 32 1713 cm'1 ( d i a g n o s t i c of ( T J 5 - C 5 H 5 )Cr (NO) 21) appear and slowly i n c r e a s e i n i n t e n s i t y at the expense of the bands at 1745 and 1673 cm" 1. A f t e r I8hrs, t h i s i o d o d i n i t r o s y l complex i s the only n i t r o s y l — c o n t a i n i n g s p e c i e s d e t e c t a b l e i n s o l u t i o n . To account f o r these observed s p e c t r a l changes the r e a c t i o n sequence presented i n Scheme 2.1 i s proposed. Scheme 2.1 +I 2r -2C0 2(r? 5-C 5H 5)Cr(CO) 2(NO) > 2 (TJ 5 — C 5 H 5 )Cr (CO) (NO) I (A) ( T j 5 - C 5 H 5 ) C r ( N O ) 2 I y(N0)=l8l7, 1713 cm"1 33 I t seems l i k e l y that C l 2 and B r 2 react with ( T J 5 - C 5 H 5 )Cr (CO) 2 (NO) i n an analogous manner to produce ( T J 5 - C 5 H 5 )Cr (NO) 2X (X=C1 or Br) u l t i m a t e l y , but s p e c t r o s c o p i c evidence to support t h i s h y p o t h e s i s i s p r e s e n t l y l a c k i n g . N e v e r t h e l e s s , i t may be noted t h a t [ ( T J 5 - C 5 H 5 )Cr (NO)Cl ] 2 , one of the intermediate complexes i n the sequence of r e a c t i o n s i n v o l v i n g C l 2 , has been p r e v i o u s l y prepared by a d i f f e r e n t s y n t h e t i c route [64]. In s o l u t i o n , even i n the absence of excess C l 2 , t h i s complex decomposes over a p e r i o d of =48hrs to ( T J 5 — C 5 H 5 )Cr (NO) 2C1 [65] . A s i m i l a r decomposition mode i s a l s o d i s p l a y e d by the i s o l a b l e i o d o — i n t e r m e d i a t e , [ ( i 7 5 - C 5 H 5 ) C r ( N O ) l ] 2 . In CH 2C1 2 or THF, i t e v e n t u a l l y c o n v e r t s t o (TJ 5—C 5H 5 )Cr (NO) 2 I but at a r a t e s u b s t a n t i a l l y slower than i n the presence of excess I 2 . Again, the P(NO) band at 1745 cm"1 which i s a t t r i b u t e d to the [ ( TJ 5— C 5 H 5 )Cr (NO) 1 2 ] 2 s p e c i e s can be d e t e c t e d , a l b e i t at much reduced i n t e n s i t y , d u r i n g the course of the decomposition. The l a b i l i t y of the c a r b o n y l l i g a n d i n the proposed i n t e r m e d i a t e formed i n r e a c t i o n (A) of Scheme 2.1 i s not without precedent, having been r e p o r t e d f o r many c a r b o n y l n i t r o s y l d e r i v a t i v e s [57,64,66,67]. A l s o , the c h l o r o analogue of t h i s i n t e r mediate has been p r e v i o u s l y invoked (although not s p e c t r o s c o p i c a l l y detected) to account f o r the formation i n low y i e l d of [ ( T J 5 - C 5 H 5 )Cr (N0)C1 ] 2 as one of the products o b t a i n a b l e by the treatment of [ ( T J 5 - C 5 H 5 )Cr (CO) 3 ] 2 34 with n i t r o s y l c h l o r i d e [64] i.e.. [ ( T ? 5 - C 5 H 5 ) C r ( C O ) 3 ] 2 + 2N0C1 > [ ( 77 5 - C 5 H 5 ) C r ( C O ) ( N O ) C l ] 2 1 + 4C0 ...(2.13) [ (T? 5-C 5H 5)Cr(CO) (N0)C1] 2 1 > [ ( 7 j 5 - C 5 H 5 ) C r ( N O ) C l ] 2 + 2C0 ... (2.14) In a separate experiment, i t has been v e r i f i e d independently that r e a c t i o n (B) of Scheme 2.1 i s r e v e r s i b l e , the i o d o n i t r o s y l dimer being c l e a v e d by carbon monoxide. As expected, the product of t h i s c o n v e r s i o n e x h i b i t s the same s p e c t r a l p r o p e r t i e s as the o r g a n o m e t a l l i c product of r e a c t i o n (A). However, IR spectroscopy i n d i c a t e s t h at ( 7 j 5 — C 5 H 5 )Cr (CO) (NO) I i s only generated i n 10-20% y i e l d and that i t r a p i d l y d e c a r b o n y l a t e s i n the absence of the CO atmosphere. The novel b i s [ ( 7 j 5 — c y c l o p e n t a d i e n y l ) i o d o n i t r o s y l — chromium] complex i s a dark green s o l i d (mp 119°C dec) which i s f r e e l y s o l u b l e i n benzene, CH 2C1 2, and a l l o r g a n i c donor s o l v e n t s , l e s s s o l u b l e i n CHC1 3, and only very s p a r i n g l y 1 I n the absence of d e f i n i t i v e evidence, i t i s a matter of p r e f e r e n c e whether the c a r b o n y l h a l o n i t r o s y l i n t e r m e d i a t e s are formulated as the 17—electron monomers, ( 7 ? 5 —C 5H 5 )Cr (CO) (NO)X, or the 18-electron dimers, [ ( 7 j 5 - C 5 H 5 ) C r ( C O ) (NO)X] 2 35 s o l u b l e i n p a r a f f i n hydrocarbons. Although i t s s o l u t i o n s are a i r — s e n s i t i v e and (as d i s c u s s e d above) th e r m a l l y u n s t a b l e , the s o l i d i t s e l f i s s t a b l e i n a i r at ambient temperatures f o r s h o r t p e r i o d s of time and can be s t o r e d unchanged i n d e f i n i t e l y i n an i n e r t atmosphere. An IR spectrum of a f r e s h CH 2C1 2 s o l u t i o n of the complex e x h i b i t s a s i n g l e s t r o n g a b s o r p t i o n at 1673 cm"1 a t t r i b u t a b l e to a t e r m i n a l , l i n e a r n i t r o s y l l i g a n d [68], The compound i s best formulated as the iodo—bridged dimer ( e i t h e r c i s or t r a n s ) , e.g. s i n c e a monomeric f o r m u l a t i o n would leave the chromium- atom with three e l e c t r o n s l e s s than the favoured 18—electron c o n f i g u r a t i o n . The d i m e r i c nature of the complex i s a l s o suggested by i t s mass spectrum (Table 2.1) which d i s p l a y s peaks due to the parent ion (m/z=548) and other C r 2 — c o n t a i n i n g ions which together c o n t r i b u t e a s i g n i f i c a n t percentage of the t o t a l ion c u r r e n t . However, the g r e a t e r r e l a t i v e abundance of monometallic ions such as ( C 5 H 5 ) C r ( N O ) I + , ( C 5 H 5 ) C r I + and ( C 5 H 5 ) 2 C r + i n d i c a t e t h a t the dimer i s r e a d i l y c l e a v e d on v a p o u r i s a t i o n or e l e c t r o n 36 Table 2.1 Low—Resolution Mass S p e c t r a l Data For  [ ( 7 ? 5 - C B H s ) C r ( N O ) l ] 2 M/z R e l . I n t e n s i t y Assignment 548 7 ( C 5 H 5 ) 2 C r 2 ( N O ) 2 I 2 + 518 42 ( C 5 H 5 ) 2 C r 2 ( N O ) I 2 + 488 21 ( C 5 H 5 ) 2 C r 2 I 2 * 371 13 ( C 5 H 5 ) C r I 2 + 304 9 ( C 5 H 5 ) C r ( N O ) 2 I + 274 1 2 ( C 5 H 5 ) C r ( N O ) I + 244 67 ( C 5 H 5 ) C r I + 182 100 ( C 5 H 5 ) 2 C r + 1 17 96 ( C 5 H 5 ) C r + 52 73 Cr + Probe "Temp 1 50°C impact. I n t e r e s t i n g l y , however, the complex d i s p l a y s s i g n i f i c a n t paramagnetism, both i n the s o l i d s t a t e and i n s o l u t i o n (Table 2.2), a f e a t u r e which p r e c l u d e s the r o u t i n e measurement of i t s 1H- and 13C-NMR s p e c t r a . T h i s paramagnetism i n d i c a t e s t h a t the complex may not possess a c o n v e n t i o n a l 2—centre, 2 — e l e c t r o n Cr—Cr l i n k a g e . 37 Table 2.2 Magnetic S u s c e p t i b i l i t y Data Complex xm(corr)x10 3 cm 3 mol" 1 u ( e f f ) , BM [ C p C r ( N O ) C l ] 2 0.349±0.014 a 0 .9110. 02 (292K) [CpCr(NO)I] 2 0.329±0.006 b 0 .9010. 02 (305K) 1.5110.06 c 1 .9410. 03 (305K) CpCr(NO)(PPh 3)Cl 1 .38 c ,d 1 .86 CpCr(NO)(PPh 3)Br 1.3110.19 c 1 .8010. 13 (305K) CpCr(NO)(PPh 3)I 1.4410.10 c 1 .8910. 07 (305K) CpCr(NO)(P(OPh) 3}I 1.3610.09 c 1 .8410. 06 (305K) CpCr(NO){P(OEt) 3}l 1.2310.08 c 1 .7410. 06 (305K) a Measured by the Faraday Method; taken from Ref 69. b Measured on a Gouy Balance i n the s o l i d s t a t e , c Measured by Evans Method (see Ref. 70). d Taken from Ref. 71. A l t e r n a t i v e l y , the complex may d i s s o c i a t e i n t o monomeric fragments, i . e . [ (T? 5-C 5H 5)Cr(NO)I 32» * 2 ( 7 ? 5 - C 5 H 5 ) C r ( N O ) l ... (2. 15) a p r o c e s s which should be more f a c i l e i n s o l u t i o n . The former e x p l a n a t i o n seems more l i k e l y , s i n c e the monomeric fragments would be 1 5 — e l e c t r o n s p e c i e s and thus very 38 e l e c t r o n d e f i c i e n t ( v i d e s u p r a ) . A l s o , i t has been proposed, on the b a s i s of bond angles i n the C r 2 Y 2 u n i t , 1 that the i s o e l e c t r o n i c complex [ ( TJ 5—C 5H 5 )Cr (NO) (OMe) ] 2 does not c o n t a i n a metal—metal bond [72], Since i n the absence of a Cr—Cr l i n k a g e , a value of /x(eff)=2.83 BM would be expected, i t i s evident that some spin p a i r i n g must be o c c u r r i n g , p o s s i b l y through the h a l i d e b r i d g e s . In a d d i t i o n to the above—mentioned methoxide and c h l o r p analogues, there e x i s t s a f a i r l y l a r g e s e r i e s of [ ( T j 5 - C 5 H 5 ) C r ( N O ) Y ] 2 complexes (Y=NH2 [43], OEt [64], NMe2 [73], NO [36,74], SR [75,76], SeR [76] or TeR [76] ) i n which the Y groups b r i d g e two (TJ 5—C 5H 5 )Cr (NO) m o i e t i e s . Not s u r p r i s i n g l y , the i o d o n i t r o s y l dimer i s a s y n t h e t i c p r e c u r s o r to the other [ (TJ 5—C 5H 5)Cr (NO) Y] 2 s p e c i e s , e.g. [ ( T J 5 - C 5 H 5 )Cr (NO)I ] 2 + NaOR > [ (T J 5 — C 5 H 5 )Cr (NO) (OR) ] 2 + 2NaI ...(2.16) where R=Me, E t . While both complexes have been p r e v i o u s l y s y n t h e s i s e d from (T? s-C 5H s)Cr(NO) 2C1 [64,71], the methoxide has not been f u l l y c h a r a c t e r i s e d . I t s mass spectrum (Table 2.3) and i t s IR 1The bond angle argument i s that i f the Y—Cr—Y angle i s gr e a t e r than the Cr-Y-Cr angle, then the complex c o n t a i n s a Cr—Cr bond. I f the reverse r e l a t i o n s h i p between the angles p e r t a i n s , then there i s no formal Cr-Cr l i n k a g e [72]. spectrum (j>(NO) (CH 2C1 2) = 1661 cm" 1) have been obtained and Table 2.3 Low—Resolution Mass S p e c t r a l Data For  [ ( T ^ - C s H j C r t N O ) (OMe) ] a m/z Rel I n t e n s i t y Assignment 356 5 ( C 5 H 5 ) 2 C r 2 ( N O ) 2 ( O M e ) 2 + 326 36 ( C 5 H 5 ) 2 C r 2 ( N O ) ( O M e ) 2 + 296 52 ( C 5 H 5 ) 2 C r 2 ( O M e ) 2 + 281 20 ( C 5 H 5 ) 2 C r 2 ( O M e ) 0 + 266 10 ( C 5 H 5 ) 2 C r 2 0 2 + 251 10 ( C 5 H 5 ) 2 C r 2 O H + 182 100 ( C 5 H 5 ) 2 C r + 148 20 ( C 5 H 5 ) C r ( O M e ) + 1 1 7 20 ( C 5 H 5 ) C r + 52 49 Cr + Probe Temp ~160°C are as expected. Reaction (D) of Scheme 2.1 a l s o has precedence i n the 40 l i t e r a t u r e , the congeneric molybdenum complex, [ (17 5—C5H5 )Mo(NO) I ] 2 , having been repo r t e d to r e a c t r e a d i l y with i o d i n e to a f f o r d [ ( TJ 5 — C 5 H 5 )Mo(NO) 1 2 ] 2 . The s h i f t i n the n i t r o s y l — s t r e t c h i n g frequency accompanying r e a c t i o n (D) ( i . e . +72 cm" 1) i s comparable to that observed f o r the molybdenum system, namely +87 cm"1 (1573 -> 1660 cm" 1) [60]. The decomposition of the iodo—dimer e i t h e r i n the presence or absence of excess i o d i n e i n v o l v e s the t r a n s f e r of n i t r o s y l groups between the two Cr atoms. I n t e r m o l e c u l a r t r a n s f e r of a metal—bound n i t r o s y l l i g a n d has been proposed to occur v i a formation of an intermediate M(/x—NO)M' l i n k a g e [77,78], although recent k i n e t i c evidence suggests that n i t r o g e n monoxide d i s s o c i a t i o n f o l l o w e d by a s s o c i a t i o n i s the p r e f e r r e d mechanism [79]. Although the presence of f r e e NO has not been d e t e c t e d , i t i s proposed that the f i r s t s tep i n r e a c t i o n (E) i s the slow d i s s o c i a t i o n of NO i . e . [ ( r ? 5 - C 5 H 5 ) C r ( N O ) l 2 ] 2 > [ ( T J 5-C 5H 5 )CrI 2 ] 2 + 2NO ...(2.17) f o l l o w e d by r a p i d r e a c t i o n of the l i b e r a t e d n i t r o g e n monoxide with any of the three d i m e r i c s p e c i e s [ ( r j 5 - C 5 H 5 ) C r ( N O ) l 2 ] 2 , [ (77 s — C 5 H 5 )Cr (NO) I ] 2 or [ ( T J 5 —C 5 H 5 )CrI 2 ] 2 . I t has been independently demonstrated that [ ( T ? 5 - C 5 H 5 ) C r ( N O ) l ] 2 i s smoothly converted to ( T J 5 — C 5 H 5 ) C r (NO) 21 r i n v i r t u a l l y q u a n t i t a t i v e y i e l d s , by the a c t i o n of NO gas. S i m i l a r r e a c t i o n s have been r e p o r t e d f o r 41 the analogous [ (?7 5-C 5H 5 ) C r C l 2 ] 2 [64], [ ( 7? 5-C 5H 5 )Cr (NO)Cl ] 2 [64] and [ (T? 5-C 5H 5 )W(NO)1 2 ] 2 [57] complexes. (b) Reactions Of ( g 5 - C 5 H 5 ) C r ( C O ) ( N O ) ( P P h 3 ) With Halogens The r e a c t i o n s of ( T J 5 - C 5 H 5 )Cr (CO) (NO) (PPh 3) with halogens are simpler than those of ( T J 5 - C 5 H 5 )Cr (CO) 2 (NO) (Scheme 2.1). Indeed, only the t r a n s f o r m a t i o n s analogous to r e a c t i o n (A) of the scheme occur i n good y i e l d s when the phosphine—containing r e a c t a n t i s t r e a t e d with c h l o r i n e , bromine or i o d i n e , i . e . 2 ( T ? 5 - C 5 H 5 )Cr (CO) (NO) (PPh 3 ) + X 2 > 2 ( T ? 5 - C 5 H 5 )Cr (NO) (PPh 3 )X + 2CO ...(2.18) where X=C1, Br or I, a f e a t u r e which r e f l e c t s the i n e r t n e s s of the t r i p h e n y l p h o s p h i n e l i g a n d i n the product complexes. For the case when X=I, such complexes may a l s o be o b t a i n e d by cleavage of the i o d i n e b r i d g e s i n [ ( r j 5 — C 5 H 5 )Cr (NO) I ] 2 with a Lewis base, L, i . e . [ ( 7 j 5 - C 5 H 5 ) C r ( N O ) l ] 2 + 2L > 2 ( TJ 5—C 5H 5 )Cr (NO) (L) I ...(2.19) where L=PPh 3, P(OPh) 3 or P ( O E t ) 3 42 co n v e r s i o n s which are analogous to the reverse of r e a c t i o n (B) i n Scheme 2.1. Of the monomeric complexes produced i n r e a c t i o n s (2.18) and (2.19), only the c h l o r o d e r i v a t i v e , ( T J 5 - C 5 H 5 )Cr(NO) (PPh 3 )C1, has been r e p o r t e d p r e v i o u s l y , having been i s o l a t e d i n low y i e l d from the r e a c t i o n of (r? 5-C 5H 5)Cr(NO) 2C1 with PPh 3 [71]. ( T J 5 - C 5 H 5 )Cr (NO) 2C1 + PPh 3 > ( T J 5 - C 5 H 5 )Cr (NO) (PPh 3 ) C l + NO ...(2.20) Reactions (2.18) and (2.19), as a p p r o p r i a t e , are thus the p r e p a r a t i v e methods of c h o i c e f o r these o r g a n o m e t a l l i c compounds. The (TJ5 — C 5 H 5 ) C r (NO) (L)X s p e c i e s are green, f a i r l y a i r — s t a b l e m i c r o c r y s t a l l i n e s o l i d s . T h e i r s o l u b i l i t i e s depend on the nature of L and X. Thus, when L=PPh 3, the s o l u b i l i t i e s vary i n the order X=Cl>Br>I, ' ( TJ5 — C 5 H 5 ) C r (NO) (PPh 3) I being only moderately s o l u b l e i n ,CH 2C1 2, l e s s so i n CHC1 3 and organic donor s o l v e n t s , and v i r t u a l l y i n s o l u b l e i n p a r a f f i n hydrocarbons. For X=I, the s o l u b i l i t i e s i n the above s o l v e n t s d i m i n i s h as L = P ( O E t ) 3 » P ( O P h ) 3 > P P h 3 , the t r i e t h y l p h o s p h i t e complex being very s o l u b l e i n a l l organic s o l v e n t s i n c l u d i n g hexanes. A l l these complexes are paramagnetic, having molar magnetic s u s c e p t i b i l i t i e s and permanent moments (jz( e f f ) ) i n d i c a t i v e of one unpaired e l e c t r o n (Table 2.2). Toluene 43 s o l u t i o n s of the complexes at ambient temperature e x h i b i t EPR' s p e c t r a which c o n s i s t of a simple two—line p a t t e r n except f o r (T? 5—C 5H s)Cr (NO) (PPh 3 ) C l which shows a s i x - l i n e p a t t e r n with approximately equal i n t e n s i t i e s (Table 2.4 and F i g u r e 2.1). The tw o — l i n e p a t t e r n s a r i s e from the h y p e r f i n e s p l i t t i n g of the s i g n a l due to i n t e r a c t i o n of the odd e l e c t r o n with the 3 1P(I=0.5) nucleus i n each molecule, whereas the s i x — l i n e p a t t e r n (a doublet of t r i p l e t s ) r e s u l t s from c o u p l i n g to both the 3 1 P and i a N ( I = l ) n u c l e i . Coupling c o n s t a n t s to 3 1 P are i n the range 20—33 G while the observed c o u p l i n g constant to 1"N i s 4.6 G. The (T7 5-C 5H 5 )Cr (NO) (L)X complexes are r e l a t i v e l y i n v o l a t i l e , but t h e i r mass s p e c t r a can be obtained at e l e v a t e d temperatures. These .spectra (Tables 2.5 and 2.6) d i s p l a y peaks due to the parent ions and ions r e s u l t i n g from the s u c c e s s i v e l o s s of l i g a n d s or ion—molecule r e a c t i o n s 1 . The IR s p e c t r a of these compounds (see Table 2.7) d i s p l a y s i n g l e , sharp n i t r o s y l — s t r e t c h i n g . a b s o r p t i o n s i n the range 1660-1690 cm'1 which are 20-40 cm"1 lower than that e x h i b i t e d by ( TJ 5—C 5H 5 )Cr (CO) (NO) I. The decrease i n p(NO) as L v a r i e s i n the order CO>P(OPh) 3>P(OEt) 3>PPh 3 i s c o n s i s t e n t with the documented e l e c t r o n — d o n a t i n g and — a c c e p t i n g 1 Due to e x c e s s i v e fragmentation of the t r i e t h y l phosphite l i g a n d , the l o w — r e s o l u t i o n mass spectrum of (T? 5—C 5H 5 )Cr (NO) {P(OEt) 3} I cannot be a s s i g n e d with c e r t a i n t y . 44 Table 2.4 E l e c t r o n Paramagnetic Resonance Data Complex g ( i s o ) a< 3 1P>,G CpCr (NO) (PPI13 )C1 1.994 a 20.4 CpCr(NO)(PPh 3)Br 2.014 24 CpCr(NO)(PPh 3)I 2.046 24.5 CpCr(NO)(P(OPh) 3}I 2.006 29 CpCr(NO)(P(OEt) 3}I 2.052 32.5 a a<1"N>=4.6G p r o p e r t i e s of these l i g a n d s [80]. I n t e r e s t i n g l y , the J>(NO) value s of the 17—electron chromium s p e c i e s occur at c o n s i d e r a b l y lower f r e q u e n c i e s than those of the analogous 18—electron manganese compounds (see Table 2.7) [67]. A s i m i l a r phenomenon has r e c e n t l y been r e p o r t e d f o r the r e l a t e d [ (rj 5 —C 5 H 5 ) M (NO) (L—L) ] + (M=Cr or Mn) c a t i o n s [81 ]. The p h y s i c a l p r o p e r t i e s of the (77 5-C 5H 5 )Cr (NO)LX compounds d e s c r i b e d above are c o n s i s t e n t with the complexes p o s s e s s i n g the f a m i l i a r "three—legged piano s t o o l " molecular s t r u c t u r e , i . e . 45 F i g u r e 2^ E l e c t r o n P a r a m a j ^ ^ Of D i l u t e Toluene S o l u t i o n s Of (a) ( ^ I ^ J ^ ^ ^ M. ( ^ 5 - C H c ) C r ( N O ) ( P P h 1 ) T , Table 2.5 Low—Resolution Mass S p e c t r a l Data For ( T ? 5 - C 5 H 5 )Cr(NO) (PPh 3)X (X=Cl,Br ,1) 46 m/z ( R e l . I n t e n s i t y ) Assignment X=C1 a X=Br b X=I c (C 5H 5)Cr(NO)LX + 444( <1) 488( 1) 536( 5) ( C 5 H 5 ) C r L X + 41 4 ( 3) 458( 8) 506( 21) ( C 5 H 5 ) C r ( N O ) L + 409( 2) 409( 1) — — ( C 5 H 5 ) C r L + 379( 2) 379( 2) 379( 2) ( C 5 H 5 ) 2 C r 2 ( N O ) 2 X 2 + 364( <1) 452( <1) 548( 2) ( C 5 H 5 ) 2 C r 2 ( N O ) X 2 + 334( 5) 422( 3) 51 8 ( 3) ( C 5 H 5 ) 2 C r 2 X 2 * 304( 6) 392( 2) 488( 4) PPh 3 + 262(100) 262(100) 262(100) ( C 5 H 5 ) 2 C r + 182 1 82 ( 25) 1 82 ( 66) (26)d ( C 5H 5)Cr(NO)X + 182 226( <1 ) 274( 3) ( C 5 H 5 ) C r X + 1 52( 16) 1 96 ( 10) 244( 14) ( C 5 H 5 ) C r + 1 17( 10) 1 17( 16) 1 17( 28) Cr + 52( 16) 52( 18) 52( 28) a Probe Temp =*170°C b Probe Temp =180°C c Probe Temp =250°C d Assignment I n d i s t i n g u i s h a b l e at Low—Resolution Table 2.6 Low—Resolution Mass S p e c t r a l Data For  U 5 - C 5 H 5 ) C r ( N O ) ( P ( O P h ) 3 } l . m/z Rel I n t e n s i t y Assignment 584 <1 ( C 5 H 5 ) C r ( N O ) { P ( O P h ) 3 } l + 554 1 ( C 5 H 5 ) C r { P ( O P h ) 3 } l + 548 1 ( C 5 H 5 ) 2 C r 2 ( N O ) 2 I 2 + 518 10 ( C 5 H 5 ) 2 C r 2 ( N O ) l 2 + 488 6 ( C 5 H 5 ) 2 C r 2 I 2 * 427 <1 ( C 5 H 5 ) C r { P ( O P h ) 3 } + 310 100 P ( O P h ) 3 + 274 4 ( C 5 H 5 ) C r ( N O ) I + 244 23 ( C 5 H 5 ) C r I + 182 31 ( C 5 H 5 ) 2 C r + 1 1.7 35 ( C 5 H 5 ) C r + 52 23 Cr + Probe Temp =*200°C Table 2.7 A Comparison Of The N i t r o s y 1 - S t r e t c h i n g  F requencies Of The New (T? 5-C 5H 5 )Cr (NO)LX With The Analogous  1 8 — e l e c t r o n Manganese Complexes. Complex v(NO) ( C H 2 C 1 2 ) , cm"1 M=Cr M=Mn a CpM(CO)(NO)I CpM(NO)(PPh 3)C1 CpM(NO)(PPh 3)Br CpM(NO)(PPh 3)I CpM(NO)(P(OPh) 3}I CpM(NO)(P(OEt) 3}I 1706 1664 1 664 1666 1686 1670 1776 1720 1748 a Taken from Ref. 67. 49 I x o even though they are f o r m a l l y i s o e l e c t r o n i c with the c a r b o n y l complexes [ (7? 5-C 5H 5 )Cr (CO) 2 L ] 2 (L=CO [82], PPh 3 [83] or P(OMe) 3 [84]) which are diamagnetic. I t must be noted, however, t h a t the Cr—Cr l i n k a g e s i n the c a r b o n y l dimers are not p a r t i c u l a r l y s t r o n g [82,84]. Thus, the s o l i d s t a t e molecular s t r u c t u r e of [ ( T? 5—C 5H 5 )Cr (CO) 3 ] 2 c o n t a i n s a very long Cr-Cr bond (3.281A) d e s p i t e the presence of the l e s s s t e r i c a l l y demanding CO l i g a n d s [82]. Moreover, upon v a p o u r i s a t i o n or d i s s o l u t i o n the dimer undergoes some d i s s o c i a t i o n i n t o paramagnetic monomers, [82,85] i . e . [ (r? 5-C 5H B )Cr(CO) 3 ] 2 ^ 1 2 (T? 5-C 5H 5 )Cr (CO) 3 ... (2.21 ) (c) Reactions Of (7? 5-C yMe; )M(CO) , (NO) (M=Cr ,Mo Or W)_ With  Halogens Due to i t s i n c r e a s e d b a s i c i t y and s t e r i c requirements, the p e n t a m e t h y l c y c l o p e n t a d i e n y l l i g a n d has been employed s u c c e s s f u l l y i n recent years to prepare s t a b l e analogues of 50 un s t a b l e or t r a n s i e n t c y c l o p e n t a d i e n y l — t r a n s i t i o n — m e t a l complexes [86]. The r e a c t i v i t y of the (7 j 5-C 5Me 5 )M(CO) 2 (NO) (M=Cr, Mo or W) compounds towards halogens was t h e r e f o r e i n v e s t i g a t e d with a view to i s o l a t i n g C 5Me 5 analogues of v a r i o u s i n t e r m e d i a t e s p e c i e s formed d u r i n g the analogous r e a c t i o n s of the c y c l o p e n t a d i e n y l r e a c t a n t s . S p e c i f i c a l l y , i t was hoped to o b t a i n (7j 5 —C 5Me 5 )Cr (CO) (NO) I (cf Scheme 2.1) and (r? 5-C 5Me 5 )M(CO) (NO)1 2 (M=Mo, W), C 5H 5 analogues of the l a t t e r complexes having been proposed f o r both M=Mo [58] and W [57]. U n f o r t u n a t e l y , while a l l three complexes were d e t e c t e d as i n t e r m e d i a t e s , they c o u l d not be i s o l a t e d from the r e a c t i o n mixture. The only n i t r o s y l — c o n t a i n i n g compound i s o l a b l e a f t e r treatment of (175 —C 5 Me 5 ) C r (CO) 2 (NO) with I 2 i n CH 2C1 2 i s ( 7 j 5 —C 5Me 5 )Cr (NO) 21 even i f the s t o i c h i o m e t r y of the r e a c t a n t s i s c a r e f u l l y c o n t r o l l e d at 2:1 ( c f . eq. 2.12) i . e . 2 (7j 5—C 5Me 5) Cr (CO) 2 (NO) + I 2 > ( TJ 5—C 5Me 5) Cr (NO) 21 ...(2.22) During the course of the t r a n s f o r m a t i o n , however, C 5Me 5 analogues of a l l the in t e r m e d i a t e s proposed f o r the C 5 H 5 r e a c t a n t (Scheme 2.1) are d e t e c t a b l e i n s o l u t i o n by IR spectroscopy ( F i g u r e 2.2), but they c o u l d not be i s o l a t e d by c o n v e n t i o n a l t e c h n i q u e s . In t h i s system, at l e a s t , the 51 F i g u r e 2.2 I n f r a - r e d S p e c t r a l Changes Accompanying The  Reaction Of (7? 5-C 5Me 5 )Cr (CO) 2 (NO) With 0.5 E q u i v a l e n t s Of 1 2 . Assignments Of Absorpt ions ; A, (7? 5-C 5Me 5 )Cr (CO) 2 (NO); Bj_ (y5-CsMes )Cr (CO) (NO)I ; Cj_ [ (77 5-C sMe „ )Cr (NO) I ] 2 ; Dj_ [ (T? 5~C 5Me;,)Cr(NO)I 2] 2; E^ (7? 5-C 5Me 5 )Cr (NO) 2 I . 2 0 0 0 1800 1600 cm - 1 52 presence of the pen t a m e t h y l c y c l o p e n t a d i e n y l l i g a n d does not seem to impart any enhanced s t a b i l i t y to the int e r m e d i a t e complexes. Upon c l o s e r i n s p e c t i o n of F i g u r e 2.2 i t i s n o t i c a b l e t hat the f i r s t step of the r e a c t i o n sequence, consumption of the d i c a r b o n y l n i t r o s y l r e a c t a n t , i s s i g n i f i c a n t l y slower f o r the C 5Me 5 d e r i v a t i v e . The consequence of t h i s f e a t u r e i s that any [ (TJ 5—C 5Me 5 )Cr (NO)I ] 2present d u r i n g the f i r s t h a l f — h o u r of the r e a c t i o n w i l l r e a c t with the i o d i n e to produce [ ( r j 5 — C 5Me 5 )Cr (NO) I 2 ] 2 • Thus the c o n c e n t r a t i o n of [ ( TJ 5—C 5Me 5 )Cr (NO) I ] 2 only b u i l d s up to a maximum a f t e r 30 mins when a l l the i o d i n e has been consumed. In an attempt to t r a p the monoiodide dimer, P(OPh) 3 was added to the r e a c t i o n mixture. U n f o r t u n a t e l y , the ( TJ 5—C 5Me 5 )Cr (NO) {P (OPh) 3 } I complex produced c o u l d not be separated from the (77 s—C 5Me 5 )Cr (NO) 2 I present i n the r e a c t i o n mixture. F i n a l l y , the r e a c t i o n of (TJ 5—C 5Me 5 )Cr (CO) 2 (NO) with B r 2 was c a r r i e d out. In t h i s case, a d d i t i o n of j u s t enough B r 2 to consume the o r i g i n a l o r g a n o m e t a l l i c r e a c t a n t r e s u l t s i n a mixture of [ (T? 5-C 5Me 5 )Cr (NO)Br 2 ] 2 and (175—C 5Me 5) Cr (NO) 2 Br. An unusual f e a t u r e of t h i s c o n v e r s i o n i s that the dihalodimer does not convert to the d i n i t r o s y l s p e c i e s upon prolonged s t i r r i n g . I t i s however, smoothly, transformed i n t o (T? 5—C 5H 5 )Cr(NO) 2 B r by the a c t i o n of NO gas. The new h a l o d i n i t r o s y l ( TJ 5— p e n t a m e t h y l c y c l o -p e n t a d i e n y l )chromium complexes, are golden—brown, a i r — s t a b l e 53 s o l i d s which are s o l u b l e i n a l l organic s o l v e n t s . T h e i r s p e c t r o s c o p i c p r o p e r t i e s (Tables 2.8 and 2.9) are s i m i l a r to those d i s p l a y e d by t h e i r c y c l o p e n t a d i e n y l analogues [ 4 9 , 8 7 ] , The r e a c t i v i t y of both (7 j 5-C 5Me 5 )M(CO) 2 (NO) (M=Mo or W) complexes i s i d e n t i c a l to that r e p o r t e d p r e v i o u s l y f o r t h e i r c y c l o p e n t a d i e n y l analogues [ 5 7 , 5 8 ] , namely ( T? 5—C 5R 5 )M(CO) 2 (NO) + I 2 > ( T J 5 - C 5 R 5 ) M ( C O ) ( N O ) l 2 + C 0 .. . ( 2 . 2 3 ) f o l l o w e d by 2 (r? 5-C 5R 5)M(CO) ( N 0 ) I 2 > [ ( TJ 5 — C 5 R 5 )M(NO) I 2 ] 2 + 2CO ... ( 2 . 2 4 ) M=Mo or W; R=H or Me. The only d i f f e r e n c e i s that d u r i n g these s e q u e n t i a l c o n v e r s i o n s the C 5Me 5 l i g a n d does have a s l i g h t s t a b i l i s i n g e f f e c t on the c a r b o n y l d i i o d o n i t r o s y l i n t e r m e d i a t e s . Thus, f o r M=Mo, complete d e c a r b o n y l a t i o n of the inte r m e d i a t e U ( C O ) = 2 0 8 0 cm" 1, v(NO)=1694 cm"1 i n C H 2 C 1 2 ) r e q u i r e s 1 hr at ambient temperature when R=CH 3, whereas when R=H no such intermediate can be de t e c t e d s p e c t r o s c o p i c a l l y [ 5 8 ] . The most t h e r m a l l y s t a b l e of a l l the intermediate complexes, (T? 5-C 5Me 5)W(CO) ( N 0 ) I 2 [ I R ( C H 2 C 1 2 ) : v(CO) 2072 cm - 1, z>(NO) 1676 cm" 1], r e q u i r e s 2-3 hrs under moderate 54 Table 2.8 IR And 1H-NMR S p e c t r a l Data For The New  Pentameth y l c y c l o p e n t a d i e n y l Complexes. Complex IR v(NO),cnr 1 ( i n C H 2 C 1 2 ) 1H-NMR 6 ( i n C D C 1 3 ) Cp"Cr(NO) 2Br 1784,1685 1 .82(s) Cp"Cr(NO) 2I 1784,1687 1 .91(s) Cp"Cr(NO){P(OPh) 3}I 1658 [Cp"Mo(NO)l 2] 2 1660 2 .05(s) Cp"Mo(NO)(PPh 3)l 2 1658 1 .99(s,15H,CH 3) 7 .36(m,15H,C 6H 5 ) Cp"Mo(NO){P(OPh) 3}I 2 1662 2 .05(s,15H,CH 3) 7 .07(m,15H,C 6H 5 ) [Cp"W(NO)l 2] 2 1629 2 .18(S) Cp"W(NO)(PPh 3)I 2 1628 2 .17(s,15H,CH 3) 7 .38(m,15H,C 6H 5 ) Cp"W(NO) {P(OPh) 3.}I 2 1640 2 .18(S,3H,CH 3) 2 .34(s,12H,CH 3) 7 .21(m,15H,C 6H 5 ) 55 Table 2.9 13C-NMR S p e c t r a l Data For The New Pe n t a m e t h y l c y c l o p e n t a d i e n y l Complexes Complex 6 i n CDC1 3 Cp"Cr(NO) 2Br 1 1 2.2(C-CH 3) 9.7(CH 3) [Cp"Mo(NO)I 2]2 1 18.6(C-CH 3) 13.2(CH 3) Cp"Mo(NO){P(OPh) 3}I 2 151.5(d,J( 3 1P- 1 3C)=15.3Hz;C 1) 129.5(C 3) 125.5(C„(maj isomer)) 124.2(C 4(min isomer)) 121.4(d,J( 3 1P-' 3C)=6.6Hz; C 2(maj isomer)) 120.6(d,J( 3 1P- 1 3C)=6.7Hz; C 2(min isomer)) 115.8(C-CH 3) 13.l(CH 3(min isomer)) 12.2(CH 3(maj isomer)) [Cp"W(NO)l 2] 2 117.5(C-CH 3) 12.8(CH 3) Cp"W(NO) {P(OPh) 3-}l 2 .151.5(d,J( 3 1P- 1 3C)=15.2HZ;C 1) 129.5(C 3) 125.5(C 4(maj isomer)) 124.2(C«(min isomer)) 121.4(d,J( 3 1P- 1 3C)=3.6Hz; C 2(maj isomer)) 120.6(d,J( 3 1P- 1 3C)=7.2Hz; C 2(min isomer)) 112.4(C-CH 3) 12.8(CH 3(min isomer)) 12.l(CH 3(maj isomer)) 56 vacuum at 25°C to remove completely the CO group, but i t again cannot be i s o l a t e d i n a pure s t a t e , even when handled in an atmosphere of carbon monoxide. The products of r e a c t i o n (2.24), i . e . [ (Tj 5-C 5Me 5)M(NO)I 2] 2 (M=Mo or W) , are pur p l e (M=Mo) or green—brown (M=W) diamagnetic s o l i d s which d i s s o l v e r e a d i l y in a l l o r g a n i c s o l v e n t s except a l i p h a t i c hydrocarbons. They are best formulated as having i o d o — b r i d g e d , dimeric molecular s t r u c t u r e s in order to provide each metal c e n t r e with the favoured 18—electron c o n f i g u r a t i o n . T h e i r p h y s i c a l p r o p e r t i e s (see Tables 2.8 and 2.9) are q u i t e s i m i l a r to those d i s p l a y e d by t h e i r C 5 H S analogues [57,58], although (as expected) t h e i r c h a r a c t e r i s t i c n i t r o s y l — s t r e t c h i n g f r e q u e n c i e s are 20—30 cm - 1 lower i n energy. J u s t as f o r the c y c l o p e n t a d i e n y l s p e c i e s , the i o d i n e b r i d g e s i n the dimers may be c l e a v e d by Lewis bases such as t r i p h e n y l p h o s p h i n e or t r i p h e n y l p h o s p h i t e , i . e . 57 [ ( 7 ? 5 - C 5 M e 5 ) M ( N O ) l 2 ] 2 + 2L > 2(T? 5-C 5Me 5 )M(NO) (L)I 2 . . . (2.25) M=Mo or W; L=PPh 3 or P(OPh) 3 to o b t a i n i n good y i e l d s the monomeric complexes (r? 5-C 5Me 5 )M(NO) ( L ) 1 2 (M=Mo or W; L=PPh 3 or P ( O P h ) 3 ) . The p h y s i c a l p r o p e r t i e s of these new complexes are given i n Tables 2.8 and 2.9. The only s i g n i f i c a n t f e a t u r e i s that f o r the t r i p h e n y l p h o s p h i t e complexes both isomers ( c i s and tr a n s ) are d e t e c t a b l e by 1H- and 13C-NMR. Th i s a t t r i b u t e has a l s o been d e t e c t e d f o r the complex (rj 5-C 5H 5)Mo(NO){P(OPh) 3}I 2 [58] but was not found f o r the analogous tungsten d e r i v a t i v e ( r j 5 — C 5 H 5 )W(NO) {P(OPh) 3} 1 2 [57]. cis trans 58 ( i i i ) Experimental S e c t i o n General Procedures A l l manipulations were performed so as to maintain a l l chemicals under an atmosphere of p r e p u r i f i e d n i t r o g e n e i t h e r on the bench using c o n v e n t i o n a l techniques f o r the manip u l a t i o n of a i r — s e n s i t i v e compounds [88] or i n a Vacuum Atmospheres Corp. D r i - L a b Model HE-43-2 drybox. A l l chemicals used were of reagent grade or comparable p u r i t y . Reagents were e i t h e r purchased from commercial s u p p l i e r s or prepared a c c o r d i n g to p u b l i s h e d procedures, and t h e i r p u r i t y was a s c e r t a i n e d by elemental analyses and/or m e l t i n g p o i n t d e t e r m i n a t i o n s . M e l t i n g p o i n t s were taken i n c a p i l l a r i e s by using a Gallenkamp M e l t i n g P o i n t apparatus and are u n c o r r e c t e d . A l l s o l v e n t s were d r i e d by standard procedures [89], d i s t i l l e d j u s t p r i o r to use and purged f o r 15—20 mins with n i t r o g e n . Unless s p e c i f i e d otherwise, the chemical r e a c t i o n s d e s c r i b e d were e f f e c t e d at ambient temperatures. I n f r a r e d S p e c t r a . I n f r a r e d s p e c t r a were recorded on Perkin—Elmer 457 or 598 spectrophotometers and were c a l i b r a t e d with the 1601cm - 1 band of p o l y s t y r e n e f i l m . Nuclear Magnetic Resonance S p e c t r a . Proton magnetic resonance s p e c t r a were obtained on V a r i a n A s s o c i a t e s T—60 or 59 EM-360 spectrometers with t e t r a m e t h y l s i l a n e (Me„Si) employed as an i n t e r n a l standard or on Bruker WP—80 or WH-400 spectrometers, with r e f e r e n c e to the s o l v e n t used. Proton decoupled Carbon—13 NMR s p e c t r a were recorded on a V a r i a n A s s o c i a t e s CFT-20 or on the Bruker WP-80 spectrometer with r e f e r e n c e to the sol v e n t used. A l l }H and 1 3 C chemical s h i f t s are repor t e d i n ppm down f i e l d from Me^Si. For low temperature measurements the Bruker WP-80 was equipped with a Bruker B-VT-1000 v a r i a b l e temperature probe. Dr. S. 0. Chan and Mrs. M. M. Tracey a s s i s t e d i n o b t a i n i n g these data. Mass S p e c t r a . Low—resolution mass s p e c t r a were recorded at 70eV on an A t l a s CH4B spectrometer using the d i r e c t i n s e r t i o n method with the a s s i s t a n c e of Dr. G. K. Eigendorf and Mr. J . W. Nip. C o n d u c t i v i t i e s . C o n d u c t i v i t i e s of 10~ 3 M s o l u t i o n s were measured with a YSI Model 31 c o n d u c t i v i t y b r i d g e at ambient temperatures, with the he l p of Dr. Y. Koga. Magnetic S u s c e p t i b i l i t y Measurements. S o l u t i o n magnetic s u s c e p t i b i l i t y measurements were e f f e c t e d by Evan's method us i n g an 8% s o l u t i o n of (CH 3) 3COH i n CHC1 3 as the so l v e n t [70]. P a s c a l ' s constants were used to c o r r e c t the measured molar s u s c e p t i b i l i t i e s f o r the diamagnetic c o n t r i b u t i o n s of the l i g a n d s [90]. S o l i d s t a t e measurements were recorded by 60 the Gouy method [91] with the a s s i s t a n c e of Ms. K. O l i v e r . E l e c t r o n Paramagnetic Resonance S p e c t r a . EPR s p e c t r a of 10" 3M toluene s o l u t i o n s were recorded on a V a r i a n E—3 spectrometer at ambient temperatures. Elemental Analyses. Elemental analyses were performed by Mr. P. Borda. Reaction of (TJ 5-C 5H b )Cr (CO) „ (NO) with 1 2. To a s t i r r e d orange s o l u t i o n of (TJ 5—C 5H 5 )Cr (CO) 2 (NO) [92] (2.03g, lO.Ommol) i n CH 2C1 2 (80mL) was added s o l i d I 2 d.24g, 4.90mmol). Reaction o c c u r r e d a f t e r 5 min as evidenced by gas e v o l u t i o n and a c o l o u r change of the r e a c t i o n mixture to green—brown. A f t e r being s t i r r e d f o r 1 hr to ensure completion of the r e a c t i o n , the mixture was taken to dryness under reduced p r e s s u r e . C r y s t a l l i z a t i o n of the r e s i d u e from CH 2Cl 2-hexanes a f f o r d e d 2.35g (88% y i e l d ) of dark green [ ( T j 5 - C 5 H 5 ) C r ( N O ) l ] 2 . A n a l . C a l c d f o r C , 0 H , 0 N 2 I 2 C r 2 0 2 : C,21.92; H,1.84; N,5.11; I, 46.33. Found: C,22.00; H,1.77; N,5.00; I, 46,08. IR ( C H 2 C 1 2 ) : v(NO) 1673 cm" 1. Mp ( i n a i r ) 119°C dec. Reaction of (T? 5—C 5H 5 )Cr (CO) r (NO) with B r 2 . A b r i g h t red s o l u t i o n of B r 2 i n CH 2C1 2 was added dropwise to a r a p i d l y s t i r r e d , orange s o l u t i o n of (TJ 5—C 5H 5 )Cr (CO) 2 (NO) (0.50g, 61 2.5mmol) i n CH 2C1 2 (30mL). Immediately, the l a t t e r s o l u t i o n became blue—green i n c o l o u r , and gas was evolved. The a d d i t i o n of bromine was continued u n t i l IR monitoring of the r e a c t i o n mixture i n d i c a t e d t hat the o r g a n o m e t a l l i c r e a c t a n t had been completely consumed. The f i n a l mixture was then c o n c e n t r a t e d i n vacuo to 5mL and was t r a n s f e r r e d to the top of a F l o r i s i l column (2x6cm). E l u t i o n of the column with CH 2C1 2 developed a golden—yellow band which was c o l l e c t e d and taken to dryness i n vacuo to o b t a i n 0.13g (42% y i e l d based on NO) of ( r j 5 — C 5 H 5 )Cr (NO) 2 B r . The product was r e a d i l y i d e n t i f i a b l e by i t s c h a r a c t e r i s t i c s p e c t r o s c o p i c p r o p e r t i e s [87] [ IR ( C H 2 C 1 2 ) : i>(NO) 1819,1711 cm" 1. 1H—NMR (CDC1 3): 5 5.74. ]. The r e a c t i o n was a l s o performed i n an i d e n t i c a l manner i n THF. Solvent was removed from the f i n a l r e a c t i o n mixture under reduced p r e s s u r e , the r e s i d u e was e x t r a c t e d with CH 2C1 2 (5mL), and the e x t r a c t s were f i l t e r e d through a F l o r i s i l column (2x4cm) supported on a medium p o r o s i t y f r i t . Removal of a l l v o l a t i l e s from the f i l t r a t e i n vacuo a f f o r d e d m i c r o c r y s t a l l i n e ( r j 5 — C 5 H S )Cr (NO) 2 B r (0.27g, 86% y i e l d based on NO). Thermal decomposition of [ (T? 5-C 5H 5 )Cr (NO)I ] 2 i n CH 2C1 2 and  THF. The two experiments were performed s i m i l a r l y . A sample (0.27g, 0.50mmol) of [ ( T J 5 - C 5 H 5 )Cr (NO) I ] 2 was d i s s o l v e d i n 25mL of the s o l v e n t , and the r e s u l t i n g s o l u t i o n was s t i r r e d 62 at room temperature. The decomposition of the o r g a n o m e t a l l i c complex was monitored by the disappearance of i t s c h a r a c t e r i s t i c P(NO) a b s o r p t i o n i n the IR spectrum of the s o l u t i o n . A f t e r decomposition was judged to be complete (45 hr i n CH 2C1 2, 200 hr i n THF), the s o l u t i o n was taken to dryness i n vacuo. The r e s i d u e was e x t r a c t e d with CH 2C1 2 (20mL), and the e x t r a c t s were f i l t e r e d through a F l o r i s i l column (2x4cm). A d d i t i o n of hexanes to the f i l t r a t e and slow c o n c e n t r a t i o n of the r e s u l t i n g s o l u t i o n under reduced p r e s s u r e induced the c r y s t a l l i z a t i o n of golden—brown needles of ( T J 5 — C 5 H 5 ) C r ( N O ) 2 I . Both c o n v e r s i o n s produced 0.06g (40% y i e l d based on NO) of t h i s complex which was i d e n t i f i e d by i t s c h a r a c t e r i s t i c IR spectrum [49] (i>(NO) ( C H 2 C 1 2 ) : 1817,1713cm" 1). Reaction of [ ( T? 5 - C 5 H 5 )Cr (NO) I ] 2 with excess I 2 . S o l i d I 2 (0.25g, I.Ommol) was added to a r a p i d l y s t i r r e d s o l u t i o n of [ ( i 7 5 - C 5 H 5 )Cr (NO)I ] 2 (0.27g, 0.50mm6l) i n C H 2 C l 2 (25mL). The progress of the r e a c t i o n was monitored by IR spectroscopy which r e v e a l e d that the t r a n s f o r m a t i o n was complete a f t e r 18hr and that the only n i t r o s y l — c o n t a i n i n g product formed was (r? 5-C 5H 5 )Cr(NO) 2 I [49]. R e a c t i o n of [ (T? 5—C 5H 5)Cr (NO)I ] 2 with NO. A dark green s o l u t i o n of [ (T7 5-C SH 5 )Cr (NO)I ] 2 (0.25g, 0.46mmol) i n CH 2C1 2 (l5mL) was t r e a t e d with a stream of NO gas f o r 10 min. The 63 s o l u t i o n r a p i d l y turned golden—brown i n c o l o u r . The r e a c t i o n mixture was f i l t e r e d through a F l o r i s i l column (3x3cm) supported on a medium p o r o s i t y f r i t , and the f i l t r a t e was co n c e n t r a t e d i n vacuo to g i v e 0.25g (89% y i e l d ) of golden (T? 5-C 5H 5)Cr(NO) 2I [ 493 . Reactions of [ ( T? 5-C BHB )Cr (NO) I ] 7. with NaOR (R=Et or Me) . An excess (0.22g, 3.2mmol) of s o l i d NaOEt was added to a r a p i d l y s t i r r e d THF s o l u t i o n (50mL) of [ (r? 5-C 5H 5 )Cr (NO) I ] 2 (0.82g, 1.5mmol). A f t e r 3 hr, removal of v o l a t i l e s from the r e a c t i o n mixture i n vacuo a f f o r d e d a green—brown o i l . T h i s o i l was e x t r a c t e d with CH 2C1 2 (3x15mL), and the combined e x t r a c t s were f i l t e r e d through a F l o r i s i l column (2x4cm) supported on a medium p o r o s i t y f r i t . The column was washed with CH 2C1 2 u n t i l the washings were c o l o u r l e s s , and the volume of the f i l t r a t e was reduced to 25mL under reduced p r e s s u r e . The a d d i t i o n of hexanes (40mL) and the slow c o n c e n t r a t i o n of the r e s u l t i n g s o l u t i o n i n vacuo r e s u l t e d i n the c r y s t a l l i z a t i o n of dark green .[ ( r j 5 - C 5 H 5 )Cr (NO) (OEt)] 2 (0.1Og, 18% y i e l d ) . The i s o l a t e d product was i d e n t i f i e d by i t s c h a r a c t e r i s t i c p h y s i c a l p r o p e r t i e s [64], e.g. Mp (under N 2 ) 230°C dec; IR(CH 2C1 2): *>(NO) 1660 cm" 1. B r i g h t green m i c r o c r y s t a l s of [ ( T ? 5 - C 5 H 5 )Cr (NO) (OMe) ] 2 were ob t a i n e d i n a s i m i l a r manner i n 15% y i e l d from the r e a c t i o n of NaOMe with the i o d o n i t r o s y l dimer. A n a l . C a l c d f o r C , 2H, 6N 2Cr 2O u: C, 40.45; H, 4.53; N, 64 7.86. Found: C, 40.30; H, 4.48; N, 7.73. IR (CH 2C1 2): P(NO) 1661 cm' 1. Mp ( i n a i r ) 172°C dec. Reaction of [ ( 77 5 - C 5 H 5 )Cr (NO) I ] 2 with CO. Carbon monoxide was bubbled through a s o l u t i o n of [ ( r j 5 — C 5 H 5 ) C r (NO) I ] 2 (0.27g, 0.50mmol) i n CH 2C1 2 (25mL) f o r a p e r i o d of 1 h r . At the end of t h i s time, an IR spectrum of the dark green s o l u t i o n r e v e a l e d 10—20% c o n v e r s i o n of the o r g a n o m e t a l l i c r e a c t a n t to a new c a r b o n y l n i t r o s y l s p e c i e s (v(CO)=2096cm" 1, v(NO)=1706cm"1). F u r t h e r exposure of the s o l u t i o n to CO d i d not, however, i n c r e a s e the amount of t h i s complex produced. Reactions of [ ( T ? 5 - C 5 H 5 ) C r ( N O ) l ] 2 with Lewis Bases, L (L=PPh 3, P(OPh) 3, P ( O E t ) 3 ) . The experimental ' procedure, u s i n g the r e a c t i o n with L=P(OPh) 3 as a r e p r e s e n t a t i v e example , was as f o l l o w s . Neat t r i p h e n y l p h o s p h i t e (0.13mL, 0.16g, 0.50mmol) was added to a s t i r r e d CH 2C1 2 (25mL) s o l u t i o n of [ ( T ? 5 - C 5 H 5 )Cr(NO)I ] 2 (0.14g, 0.25mmol) and the mixture was s t i r r e d f o r 1 hr to ensure complete r e a c t i o n . The f i n a l blue-green s o l u t i o n was f i l t e r e d through a F l o r i s i l column (2x4cm) supported on a medium p o r o s i t y f r i t . Hexanes (30mL) were added to the f i l t r a t e , and the r e s u l t i n g s o l u t i o n was c o n c e n t r a t e d under reduced p r e s s u r e to o b t a i n green c r y s t a l s of (T? 5-C 5H 5 )Cr(NO) {P(OPh) 3 } I (0.20g, 68% y i e l d ) . Green m i c r o c r y s t a l s of (TJ 5—C 5H 5)Cr(NO) (PPh 3) I were i s o l a t e d 65 s i m i l a r l y i n 64% y i e l d . The r e a c t i o n of [ ( T J 5 - C 5 H 5 )Cr (NO) I ] 2 and P ( O E t ) 3 was e f f e c t e d i d e n t i c a l l y . However, the ( r j s - C 5 H 5 )Cr (NO) (P(OEt) 3 }l product was obtained a n a l y t i c a l l y pure (32% y i e l d ) by chromatography of the f i n a l r e a c t i o n mixture on a F l o r i s i l column (2x6cm) with CH 2C1 2 as e l u a n t and subsequent r e c r y s t a l l i z a t i o n of the m a t e r i a l thus i s o l a t e d from hexanes. For L=PPh 3: Anal . C a l c d f o r C 2 3 H 2 0 N C r I O P : C, 51.51; H, 3.76; N, 2.61. Found: C, 51.21; H, 3.77; N, 2.59. IR (CH 2C1 2): ?(NO) 1666 cm" 1. Mp ( i n a i r ) 158°C dec. For L=P(OPh) 3: A n a l . C a l c d f o r C 2 3H 2oNCrlO,.?: C, 47.26; H., 3.42; N, 2.40. Found: C, 47.15; H, 3.39; N, 2.40. IR (CH 2C1 2): f(NO) 1686 cm" 1. Mp ( i n a i r ) 132°C. For L=P(OEt) 3: A n a l . C a l c d f o r C,,H 2 0NCrIO„P: C, 30.00; H, 4.55; N, 3.18. Found: C, 29.87; H, 4.57; N, 3.30. IR (CH 2C1 2): p(NO) 1670 cm" 1. Mp ( i n a i r ) 49-50°C. Reactions of (T} 5-C 5H 5 )Cr (CO) (NO) (PPh 3) with the halogens  C I 2 , B r 2 , 1 2. These r e a c t i o n s were a l l performed s i m i l a r l y , and the r e a c t i o n with C l 2 i s d e s c r i b e d i n d e t a i l as a r e p r e s e n t a t i v e example. A s a t u r a t e d s o l u t i o n of c h l o r i n e i n CH 2C1 2 was prepared by purging 20mL of CH 2C1 2 with a stream of c h l o r i n e gas f o r 10 mins. An a l i q u o t (VmL) of t h i s s o l u t i o n was t r a n s f e r r e d by s y r i n g e i n t o a dropping funnel c o n t a i n i n g CH 2C1 2 (lOmL). 66 T h i s d i l u t e d s o l u t i o n of C l 2 was then added dropwise to a r a p i d l y s t i r r e d , yellow-brown s o l u t i o n of ( T ? 5 - C 5 H 5 )Cr (CO) (NO) (PPh 3) [93] (0.58g, 1.33mmol) in CH 2C1 2 (30mL). The s o l u t i o n immediately became dark green, and gas was .evolved. J u s t enough c h l o r i n e was added to consume a l l the o r g a n o m e t a l l i c r e a c t a n t , as monitored by the disappearance of i t s c h a r a c t e r i s t i c c a r b o n y l a b s o r p t i o n i n the IR spectrum of the r e a c t i o n mixture. The f i n a l green s o l u t i o n was c o n c e n t r a t e d under reduced pressure to a volume of 1OmL and was f i l t e r e d through a F l o r i s i l column (2x5cm) supported on a medium p o r o s i t y f r i t . The column was washed with CH 2C1 2 (60mL) u n t i l the washings were c o l o u r l e s s . Hexanes (60mL) were added to the f i l t r a t e and the r e s u l t i n g s o l u t i o n was c o n c e n t r a t e d i n vacuo to induce the c r y s t a l l i z a t i o n of 0.34g (57% y i e l d ) of b r i g h t green, a n a l y t i c a l l y pure ( T? 5 - C 5 H 5 )Cr (NO) (PPh 3 )C1. The analogous bromide and i o d i d e complexes were prepared i n a s i m i l a r manner ( i n i s o l a t e d y i e l d s of 43% and 41% r e s p e c t i v e l y ) by the dropwise a d d i t i o n of a s o l u t i o n of bromine i n CH 2C1 2 or by the a d d i t i o n of a s t o i c h i o m e t r i c amount of s o l i d i o d i n e to a CH 2C1 2 s o l u t i o n of (7} 5—C 5H 5 )Cr (CO) (NO) (PPh 3 ) . For X=C1: A n a l . C a l c d f o r C 2 3 H 2 0 N C l C r O P : C, 62.10; H, 4.53; N, 3.15. Found: C, 61.90; H, 4.56; N, 3.09. IR ( C H 2 C 1 2 ) : i>(NO) 1664 cm" 1. Mp ( i n a i r ) 157°C dec. For X=Br: A n a l . C a l c d f o r C 2 3H 2 0NBrCrOP: C, 56.46; H, 67 4.12; N, 2.86. Found: C, 56.44; H, 4.19; N, 2.88. IR (CH 2C1 2): v(NO) 1664 cm' 1. Mp ( i n a i r ) 162°C dec. Reaction of (7? 5-C 5Me 5 )Cr (CO) 2 (NO) with I 2 . S o l i d i o d i n e (0.13g, 0.5mmol) was added to a s t i r r e d , red s o l u t i o n of (7? 5-C 5Me 5)Cr(CO) 2(NO) [62] (0.27g, I.Ommol) i n CH 2C1 2 (25mL). Gas e v o l u t i o n o c c u r r e d , and the s o l u t i o n became p u r p l e — r e d i n i t i a l l y and then brown i n c o l o u r . A f t e r being s t i r r e d f o r 24 hr, the s o l u t i o n was co n c e n t r a t e d i n vacuo to 1mL and was t r a n s f e r r e d by s y r i n g e to the top of a F l o r i s i l column (2x5cm) made up i n CH 2C1 2. E l u t i o n of the column with CH 2C1 2 developed an orange—brown band which was e l u t e d from the column and c o l l e c t e d . Hexanes (70mL) were added to the e l u a t e , and the r e s u l t i n g s o l u t i o n was c o n c e n t r a t e d to 20mL under reduced pressure whereupon a small amount of an orange—brown s o l i d p r e c i p i t a t e d . . The mixture was then g e n t l y warmed to r e d i s s o l v e t h i s s o l i d , and the warm s o l u t i o n was c o o l e d overnight to -10°C to o b t a i n golden—brown c r y s t a l s of (7? 5-C 5Me 5)Cr(NO) 2I (0.08g, 42% y i e l d based on NO). An a l . C a l c d f o r C , 0 H , 5 N 2 C r I 0 2 : C, 32.10; H, 4.04; N, 7.49. Found: C, 31.83; H, 3.91; N, 7.19. IR (CH 2C1 2): v(NO) 1786,1687 cm" 1. 1H—NMR (CDC1 3): 5 1.91(S). Mp ( i n a i r ) 119°C dec. Mass spectrum m/z(Rel. I n t e n s i t y ) : 374(39) [ P ] + , 344(19) [P-NO] +, 314(100) [P-2NO] +. 68 Reaction of ( TJ 5 —C 5 Me B) C r (CO) 2 (NO) with B r 2 and NO. A s o l u t i o n of B r 2 i n CH 2C1 2 was added dropwise to a s t i r r e d red s o l u t i o n of ( TJ 5—C 5Me 5 )Cr (CO) 2 (NO) (0.55G, 2.0mmol) i n CH 2C1 2 (30mL). Gas was evolved and the s o l u t i o n became b r i g h t green i n c o l o u r . The a d d i t i o n of bromine was monitored by the disappearance of the v{CO) a b s o r p t i o n s of the o r g a n o m e t a l l i c r e a c t a n t . When a d d i t i o n was complete the i n f r a r e d spectrum of the r e a c t i o n mixture e x h i b i t e d three y(NO) bands (1784, 1730 and 1685 c m - 1 ) . Even upon prolonged s t i r r i n g (24 hrs) there was no change i n the r e l a t i v e i n t e n s i t i e s of these bands. Treatment of the s o l u t i o n with NO gas f o r 15 mins caused a d i m i n u t i o n of the band at 1730cm - 1, together with a concomitant i n c r e a s e i n i n t e n s i t y of the other two bands. The s o l u t i o n , now golden—brown i n c o l o u r , was chromatographed on a 2x6cm F l o r i s i l column u s i n g CH 2C1 2 as e l u a n t . A golden—brown band was e l u t e d , c o l l e c t e d , and the s o l u t i o n taken to dryness. R e c r y s t a l l i z a t i o n from CH 2Cl 2/hexanes produced 0.29g (53% y i e l d w.r.t. Cr) of golden m i c r o c r y s t a l l i n e (TJ 5—C 5Me 5 )Cr (NO) 2 B r . A n a l . C a l c d f o r C , 0 H , 5 N 2 B r C r 0 2 : C, 36.71; H, 4.62; N, 8.57. Found: C, 36.77; H, 4.84; N, 8.47. IR (CH 2 C 1 2 ) : t>(NO) 1784,1685 cm" 1. 1H—NMR (CDC1 3): 5 1.82(s). 13C-NMR (CDC1 3): 6 112.2(C-CH 3), 9.7(CH 3). Mp ( i n a i r ) 149°C dec. Mass spectrum m/z(Re1. I n t e n s i t y ) : 326(18) [ P ] + , 296(23) [P-NO] +, 266(100) [P-2NO] +. 69 Reactions of (T? 5-C 5Me 5 )M(CO) 2 (NO) (M=Mo or W)_ with 1 2. These experiments were performed s i m i l a r l y ; only the c o n v e r s i o n i n v o l v i n g M=Mo i s d e s c r i b e d here i n d e t a i l . A s t i r r e d , red CH 2C1 2 s o l u t i o n (80mL) of (175 —C 5 Me 5) Mo (CO) 2 (NO) [62] d.59g, 5.00mmol) was t r e a t e d with s o l i d i o d i n e ( l . 1 7 g , 4.61mmol). The s o l u t i o n became deep p u r p l e i n c o l o u r , and r a p i d gas e v o l u t i o n o c c u r r e d . Hexanes (80mL) were added a f t e r 1 hr, and the s o l u t i o n was conc e n t r a t e d under reduced p r e s s u r e to induce the c r y s t a l l i z a t i o n of 2.26g (88% y i e l d ) Of p u r p l e [ ( 7 j 5 - C 5 M e 5 ) M o ( N O ) I 2 ] 2 . The tungsten congener was prepared i n a s i m i l a r manner, but the r e a c t i o n mixture was slowly c o n c e n t r a t e d i n vacuo so as to d r i v e the. r e a c t i o n t o completion ( i . e . to decarbonylate completely the in t e r m e d i a t e c a r b o n y l — n i t r o s y l : complex formed d u r i n g t h i s t r a n s f o r m a t i o n ) . R e c r y s t a l l i z a t i o n of the f i n a l r e s i d u e from CH 2C1 2/hexanes a f f o r d e d green—brown m i c r o c r y s t a l s of [ ( TJ 5—C 5Me 5 )W(NO) I 2 ] 2 i n 78% y i e l d . For M=Mo: A n a l . C a l c d f o r C 2 0 H 3 0 N 2 I i,Mo 20 2 : C, 2.3.32; H,2.94; N,2.72; I, 49.28. Found: C,23.55; H,2.81; N,2.59; I, 49.11. IR (C H 2 C 1 2 ) : i>(NO) 1660 cm" 1. 1H—NMR (CDC1 3) : 5 2.05(s). 13C-NMR (CDC1 3): 5 118.6(C-CH 3), 13.2(CH 3). Mp ( i n a i r ) 164°C dec. For M=W: An a l . C a l c d f o r C 2 0 H 3 0 N 2 I U 0 2 W 2 : C,19.91; H,2.51; N,2.32; I, 42.09. Found: C,20.14; H,2.45; N,2.25; I, 70 41.91. IR (CH 2C1 2): v(m) 1629 cm" 1. 'H-NMR (CDC1 3): 6 2.18(S). 13C-NMR (CDC1 3): 5 117.5(C-CH 3),12.8(CH 3). Mp ( i n a i r ) 74°C dec. Reactions of [ (T? 5-C 5Me s)M(NO) 1 2 ] 2 (M=Mo or W) with Lewis  Bases L (L=PPh 3 or P( O P h ) 3 ) . A d d i t i o n of s o l i d PPh 3 (0.26g, I.Ommol) to a s t i r r e d p u rple s o l u t i o n of [ (T) 5-C 5Me 5 )Mo(NO)l 2 ] 2 (0.52g, 0.50mmol) i n CH 2C1 2 (30mL) r e s u l t e d i n the s o l u t i o n becoming red i n c o l o u r . Hexanes (30mL) were added a f t e r 30 mins, and the s o l u t i o n was conc e n t r a t e d i n vacuo to o b t a i n 0.65g (84% y i e l d ) of (T? 5-C 5Me 5)Mo(NO) ( P P h 3 ) I 2 as a dark red s o l i d . The other complexes were prepared s i m i l a r l y i n comparable y i e l d s (64—84%). For M=Mo; L=PPh 3: A n a l . C a l c d f o r C 2 8H 3 0NI 2MoOP: C, 43.27; H, 3.89; N, 1.80. Found: C, 42.98; H, 3.86; N, 1.67. IR ( C H 2 C 1 2 ) : u(HO) 1658 cm" 1. 'H-NMR (CDC1 3): 6 7.36(m,15H,C 6H 5), 1.99(s,15H,CH 3). Mp 106° dec. For M=Mo; L=P(OPh) 3: A n a l . C a l c d f o r C 2 8H 3 0NI 2MoO aP: C, 40.75; H, 3.66; N, 1.70. Found: C, 40.72; H, 3.69; N, 1.68. IR ( C H 2 C 1 2 ) : i/(NO) 1662 cm - 1. 'H-NMR (CDC1 3): 5 7.07(m,15H,C 6H 5), 2.05(s,15H,CH 3). 13C-NMR (CDC1 3): (see Table 2.9). Mp 118°C dec. For M=W; L=PPh 3: A n a l . C a l c d f o r C 2 8H 3 0NI 2OPW: C, 38.87; H, 3.50; N, 1.62. Found: C, 38.62; H, 3.44; N, 1.63. IR ( C H 2 C 1 2 ) : »>(NO) 1628 cm' 1. 1H—NMR (CDC1 3): 6 71 7.38(m,15H,C 6H 5), 2.17(s,15H,CH 3). Mp 128°C dec. For M=W; L=P(OPh) 3: A n a l . C a l c d f o r C 2 8 H 3 0 N I 2 0 „ P W : C, 36.82; H, 3.31; N, 1.53. Found: C, 36.99; H, 3.44; N, 1.65. IR ( C H 2 C 1 2 ) : viHO) 1640 cm" 1. 1H—NMR (CDC1 3): 8 7.21(m,15H,C 6H 5), 2.34(s,12H,CH 3), 2.18(S,3H,CH 3). 13C-NMR (CDC1 3): (see Table 2.9). Mp 133°C dec. 72 CHAPTER THREE SYNTHESIS AND CHARACTERISATION OF NEW CYCLOPENTADIENYL AND  DIENE COMPLEXES DERIVED FROM [ (77 5 —C s H 5 ) M (NO )l ?] ?. (M=Mo OR W). ( i ) I n t r o d u c t i o n The formation and chemistry of M—C bonds i s the quintessence of o r g a n o m e t a l l i c c h e m i s t r y . In o r g a n o m e t a l l i c n i t r o s y l chemistry there are only a few examples of complexes which c o n t a i n organic groups (other than the u b i q u i t o u s c y c l o p e n t a d i e n y l group), mainly because of a l a c k of general p r e p a r a t i v e r o u t e s . For example, commonly used n i t r o s y l a t i n g agents such as NO, N0 + or N0C1 commonly d i s p l a c e the organic groups from complexes such as ( C 8 H 8 ) F e ( C O ) 3 [68] or ( C 6 H 6 ) W ( C O ) 3 [64]. However, with the p r e p a r a t i o n of a s e r i e s of Group VIA c y c l o p e n t a d i e n y l n i t r o s y l h a l i d e s , the r e q u i s i t e p r e c u r s o r s are a v a i l a b l e f o r the formation of a new s e r i e s of o r g a n o m e t a l l i c complexes. T h i s chapter p r e s e n t s the r e s u l t s of two r e a c t i o n s which l e a d to the formation of M—C bonds:— a) the r e a c t i o n of [ ( T J 5 - C 5 H 5 )W(NO)1 2 ] 2 with 2 or 4 73 e q u i v a l e n t s of M(C 5H 5) (M=Na or T l ) to give ( C 5 H 5 ) 2 W ( N 0 ) I or (C 5H 5) 3W(NO), and b) the r e d u c t i o n of [ (r? b-C 5H 5 )Cr (NO) I ] 2 and [ ( T J 5 - C 5 H 5 ) M ( N O ) I 2 ] 2 (M=MO or W) by Na/Hg i n the presence of an excess of o l e f i n or diene. ( i i ) R e s u l t s And D i s c u s s i o n (a) Reaction Of [ (^-CsHs )w(NO)l, ], With M(C 5H 5)  (M=Na or T l ) The r e a c t i o n of [ ( TJ5 —C 5H 5 )W(NO) I 2 ] 2 i n THF with t h a l l i u m or sodium c y c l o p e n t a d i e n i d e i n a p p r o p r i a t e s t o i c h i o m e t r i e s a f f o r d s the novel complexes (C 5H 5) 2W(NO)I and (C 5H 5) 3W(NO). [ . ( T J 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 + 2M(C 5H 5) > 2 ( C 5 H 5 ) 2W(NO) I + 2MI ...(3.1) [ ( T J 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 + 4M(C 5H 5) > 2 ( C 5 H 5 ) 3W(NO) + 4MI . . . ( 3 . 2 ) M=T1 or Na. Analogous conve r s i o n s i n v o l v i n g [ (TJ 5— C 5H 5 )Mo(NO) 1 2 ] 2 can only be e f f e c t e d with T l ( C 5 H 5 ) s i n c e Na(C 5H 5) i s too r e a c t i v e and f a i l s to form any c y c l o p e n t a d i e n y l d e r i v a t i v e s 74 [59]. IR monitoring of r e a c t i o n s 3.1 and 3.2 i n d i c a t e s that the i o d i d e l i g a n d s of the o r g a n o m e t a l l i c r e a c t a n t (which may be present as the s o l v a t e d monomer (7 1 5 —C 5H 5 )W(NO) 1 2 (THF)) are r e p l a c e d s e q u e n t i a l l y , and indeed the t r a n s f o r m a t i o n s (C 5H 5) 2W(N0)I + M(C 5H 5) > (C 5H 5) 3W(NO) + MI ...(3.3) M=T1 or Na can be performed independently. Golden-brown (C 5H 5) 2W(NO)I and b r i c k - r e d (C 5H 5) 3W(NO) are diamagnetic, r e l a t i v e l y a i r — s t a b l e s o l i d s which are f r e e l y s o l u b l e i n common organic s o l v e n t s (except p a r a f f i n hydrocarbons) to gi v e a i r — s e n s i t i v e s o l u t i o n s . T h e i r l o w — r e s o l u t i o n mass s p e c t r a c o n f i r m t h e i r monomeric natures (parent ions at m/z=47l and 409 r e s p e c t i v e l y ) and d i s p l a y fragmentation p a t t e r n s corresponding to the stepwise l o s s of l i g a n d s from the metal c e n t r e . S o l u t i o n s of both complexes i n CH 2C1 2 e x h i b i t s i n g l e , s t r o n g a b s o r p t i o n s i n t h e i r IR s p e c t r a i n the range normally a s s o c i a t e d with l i n e a r l y bonded, t e r m i n a l NO l i g a n d s , the r e s p e c t i v e P(NO) value s being 1622 and 1588 cm"1 f o r ( C 5 H 5 ) 2 W ( N O ) I and (C 5H 5) 3W(NO). The v a r i a b l e temperature 'H—NMR s p e c t r a of both complexes i n C 6D 5CD 3 resemble those d i s p l a y e d by t h e i r molybdenum congeners [59,94,95]. Thus, f o r (C 5H 5) 2W(NO)I, the spectrum c o n s i s t s of a s i n g l e , sharp resonance (55.77 at 27°C) i n the temperature range -90 to +30°C. For 75 (C 5H 5) 3W(NO), the s i n g l e sharp resonance (55.64 at 27°C) due to a l l three r a p i d l y i n t e r c o n v e r t i n g c y c l o p e n t a d i e n y l r i n g s s t a r t s to broaden at 0°C (see F i g u r e 3.1). At about -40°C, two new broad peaks begin to grow, i n d i c a t i n g the presence of a s l o w l y moving r}^-C5U5 r i n g . Between -40°C and -80°C these two peaks sharpen c o n s i d e r a b l y . The l o w - f i e l d resonance (66.92 at -80°C) shows some degree of c o u p l i n g and may be a t t r i b u t e d to the o l e f i n i c hydrogens, while the h i g h — f i e l d resonance (64.32 at -80°C) can be a s s i g n e d to the remaining hydrogen. (The lower f i e l d p o r t i o n of the expected AA'BB' spectrum i s not observable, presumably due to masking by the s o l v e n t resonance). The s i g n a l due to the other two c y c l o p e n t a d i e n y l r i n g s sharpens somewhat between -30°C and -50°C, but below -50°C i t c o l l a p s e s , and by -90°C i t has separated i n t o two e q u a l l y i n t e n s e peaks (64.82 and 5.57). Both molecules ( C 5 H 5 ) 2W(NO)X (X=I or T J 1 - C 5 H 5 ) are thus probably s t e r e o c h e m i c a l ^ n o n r i g i d i n s o l u t i o n at room temperature, undergoing rearrangement processes which r a p i d l y i n t e r c o n v e r t and e q u i l i b r a t e the c y c l o p e n t a d i e n y l r i n g s . To maintain an 18—electron valence c o n f i g u r a t i o n at the c e n t r a l metal, t h e i r instantaneous molecular s t r u c t u r e s may i n v o l v e two C 5 H 5 r i n g s bonded i n the same, g r o s s l y unsymmetrical manner as that found f o r (C 5H 5) 3Mo(NO) [96] and ( C 5 H 5 ) 2 M o ( N O ) C H 3 [97] i n the s o l i d s t a t e ( F i g u r e 3.2a). A l t e r n a t i v e l y , one r i n g may be bonded i n a planar rj 5 f a s h i o n and the other i n a bent rj 3 f a s h i o n i n a manner analogous to 76 F i g u r e 3.1 80MHz 1H-NMR Spectra Of (C 5H 5),W(NO) In The Temperature Range -95°C -> 27°C.  (s=solvent, X=impurity) i i c i i r 1 1— z 1 1 r 7 6 o 5 PP m 4 3 7 6 S 5 ppm 4 3 77 th a t observed i n the c r y s t a l s t r u c t u r e of the valence i s o e l e c t r o n i c ( C 5 H 5 ) 2 W ( C O ) 2 [98] and ( C 9 H 7 ) 2 W ( C O ) 2 [99] ( F i g u r e 3.2b). Recently, i t has been suggested that the s o l u t i o n behaviour of the molybdenum complex ( C 5 H 5 ) 2 M o ( N O ) I may be e x p l a i n e d i f the molecule e x i s t s t r a n s i t i o n a l l y as ( r ? 5 - C 5 H 5 ) (TJ'-CSHS )Mo(NO)I ( p o s s i b l y s o l v a t e d ) with the TJ 1-and r j 5 — C 5 H 5 r i n g s r a p i d l y exchanging t h e i r e l e c t r o n i c r o l e s [100] (Figure 3.2c). A f i n a l , a l b e i t l e s s l i k e l y , s t r u c t u r e would i n v o l v e two planar r j 5 — C 5 H 5 r i n g s and a bent M—NO l i n k a g e (Figure 3.2d). U n f o r t u n a t e l y , a l l attempts to prepare s i n g l e c r y s t a l s of e i t h e r tungsten complex have so f a r r e s u l t e d i n h i g h l y d i s o r d e r e d or twinned c r y s t a l s . F i n a l l y , i t may be noted that the analogous a l l y l complexes (*TJ 5—C 5H 5 )M(NO) ( r j 3 — C 3 H 5 ) I have been prepared [61,101,102], These complexes c o n t a i n a very assymetric a l l y l l i g a n d , a f a c t which i s a m a n i f e s t a t i o n of the e l e c t r o n i c assymetry . at the metal c e n t r e . I t i s q u i t e probable that the f a c t o r s r e s p o n s i b l e f o r the a,is d i s t o r t i o n of the r j 3 — C 3 H 5 group i n these compounds are a l s o o p e r a t i v e i n the ( C 5 H S ) 2W(NO)X (X=I or TJ'-CSHS) s p e c i e s d e s c r i b e d above. 78 F i g u r e 3.2 P o s s i b l e M o l e c u l a r S t r u c t u r e s For The Complexes  (C 5H 5) 2M(N0)X. (b) S y n t h e s i s And C h a r a c t e r i s a t i o n Of (T? 5-C 5H 5)MO(NO) (T?"-diene) I t was r e c e n t l y r e p o r t e d that the r e d u c t i o n of ZrCl« (dmpe) 2 or [ ( 7} 5-C 5H 5)Col 2 ] 2 with a sodium amalgam i n 79 the presence of excess diene a f f o r d e d the complexes [ (i? 4-diene) 2Zr(dmpe) ] 2 (dmpe) [103] and ( r j 5 - C 5 H 5 )Co (r} f l-diene) [104] r e s p e c t i v e l y . In a s i m i l a r v e i n , the r e d u c t i o n of [ ( T J 5 - C 5 R 5 )CoI 2 ] 2 (R=H or CH 3) with Na/Hg i n the presence of ethylene r e s u l t s i n the formation of (r? 5— C 5 R 5 )Co(C 2H„) 2 i n good y i e l d s [105]. The molybdenum and tungsten dimers, [ ( 7 j 5 —C 5H 5)M(NO) I 2 ] 2 (M=Mo or W) are valence i s o e l e c t r o n i c with the c o b a l t d i i o d i d e dimer [ (T? 5—C 5H 5 )CoI 2 ] 2 , and so the same r e a c t i o n s of the two complexes together with the new chromium complex, [ (TJ 5— C 5H 5 )Cr (NO)I ] 2 , were performed i n an attempt to prepare d e r i v a t i v e s of the type (T? 5-C 5H 5)M(NO) (rj'-diene) or ( T? 5 - C 5 H 5 )M(NO) ( o l e f in) 2 . U n f o r t u n a t e l y , the only combination of r e a c t a n t s to produce an i s o l a b l e o r g a n o m e t a l l i c n i t r o s y l complex was the r e d u c t i o n of the molybdenum dimer i n the presence of n o n — c y c l i c conjugated d i e n e s . (Other combinations which f a i l e d to produce i s o l a b l e . complexes were [ ( T 7 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 / diene, [ ( 77 5 - C 5 H 5 )Cr (NO) I ] 2 / diene, [ ( 7 ? 5 - C 5 H 5 )Mo(NO)l 2 ] 2 / c y c l o h e p t a t r i e n e , [ ( T ? 5 - C 5 H 5 )Mo-( N 0 ) I 2 ] 2 / 1 , 5 - c y c l o o c t a d i e n e , [ ( T? 5 - C 5 H 5 )MO (NO) I 2 ] 2 / ethylene and [ ( T? 5— C 5H 5 )MO(NO) 1 2 ] 2 / d i p h e n y l a c e t y l e n e ) . In a l l r e a c t i o n s a 10% excess of sodium amalgam was used to c a r r y out the r e d u c t i o n , the l i g a n d being present i n 10—20 f o l d excess, (A s a t u r a t e d s o l u t i o n was used f o r the ethylene r e a c t i o n ) . The r e d u c t i o n of a THF s o l u t i o n of [ (T? 5-C 5H 5 )MO(NO) 1 2 ] 2 80 with Na/Hg i n the presence of a 10-20 f o l d excess of the n o n — c y c l i c conjugated diene r e s u l t s i n the formation i n low y i e l d of yellow ( r j 5 - C 5 H 5 )Mo(NO) (T?"-diene) (diene=2—methylbutadiene J_, 2,3—dimethylbutadiene 2, or 2,5—dimethyl—2,4—hexadiene 3). [ ( T } 5 - C 5 H 5 ) M O ( N O ) I 2 ] 2 + 4Na/Hg + 2diene > ( T ? 5 - C 5 H 5 )MO(NO) ( 7 j a-diene) + 4NaI ...(3.4) The complexes may be i s o l a t e d from the r e a c t i o n mixture by f i l t r a t i o n through alumina, f o l l o w e d by e x t r a c t i o n of the re s i d u e with hexanes. C o n c e n t r a t i o n of t h i s s o l u t i o n i n vacuo g i v e s a n a l y t i c a l l y pure j_; 2 and 3 c o u l d be obtained by c o o l i n g the hexane s o l u t i o n s to -10°C. The complexes are t h e r m a l l y unstable and are best s t o r e d at or below 0°C. They are a l s o s l i g h t l y a i r — s e n s i t i v e , but they may be exposed to a i r f o r short p e r i o d s of time (5—10 mins) without n o t i c e a b l e decomposition. They are s o l u b l e i n a l l organic s o l v e n t s to giv e yellow a i r — s e n s i t i v e s o l u t i o n s . T h e i r i n f r a r e d s p e c t r a in CH 2C1 2 s o l u t i o n d i s p l a y strong a b s o r p t i o n s i n the range 1584—1 591 cm--1 , the i>(NO) valu e s d e c r e a s i n g with i n c r e a s i n g methyl s u b s t i t u t i o n i n the diene l i g a n d . Although these v a l u e s are q u i t e low, they may be a t t r i b u t e d to a l i n e a r n i t r o s y l l i g a n d , r a t h e r than a bent or b r i d g i n g NO. The f i r s t a l t e r n a t i v e may be r u l e d out by c o n s i d e r i n g the 81 e f f e c t i v e atomic number formalism, as t h i s would leave the molybdenum atom with a 1 6 — e l e c t r o n c o n f i g u r a t i o n , while the second a l t e r n a t i v e may be e l i m i n a t e d on the b a s i s of the mass s p e c t r a of J_ and 3, which only r e v e a l peaks c o n t a i n i n g one Mo atom. The u s u a l c o o r d i n a t i o n mode f o r a conjugated diene i s s - c i s e.g. (T?"-s-cis-diene)Fe(CO) 3 [ 1 0 6 , 1 0 7 ] , ( T ^ - S - C J s-diene) 2Fe(CO) [ 1 0 8 ] , (T? 5-C 5H 5 )M( T?"-S-C i s-diene) (M=Rh or Co) [ 1 0 4 , 1 0 7 ] , [ (T? 5-C 5H 5 )MoL 2 ( T?*-S-C i s-diene) ] * ( L 2 = (CO) 2 [ 1 0 9 ] or dppe [ 1 1 0 ] ) and ( T? "—s—c i s—diene) Cr (CO), [ 1 1 1 ] . However, the 1H—NMR and 13C-NMR s p e c t r a of the* complexes (see Tables 3.1 and 3.2 and F i g u r e 3.3) r e v e a l that the much r a r e r s — t r a n s c o o r d i n a t i o n mode i s favoured by these complexes. Evidence t h a t supports t h i s c o n c l u s i o n i s as f o l l o w s : — (a) The 1H—NMR s p e c t r a of the complexes which c o n t a i n s y m m e t r i c a l l y s u b s t i t u t e d d i e n e s , 2 and 3_, r e v e a l t h a t H 12 82 the two ends of the diene are c h e m i c a l l y i n e q u i v a l e n t . A s i m i l a r r e s u l t i s found i n the 13C—NMR spectrum of 2. (b) The s — v i c i n a l c o u p l i n g constant J ( H 2 i H 3 1 ) f o r 3 i s in the range normally a s s o c i a t e d with t r a n s c o u p l i n g c o n s t a n t s (10—14Hz), r a t h e r than c i s c o u p l i n g s (4-9Hz). (c) Compared to t y p i c a l c i s — c o o r d i n a t e d dienes [106—111] the c e n t r a l protons ( H 2 1 , H 3 1 ) resonate at higher f i e l d and the a n t i protons ( H 1 2 , H 4 1 ) are s i g n i f i c a n t l y d e s h i e l d e d ; the syn protons ( H 1 1 , H 4 2 ) are r e l a t i v e l y u n a f f e c t e d . T h i s l a s t e f f e c t has a l s o been observed f o r the s—trans isomer of (TJ 5—C 5H 5) 2Zr(T7 A — diene) (s—c i s and s—tr a n s ) [112]. T h i s complex i s one of only three p r e v i o u s l y r e p o r t e d s—trans c o o r d i n a t e d diene complexes, the other two complexes i n v o l v i n g the diene l i g a n d b r i d g i n g two metal atoms (Mn 2 (CO) B ( M 2—T? " — s — t ran s—C a H g ) [113] and O s 3 ( C O ) 1 0 -(M 2-T? a-s-trans-C nH 6) [114]). The isoprene complex J_ e x i s t s as a 3:1 mixture of diastereomers, which presumably d i f f e r i n the o r i e n t a t i o n of the methyl s u b s t i t u e n t . I t seems l i k e l y , from p u r e l y s t e r i c arguments, that the major isomer i n v o l v e s the methyl group being d i r e c t e d away from the c y c l o p e n t a d i e n y l group. At any r a t e , there appears to be no evidence f o r the e x i s t e n c e of an s — c i s — d i e n e complex. These r e s u l t s demonstrate that the c o o r d i n a t i o n of a conjugated diene e x c l u s i v e l y i n the s—tr a n s geometry does F i g u r e 3^3 400MHz 1H—NMR Spectrum Of ( r ^ - C H , )MO(NO)(w'-s-trans-CH.) j _ ( v i n y l region) 84 Table 3.1 1H—NMR Chemical S h i f t Data _(_6 In CDC1 3)  For The New Diene Complexes Assignment J a b 2 3 ( T J 5 - C 5 H 5 ) 5.53 5.49 5.48 5.30 HI ^  3.45 3.54 3.61 H, 2 1 .94 2.76 2.96 H 2 1 3.34 H 3 1 2.37 3.17 2.71 Hi, i 2.88 2.73 2.66 Hi, 2 3.35 3.74 3.59 CH 3 1 .53 1 .25 1 .56 1 .28 2.09 1 .93 1 .72 1 .32 a major isomer b minor isomer not r e q u i r e two metal c e n t r e s . The complexes ( T ? 5 - C 5 H 5 )MO(NO) (7? q-s-trans-diene) represent the f i r s t examples of monometallic diene c o o r d i n a t i o n where the s — t r a n s geometry i s s i g n i f i c a n t l y favoured over the s — c i s geometry. In c o n t r a s t , the analogous z i r c o n i u m complexes, 85 Table 3.2 Proton-proton Coupling Constants ( i n Hz) For  The New Diene Complexes Assignment J a b 2 3 J (H ] 1H 1 2 ) 3.1 1.9 2.4 J ( H 2 1 H 3 1 ) 12.0 J (H 3 1H a 1 ) 14.4 14.0 j ( H 3 i H 4 2 ) 7.0 6.6 J (H 4 1H4 2 ) 2.8 3.6 3.7 a major isomer b minor isomer (r? 5— C 5 H 5 ) 2 Z r ( T j a — diene) , e x i s t i n an e q u i l i b r i u m mixture of the two geometries. For most dienes, the s — c i s isomer predominates but 1 , 4 — s u b s t i t u t e d dienes do favour the s — t r a n s conformation, p o s s i b l y f o r s t e r i c reasons. In a d d i t i o n , i t has been demonstrated that the s — t r a n s isomer i s the i n i t i a l k i n e t i c product i n a l l cases, e q u i l i b r i u m o n l y being e s t a b l i s h e d above -10°C [112]. I t i s p o s s i b l e t h a t (T? 5-C 5H 5 )MO(NO) (T?"-s-trans-diene) i s a l s o the k i n e t i c product, but has a much higher a c t i v a t i o n b a r r i e r towards i s o m e r i s a t i o n . 86 The reasons f o r these new complexes' p r e f e r e n c e f o r the s — t r a n s geometry are not e n t i r e l y obvious. There would appear to be no s t e r i c r e s t r i c t i o n to s — c i s c o o r d i n a t i o n as the much more s t e r i c a l l y crowded complex [ ( r j 5 — C 5 H 5 )Mo(dppe)(rj f l— d i e n e ) ] + adopts the endo—s—cis conformation. I t i s probable, t h e r e f o r e , that the cause i s e l e c t r o n i c i n nature. However, c o n f i r m a t i o n of t h i s would r e q u i r e a d e t a i l e d molecular o r b i t a l a n a l y s i s of the " ( i ? 5 - C 5 H 5 )M(NO) " fragment and i t s bonding c a p a b i l i t i e s . ( i i i ) Experimental S e c t i o n General procedures employed in t h i s r e s e a r c h were d e s c r i b e d i n Chapter 2 s e c t i o n ( i i i ) . R e a c tion of [ (T? 5—C 5H 5 )W(NO) 1 7 ] a with T l ( C 5 H 5 ) . To a green s o l u t i o n of [ (T? 5-C 5H 5 )W(NO) I 2 ] 2 (0.42g, 0.39mmol) [57] i n THF (40ml) was added s o l i d T l ( C 5 H s ) 1 (0.21g, 0.78mmol). The r e a c t i o n mixture was s t i r r e d at room temperature f o r 1 hr whereupon i t g r a d u a l l y darkened to a deep red c o l o u r , and a yellow p r e c i p i t a t e of T i l formed. The mixture was then taken to dryness i n vacuo, and the residue was e x t r a c t e d with CH 2C1 2 (3x15mL). The e x t r a c t s were f i l t e r e d through a C e l i t e Warning: T h a l l i u m and i t s compounds are extremely t o x i c and must be handled with c a r e . 87 column (3x3cm) supported on a medium-porosity f r i t , and the f i l t r a t e was con c e n t r a t e d under reduced pressure to ca. 5mL. The a d d i t i o n of hexanes (60mL) to t h i s s o l u t i o n induced the p r e c i p i t a t i o n of golden—brown, m i c r o c r y s t a l l i n e (C 5H 5) 2W(NO)l (0.22g, 60% y i e l d ) . A n a l . C a l c d f o r C 1 0H 1 0NIOW: C,25.48; H,2.12; N,2.97; I, 27.00. Found: C,25.13; H,2.01; N,3.13; I, 27.00. IR (C H 2 C 1 2 ) : i>(NO) 1622 cm' 1. 1H—NMR (CDC1 3): 6 6.16(s). 13C-NMR (CDC1 3): 5 109.5. Mp (under N 2 ) : 127°C dec. Mass spectrum m/z ( R e l . I n t e n s i t y ) : 471(21) [ P ] + , 441(100) [P-NO] +, 314(85) [ P - N 0 - I ] + . When Na(C 5H 5) (0.78mmol i n 1OmL of THF) was employed i n s t e a d of T l ( C 5 H 5 ) i n the above r e a c t i o n , the f i n a l o r g a n o m e t a l l i c product was i s o l a t e d i n comparable y i e l d . R eactions of [ (775 —C 5 H 5 ) W (NO) I 7 ] and (C 5H 5) 2W(NO)I with  T K C 5 H 5 ) . S o l i d T 1 ( C 5 H S ) (0.27g, I.Ommol) was added to a brown s o l u t i o n of (C 5H 5) 2W(NO)I (0.47g, I.Ommol) i n THF (30mL) at ambient temperature. The mixture was s t i r r e d f o r 1hr, d u r i n g which time a yellow s o l i d p r e c i p i t a t e d . The f i n a l r e a c t i o n mixture was f i l t e r e d through a C e l i t e column (3x5cm) supported on a f r i t , and the deep red f i l t r a t e was taken to dryness i n vacuo. The r e s u l t i n g r e s i d u e was d i s s o l v e d i n benzene (8mL), and the s o l u t i o n was t r a n s f e r r e d to a short (3x5cm) column of s i l i c a . I n i t i a l e l u t i o n of the column with benzene developed a p a l e yellow band which was 88 c o l l e c t e d . Removal of s o l v e n t from t h i s e l u a t e under reduced pressure a f f o r d e d a small amount of an a i r — s e n s i t i v e , yellow s o l i d whose i d e n t i t y remains t o be a s c e r t a i n e d . F u r t h e r e l u t i o n of the column with benzene—THF (3:1) r e s u l t e d i n the development of a s i n g l e red band which was c o l l e c t e d and taken to dryness i n vacuo. R e c r y s t a l l i z a t i o n of the t a r r y , red r e s i d u e from CH 2C1 2/hexanes produced b r i c k — r e d m i c r o c r y s t a l s of (C 5H 5) 3W(NO) (O.lOg, 24% y i e l d ) . A n a l . C a l c d f o r C 1 5H 1 5NOW: C, 44.01; H, 3.67; N, 3.42. Found: C, 43.71; H, 3.55; N, 3.45. IR (CH 2 C 1 2 ) : y(NO) 1588 .cm-1. 1H—NMR (CDC1 3 ) : 6 5.73(s). 1 3C-NMR (CDC1 3): 5 110.6. Mass spectrum m/z(Rel. I n t e n s i t y ) : 409(26) [ P ] + , 379(14) [P-NO] +, 344(44) [ P - C 5 H 5 ] + , 314(100) [P-NO-C 5H 5] +. The complex may be i s o l a t e d i n comparable y i e l d s by the r e a c t i o n of Na(C 5H 5) with (C 5H 5) 2W(NO)I or the a d d i t i o n of e i t h e r Na(C 5H 5) or T l ( C 5 H 5 ) to a THF s o l u t i o n of [ ( T J 5 - C 5 H 5 ) W ( N O ) I 2 ] 2 . Reaction of [ (7? 5-C 5H 5 )Mo(NO) 1 2 ] 2 with Na/Hg/diene. A red s o l u t i o n of [ (TJ 5-C 5H 5 )Mo(NO)I 2 ] 2 (2.00g, 2.25mmol) i n THF (75mL) c o n t a i n i n g 2mL of diene was added to a Na amalgam (0.23g, 1Ommol Na i n 5mL Hg). An immediate r e a c t i o n o c c u r r e d , and the s o l u t i o n turned a yellow—brown c o l o u r . A f t e r being s t i r r e d f o r 15 min to ensure complete r e a c t i o n , the r e a c t i o n mixture was f i l t e r e d through a 3x6cm alumina column. The column was washed with THF u n t i l the washings 89 were c o l o u r l e s s . The yellow—orange e l u a t e was the taken to dryness i n vacuo. E x t r a c t i o n of the orange r e s i d u e with hexanes (3x15mL) fo l l o w e d by f i l t r a t i o n of the combined e x t r a c t s through a 2x4cm C e l i t e column produced a pa l e yellow f i l t r a t e . T h i s f i l t r a t e was taken to dryness i n vacuo to give a yellow s o l i d . In the case of j_ t h i s s o l i d proved to be a n a l y t i c a l l y pure. For the other two complexes a n a l y t i c a l l y pure m a t e r i a l c o u l d be obt a i n e d by r e c r y s t a l l i z a t i o n from hexanes at -10°C. The complexes, ( T ? 5 - C 5 H s )MO(NO) (?7 f t-s-trans-diene) were i s o l a t e d i n 6-10% y i e l d . For diene=C 5H 8: A n a l . C a l c d f o r C 1 0H 1 3NMoO: C, 46.34; H, 5.06; N, 5.41. Found: C, 46.41; H, 5.24; N, 5.16. IR (C H 2 C 1 2 ) : »>(NO) 1591 cm" 1. 1H—NMR (CDC1 3): (see Tables 3.1 and 3.2). 13C-NMR (CDC1 3): 6 96.82(C 2), 95.29(C 5H 5), 80.42(C 3), 55.60(0,), 50.84(C«), 17.55(CH 3). Mass spectrum m/z:•[P] +=261 (based on 9 8 M o ) . For diene=C 6H, 0: A n a l . C a l c d f o r C^H^NMoO: C, 48.36; H, 5.53; N, 5.13. Found: C, 48.94; H, 5.84; N, 4.54. IR (C H 2 C 1 2 ) : ?(NO) 1590 cm' 1. 1H-NMR(CDC1 3): (see Tables 3.1 and 3.2). 13C-NMR (CDC1 3): 6 111.09, 104.68(C 2 and C 3 ) , 96.76(C 5H 5), 55.05, 54.08(0, and C,), 23.89, 20.96(CH 3). For diene=C 6H, f t: A n a l . C a l c d f o r C l 3H 1 9NMoO: C, 51.83; H, 6.36; N, 4.65. Found: C, 51.95; H, 6.44; N, 4.66. IR ( C H 2 C 1 2 ) : v(NO) 1584 cm" 1. 'H-NMR (CDC1 3): (see Tables 3.1 and 3.2). Mass spectrum m/z: [P] +=303 (based on 9 8 M o ) . 90 CHAPTER FOUR SOLVENT CONTROL OF THE REACTIONS OF PICYCLOPENTADIENYLIODO—  NITROSYLMOLYBDENUM WITH SOME SILVER (I) SALTS. ( i ) I n t r o d u c t i o n Since the f i r s t r e p o rt of i t s e x i s t e n c e i n 1968 [59], (C 5H 5) 2Mo(NO)I has a t t r a c t e d c o n s i d e r a b l e a t t e n t i o n [100,115]. In p a r t i c u l a r , the molecular s t r u c t u r e of the complex i n s o l u t i o n and the mode of attachment of the c y c l o p e n t a d i e n y l r i n g s to the metal c e n t r e have been the s u b j e c t s of much s p e c u l a t i o n (see Chapter 3 ( i i ) ) . I t i s c l e a r from the pr e v i o u s s t u d i e s that not a l l of the a v a i l a b l e e l e c t r o n d e n s i t y on the c y c l o p e n t a d i e n y l l i g a n d s i s being u t i l i s e d by the metal. Consequently, i t should be p o s s i b l e to e f f e c t the i o d i d e — a b s t r a c t ion r e a c t i o n ( C 5 H 5 ) 2Mo(NO)l - I" > [ ( T J 5 - C 5 H 5 ) 2Mo(NO) ] + ...(4.1) a process that would be f a c i l i t a t e d by the concommitant l i n k a g e of both C 5 H 5 r i n g s to the molybdenum atom i n an r j 5 — f a s h i o n i n order that the metal c e n t r e may r e t a i n the 91 favoured 18—electron c o n f i g u r a t i o n . One of the p r i n c i p a l methods f o r accomplishing c o n v e r s i o n s of the type (4.1) i n v o l v e s treatment of the or g a n o m e t a l l i c h a l i d e with v a r i o u s s i l v e r (I) s a l t s . G e n e r a l l y , the c a t i o n i c complexes thus produced are 18—electron s p e c i e s i n which e i t h e r a donor s o l v e n t (e.g., CH 3CN, THF, acetone e t c . ) or a l i g a t e d c o u n t e r i o n (e.g., BF„-, P F 6 _ , S b F 6 _ etc.) has r e p l a c e d the h a l i d e i n the metals c o o r d i n a t i o n sphere, the l a t t e r s i t u a t i o n o c c u r r i n g i n weakly c o o r d i n a t i n g s o l v e n t s [81,116,117]. T h i s chapter d e s c r i b e s i n v e s t i g a t i o n s i n t o the r e a c t i o n s of (C 5H 5) 2Mo(NO)l with AgY (Y=BF, or S b F 6 ) . These i n v e s t i g a t i o n s r e v e a l a more pronounced i n f l u e n c e of the sol v e n t on the outcome of these t r a n s f o r m a t i o n s . ( i i ) R e s u l t s And D i s c u s s i o n (a) Reaction Of S i l v e r (I) S a l t s With (C 5H 5) 2Mo(NO)I In A c e t o n i t r i l e . The a d d i t i o n of a s t o i c h i o m e t r i c amount of AgBF 4 or AgSbF 6 to a s o l u t i o n of (C 5H 5) 2Mo(NO)l i n CH 3CN r e s u l t s i n the r a p i d p r e c i p i t a t i o n of s i l v e r i o d i d e and the formation of the new o r g a n o m e t a l l i c c a t i o n [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + . 92 ( C 5 H 5 ) 2 M o ( N O ) l + CH 3CN + AgY > [(C 5H 5) 2Mo(NO)(CH 3CN)]Y + Agl ...(4.2) The o r g a n o m e t a l l i c products from these c o n v e r s i o n s can be i s o l a t e d i n good y i e l d s (71-85%). T h e i r formation i n d i c a t e s that under these c o n d i t i o n s the metal c e n t r e p r e f e r s to a t t a i n the 18—e l e c t r o n c o n f i g u r a t i o n by c o o r d i n a t i o n of a molecule of the donor s o l v e n t r a t h e r than by a l t e r i n g the nature of i t s l i n k a g e s to the C 5 H 5 r i n g s from that which e x i s t s i n the i o d i d e r e a c t a n t . The black s a l t s [(C 5H 5) 2Mo(NO)(CH 3CN)]Y (Y=BF„ or SbF 6) are diamagnetic s o l i d s that can be handled i n a i r f o r short p e r i o d s of time without the occurrence of n o t i c e a b l e decomposition. They are f r e e l y s o l u b l e i n most p o l a r organic s o l v e n t s t o produce red—black, a i r — s e n s i t i v e , and m o i s t u r e — s e n s i t i v e s o l u t i o n s . T h e i r s p e c t r a l p r o p e r t i e s are c o n s i s t e n t with the c a t i o n p o s s e s s i n g a monomeric molecular s t r u c t u r e . Thus, t h e i r N u j o l mull i n f r a r e d s p e c t r a e x h i b i t s i n g l e s t r o n g a b s o r p t i o n s i n the re g i o n normally a s s o c i a t e d with t e r m i n a l n i t r o s y l l i g a n d s [68] (e.g., y(NO)=1665 cm"1 f o r Y=SbF 6) as w e l l as weaker bands a t t r i b u t a b l e to the co o r d i n a t e d a c e t o n i t r i l e l i g a n d (e.g., v(CN)=2320 and 2298 cm"1 f o r Y=SbF 6; c f . 2298 and 2258 cm"1 f o r f r e e a c e t o n i t r i l e ) . The presence of the CH 3CN l i g a n d i s a l s o confirmed by the 1H—NMR s p e c t r a , those of the SbF 6 s a l t being presented i n F i g u r e 4.1. The 1H—NMR spectrum of the F i g u r e 4.1 80MHz 1H—NMR Spectra Of [(C 5H,) 2Mo(NO)(CH 3CN)]SbF K. (a) i n CD,NO: (b) i n CD 3CN 94 s a l t i n CD 3N0 2 d i s p l a y s a broad resonance at 86.4 due to the c y c l o p e n t a d i e n y l protons and a sharp s i n g l e t at 52.70 due to the protons of the c o o r d i n a t e d CH 3CN ( c f . 62.00 f o r f r e e CH 3CN). In CD 3CN, the peak due to the C 5 H 5 protons i s a sharp s i n g l e t while the resonance due to the c o o r d i n a t e d a c e t o n i t r i l e i s superimposed on the r e s i d u a l s o l v e n t s i g n a l . A 13C-NMR spectrum of [(C 5H 5) 2Mo(NO)(CH 3CN)]BF« i n CD 3CN only d i s p l a y s a s i n g l e sharp resonance due to the C 5 H 5 carbons at 6114.6 and s i g n a l s at 5118.5 and 1.3 due to CH 3CN. The broadness of the c y c l o p e n t a d i e n y l resonance i n the 1H—NMR spectrum of [(C 5H 5) 2Mo(NO)(CH 3CN)]SbF 6 i n CD 3N0 2 probably r e f l e c t s the e x i s t e n c e " of a f l u x i o n a l process analogous to that b e l i e v e d to occur f o r the parent (C 5H 5) 2Mo(NO)I [100,115]. However, the f a c t that t h i s resonance becomes sharp when the s a l t i s d i s s o l v e d i n CD 3CN i n d i c a t e s some dependence of the rearrangement processes on the s o l v e n t . In a d d i t i o n , the 1H- and 13C-NMR s p e c t r a recorded i n CD 3CN i n d i c a t e t h a t i n s o l u t i o n t h e r e i s a r a p i d chemical exchange (on the NMR time s c a l e ) between f r e e and co o r d i n a t e d CH 3CN. [( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + + CD 3CN 1 * [ ( C 5 H 5 ) 2 M o ( N O ) ( C D 3 C N ) ] + + CH 3CN ...(4.3) 95 (b) 1t\ Aqueous Acetone The i n i t i a l r e a c t i o n between AgY (Y=BF„ or SbF 6) and an equimolar amount of (C 5H 5) 2Mo(NO)I i n aqueous acetone proceeds as i n a c e t o n i t r i l e , p r e c i p i t a t i o n of Agl and formation of a red—black s o l u t i o n o c c u r r i n g r a p i d l y . However, over a p e r i o d of s e v e r a l hours, the s o l u t i o n becomes b r i g h t orange; s a l t s of the t r i m e t a l l i c c a t i o n [ ( ( T J 5 — C 5 H 5 )Mo (NO) ( 0 H ) } 3 0 ] + can be i s o l a t e d i n moderate y i e l d s from the f i n a l r e a c t i o n mixture. Since the same products r e s u l t when acetone s o l u t i o n s of the [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] Y compounds are t r e a t e d with water, i t seems l i k e l y t h a t the f i r s t step i n both c o n v e r s i o n s i n v o l v e s the formation of the aquo c a t i o n [ ( C 5 H 5 ) 2 M o ( N O ) ( O H 2 ) ] + (Scheme 4.1). Once i s o l a t e d , the hexafluoroantimonate or t e t r a f l u o r o b o r a t e s a l t s of [ { ( T J 5 - C 5 H 5 ) M O ( N O ) ( O H ) } 3 0 ] + can be converted to the t e t r a p h e n y l b o r a t e s a l t by simple metathesis with N a B ( C 6 H 5 ) „ i n H 20. The t r i s [ ( T J 5 — c y c l o p e n t a d i e n y l ) h y d r o x o n i t r o s y l — molybdenio]oxonium s a l t s are yellow (Y=B(C 6H 5)«) or orange (Y=BF„ or SbF 6) a i r - s t a b l e s o l i d s t h a t c r y s t a l l i z e from s o l u t i o n with one or two molecules of the s o l v e n t of c r y s t a l l i z a t i o n . T h e i r t r i m e t a l l i c nature can be determined from elemental analyses and confirmed by c a r e f u l i n t e g r a t i o n of the 1H-NMR spectrum of the t e t r a p h e n y l b o r a t e s a l t . They Scheme 4.1 (C 5H 5) 2Mo(NO)l + AgY 96 H 20,acetone -AgY [(C 5H 5) 2Mo(NO)(OH 2)]Y H 20,acetone -CH 3CN [(C 5H 5) 2Mo(NO)(CH,CN)]Y H 20,acetone [ { ( T J 5 - C 5 H 5 ) M O ( N O ) ( O H ) } 3 0 ] Y are s o l u b l e i n s t r o n g l y s o l v a t i n g s o l v e n t s to a f f o r d b r i g h t orange a i r — s t a b l e s o l u t i o n s . The s p e c t r a l p r o p e r t i e s of the SbF 6" s a l t , i s o l a b l e as the acetone s o l v a t e , are t y p i c a l of t h i s c l a s s of compounds. I t s N u j o l mull i n f r a r e d spectrum e x h i b i t s a strong p(NO) at 1666 cm"' and a weaker v(OH) at 3510 cm - 1. I t s 1H—NMR spectrum i n CD 3CN c o n s i s t s of s i n g l e sharp peaks at 56.17, 2.08 and 1.67 of r e l a t i v e i n t e n s i t y 5:2:1, which are a s s i g n a b l e to the protons of the C 5H 5, (CH 3) 2CO and OH groups r e s p e c t i v e l y . The a d d i t i o n of a small q u a n t i t y of D 20 to t h i s CD 3CN s o l u t i o n causes the resonance at 51.67 to s h i f t downfield to 63.73, thereby i n d i c a t i n g r a p i d H—D chemical exchange, a fe a t u r e t y p i c a l of hyd r o x y l 97 groups. The 1H—NMR sp e c t r a of the BF,' and B ( C 6 H 5 ) f l _ s a l t s (both diaquo s o l v a t e s ) i n (CD 3) 2CO d i s p l a y a resonance at 62.77, which i n t e g r a t e s f o r seven protons (3 due to c o o r d i n a t e d OH p l u s 4 due to s o l v a t e d H 2 0 ) . Upon a d d i t i o n of D 20, t h i s s i g n a l a l s o s h i f t s to 64—5. These p r o p e r t i e s are i n acco r d with the t r i m e t a l l i c c a t i o n p o s s e s s i n g the b a s i c s t r u c t u r e , an arrangement having o v e r a l l C 3 symmetry.. A l t e r n a t i v e l y , the OH groups may bri d g e the edges of the Mo 3 t r i a n g l e as i n the s t r u c t u r e below. 98 Both arrangements s a t i s f y the e f f e c t i v e atomic number r u l e , the capping oxygen atom f u n c t i o n i n g as . a formal f o u r — e l e c t r o n donor. T h i s l a t t e r f e a t u r e has ample precedence i n the l i t e r a t u r e e.g. [ { ( T J 5 - C 5 H 5 )MO(CO) 2} 3 — ( M 3 - 0 ) ] + [118], [ ( T ? 5 - C 5 H 5 ) C O ] 3 ( M 3 - C O - ) U 3 - 0 ) [119], [ { ( O C ) 3 R e } 3 ( M 2 - H ) 3 ( u 3 - 0 ) ] 2 " [120], [ ( F 3 W ) 3 ( M 2 - 0 ) 3 ( u 3 - 0 ) ] 5 -[121] and [ N a { M o 3 ( C O ) 6 ( N O ) 3 ( n 2 - O M e ) 3 ( M 3 - 0 ) } 2 ] 3 " [122]. The molybdenum complex [ { ( T J 5 - C 5 H 5 )MO(CO) 2} 3 (n3-0) ] + i s of p a r t i c u l a r r elevance s i n c e i t i s valence i s o e l e c t r o n i c with the h y d r o x o n i t r o s y l c a t i o n . I t can be s y n t h e s i s e d by the r e a c t i o n s of [ ( T J 5 — C 5 H 5 )Mo(CO) 3 ] + or [ ( T J 5 - C 5 H 5 )Mo(CO) 3 ( C 3 H 6 0 ) ] + with water v i a the i n t e r m e d i a t e aquo complex, [ ( T J 5 — C 5 H 5 )Mo (CO) 3 ( O H 2 ) ] * [118]. By analogy, the formation of [ {( T J 5 - C 5 H 5 )MO(NO) (OH)} 3 0 ] + c o u l d i n v o l v e 99 the decomposition of the i n i t i a l l y formed [ ( C 5 H 5 ) 2 M o ( N O ) ( 0 H 2 ) ] • c a t i o n ( c f . Scheme 4.1) by a s e r i e s of Lowrey-Bronsted acid-base* e q u i l i b r i a (see Scheme 4.2) to g i v e [ { ( C 5 H 5 ) 2 M o ( N 0 ) } 3 0 ] * i n a f a s h i o n s i m i l a r to that Scheme 4.2 [ ( C 5 H 5 ) 2 M o ( N O ) ( 0 H 2 ) ] + + H 20 ^ [(C 5H 5) 2Mo(NO)(OH)] + H 3 0 + A B A + B i % [ { ( C 5 H 5 ) 2 M o ( N 0 ) } 2 0 H ] + + H 20 C C + H 20 % s [ ( C 5 H 5 ) 2 M o ( N O ) ] 2 0 + H 3 0 + D A + D , > [ { ( C 5 H 5 ) 2 M o ( N 0 ) } 3 0 ] + + H 20 E E + 3 H 2 0 > [ { (T? 5-C 5H 5)MO(NO) ( O H ) } 3 0 ] + + 3 C 5 H 6 F proposed f o r the c a r b o n y l d e r i v a t i v e . The f i n a l s t e p to form the observed product would then r e q u i r e an i r r e v e r s i b l e h y d r o l y s i s of one of the c y c l o p e n t a d i e n y l l i g a n d s . Support f o r the involvement of such a mechanism i s p r o v i d e d by the 100 f a c t t h a t , whereas [(C 5H 5) 2Mo(NO)(CH 3CN)]BF„ r e a d i l y c o n v e r t s to [ {(7? 5-C 5H 5 )Mo(NO) (OH)} 30]BF„ i n aqueous acetone, i t i s s t a b l e to h y d r o l y s i s i n CH 3CN where the bulk s o l v e n t competes as a l i g a n d , ' t h e r e b y suppressing the formation of the r e q u i s i t e aquo c a t i o n . (c) In Dichloromethane Since i o d i d e a b s t r a c t i o n from (C 5H 5) 2Mo(NO)I i n c o o r d i n a t i n g s o l v e n t s a p p a r e n t l y leads to [ ( C 5 H 5 ) 2 M o ( N O ) ( s o l v e n t ) ] + c a t i o n s r a t h e r than [ (T? 5—C 5H 5) 2Mo(NO) ] + , r e a c t i o n 4.1 was next attempted i n CH 2C1 2, a non — c o o r d i n a t i n g s o l v e n t . Under these c o n d i t i o n s , the d e s i r e d c o n v e r s i o n again does not occur i n the presence of s i l v e r (I) s a l t s as the adducts (C 5H 5) 2Mo(NO)I.AgY p r e c i p i t a t e i n s t e a d i n hig h y i e l d s . The r e a c t i o n proceeds s i m i l a r l y f o r the congeneric tungsten complex prepared i n Chapter 3. (C 5 H 5 ) 2 M ( N O ) l + AgY > (C 5H 5) 2M(NO)I.AgY ...(4.4) M=Mo or W; Y=BF„ or SbF 6. These adducts are red—brown, a i r — s t a b l e (but l i g h t — s e n s i t i v e ) s o l i d s , which only d i s s o l v e i n s o l v e n t s with which they r e a c t at v a r y i n g r a t e s . For i n s t a n c e , decomposition of (C 5H 5) 2Mo(NO)I.AgBF, i n CH 3N0 2, as 101 evidenced by p r e c i p i t a t i o n of A g l , i s only s i g n i f i c a n t a f t e r more than 10 mins. N e v e r t h e l e s s , i t s i n i t i a l s o l u b i l i t y i n t h i s s o l v e n t p r e c l u d e s i t s being a p h y s i c a l mixture of [ ( T J 5 - C S H 5 ) 2Mo(NO) ]BF f t and A g l . The N u j o l mull i n f r a r e d s p e c t r a of the adducts d i s p l a y broad a b s o r p t i o n s a t t r i b u t a b l e to t e r m i n a l n i t r o s y l l i g a n d s i n the range 1615-1660 cm - 1 (Table 4.1). Furthermore, these s p e c t r a show strong a b s o r p t i o n s due to the anions, which i n d i c a t e some degree of c o o r d i n a t i o n of these s p e c i e s . Thus i n s t e a d of d i s p l a y i n g the c h a r a c t e r i s t i c s i n g l e v(BF) a b s o r p t i o n at 984 cm"1 a s s i g n a b l e to the T 2 s t r e t c h i n g mode of a f r e e BFfl anion, the spectrum of (C 5H 5) 2Mo(NO)I.AgBF f t d i s p l a y s *>(BF) bands at 1083, 1053, 1018 and 1003 cm" 1. The appearance of these bands may be a t t r i b u t e d to a lowering of the l o c a l symmetry of the BF„" anions from T d to C 2 V , a change which produces four i n f r a r e d — a c t i v e v i b r a t i o n s due to the 2 A 1 r B, and B 2 s t r e t c h i n g modes [118]. S i m i l a r l y , the i n f r a r e d spectrum of (C 5H S) 2Mo(NO)I.AgSbF 6 e x h i b i t s two p(SbF) bands at 659 and 639 cm" 1, a f e a t u r e which i n d i c a t e s a lowering of the l o c a l symmetry of the hexafluoroantimonate anion from 0|, to C F L V or C 2 V [ 1 2 3 ] . The mull i n f r a r e d s p e c t r a a l s o provide some i n s i g h t i n t o the nature of the adducts produced by r e a c t i o n (4.4). The. r e a c t a n t , ( C 5 H 5 ) 2 M o ( N O ) I , molecules c o n t a i n four p o t e n t i a l Lewis base s i t e s with which the s o f t Lewis a c i d Ag + may i n t e r a c t . Table 4.1 N i t r o s y l S t r e t c h i n g Frequencies Of Some Molybd  And Tungsten Complexes. Complex medium v(NO),cm" 1 (C 5H 5) 2Mo(NO)I CH 2C1 2 Nu j o l 1642 a 1 621 (TJ 5-C 5H 5)MO(NO) ( T ? 3 - C 3 H 5 ) I KBr 1651 b (C 5H 5) 2Mo(NO)l.AgBF 4 N u j o l 1644 (C 5H 5) 2Mo(NO)l.AgSbF 6 Nu j o l 1658 ( C 5 H 5 ) 2 W ( N 0 ) I CH 2C1 2 N u j o l 1622 c 1581 (7? 5-C 5H 5)W(NO) ( T J 3 - C 3 H 5 ) I CH 2C1 2 1636 d (C 5H 5) 2W(NO)l.AgBF„ N u j o l 1618 (C 5H 5) 2W(NO)l.AgSbF 6 N u j o l 1616 a Taken from r e f . 59. b Taken from r e f . 101. c See chapter 3. d Taken from r e f . 61. 103 \ M*-b I * - c d - C 5 H 5 That s i t e s (a) and (b) are not i n v o l v e d i n l i n k a g e s to Ag + i s i n d i c a t e d by the P(NO) data presented i n Table 4.1 which r e v e a l a s h i f t to higher frequency of 25—40 cm - 1 upon adduct fo r m a t i o n . T y p i c a l l y , the formation of i s o n i t r o s y l l i n k a g e s ( s i t e (a)) r e s u l t s i n the d i m i n u t i o n of i>(NO) by 100-200 cm - 1 [32,33,124], and s t u d i e s with r e l a t e d c a r b o n y l complexes [125] suggest that formation of a M—Ag bond should be r e f l e c t e d by an i n c r e a s e i n p(NO) of at l e a s t 100 cm - 1 However, the i n f r a r e d data are not s u f f i c i e n t to permit a d i f f e r e n t i a t i o n between the two other p o s s i b l e s t r u c t u r e s . 1 A study of the i n t e r a c t i o n of ( T J 5 - C 5 H 5 )M(CO) (NO) (PPh 3) (M=Mo or W) with A1C1 3 and SnCl« shows that both the c a r b o n y l and n i t r o s y l a b s o r p t i o n s i n c r e a s e by 120—170 cm*1 upon adduct formation v i a the t r a n s i t i o n metal [32,124]. 1 04 For both arrangements a s l i g h t i n c r e a s e i n the n i t r o s y l s t r e t c h i n g frequency from that d i s p l a y e d by the parent ( C 5 H 5 ) 2 M ( N O ) I complex i s to be expected [32,124]. The 1H—NMR sp e c t r a of the adducts do not p r o v i d e any f u r t h e r i n s i g h t as to t h e i r s t r u c t u r e s . For i n s t a n c e , the spectrum of (C 5H 5) 2Mo(NO)I.AgBF„ i n CD 3N0 2 c o n t a i n s m u l t i p l e s i g n a l s i n the region 65.86—6.88, which cannot be r e a d i l y a s s i g n e d . Consequently, d e f i n i t i v e r e s o l u t i o n of t h i s 1 05 q u e s t i o n w i l l r e q u i r e a s i n g l e — c r y s t a l X—ray d i f f r a c t i o n a n a l y s i s of one of the adducts. As s t a t e d e a r l i e r , the molybdenum adducts react with the donor s o l v e n t s i n which they d i s s o l v e , the s o l v e n t s being b e t t e r Lewis bases than (C 5H 5) 2Mo(NO)I and complexing the s i l v e r ion p r e f e r e n t i a l l y . Thus, in a c e t o n i t r i l e the adducts convert to the [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + c a t i o n and A g l , and i n aqueous acetone they t r a n s f o r m to the metallooxonium s a l t s [ {(rj 5 —C 5H 5)Mo(NO) (OH)} 30]Y. The i n t e r r e l a t i o n s h i p of these r e a c t i o n s and those d e s c r i b e d e a r l i e r i n the Chapter i s p r e s e n t e d i n Scheme 4.3. C l e a r l y , Scheme 4.3 AgY [CC5H5)2Mo(NO)(CH3CN)]V CH3CN (C6H5)2Mo (NO) I AgY • (C5H5)2Mo(NO)I.AgY H20, ocetone CHZC[Z AgY, H p [!(T;5-C5H5) MO(N0)(0H)j3OfY" acetone 106 the s o l v e n t e x e r t s a pronounced i n f l u e n c e on the outcome of these t r a n s f o r m a t i o n s . In a non—donor s o l v e n t , the s i l v e r c a t i o n a c t s as a Lewis a c i d and forms an adduct with the o r g a n o m e t a l l i c complex. However, i n a donor s o l v e n t that i s a stronger Lewis base than the complex, the Ag + ion r e v e r t s to i t s more common mode of r e a c t i v i t y , namely, h a l i d e a b s t r a c t i o n . (d) Reaction Of A1C1 3 With ( C 5 H 5 ) 2Mo(N0)I in CH 2C1 2. In view of the s o l v e n t c o n t r o l of the r e a c t i o n s of ( C 5 H 5 ) 2 M o ( N O ) l with s i l v e r (I) s a l t s (Scheme 4.3), i t thus appears that r e a c t i o n 4.1 cannot be e f f e c t e d when Ag + i s employed as the i o d i d e a c c e p t o r . M i n d f u l of these r e s u l t s , the d e s i r e d c o n v e r s i o n was t h e r e f o r e attempted with A1C1 3 (a harder Lewis A c i d than Ag +) as the h a l i d e a b s t r a c t o r i n CH 2C1 2, a no n — c o o r d i n a t i n g s o l v e n t . When attempted i n t h i s manner, the a n t i c i p a t e d c o n v e r s i o n (equation 4.5) does indeed occur, a l b e i t i n low y i e l d s . ( C 5 H 5 ) 2Mo(NO)l + A I C I 3 > [ ( T 7 5 - C 5 H 5 ) 2Mo(NO) ]A1C1 3I ...(4.5) An excess of aluminum c h l o r i d e i s r e q u i r e d to d r i v e the r e a c t i o n to completion, and the new o r g a n o m e t a l l i c s a l t i s o l a t e d i s a dark red, m o i s t u r e - s e n s i t i v e s o l i d , which i s 1 07 f a i r l y s o l u b l e i n p o l a r organic s o l v e n t s . An i n f r a r e d spectrum of a dichloromethane s o l u t i o n of the complex e x h i b i t s a strong a b s o r p t i o n at 1690 cm"1 a t t r i b u t a b l e to the t e r m i n a l n i t r o s y l l i g a n d . T h i s band i s at s i g n i f i c a n t l y h igher frequency than the corresponding a b s o r p t i o n s of the (C 5H 5) 2Mo(NO)I p r e c u r s o r U(NO)=1642 cm" 1) and the [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + c a t i o n U(NO) = 1673 cm"1 f o r the SbF 6" s a l t i n CH 2C1 2). Not s u r p r i s i n g l y , the 1H—NMR spectrum of the complex i n (CD 3) 2CO c o n s i s t s of a s i n g l e sharp resonance at 56.27 due to the e q u i v a l e n t r j 5 — C 5 H 5 l i g a n d s . The molar conductance of [ (r} 5-C 5H 5) 2Mo(NO) ]A1C1 3I i n CH 3N0 2 i s 57.5 O" 1cm 2mol" 1, a value which i s i n the range a s s o c i a t e d with 1:1 e l e c t r o l y t e s [126]. I n t e r e s t i n g l y , the 1 8 — e l e c t r o n [ (rj 5 —C 5H 5) 2Mo(NO) ] + c a t i o n r e t a i n s i t s i d e n t i t y i n CH 3CN ( i . e . , P(NO)=1678 cm" 1) and does not convert to the [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + s p e c i e s U(NO)=1651 cm"1 i n CH 3CN). Both of these o b s e r v a t i o n s are c o n s i s t e n t with the complex being an i o n i c s p e c i e s 108 -I + Mo—NO r a t h e r than a Lewis acid—base adduct v i a a Mo—I—>A1 l i n k a g e . Furthermore, the second o b s e r v a t i o n a l s o i n d i c a t e s that [ (r? 5— C 5H 5) 2Mo(NO) ] + i s not an int e r m e d i a t e e i t h e r d u r i n g the formation of the a c e t o n i t r i l e c a t i o n by r e a c t i o n 4.2 or du r i n g the exchange process shown i n equation 4.3. P l a u s i b l e mechanisms f o r these r e a c t i o n s are thus:— (C 5H 5) 2Mo(NO)I + CH 3CN > ( T J 5 - C 5 H 5 ) (TJ'-CBHS )Mo(NO) ( C H 3 C N ) I ... (4.6) ( T J 5 - C 5 H 5 ) ( T J 1 - C 5 H 5 )Mo(NO) ( C H 3 C N ) I + Ag + > [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + +AgI ...(4.7) and 109 [ ( C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] + + CD 3CN > [ (i? 5 - C 5 H 5 ) (T? 1-C5H 5)MO(NO) (CH 3CN) (CD 3CN) ] + ... (4.8) [ ( 77 5 - C 5 H 5 ) ( r j 1 - C 5 H 5 )Mo(NO) (CH 3CN) (CD 3CN) ] + > [ ( C 5 H 5 ) 2 M o ( N O ) ( C D 3 C N ) ] + + CH 3CN ...(4.9) These sequences of steps are i n accord with McCleverty's p r o p o s a l concerning the t r a n s i t i o n a l s t r u c t u r e of (C 5H 5) 2Mo(NO)I i n s o l u t i o n [100]. ( i i i ) Experimental S e c t i o n General procedures employed i n t h i s r e s e a r c h were d e s c r i b e d i n Chapter 2 s e c t i o n ( i i i ) . R e action of ( C 5 H 5 ) 2 M o ( N 0 ) l with AgY (Y=BF a or SbF 6) i n  CH 3CN. . To a r a p i d l y s t i r r e d green—brown s o l u t i o n of (C 5 H 5 ) 2 M o ( N O ) l [59] (0.77g, 2.0mmol) i n CH 3CN (40mL) was added s o l i d AgBFft (0.39g, 2.0mmol). A white p r e c i p i t a t e formed immediately, and the supernatant became re d — b l a c k . A f t e r being s t i r r e d f o r 1 hr to ensure completion of the r e a c t i o n , the r e a c t i o n mixture was f i l t e r e d through a column of C e l i t e (3x3cm) supported on a medium p o r o s i t y f r i t . The f i l t r a t e was conc e n t r a t e d under reduced p r e s s u r e to a volume of lOmL. A d d i t i o n of d i e t h y l ether (40mL) induced the c r y s t a l l i z a t i o n of black [ (C 5H 5) 2Mo(NO)(CH 3CN)]BF„: (0.54g, 110 71% y i e l d ) . A n a l . C a l c d f o r C , 2 H , 3 N 2 B F „ M o O : C, 37.53; H, 3.41; N, 7.30. Found: C, 37.58; H, 3.43; N, 7.26'. IR (Nujol m u l l ) : »>(CN) 2319, 2297 cm" 1; ?(N0) 1666(br) cm" 1. IR (CH 3CN) : p(N0) 1651 cm" 1. 1H—NMR (CD 3CN): 5 6.36(s). 1H—NMR (CD 3N0 2): 5 6.34(br,l0H,C 5H 5), 2.70(s,3H,CH 3). 13C-NMR (CD 3CN): 6 114.6. Mp 125°C dec. A n a l y t i c a l l y pure [(C 5H 5) 2Mo(NO)(CH 3CN)]SbF 6 can be obtained s i m i l a r l y i n 85% y i e l d from (C 5H 5) 2Mo(NO)I and AgSbFg. A n a l . C a l c d f o r C t 2H, 3N 2F 6MoSbO: C, 27.04; H, 2.46; N, 5.26. Found: C, 27.14; H, 2.40; N, 5.20. IR (Nujol m u l l ) : y(CN) 2320, 2298 cm" 1; ^(NO) 1665 cm" 1; j/(SbF) 650(br) cm" 1. IR(CH 3CN): i>(NO) 1651 cm" 1; v(SbF) 663 cm" 1. 1H—NMR (CD 3CN) : 8 6.37(s). 1H—NMR (CD 3N0 2): 5 6.40(br,10H,C 5H 5), 2.70(s,3H,CH 3). Mp 117°C dec. Reaction of (C 5H 5) 2Mo(N0)-I with AgY (Y=BF U or SbF 6) i n aqueous acetone. S o l i d AgBF„ (0.59g, 3.0mmol) was added to a s t i r r e d dark green s o l u t i o n of (C 5H 5) 2Mo(NO) I (1.15g,F 3.0mmol) i n acetone (125mL) c o n t a i n i n g H 20 (2mL). Immediately the s o l u t i o n became red—black, and white Agl p r e c i p i t a t e d . The r e a c t i o n mixture was s t i r r e d at ambient temperature f o r 3 hr, whereupon the s o l u t i o n g r a d u a l l y became b r i g h t orange. The f i n a l mixture was f i l t e r e d through C e l i t e (vide supra), and the volume of the f i l t r a t e was 111 reduced to ca. 25mL i n vacuo. D i e t h y l ether (40mL) was then sl o w l y added to induce the c r y s t a l l i z a t i o n of 0.37g (48% y i e l d ) of orange, m i c r o c r y s t a l l i n e [ { (T} 5-C 5H 5)MO(NO) (OH) } 30]BF« .2H 20. An a l . C a l c d f o r C, 5H 2 2N 3Mo 3BF 40 9: C,23.61; H,2.91; N,5.51; Mo, 37.72. Found: C,23.60; H,2.45; N,5.06; Mo, 37.83. IR(Nujol m u l l ) : v(OH) 3460(br) cm" 1; »>(N0) 1662 cm" 1; »>(BF) 1082, 1049, 1020, 999 cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 5 6.27(s,15H,C 5H 5), 2.77(s,7H,OH). 13C-NMR ( D 2 0 ) : 5 112.3. Mp 192°C dec. The r e a c t i o n of (C 5H 5) 2Mo(NO)I with AgSbF s was e f f e c t e d s i m i l a r l y except that 15mL of H 20 was employed. The f i n a l orange f i l t r a t e was taken to dryness i n vacuo, and the r e s u l t i n g r e s i d u e r e c r y s t a l l i z e d from a c e t o n e / d i e t h y l ether to o b t a i n [ { ( T? 5—C 5H 5 )Mo (NO) (OH) } 3 0 ] S b F 6 . (CH 3 ) 2CO as an orange s o l i d i n 18% y i e l d . A n a l . C a l c d f o r C , 8 H 2 4 N 3 F 6 M o 3 0 B S b : C, 23.15; H, 2.59;. N, 4.50. Found: C, 23.29; H, 2.64; N, 4.26. IR (Nujol m u l l ) : v(OH) 3510 cm" 1; v(UO) 1666(br) cm" 1; »>(SbF) 655 cm" 1. IR (CH 3CN): ?(NO) 1674 cm" 1. 1H—NMR (CD 3CN): 5 6. 17(s,15H,C 5H 5), 2.08(s,6H,CH 3), 1.67(s,3H,OH). M p 2 0 3 ° C dec. P r e p a r a t i o n of [ { (T? 5-C 5H 5 )MO(NO) (OH)} 3 Q ] B ( C S H 5 ) 4 . 2H 20. A s a t u r a t e d s o l u t i o n of N a B ( C 6 H 5 ) 4 (0.2g) i n H 20 (lOmL) was added dropwise to an orange s o l u t i o n of 1 12 [ { ( TJ 5 —C 5 H 5 ) Mo (NO) (OH )} 30]BF(,.2H 20 (0.15g, 0.20mmol) i n H 20 (lOOmL). A yellow p r e c i p i t a t e formed immediately, and the mixture was s t i r r e d f o r 0.5 hr to ensure complete p r e c i p i t a t i o n . The s o l i d was then c o l l e c t e d by f i l t r a t i o n and r e c r y s t a l l i z e d from acetone/water to i s o l a t e 0.1g (50% y i e l d ) of [ { (T? 5-C 5H 5 )MO(NO) (OH)} 3 0 ] B ( C e H 5 ) „ .2H 20 as a yellow s o l i d . A n a l . C a l c d f o r C 3 9 H a 2 N 3 M o 3 B 0 3 : C,47.06; H,4.25; N,4.22; Mo, 28.92. Found: C,47.00; H,4.00; N,4.45; Mo, 29.50. IR (N u j o l m u l l ) : P(NO) 1661(br) cm" 1. IR (CH 3CN): »>(NO) 1675 cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 6 7.00(m,20H,C 6H 5), 6.20(s,15H,C 5H 5), 2.77(s,7H,OH). Mp 176°C dec. Reaction of [(C SH 5) 2Mo(NO)(CH 3CN)]BF a with H 20. To a s t i r r e d dark red s o l u t i o n of [(C 5H 5) 2Mo(NO)(CH 3CN)]BF„ (0.34g, 0.90mmol) i n acetone (50mL) was added H 20 (1mL). The mixture g r a d u a l l y became orange over a p e r i o d of 2 hr. I t was then c o n c e n t r a t e d under reduced p r e s s u r e to a volume of 15mL, and d i e t h y l ether (30mL) was added dropwise to induce the c r y s t a l l i z a t i o n of 0.08g (35% y i e l d ) of orange [ {(77 s — C 5 H 5 )Mo (NO) (OH)} 30]BF„. 2H 20, which was i d e n t i f i e d by i t s c h a r a c t e r i s t i c p h y s i c a l p r o p e r t i e s (vide s u p r a ) . Reaction of (C5H.;) 2M(NO)l (M=Mo or W| with AgY (Y=BF n or SbF 6) i n CH 2C1 2. These experiments were a l l performed i n the same manner. The procedure, u s i n g the r e a c t i o n of 113 (C 5H 5) 2Mo(NO)I with AgBF„ as a t y p i c a l example, was as f o l l o w s . S o l i d AgBFn (0.59g, 3.0mmol) was added to a dark green s o l u t i o n of (C SH 5) 2Mo(NO)I d.15g, 3.0mmol) i n CH 2C1 2 (lOOmL), and the r e a c t i o n mixture was s t i r r e d f o r 16 hr. During t h i s time the s o l u t i o n became red, and a dark red s o l i d slowly p r e c i p i t a t e d . T h i s s o l i d was c o l l e c t e d by f i l t r a t i o n , washed thoroughly with CH 2C1 2 (3x40mL) and d r i e d i n vacuo to o b t a i n 1.30g (75% y i e l d ) of a n a l y t i c a l l y pure (C 5H 5) 2Mo(NO)l.AgBF 9. The other red—brown adducts were i s o l a t e d analogously i n y i e l d s of 60% (M=Mo, Y=SbF 6), 74% (M=W, Y=BFfl) and 95% (M=W, Y=SbF 6). For M=Mo, Y=BF„: A n a l . C a l c d f o r C, 0H, 0NAgIMoBF uO: C,20.79; H,1.74; N,2.42; Ag, 18.68; I , 21.96; Mo, 16.61. Found: C,20.61; H,1.98; N,1.99; Ag, 18.50; I , 21.90; Mo, 16.28. IR (Nujol m u l l ) : i>(NO) 1644(br); p(BE) I083(sh), I053(m), I 0 l 8 ( s h ) , I003(sh) cm" 1. 1H—NMR (CD 3N0 2): 5 5.86-6.88 ( m u l t i p l e s i g n a l s ) . Mp 75°C dec. For M=Mo, Y=SbF 6: A n a l . C a l c d f o r C, 0H, 0NIAgF 6MoOSb: C,16.53; H,1.39; N,1.93; I , 17.46. Found: C,16.76; H,1.60; N,1.66; I , 17.29. IR (Nujol m u l l ) : P(NO) 1658(br); i^(SbF) 659(s), 639(sh) cm" 1. 1H—NMR (CD 3N0 2): 5 5.60-7.00 ( m u l t i p l e s i g n a l s ) . Mp 58°C dec. For M=W, Y=BF 4 : A n a l . C a l c d f o r C, 0H, 0NIAgBF„OW: C,18.02; H,1.50; N,2.10; I , 19.07. Found: C,17.35; H,1.70; 1 1 4 N,1.99; I, 18.88. IR (Nujol m u l l ) : J>(NO) 1618, v(BF) I09l(m), I059(m), I024(sh), I009(sh) cm" 1. Mp 61°C dec. For M=W, Y=SbF 6: An a l . C a l c d f o r C, 0H, 0NIAgF 6OSbW: C f14.72; H,1.23; N,1.72; I, 15.58. Found: C,15.20; H,1.51; N,1.48; I, 15.26. IR (Nujol m u l l ) : v(NO) 1616 cm" 1; *>(SbF) 658(s) cm" 1. Mp 58°C dec. Reactions of (C 5H 5) 2Mo(NO)IAgBF a with donor s o l v e n t s . (a) with a c e t o n i t r i l e . (C 5H 5) 2Mo(NO)IAgBF„ OOOmg) was added to a c e t o n i t r i l e (5mL) with s t i r r i n g to o b t a i n a dark red—brown s o l u t i o n and a small amount of an o f f — w h i t e s o l i d . An i n f r a r e d spectrum of the supernatant s o l u t i o n d i s p l a y e d a j>(NO) a b s o r p t i o n at 1651 cm - 1 c h a r a c t e r i s t i c of [(C 5 H 5 ) 2 M o ( N O ) ( C H 3 C N ) ] B F „ . R e p e t i t i o n of the experiment with CD 3CN as solv e n t a f f o r d e d a red—brown supernatant s o l u t i o n whose 1H—NMR spectrum e x h i b i t e d a s i n g l e s t r o n g resonance at 6-6.36 i n a d d i t i o n to s e v e r a l weak s i g n a l s i n the region 86.0—6.6. (b) with acetone/water Attempted d i s s o l u t i o n of (C 5 H 5 ) 2 Mo (NO) I .AgBFj, (50mg) i n 2:1 (CD 3) 2CO/D 20 (2mL) produced an orange—brown s o l u t i o n and an o f f — w h i t e s o l i d . A 'H—NMR spectrum of the orange—brown s o l u t i o n c o n t a i n e d a stron g s i g n a l at 86.36 and weaker, sharp s i g n a l s at 86.48, 6.20 and 6.10. A f t e r 2 days, the resonance a t 1446.36 was u n a l t e r e d , but the l e s s i n t e n s e peaks had dim i n i s h e d i n i n t e n s i t y by ca. 50%. 115 A 1H—NMR spectrum of an a u t h e n t i c sample of [ { ( T J 5 — C 5 H 5 )Mo(NO) (OH)} 30]BF(, . 2H 20 i n the same s o l v e n t mixture d i s p l a y e d a sharp s i g n a l at 66.36. Reaction of ( C 5 H 5 ) 2 M o ( N 0 ) l with A1C1 3. To a s t i r r e d dark green s o l u t i o n of (C 5H 5) 2Mo(NO)I (0.77g, 2.0mmol) i n CH 2C1 2 (40mL) was added an excess of s o l i d A l C l 3 (0.54g, 4.0mmol). The s o l u t i o n became dark red immediately, and a brown p r e c i p i t a t e formed. The r e a c t i o n mixture was s t i r r e d at ambient temperature f o r 10 mins and was then f i l t e r e d through a short C e l i t e column (3x2cm) supported on a medium p o r o s i t y f r i t . The f i l t r a t e was con c e n t r a t e d under reduced pressure to ca. 1OmL and was f i l t e r e d i n t o a f l a s k c o n t a i n i n g d i e t h y l ether (lOOmL) to induce the p r e c i p i t a t i o n of 0.13g (13% y i e l d ) of dark red [ (TJ 5-C 5H 5 ) 2Mo(NO) ]A1C1 3I . An a l . C a l c d f o r C, 0H, 0NCl 3IAlMoO: C,23.26; H,1.95; N,2.71; CI, 20.60; I, 24.58. Found: C,23.34; H,2.12; N,2.66; CI, 20.50; I, 24.33. IR (C H 2 C 1 2 ) : »>(NO) 1690 cm" 1. IR (CH 3CN): i>(NO) 1678 cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 6 6.27(s). Mp 95°C dec. Am (CH 3N0 2): 57.5 fl"1cm2mol"1. 1 16 CHAPTER FIVE ELECTROPHILE—INDUCED REDUCTION OF COORDINATED NITROGEN  MONOXIDE. SEQUENTIAL CONVERSION OF A M 3-NO GROUP TO M3-NOH  AND n3—NH LIGANDS ( i ) I n t r o d u c t i o n Much a t t e n t i o n has been focussed on the a c t i v a t i o n of carbon monoxide, [127,128] i n an attempt to understand b e t t e r the heterogeneous r e d u c t i o n of CO [129,130] and to develop s u i t a b l e homogeneous analogues [131]. The a c t i v a t i o n of n i t r o g e n monoxide, however, has r e c e i v e d c o n s i d e r a b l y l e s s a t t e n t i o n [19,128], although, as d i s c u s s e d i n Chapter 1, i t has r e c e n t l y been recognised as a major source of a c i d r a i n and photochemical smog. I n i t i a l s t u d i e s with regard to p o s s i b l e a c t i v a t i o n of c o o r d i n a t e d NO were focussed p r i m a r i l y on the behaviour of n u c l e o p h i l e s or e l e c t r o p h i l e s towards l i n e a r or bent M—NO l i n k a g e s , r e s p e c t i v e l y [19,31,35,132], e.g. 1 17 [ I r C l 3 ( N O ) ( P P h 3 ) 2 ] + + OEt" > I r C l 3 ( N ( O ) O E t ) ( P P h 3 ) 2 ...(5.1) O s ( P P h 3 ) 2 ( C O ) ( N O ) C l + HC1 > Os ( P P h 3 ) 2 ( C O ) ( H N O ) C l 2 . . . (5.2) O s ( P P h 3 ) 2 ( N O ) 2 + 2HC1 > Os(PPh 3)2(NO)(NHOH)Cl 2 ...(5.3) I r ( P P h 3 ) 3 ( N O ) + 3HC1 > Os(PPh 3) 2(NH 20H)C1 3 +PPh 3 ...(5.4) More recent r e s e a r c h has begun to examine the analogous r e a c t i v i t y p a t t e r n s of t r a n s i t i o n — m e t a l complexes c o n t a i n i n g d o u b l y - b r i d g i n g NO groups [43,133,134] e.g. [ ( r ? 5 - C 5 H 5 ) C r ( N O ) 2 ] 2 + Me" > ( T? 5 - C 5 H 5 ) 2 C r 2 (NO) 3 (N=CH2 ) ...(5.5) [ R u 3 ( C O ) 1 0 ( N O ) ] " + Me+ > Ru 3(CO) 9(NOCH 3) ...(5.6) However, maximum r e d u c t i o n of the NO bond order (and hence optimum a c t i v a t i o n of the bound NO) should occur i n M 3(M3—NO) systems. A c c o r d i n g l y , t h i s Chapter d e s c r i b e s the r e a c t i o n s of one such system, (TJ 5-C 5H f lMe) 3Mn 3 (NO) 4 , with s t r o n g p r o t o n i c a c i d s . 118 ( i i ) R e s u l t s And D i s c u s s i o n The r e a c t i o n of (T? 5-C 5H„Me) 3Mn 3 (NO), with the str o n g p r o t o n i c a c i d s HBF„.OMe 2 or HPF 6(aq) r e s u l t s i n the unprecedented s e q u e n t i a l t r a n s f o r m a t i o n s 3 H + , 2e" where M = ( n 5 - C 5 H 4 Me) Mn(NO) which i n v o l v e an o v e r a l l , formal r e d u c t i o n of the u3—NO l i g a n d . A d d i t i o n of one e q u i v a l e n t of a c i d [HBF„OMe 2 or HPF 6 ( a q ) ] to a CH 2C1 2 s o l u t i o n of (r? 5-C 5H aMe) 3Mn 3 (NO) , (J_) r e s u l t s i n the r a p i d formation of [ (rj 5 —C 5 H ttMe) 3 Mn 3 (NO) 3 (NOH) ] Y (Y=BF 4,2a; Y=PF 6 ,2b) which may be i s o l a t e d i n 43-66% y i e l d as b l a c k , r e l a t i v e l y a i r - s t a b l e , m i c r o c r y s t a l l i n e s o l i d s . The r e a c t i o n i s r e v e r s i b l e as evidenced by the f a c t t h a t the re v e r s e t r a n s f o r m a t i o n s 2—>j_ 119 may be c l e a n l y e f f e c t e d with a s t o i c h i o m e t r i c amount of E t 3 N . F u r t h e r treatment of 2a or 2b with two e q u i v a l e n t s of a c i d a f f o r d s [ (rj 5-C 5H nMe) 3Mn 3 (NO) 3 (NH) ]Y (Y=BF«,3a; Y=PF 6,3b), which are more c o n v e n i e n t l y obtained from the r e a c t i o n of _1_ with an excess of the a p p r o p r i a t e a c i d i n C H 2 C 1 2 . 3a or 3b may a l s o be i s o l a t e d from the r e a c t i o n mixture as black m i c r o c r y s t a l l i n e s o l i d s i n 13—14% y i e l d . S i n g l e - c r y s t a l X-ray c r y s t a l l o g r a p h i c analyses of 2a 1 and 3b 2 confirmed the i d e n t i t i e s of the hydroxyimido— and im i d o - c o n t a i n i n g c a t i o n s , r e s p e c t i v e l y , and r e v e a l e d t h e i r molecular s t r u c t u r e s ( F i g u r e s 5.1—5.3) 3. The complexes, 2a and 3b represent the f i r s t s t r u c t u r a l l y c h a r a c t e r i s e d examples of M 3(M 3-NOH) and M 3(M 3-NH) l i n k a g e s [135], although r e c e n t l y the analogous complexes R u 3 ( C O ) , 0 ( M 3 — N O H ) [134] and F e 3 ( C O ) , 0 ( M 3 — N H ) [136] have been s p e c t r o s c o p i c a l l y c h a r a c t e r i s e d . In both complexes, the c e n t r a l (rj 5—C 5H(,Me) 3Mn 3 (NO) 3 core i s e s s e n t i a l l y the same as that found f o r ( r ? 5 - C 5 H 5 ) 3Mn 3 (NO)« (_T ) [37], the c y c l o p e n t a d i e n y l ' S i n g l e c r y s t a l s o b t a i n e d by slow c o o l i n g of a 1:1 C H 2 C 1 2 — d i e t h y l ether s o l u t i o n . 2 S i n g l e c r y s t a l s o b t a i n e d by slow c o o l i n g of a s a t u r a t e d C H 2 C 1 2 s o l u t i o n . 3The c r y s t a l s t r u c t u r e d e t e r m i n a t i o n was k i n d l y performed by Dr. S. J . R e t t i g of t h i s department. See Appendix 1 f o r X-ray d i f f r a c t i o n data, and t a b l e s of f r a c t i o n a l c o o r d i n a t e s , bond l e n g t h s , bond angles and i s o t r o p i c and a n i s o t r o p i c thermal parameters f o r 2a and 3b. 5.1 S t e r e o s c o p i c Views Of 2a And 3b FI2) I FOI FQll 121 F i g u r e 5.2 Molecular S t r u c t u r e Of 2a. 122 123 analogue of J_. The most c h e m i c a l l y i n t e r e s t i n g f e a t u r e s of both s t r u c t u r e s i n v o l v e the unique a p i c a l l i g a n d s . Both l i g a n d s are attached c l o s e r to the e q u i l a t e r a l Mn 3 t r i a n g l e than the t r i p l y - b r i d g i n g n i t r o s y l l i g a n d i n V ( i . e . Mn-N(4)(av)=1.872(3)A f o r 2a or 1.873(3) f o r 3b vs. 1.929(11)A f o r J _ ' ) . A l s o , the N-0 bond l e n g t h of the NOH l i g a n d i n 2a ( i . e . 1.393(4)A) i s c o n s i d e r a b l y longer than that of the M 3-NO l i g a n d i n J_' ( i . e . 1 .247(5)A). These two s t r u c t u r a l f e a t u r e s are i n d i c a t i v e of the r e l a t i v e l y g r e a t e r e l e c t r o n - a c c e p t i n g a b i l i t i e s of the M3-NOH and M 3-NH groups. Both the hydroxyimido and the imido l i g a n d s i n 2a and 3b, r e s p e c t i v e l y , are a l s o l i n k e d by hydrogen bonds to the counter an i o n s . T h i s hydrogen bonding i n 2a (H-F=1.91(6)A) produces a pronounced d i s t o r t i o n of the BF„- anion to l o c a l C 3v symmetry, but i n 3b (H-F = 2.24 (4) A) i t i s not s u f f i c i e n t l y strong to r e s u l t i n a unique P-F bond l e n g t h i n the PF 6" anion. T h i s f e a t u r e i s i n agreement with both the known hydrogen-bonding c a p a b i l i t i e s of NH vs. OH [137] and the documented donor c a p a c i t y of the anion (BF„>PF 6) [138]. The s p e c t r o s c o p i c p r o p e r t i e s (see Table 5.1) of the t r i m e t a l l i c c a t i o n i c complexes can be r e a d i l y understood i n terms of t h e i r s o l i d — s t a t e molecular s t r u c t u r e s , thus c o n f i r m i n g t h a t the b a s i c s t r u c t u r a l u n i t s a l s o p e r s i s t i n s o l u t i o n . The IR a b s o r p t i o n s a t t r i b u t a b l e to the M2-N0 groups i n both 2 and 3 occur some 40 cm"1 higher i n energy than i n J_, thereby i n d i c a t i n g d i m i n i s h e d e l e c t r o n d e n s i t y on 124 Table 5.1 S p e c t r o s c o p i c P r o p e r t i e s Of The New Hydroxyimido  And Imido Complexes. Complex IR(CH 2 C I 2 ) i n cm"1 'H-NMR 5 2a v(OH) 3270 5.34(s,12H,C 5H 4Me) a v (NO) 1582,1523 1.86(s,9H,C 5H 4Me) »>(NOH) 1030 »>(BF) 1096(E), 968(A,) 2b i>(OH) 3408 5.32(s,12H,C 5H 4Me) a v (NO) 1581,1524 1.86(s,9H,C 5H f lMe) v(NOH) 1035 v(PF) 848 3a »>(NH) 3275 5.26(s,6H,C 5H 4Me) b HNO) 1579,1521 5.l8(s,6H,C 5H 4Me) v(BF) 1068 1.80(s,9H,C 5H 4Me) 21. 9 5 ( t , 1 H , J ( 1 T N - 1 H) = 61Hz,NH) 3b »>(NH) 3326 5.28(s,6H,C 5H 4Me) b y(NO) 1581,1525 5. 17(s,6H,C 5H 4Me) v(PF) 847 1.82(s,9H,C 5H 4Me) 21 . 5 3 ( t , 1 H , J ( 1 T N - 1 H) = 60.5Hz,NH) a i n (CD 3) 2CO b i n CD 2C1 2 the Mn 3(M2 _NO) 3 framework i n the former s p e c i e s . The d i s t o r t i o n of the BF 4" anion i n 2a i s a l s o d e t e c t a b l e by IR spectroscopy both i n the s o l i d s t a t e (Nujol mull) and i n wea k l y — c o o r d i n a t i n g s o l v e n t s such as CH 2C1 2. Thus, f o r example, i n s t e a d of a s i n g l e s t r o n g a b s o r p t i o n at 984 cm"1 125 due to the T 2 s t r e t c h i n g mode of the BF„" anion, the complex e x h i b i t s two a b s o r p t i o n s at 1098 and 974 cm"1 due to the E and A, modes of a Cj, symmetry anion. Analogous e f f e c t s of hydrogen bonding are not observable i n the IR s p e c t r a of the other complexes. The s p e c t r a of both 2a and 2b a l s o e x h i b i t medium i n t e n s i t y a b s o r p t i o n s at 1030 and 1035cm"1 r e s p e c t i v e l y , which may be ass i g n e d to the P(NO) s t r e t c h of the hydroxyimido l i g a n d ( c f . Ru 3(CO), 0(NOH), v(NO)=1120cm"1 [134]). A l l four complexes g i v e r i s e to f a i r l y weak ab s o r p t i o n s i n the range 3200-3500cm* 1 due to the OH and NH groups. Again, the d i f f e r e n c e i n the energy of these a b s o r p t i o n s , due to the anions, may be e x p l a i n e d by the expected hydrogen-bond s t r e n g t h s (BF f l>PF 6 [138]) 1 . The 1H—NMR s p e c t r a of 3a (Fi g u r e 5.4) and 3b i n CD 2C1 2 v e r i f y that the imido hydrogen remains a t t a c h e d to the n3—N atom ( i . e . f o r 3a, 6 21.95(t,1H,J( 1*N- 1H)=61 Hz); f o r 3b, 6 21.53(t,1H,J( 1 f lN- 1H)=60.5Hz)). In a d d i t i o n the s p e c t r a r e v e a l the expected resonances due to the c o o r d i n a t e d m e t h y l c y c l o p e n t a d i e n y l l i g a n d . S i m i l a r s p e c t r a of 2a and 2b in (CD 3) 2CO a l s o d i s p l a y s i g n a l s due to the me t h y l c y c l o p e n t a d i e n y l l i g a n d , but, do not, however, r e v e a l s i g n a l s due to the ^3—NOH i n the range 5=+30—>-35 ppm, a 1X—H bonds which are i n v o l v e d i n hydrogen bonding absorb at lower f r e q u e n c i e s , as the hydrogen bonding tends to reduce the X-H bond s t r e n g t h [139]. 127 probable consequence of the hydrogen bonding. The proton induced t r a n s f o r m a t i o n s l->2->3 represent two steps of a p o s s i b l e process f o r the r e d u c t i o n of NO to NH 3. 3 H + , 2e~ where M = ( n 5 - C 5 H 4 Me) Mn(NO) The two e l e c t r o n s r e q u i r e d i n the second step are most l i k e l y p r o v i d e d i n t e r m o l e c u l a r l y by the manganese atoms of the c l u s t e r . In t h i s sense, the process i s analogous to t h a t d e s c r i b e d by S h r i v e r and co-workers f o r the c o n v e r s i o n of c o o r d i n a t e d CO to CH„ by s t r o n g a c i d s [140]. However, there are two major d i f f e r e n c e s i n the t r i m e t a l l i c manganese n i t r o s y l system:— (a) a c t i v a t i o n of the N—0 bond does not r e q u i r e b i n d i n g of the oxygen atom to form an TJ2—NO l i n k a g e as i n the Fe«(CO) case (see Scheme 5.1) and CO + CH + F e 2 + + <• 4 129 (b) the f i n a l imido complex i s s t a b l e to excess a c i d . R e c e n t l y , i t was r e p o r t e d t h a t the ruthenium n i t r o s y l complex [ R u ( t r p y ) ( b p y ) ( N O ) ] 3 * c o u l d be r e v e r s i b l y e l e c t r o c h e m i c a l l y reduced in a c i d media to the corresponding ammonia complex [141]. [ R u ( t r p y ) ( b p y ) ( N O ) ] 3 + + 6e" + 5H + > [ R u ( t r p y ) ( b p y ) ( N H 3 ) ] 2 + + H 20 ...(5.7) However, i n t h i s system, the o r i g i n a l n i t r o s y l r e a c t a n t i s s t a b l e to a c i d alone, the r e a c t i o n proceeding v i a 2 o n e - e l e c t r o n r e d u c t i o n s to g i v e [ R u ( t r p y ) ( b p y ) ( N O ) ] + . T h i s reduced s p e c i e s , which presumably c o n t a i n s a bent Ru—NO l i n k a g e , i s then r a p i d l y protonated (Scheme 5.2). The i n i t i a l p r o t o n a t i o n i n the ruthenium system i s t h e r e f o r e at the n i t r o g e n atom of a bent n i t r o s y l l i g a n d , whereas r e a c t i o n of the t r i m e t a l l i c manganese complex with a c i d i s at oxygen, r e s u l t i n g i n the f i r s t c h a r a c t e r i s e d example of the a l t e r n a t e NOH c o n n e c t i v i t y . F u r t h e r p r o t o n a t i o n of [ ( t r p y ) ( b p y ) R u ( H N O ) ] 2 + r e s u l t s i n the cleavage of the N=0 bond, probably v i a the hydroxyamido complex [( t r p y ) ( b p y ) R u ( N H O H ) ] 3 + f o l l o w e d by e l i m i n a t i o n of H 20. (Analogous complexes of both l i g a n d s have p r e v i o u s l y been r e p o r t e d [31,35,132]). I n t e r e s t i n g l y , f u r t h e r p r o t o n a t i o n of 2 should a l s o occur at the lone p a i r of the oxygen atom to give [ ( TJ 5—C 5H f lMe) 3Mn 3 (NO) 3 (NOH 2) ] 2 + , which probably would r a p i d l y l o s e water to give the n i t r i d e [ (7 j 5-C 5H £ (Me) 3Mn 3 (NO) 3 N ] 2 + . Reduction i s presumed to occur at t h i s p o i n t to g i v e the n e u t r a l n i t r i d e , which i s then protonated to g i v e the u l t i m a t e imido product, 3 (Scheme 131 5.3). Scheme 5.3 2-h Mn3N-0 H +H Mn3N-C( H +2e" H H20 Mn.NH Mn3N ( i i i ) Experimental S e c t i o n General procedures employed i n t h i s r e s e a r c h were d e s c r i b e d i n Chapter 2 s e c t i o n ( i i i ) . [ (rj 5—C 5H„Me)Mn(CO) (NO) ] 2 and ( 7? 5-C 5H„Me) 3Mn 3 (NO), were prepared by a m o d i f i c a t i o n of the l i t e r a t u r e procedures [56a,74]. 132 P r e p a r a t i o n of [ ( TJ 5 —C sHuMe)Mn(CO) (NO) ] 2 . A suspension of [ ( TJ5—C5Hi,Me )Mn (CO) (NO) ]PF 6 (14g, 38mmol) i n H 20 (60mL)/toluene (120mL) was t r e a t e d dropwise over a p e r i o d of about 30 mins with a s o l u t i o n of NaBH„ (2g, 52mmol) i n H 20 (30mL). Reaction occured as was evidenced by gas e v o l u t i o n and a darkening of the r e a c t i o n mixture. A f t e r 2 hrs the toluene l a y e r was f i l t e r e d through a C e l i t e column (3x5cm) supported on a coarse p o r o s i t y f r i t . The aqueous f r a c t i o n was f u r t h e r e x t r a c t e d with toluene (3x20mL) and the combined e x t r a c t s were c o n c e n t r a t e d i n vacuo, to y i e l d a deep red s o l i d . The crude product was p u r i f i e d by chromatography on a short alumina column (5x6cm) using benzene as e l u a n t . C o n c e n t r a t i o n of the e l u a t e i n vacuo r e s u l t e d i n 5.56g (75% y i e l d ) of [ (TJ5—C5H,,Me)Mn (CO) (NO) ] 2 . P r e p a r a t i o n of (Tj 5-C sH uMe) 3Mn 3(NO) a. 2.0g (5.2mmol) of [ ( TJ 5 —C 5 H 4 Me) Mn (CO) (NO) ] 2 was d i s s o l v e d i n THF (l20mL) and heated at r e f l u x f o r 18 hr. The r e s u l t i n g dark green r e a c t i o n mixture was cooled to rooom temperature and con c e n t r a t e d i n vacuo to 20mL, whereupon i t was f i l t e r e d through F l o r i s i l (2x3cm). The remaining s o l i d r e s i d u e was e x t r a c t e d with THF (3x15mL) and the combined f i l t r a t e s were taken to dryness i n vacuo. R e c r y s t a l l i z a t i o n of the crude s o l i d from CH 2Cl 2/hexanes r e s u l t e d i n 0.78g (57% w.r.t. NO) of black m i c r o c r y s t a l l i n e (TJ5 —C 5 H <,Me) 3Mn 3 (NO) a . 133 Reaction of ( T;5 —C 5H aMe) 3Mn 3 (NO) a with one e q u i v a l e n t of  ac i d . To a r a p i d l y s t i r r e d dark green s o l u t i o n of ( TJ 5—C 5H„Me) 3Mn 3 (NO) 4 (0.30g, 0.57mmol) i n CH 2C1 2 (20mL) was added HBF a.OMe 2 (0.6mmol). Immediate r e a c t i o n occured, the co l o u r darkened a l i t t l e , and a small amount of s o l i d p r e c i p i t a t e d from s o l u t i o n . A f t e r being s t i r r e d f o r 2 h r s , the r e a c t i o n mixture was f i l t e r e d through C e l i t e (2x3cm), and the r e a c t i o n r e s i d u e e x t r a c t e d with CH 2C1 2 (3x5mL). The combined f i l t r a t e s were concentrated i n vacuo to ca. 1OmL and E t 2 0 (25mL) was added to induce the c r y s t a l l i z a t i o n of black [ ( TJ 5—C 5H 4Me) 3Mn 3 (NO) 3 (NOH) ] BF „. (0.23g, 66% y i e l d ) . A n a l . C a l c d f o r C, 8 H 2 2N 3BF,Mn 30,: C, 35.44; H, 3.64; N, 9.19. Found: C, 35.07; H, 3.61; N, 8.98. IR (Nuj o l m u l l ) : i>(OH) 3270(br) cm" 1; i>(NO) 1 581, 1 514, 1034 cm" 1; v(BF) 1098(E), 974(A,), 71 3 (A, ) cm" 1. IR (CH 2C1 2): v(NO) 1582, 1523 cm" 1; y(BF) 1096(E), 968(A,) cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 6 5.34(s,12H,C 5H,), 1.86(s,9H,CH 3). The hexafluorophosphate s a l t was prepared s i m i l a r l y i n 43% y i e l d by using aqueous HPF 6 as the stro n g a c i d . A n a l . C a l c d f o r C , 8H 2 2N 3F 6Mn 30 4P: C, 32.35; H, 3.32; N, 8.39. Found: C, 32.38; H, 3.36; N, 8.24. IR (CH 2 C 1 2 ) : j/(OH) 3408(br) cm" 1; i/(NO) 1581, 1524, 1035 cm" 1; v(PF) 848 cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 5 5.32(s,12H,C 5H,), 1.86(S,9H,CH 3). Re a c t i o n of [ (Tj 5-C 5H aMe) 3Mn 3 (NO) 3 (NOH) ] BF a with NEt 3 . A s o l u t i o n of [ (Tj 5-C 5H«Me) 3Mn 3 (NO) 3 (NOH) ]BF« (0. 06g, 0. Immol) 1 34 in CH 2C1 2 (3mL) was t r e a t e d with NEt 3 (0.014mL,0.1mmol). A small amount of a white s o l i d p r e c i p i t a t e d from s o l u t i o n and an i n f r a r e d spectrum of the supermatant s o l u t i o n i n d i c a t e d e s s e n t i a l l y q u a n t i t a t i v e formation of (r?5—C5H<,Me) 3Mn 3 (NO) 4 . Reaction of (7}5-C5HuMe) 3Mn 3 (NO) u with excess a c i d . To a r a p i d l y s t i r r e d dark green s o l u t i o n of (7? 5-C 5H„Me) 3Mn 3 (NO) „ (0.30g,0.57mmol) i n CH 2C1 2 (1OmL) was added 0.5mL HBF„.OMe 2 i n s e v e r a l a l i q u o t s . The s o l u t i o n l i g h t e n e d a l i t t l e i n co l o u r and a red o i l y s o l i d p r e c i p i t a t e d . A f t e r 1 hr, the r e a c t i o n was quenched with water (60mL), and then co n c e n t r a t e d i n vacuo to remove the CH 2C1 2. The r e s u l t i n g black-green s o l i d was c o l l e c t e d on a C e l i t e column (2x3cm) supported on a medium p o r o s i t y f r i t , and d r i e d f o r 6 hrs under high vacuum. E x t r a c t i o n of the C e l i t e bed with CH 2C1 2 (3x1OmL) r e s u l t e d i n a dark green s o l u t i o n which was concen t r a t e d to 5mLs. A d d i t i o n of E t 2 0 (25mL) caused the c r y s t a l l i z a t i o n of black m i c r o c r y s t a l l i n e [ (rj 5—C 5HijMe) 3Mn 3 (NO) 3 (NH) ] BF 4 (0.06g, 17% y i e l d ) . A n a l . C a l c d f o r C , 8 H 2 2 N t t B F „ M n 3 0 3 : C, 36.39; H, 3.73; N, 9.43. Found: C, 36.18; H, 3.74; N, 9.18. IR (CH 2 C 1 2 ) : y(NH) 3275 cm' 1; v(UO) 1 579, 1 521 cm' 1; *>(BF) 1068 cm' 1. 1H—NMR (CD 2C1 2): 6 21.95(t,1H,J( 1"N- 1H)=61HZ,NH), 5.26(s,6H,C 5H«), 5.18(S,6H,C 5H«), 1 ,80(s,9H,CH 3). The hexafluorophosphate s a l t was prepared s i m i l a r l y i n 13% y i e l d by a d d i t i o n of an excess of aquous HPF 6 to 135 ( TJ 5—C 5H„Me ) 3Mn 3 (NO)«. IR ( C H 2 C 1 2 ) : vim) 3326 cm" 1; »{HO) *»(PF) 847 cm" 1. 1H—NMR 21.53(t,1H,J( 1 4H-'H)=60.5Hz,NH), 5.17(s,6H,C 5H 4), 1.82(s,9H,CH 3). 1581, 1525 cm" 1; ( C D 2 C 1 2 ) : 6 5.28(s,6H,C 5H f t), 1 36 CHAPTER SIX ELECTROPHILE-INDUCED REDUCTION OF COORDINATED NITROGEN  MONOXIDE. CONVERSION OF A M2-NO GROUP TO A fx7 —NH•> LIGAND ( i ) I n t r o d u c t i o n The p r e p a r a t i o n and c h a r a c t e r i s a t i o n of the b i m e t a l l i c c a t i o n s [ ( T ? 5 - C 5 H 5 )M 2 (NO) « H ] + (M=Mo or W) [55b] and [ ( T } 5 - C s H 5 ) 2 R e 2 ( C O ) 2 ( N O ) 2 H ] + [142] were r e c e n t l y r e p o r t e d . S a l t s c o n t a i n i n g these c a t i o n s were s y n t h e s i s e d i n good y i e l d s by treatment of the monomeric hy d r i d e s (T? 5-C 5H 5)M(NO) 2H (M=Mo or W) and ( T? 5 - C 5 H 5 )Re(CO) (NO)H, with h y d r i d e — a b s t r a c t i n g c a r b o c a t i o n s i n non—donor s o l v e n t s , e.g. 2(r? 5-C 5H 5 )W(NO) 2H + Ph 3CBF q > [ ( T? 5 - C 5 H 5 ) 2W2 (NO) uH]BF f t + Ph 3CH ...(6.1) While the rhenium complex c o u l d be r e a d i l y deprotonated to y i e l d [ (7 7 5—C 5H 5) Re (CO) (NO) ] 2 , the group VI b i m e t a l l i c c a t i o n s only r e s u l t i n the monomeric products ( 7 j 5 - C 5 H 5 )M(NO) 2H and [ ( r? 5—C 5H 5 )M(NO) 2 (B) ] * (B=base) when t r e a t e d with a v a r i e t y of bases. Furthermore, while 137 p r o t o n a t i o n of [ ( T J 5 - C 5 H 5 )Fe(CO) 2 ] 2 r e s u l t s i n the analogous h y d r i d o - b r i d g e d c a t i o n s [ ( T J 5 - C 5 H 5 ) 2 F e 2 (CO) « H ] + [143], r e a c t i o n of [ (T? 5-C 5H 5 )Cr (NO) 2 ] 2 with strong a c i d s only r e s u l t s i n the o x i d a t i v e cleavage of the Cr—Cr bond and formation of [ ( T? 5 - C 5 H 5 )Cr (NO) 2 ] + [144]. [ ( r ? 5 - C 5 H 5 ) F e ( C O ) 2 ] 2 + H + > [ ( r j 5 - C 5 H 5 ) 2 F e 2 (CO) „ H ] + ...(6.2) [ ( T ? 5 - C 5 H 5 ) C r ( N O ) 2 ] 2 + 2H + > 2[ ( 77 5 - C 5 H 5 )Cr(NO) 2 ] + + H 2 ...(6.3) In order to , attempt to r a t i o n a l i s e these r e s u l t s , the r e a c t i o n s of the manganese dimers [ (175— C 5H f lR)Mn (CO) (NO) ] 2 (R=H or Me) with HBF a.OMe 2 have been performed. These r e a c t i o n s r e s u l t i n a complex mixture of products, two of which r e s u l t from e l e c t r o p h i l e — i n d u c e d r e d u c t i o n of a c o o r d i n a t e d n i t r o s y l l i g a n d . T h i s Chapter d e s c r i b e s these r e a c t i o n s i n d e t a i l , and proposes a u n i f y i n g r a t i o n a l e f o r the a p p a r e n t l y d i s p a r a t e r e a c t i v i t i e s of the i s o e l e c t r o n i c complexes [ ( T? 5 - C 5 H 5 )M(LO) 2 ] 2 (M=Cr, Mn, Fe; L=N, C) . 138 ( i i ) R e s u l t s And D i s c u s s i o n Treatment of r e d - v i o l e t [ (TJ 5—C 5H f lR)Mn(CO) (NO) ] 2 (R=H or Me) with HBF a.OMe 2 i n CH 2C1 2 r e s u l t s i n an immediate r e a c t i o n , the mixture becoming brown i n c o l o u r . As f o r the r e a c t i o n of the i s o e l e c t r o n i c [ ( T J 5 — C 5 H 5 ) C r ( N O ) 2 ] 2 , two e q u i v a l e n t s of a c i d are r e q u i r e d to consume completely the dimeric r e a c t a n t s . However, u n l i k e the analogous chromium and i r o n complexes, these r e a c t i o n s i n v o l v i n g the manganese dimers a f f o r d a complex mixture of products. F o r t u n a t e l y , most of the o r g a n o m e t a l l i c products may be separated by v i r t u e of t h e i r d i f f e r i n g s o l u b i l i t y p r o p e r t i e s i n the manner summarised i n Scheme 6.1. C a r e f u l m o n i t o r i n g of the progress of the o r i g i n a l ' r e a c t i o n v e r i f i e s that the n i t r o s y l — c o n t a i n i n g complexes i n d i c a t e d i n the Scheme, as w e l l as [ (TJ 5—C 5H 4R)Mn(CO) 2 (NO) ] + (R=H or Me) which probably ends up as a component of the yellow s o l i d , are formed i n i t i a l l y and not d u r i n g subsequent work—up procedures. U n f o r t u n a t e l y , the d i c a r b o n y l — n i t r o s y l c a t i o n can not be separated from the other components of the yellow s o l i d . The p r o t o n a t i o n of [ ( TJ 5—C 5H 4R)Mn (CO) (NO) ] 2 (R=H or Me) thus produces u l t i m a t e l y two well—known and two novel o r g a n o m e t a l l i c n i t r o s y l complexes of manganese i n each case. The f a m i l i a r [ (T7 5-C 5H«R)Mn(CO) 2 (NO) ] + c a t i o n s [74, 145] (IR ( C H 2 C 1 2 ) : R=H, u(CO) 2125, 2075 cm" 1; p(NO) 1840 cm" 1; R=Me, v(CO) 2116, 2075 cm' 1; i>(NO) 1846 cm' 1) have been 139 Scheme 6.1 f inal r e a c t i o n mixture odd H20 I remove CH2CI2 R e d - b r o w n solution J N a B P h 4 Brown solid I extract with CH2CI2 Brown solution } Yellow solid odd Et20 f Brown solution Black solid extract with toluene concentrate in vacuo Black solid [ ( i 7 9 - C 5 H 4 R ) 2 M n 2 ( N O ) 2 ( C O ) ( N H 2 ) ] B P h 4 ( - r j 6 - C s H 4 R ) 2 M n 2 ( N O) 3(N0 2) f T?9- C 6 H 4 R ) 3 M n 3(N0 ) 3 N H ] B F 4 crystallize from CHjClj-toluene s y n t h e s i s e d by the h i g h — y i e l d r e a c t i o n ( 77 5-C 5H„R)Mn(CO) 3 + NO* > [ ( TJ5 —C 5H 4R)Mn (CO) 2 (NO) ] * + CO ...(6.4) and the subsequent c o n v e r s i o n of these c a t i o n s to (T? 5-C 5H4R) 2Mn 2(NO) 3(N0 2) (IR ( C H 2 C 1 2 ) : R=H, p(NO) 1754, 1532 cm - 1; R=Me, v(NO) 1744, 1536 cm - 1) i n moderate y i e l d s has r e c e n t l y been r e p o r t e d [67], i . e . [ (T? 5-C 5H4R)Mn(CO) 2 (NO) ] + + N0 2" > (T? 5-C 5H4R) 2Mn 2(NO) 3(N0 2) ... (6.5) 1 40 The t r i m e t a l l i c imido complexes were de s c i b e d i n the pre v i o u s Chapter f o r the case R=Me and the pe r h y d r o c y c l o p e n t a d i e n y l d e r i v a t i v e (R=H) e x h i b i t s very s i m i l a r p h y s i c a l p r o p e r t i e s ( i . e . IR (CH 2C1 2): *>(NO) 1586, 1532 cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 5 22.52(t,1H,J( 1 f lN- 1H)=62.5Hz,NH), 5.59(s,15H,C 5H 5). The p r e v i o u s l y unreported b i m e t a l l i c amido complexes, [ (rj 5-C 5H«R) 2Mn 2 (NO) 2 (CO) (NH 2) ]BPh„, are o b t a i n a b l e i n 15% y i e l d from the o r i g i n a l p r o t o n a t i o n r e a c t i o n (see Scheme 6.1), the c y c l o p e n t a d i e n y l complex c r y s t a l l i z i n g from C H 2C1 2/Et 20 as the CH 2C1 2 hemi—solvate. The compounds are brown, m i c r o c r y s t a l l i n e s o l i d s which d i s s o l v e i n p o l a r organic s o l v e n t s to produce a i r — s e n s i t i v e s o l u t i o n s . T h e i r s p e c t r o s c o p i c p r o p e r t i e s are c o n s i s t e n t with the c a t i o n s e x i s t i n g i n s o l u t i o n s as a mixture of the diastereomers R cis 141 R the t r a n s form being predominant i n l e s s p o l a r s o l v e n t s and the c i s isomer (an enantiomeric p a i r ) becoming r e l a t i v e l y more abundant i n more p o l a r s o l v e n t s 1 . Thus, t h e i r CH 2C1 2 s o l u t i o n s d i s p l a y IR a b s o r p t i o n s a t t r i b u t a b l e to b r i d g i n g NH 2 groups (R=H, f(NH) 3330, 3259 cm' 1; R=Me, y(NH) 3336, 3272 cm" 1), b r i d g i n g c a r b o n y l (R=H, i>(CO) 1855 cm' 1, R=Me, v(CO) 1856 cm" 1) and t e r m i n a l n i t r o s y l l i g a n d s (R=H, »>(NO) 1764 cm" 1; R=Me, P(NO) 1754 cm" 1). However, when d i s s o l v e d i n the more p o l a r CH 3CN, the complexes e x h i b i t two IR ab s o r p t i o n s due to the NO groups (R=H, v(NO) 1785(m), 1759(s) cm" 1; R=Me, y(NO) I785(m), 1754(s) cm" 1), the higher 1 I t has p r e v i o u s l y been e s t a b l i s h e d that the c i s / t r a n s isomer r a t i o of the r e l a t e d (7j 5-C sH f lR) 2Mn 2 (NO) 3X complexes i n c r e a s e s i n more p o l a r s o l v e n t s [67], 142 energy bands being a s s i g n a b l e to the c i s isomer (as they do not appear i n l e s s p o l a r s o l v e n t s ) . The 1H—NMR spectrum of the c y c l o p e n t a d i e n y l complex in (CD 3) 2CO (a s o l v e n t of i n t e r m e d i a t e p o l a r i t y ) r e v e a l s the presence of the CH 2C1 2 of s o l v a t i o n and t e t r a p h e n y l b o r a t e anion, but does not c o n t a i n d e t e c t a b l e s i g n a l s due to the NH 2 group. Furthermore, i t d i s p l a y s two sharp resonances i n the c y c l o p e n t a d i e n y l region at 55.81 and 5.58 of r e l a t i v e i n t e n s i t y 9:1 which may be a s s i g n e d to the t r a n s and c i s isomers, r e s p e c t i v e l y . The analogous spectrum of the m e t h y l c y c l o p e n t a d i e n t l compound i s more complex, e x h i b i t i n g s i x d i s t i n c t s i g n a l s f o r the r i n g protons and two separate s i g n a l s f o r the methyl protons i n a d d i t i o n to the complex m u l t i p l e t due to the BPh„- anion. While the exact assignment of these resonances due to the T? 5— C5H£,Me l i g a n d s i s not p o s s i b l e , t h i s complexity i s n e v e r t h e l e s s i n d i c a t i v e of each m e t h y l c y c l o p e n t a d i e n y l l i g a n d being bound to an asymmetric manganese c e n t r e [67]. I t i s c l e a r from the preceding r e s u l t s t h a t treatment of the [ (T7 5-C 5H f lR)M(LO) 2 ] 2 (M=Cr, Mn or Fe; L=C or N; R=H or Me) dimers with HBFft.OMe2 i n CH 2C1 2 r e s u l t s i n markedly d i f f e r e n t types of p r o d u c t s . A p o s s i b l e e x p l a n a t i o n f o r these v a r i e d experimental o b s e r v a t i o n s i s that e n t i r e l y d i f f e r e n t pathways are being f o l l o w e d d u r i n g the v a r i o u s c o n v e r s i o n s . For i n s t a n c e , one pathway might i n v o l v e i n i t i a l proton t r a n s f e r ( p r o t o n a t i o n ) , i . e . 143 [ (i7 5-C 5H 4R)M(LO) 2 1 2 + H + > [ (i7 5-C 5H 4R) 2M 2 (LO) „H] + . . . (6.6) whereas another might have e l e c t r o n t r a n s f e r ( o x i d a t i v e cleavage) as the f i r s t step, i . e . [ ( 77 5-C 5H 4R)M(LO) 2 ] 2 + 2H + > 2[ ( 77 5-C 5H 4R)M(LO) 2 ] + + H 2 ...(6.7) In other words, i t i s p o s s i b l e that the d i f f e r i n g chemical behaviour of the o r g a n o m e t a l l i c dimers towards H + may simply be a m a n i f e s t a t i o n of t h e i r i n t r i n s i c a l l y d i f f e r i n g t e n d encies to undergo o x i d a t i o n . T h i s view seems to be supported at f i r s t glance by p r e v i o u s l y documented chemistry of [ ( 77 5 - C 5 H 5 ) F e ( C O ) 2 ] 2 and [ ( r j 5 - C 5 H 5 )Cr (NO) 2 ] 2 which i n d i c a t e s that the Cr—Cr bond i n the chromium dimer i s more r e a d i l y c l e a v e d by e l e c t r o p h i l e s . Thus while the r e a c t i o n [ ( 77 5 - C 5 H 5 ) C r ( N O ) 2 ] 2 + P b C l 2 > 2 ( T J 5 - C 5 H 5 )Cr (NO) 2C1 + Pb . . . (6.8) proceeds c l e a n l y , the i r o n dimer a p p a r e n t l y does not r e a c t with P b C l 2 [56]. In s i m i l a r f a s h i o n , the chromium complex dehalogenates v i c i n a l or„ b e n z y l i c organic h a l i d e s whereas the i r o n complex does not [56]. Furthermore, [ ( 7 j 5 - C 5 H 5 )Cr (NO) 2 ] 2 i s o x i d i s e d r a p i d l y (10 mins) by two 1 44 e q u i v a l e n t s of Ph 3CBF«, i . e . [ ( T ? 5 - C 5 H 5 )Cr(NO) 2 ] 2 + 2Ph 3C + > 2 [ ( r j 5 - C 5 H 5 ) C r ( N O ) 2 ] + + "2Ph 3C" ...(6.9) wheras when [ ( T J 5 - C 5 H 5 )Fe (CO) 2 ] 2 i n CH 2C1 2 i s t r e a t e d with approximately three e q u i v a l e n t s of Ph 3CBF«, the dimer i s only slowly consumed i n 45 hr [146] 1 . P r e l i m i n a r y e l e c t r o c h e m i c a l measurements [147] i n d i c a t e , however, that t h i s i n t e r p r e t a t i o n i s too s i m p l i s t i c . Thus, the i r o n complex e x h i b i t s a r e v e r s i b l e o x i d a t i o n (E =+0.68V vs SCE), while the chromium complex i s o x i d i s e d i r r e v e r s e i b l y (E =+0.85V vs SCE). Although a d i r e c t comparison of E values cannot be made, i t i s c l e a r t h a t the i r o n complex i s more prone to o x i d a t i o n and thus, i n the context of the p r o t o n a t i o n r e a c t i o n s , i f H + i s s u f f i c i e n t l y s t r o n g an oxidant to o x i d i s e [ ( T ? 5 - C 5 H 5 )Cr (NO) 2 ] 2 a c c o r d i n g to equation 6.7, then i t should a l s o be s u f f i c i e n t l y potent to e f f e c t the o x i d a t i o n of the i r o n complex. On the b a s i s of the c u r r e n t l y a v a i l a b l e data, a more 1 I t i s tempting to formulate the o r g a n o m e t a l l i c product formed i n t h i s r e a c t i o n as (TJ 5-C 5H 5 )Fe(CO) 2 B F a . However, the IR data r e p o r t e d [146] do not agree with those d i s p l a y e d by a u t h e n t i c ( TJ 5—C 5H 5 )Fe(CO) 2 B F 0 r e c e n t l y i s o l a t e d by Mattson and Graham [117]. 145 u n i f i e d r a t i o n a l e of the r e a c t i o n s of the dimers with H + may be proposed. The f i r s t step c o n s i s t s of adduct formation to produce the c a t i o n i c [ (Tj s-C 5H f lR) 2M 2 (LO) a H ] + s p e c i e s as summarised i n equation 6.6. T h i s adduct may prove to be s u f f i c i e n t l y s t a b l e to be i s o l a b l e (as i n the case of M=Fe). A l t e r n a t i v e l y , the adduct may undergo unsymmetrical d i s s o c i a t i o n . For i n s t a n c e , i n the case of M=Cr, such d i s s o c i a t i o n , i . e . [ ( 7 7 5 - C 5 H 5 ) 2 C r 2 ( N O ) 4 H ] + > [ ( 7 ? 5 - C 5 H 5 ) C r ( N O ) 2 ] + + (TJ 5 — C 5 H 5 )Cr (NO) 2H ...(6.10) would a f f o r d the u l t i m a t e [ ( TJ 5—C 5H 5 )Cr (NO) 2 ] + product and the n e u t r a l hydrido complex, ( r j 5 — C 5 H 5 )Cr (NO) 2H. However, t h i s l a t t e r compound i s th e r m a l l y unstable [45] and r e v e r t s to the o r i g i n a l d i m e r i c r e a c t a n t v i a 2 ( TJ 5—C 5H 5 )Cr (NO) 2H > [ ( T J 5 — C 5 H 5 ) C r ( N O ) 2 ] 2 + H 2 ...(6.11) S e q u e n t i a l r e c y c l i n g of co n v e r s i o n s 6.6, 6.10 and 6.11 f i n a l l y r e s u l t s i n the net t r a n s f o r m a t i o n 6.3. Evidence i n support of t h i s i n t e r p r e t a t i o n comes from the observed chemistry of the i s o l a b l e [ (T7 5-C 5H 5) 2M 1M 2 (NO) „ H ] + (M1=M2=Mo or W; M1=Mo, M2=W) c a t i o n s . D i s s o l u t i o n of a 1:1 mixture of the Mo 2 and W2 c a t i o n s or the pure Mow c a t i o n r e s u l t s i n the same e q u i l i b r i u m mixture [55b]. 1 46 [ ( T 7 5 - C 5 H 5 ) 2 M O 2 ( N O ) 4 H ] + + [ ( T 7 E - C 5 H 5 ) 2 W 2 ( N O ) 4 H ] + I N 2[ (r) 5-C 5H 5). 2MoW(NO)«H] + .... (6. 12) Th i s r e a c t i o n suggests that the b i m e t a l l i c c a t i o n s e x i s t i n e q u i l i b r i u m with t h e i r monometallic components e.g. The molybdenum and tungsten h y d r i d e s have reasonable thermal s t a b i l i t y i n s o l u t i o n . However, the congeneric chromium complex i s unknown, a l l attempts at p r e p a r i n g i t i n a s i m i l a r r e a c t i o n to that used to s y n t h e s i z e the Mo and W spe c i e s r e s u l t i n g i n the [ ( TJ 5 —C 5 H 5) C r (NO) 2 ] 2 dimer. Thus, fo r M=Cr the e q u i l i b r i u m 6.13 would be d r i v e n to the r i g h t by the thermal i n s t a b i l i t y of the h y d r i d e . In a s i m i l a r manner when M=Mn, the i n i t i a l [ ( T J 5 - C 5 H 4 R ) 2Mn 2 (CO) 2 (NO) 2 H ] + adduct c o u l d c l e a v e i n a number of ways. One such unsymmetrical cleavage would produce the observed [ (TJ5 —C 5H f tR)Mn(CO) 2 (NO) ] * c a t i o n s and " (T? 5-C 5H AR)Mn(NO)H" . [ ( T 7 5 - C 5 H 5 ) 2 M 2 ( N O ) « H ] + ^ i [ ( T ? 5 - C 5 H 5 ) M ( N O ) 2 ] + + (TJ 5-C 5H 5)M(NO) 2 H ...(6.13) [ (T? 5-C 5H 1 (R) 2Mn 2(CO) 2(NO) 2H] + > [ ( TJ 5 —C s H K R) Mn (CO) 2 (NO) ] + + " (T^-CsH^RjMntNOjH" ...(6.14) Since the c o o r d i n a t i v e l y s a t u r a t e d manganese hydride 147 (r?5 —C 5 H a Me) Mn (NO) (PPh 3) H r e a d i l y l o s e s PPh 3 i n s o l u t i o n to giv e the t r i m e t a l l i c c l u s t e r (rj 5-C 5H f tMe) 3Mn 3 (NO) „, the c o o r d i n a t i v e l y unsaturated hydride complex would be expected to spontaneously t r i m e r i s e . As d i s c u s s e d i n Chapter 5, the t r i m e t a l l i c n i t r o s y l c l u s t e r r e a c t s with excess a c i d to produce the c a t i o n i c imido complex [ (rj 5 —C 5H aR) 3Mn 3 (NO) 3 (NH) ] + . The o r i g i n s of the b i m e t a l l i c n i t r o s y l products presented i n Scheme 6.1 remain to be a s c e r t a i n e d , r e a c t i o n s 6.4 and 6.5 being u n l i k e l y i n t h i s system. However, the formation of the amide complex does represent a second example of the proton—induced r e d u c t i o n of c o o r d i n a t e d NO. One f i n a l p o i n t merits mention. In p r i n c i p l e , the i n i t i a l c a t i o n i c adducts formed v i a r e a c t i o n 6.6 c o u l d a l s o undergo inner—sphere e l e c t r o n t r a n s f e r p r o cesses, i . e . 2[ (r? 5-C 5H aR) 2M 2 (LO) « H ] + > 2 [ (T? 5-C 5H„R)Mn (LO) 2 ] 2 + + H 2 ...(6.15) the net r e s u l t being formation of the r a d i c a l b i m e t a l l i c monocations. No d i r e c t p h y s i c a l evidence f o r the e x i s t e n c e of such b i m e t a l l i c s p e c i e s has been found f o r any of the i r o n , chromium or manganese systems. I n t e r e s t i n g l y , however, t h i s i s the p r i n c i p a l mode of r e a c t i o n when [ (7? 5-C 5H 5 )Co(NO) ] 2 i s t r e a t e d with a s l i g h t excess of HBF n.OMe 2 i n CH 2C1 2, i . e . 148 2[ ( r j 5 - C 5 H 5 )Co(NO) ] 2 + 2H + > 2 [ ( 7 7 5—C 5H 5 ) Co (NO) ] 2 + + H 2 ... (6.16) The p r e v i o u s l y r e p o r t e d [148], paramagnetic [ ( T ) 5 - C 5 H 5 )CO(NO) ] 2BF„ may be e a s i l y i s o l a t e d as a purple m i c r o c r y s t a l l i n e s o l i d i n 73% y i e l d from the f i n a l r e a c t i o n mixture. ( i i i ) Experimental S e c t i o n General procedures employed d u r i n g t h i s work were d e s c r i b e d i n Chapter 2 s e c t i o n ( i i i ) . R e a c tion of [ (T? 5-C 5H 5 )Mn(CO) (NO) ] 2 with HBF, .OMe. T y p i c a l l y , 13.6M HBFftOMe2 (0.29mL, 4.0mmol) was added to a s t i r r e d , r e d - v i o l e t s o l u t i o n of [ ( TJ 5—C 5H 5 )Mn (CO) (NO) ] 2 (0.71g, 2.0mmol) i n CH 2C1 2 (30mL). The s o l u t i o n became brown in c o l o u r immediately, and a brown s o l i d p r e c i p i t a t e d . A f t e r being s t i r r e d f o r 2 hr to ensure complete r e a c t i o n , H 20 (60mL) was added, and the mixture was c o n c e n t r a t e d i n vacuo to remove the CH 2C1 2. At t h i s stage, the r e a c t i o n mixture, which c o n s i s t e d of a black s o l i d and a red—brown aqueous s o l u t i o n , was f i l t e r e d through C e l i t e (2x3cm), and the c o l l e c t e d s o l i d was washed with H 20 (4x20mL). The black s o l i d and the combined red—brown f i l t r a t e s were then worked up s e p a r a t e l y i n the manner d e s c r i b e d below. 1 49 Work-up of the black s o l i d . The c o l l e c t e d s o l i d was f i r s t d r i e d f o r 2 hrs at room temperature and 5 x 1 0 - 3 mm Hg p r e s s u r e . I t was then removed from the C e l i t e column with CH 2C1 2 (3xl5mL), a process that a f f o r d e d a dark green s o l u t i o n which i n turn was taken to dryness under reduced p r e s s u r e . E x t r a c t i o n of t h i s r e s i d u e with toluene (3x2mL) produced a brown s o l u t i o n which upon slow c o n c e n t r a t i o n i n vacuo d e p o s i t e d a small amount of a brown s o l i d . T h i s s o l i d was t e n t a t i v e l y i d e n t i f i e d as (TJ 5—C 5H 5 ) 2Mn 2 (NO) 3 (N0 2 ) by IR spectroscopy (IR (CH 2C1 2): p(NO) 1754, 1532 cm" 1) [67]. F u r t h e r e x t r a c t i o n of the r e s i d u e with CH 2C1 2 (3x1OmL) a f f o r d e d a dark green s o l u t i o n . A d d i t i o n of toluene (lOmL) to t h i s s o l u t i o n and c a r e f u l c o n c e n t r a t i o n of the r e s u l t i n g s o l u t i o n under reduced pressure caused the c r y s t a l l i z a t i o n of 80mg (10% y i e l d ) of black [ ( n 5 - C 5 H 5 ) 3 M n 3 ( N O ) 3 ( N H ) ] B F „ which was c o l l e c t e d by f i l t r a t i o n (IR (CH 2C1 2): f(NO) 1586, 1532 cm" 1. 1H—NMR ( ( C D 3 ) 2 C O ) : 6 22.52(t,1H,J( 1 aN- 1H)=62.5Hz,NH), 5.59(s,15H,C 5H 5). Work—up of the red—brown aqueous s o l u t i o n . The o r i g i n a l combined f i l t r a t e s were t r e a t e d with a s a t u r a t e d aqueous s o l u t i o n of NaBPhtt ( l . 0 3 g , 3.00mmol) whereupon a brown s o l i d p r e c i p i t a t e d , l e a v i n g an e s s e n t i a l l y c o l o u r l e s s supernatant s o l u t i o n . The brown s o l i d was c o l l e c t e d by f i l t r a t i o n , washed with H 20 (3x20mL), and d r i e d f o r 2 hr at room temperature under high vacuum. E x t r a c t i o n of the d r i e d s o l i d with CH 2C1 2 (3x20mL) produced a brown s o l u t i o n which was 150 con c e n t r a t e d to ca. 1OmL under reduced p r e s s u r e . Dropwise a d d i t i o n of E t 2 0 (40mL) to t h i s s o l u t i o n caused the p r e c i p i t a t i o n of a brown, m i c r o c r y s t a l l i n e s o l i d i n 15% y i e l d with respect to Mn. T h i s s o l i d was i d e n t i f i e d as [ (7} 5-C 5H 5) 2Mn 2(NO) 2(CO) (NH 2 ) ]BPh f t . 0 . 5CH 2C1 2 . An a l . C a l c d f o r C 3 3 5 H 3 3 N 3 B C l M n 2 0 3 : C, 60.41; H, 4.71; N, 5.96. Found: C, 60.69; H, 4.85; N, 6.25. IR (CH 2C1 2): p(NH) 3330(w), 3259(w) cm" 1; »<(CO) I855(m) cm" 1; »»(NO) 1764(s)- cm" 1. IR (CH 3CN): i>(CO) I864(m) cm" 1; v(NO) 1785(m), 1759(s) cm" 1. 'H-NMR ( ( C D 3 ) 2 C O ) : 8 7.35-6.75(m,20H,C 6H 5), 5.81(s,9H,C 5H 5), 5.62(s,1H,CH 2C1 2), 5.58(s,1H,C 5H 5). When [ (r? 5-C 5H«Me)Mn(CO) (NO) ] 2 was su b j e c t e d to the i d e n t i c a l experimental procedure, m e t h y l c y c l o p e n t a d i e n y l analogues of the products d e s c i r e d above were obtained i n comparable y i e l d s . The s p e c t r o s c o p i c p r o p e r t i e s of the C 5H aMe—containing complexes are presented below:— ( 77 5 - C 5 H „ M e ) 2Mn 2 (NO) 3 (NO, ) . IR (CH 2C1 2): *>(NO) 1744, 1536 cm'1 [67]. [ (77 s—C 5H aMe) 2Mn 2 (NO) 2 (CO) (NH 2 ) ]BPh a . IR (CH 2C1 2): v (NH) 3336(w), 3272(w) cm" 1; ^ (CO) I856(m) cm" 1; /^(NO) 1754(S) cm" 1. IR (CH 3CN): J^(CO) I864(m) cm" 1; f(NO) 1785(m), 1754(S) cm" 1. 1H—NMR (CD 3) 2CO: 6 7.35-6.76(m,20H,C 6H 5), 5.96(s,2H,C 5H aMe), 5.72(s,1H,C 5H uMe), 5.59(s,1H,C 5H 4Me), 5.34(s,1H,C 5H aMe), 5.19(s,2H,C 5H aMe), 4.99(s,1H,C 5H aMe), 2.38(s,3H,C 5H aMe), 2.26(s,3H,C 5H aMe). 151 Reaction of [ ( T ? S - C S H S )CO(NO) ] , with HBF„.OMe 2. A r a p i d l y s t i r r e d brown s o l u t i o n of [ (T? 5-C 5H s )Co(NO) ] 2 [26] (0.55g, 1.8mmol) i n CH 2C1 2 (30mL) was t r e a t e d with 13.6M HBF s.OMe 2 (0.26mL, 3.5mmol). The s o l u t i o n became r e d — v i o l e t , and a small amount of a dark s o l i d p r e c i p i t a t e d . A f t e r being s t i r r e d f o r 30 mins, the r e a c t i o n mixture was f i l t e r e d through a C e l i t e column (2x3cm) supported on a medium p o r o s i t y f r i t . The column was then washed with CH 2C1 2 (3x15mL) and the combined f i l t r a t e s were co n c e n t r a t e d under reduced p r e s s u r e to a volume of 15mL. Dropwise a d d i t i o n of E t 2 0 (50mL) to t h i s s o l u t i o n induced the p r e c i p i t a t i o n of 0.51g (73% y i e l d ) of p u r p l e , m i c r o c r y s t a l l i n e [ ( T ? 5 - C 5 H 5 )Co(NO) ] 2BF„ which was c o l l e c t e d by f i l t r a t i o n . A n a l . C a l c d f o r C , 0 H , 0 N 2 B C o 2 F „ 0 2 : C, 30.42; H, 2.55; N, 7.10. Found: C, 30.59; H, 2.75; N, 6.95. IR (CH 2C1 2): f(NO) 1622 cm' 1; v(BF) 1057, 1034 cm" 1. 152 EPILOGUE At the outset of the r e s e a r c h d e s c r i b e d h e r e i n , the p r e v a i l i n g p o i n t of view was that a c o o r d i n a t e d n i t r o g e n monoxide i s l a r g e l y u n r e a c t i v e . I t i s c e r t a i n l y t r u e that other l i g a n d s i n the metal's c o o r d i n a t i o n sphere are o f t e n a t t a c k e d p r e f e r e n t i a l l y . However, the r e s u l t s d e s c r i b e d i n Chapters 5 and 6 demonstrate t h a t , i n the absence of other r e a c t i v e s i t e s , b r i d g i n g n i t r o s y l l i g a n d s can be converted i n t o M3—NOH, u3— NH and / i 2 _NH 2 groups. While the o b j e c t i v e s o u t l i n e d i n the i n t r o d u c t i o n have been accomplished, i t i s obvious that much f u r t h e r work w i l l be r e q u i r e d to f i n d systems which can be used i n d u s t r i a l l y t o convert NO to u s e f u l products. With regard to the p a r t i c u l a r system s t u d i e d , an e x t e r n a l source of e l e c t r o n s must be found so t h a t the c o n v e r s i o n s may be performed in much higher y i e l d s . In a d d i t i o n , the chemistry of the hydroxyimido and imido complexes should be i n v e s t i g a t e d i n order to f i n d ways of r e l e a s i n g the n i t r o g e n — c o n t a i n i n g groups. Since i t appears that the b i n d i n g of the NO l i g a n d to 3 m e t a l l i c c e n t r e s a c t i v a t e s i t and s t a b i l i s e s the products, a separate l i n e of 1 53 re s e a r c h worth i n v e s t i g a t i n g i s the r e a c t i v i t y of the o r i g i n a l r e a c t a n t , ( T? 5-C 5H„R) 3Mn 3 (NO) <, (R=H or Me), towards n u c l e o p h i l e s , such as H - or R". The r e s u l t s d e s c r i b e d i n chapters 2, 3 and 4 show that the n i t r o s y l l i g a n d can a l s o impart some unique chemical p r o p e r t i e s to some other l i g a n d i n the metal's c o o r d i n a t i o n sphere, or to the molecule as a whole. For example, the n i t r o s y l l i g a n d seems to favour the formation of paramagnetic monomers i n the system, ( r ? 5 — C 5 H 5 )Cr (NO)LX, ra t h e r than diamagnetic dimers. In a d d i t i o n , the presence of the NO l i g a n d may be the reason behind the pr e f e r e n c e f o r s—t r a n s c o o r d i n a t i o n of the diene i n (7j 5 — C 5 H 5 )Mo(NO) ( TJ " —diene). In c o n c l u s i o n , i t i s becoming i n c r e a s i n g l y c l e a r that c o n s i d e r a b l e c a u t i o n should be e x e r c i s e d when p r e d i c t i n g the p r o p e r t i e s of o r g a n o m e t a l l i c n i t r o s y l complexes on the b a s i s of the much more f u l l y — d e v e l o p e d and be t t e r — u n d e r s t o o d c a r b o n y l chemistry. 1 54 BIBLIOGRAPHY 1) (a) Bartok,W.; Crawford,A.R.; Skopp,A. Chem. Eng. Prog.  (1971), 67(2), 64. (b) " A i r P o l l u t i o n " ; ACS Repr. C o l l e c t . : American Chemical S o c i e t y : Washington, D.C., 1973. 2) Cade,P.E.; Hue,W.M.; Gr e e n s h i e l d s , J . B . At. Data N u c l .  Data Tables (1975), 15, 1. 3) Ember,L.R. Chem. Eng. News (1981 ) , 59(37), 20. 4) "Smog: A Report to the People"; Environmental Q u a l i t y Laboratory, C a l i f o r n i a I n s t i t u t e of Technology: Anderson, R i t c h i e and Simon: Los Angeles, C a l i f o r n i a , 1972. 5) Wark,K.; Warner,C.F. " A i r P o l l u t i o n : I t s O r i g i n and C o n t r o l " , 2nd Ed.; Harper and Row: New York, NY, 1981. 6) (a) Hecht,T.A.; S e i n f e l d , J . H . ; Dodge,M.C. E n v i r o n . S c i .  Tech. (1974), 8^ 327. (b) Levy,H. Science (1971), 173, 141. (c) Weinstock,B. Science (1969), 166 224. 7) Chameides,W.L.; Davis,D.D. Chem. Eng. News (1982)>  60(49), 38. 8) Pearce,F. New S c i e n t i s t (1982) , 12Auqust, 419. 9) Glass,N.R.; Glass,G.U.E.; Rennie,P.J. E n v i r o n . S c i .  Tech. (1979), 13(11), 1350. 10) " L e g i s l a t u r e of the P r o v i n c e of O n t a r i o Standing Commitee on Resource Development: F i n a l Report", October, 1979. 11) Weller,P. "Acid Rain: The S i l e n t C r i s i s " ; Between the L i n e s and the Waterloo P u b l i c I n t e r e s t Research Group: K i t c h e n e r , O n t a r i o , 1980. 12) "Great Lakes Science A d v i s o r y Board Annual Report to the I n t e r n a t i o n a l J o i n t Commision", J u l y 1979. 13) "Nitrogen Oxides from Coal Combustion—Abatement and C o n t r o l " ; I n t e r n a t i o n a l Energy Agency, Report No. 1 55 ICTIS/TR 11, London, 1980. 14) Kubota,M.; Evans,K.J.; Koerntgen,C.A.; Marstens,J.C. J.Amer. Chem. Soc. (1978), 100, 342. 15) Eisenberg,D.E.; Meyer,CD. J\ Am. Chem. Soc. (1976),  98, 1364. 16) Hendriksen,D.E.; Meyer,CD.; Eisenberg,R. Inorg. Chem.  (1977) , 16, 970. 17) Caulton,K.G. Coord. Chem. Rev. (1975), 14, 317. 18) Bottomley,F. Acc. Chem. Res. (1978), 11, 158. 19) McCleverty,J.A. Chem. Rev. (1979), 79, 53. 20) B r a d l e y , D . C ; Newing,C.W. Chem. Commun. ( 1970) , 219. 21) B r o c k , C P . ; Collman,J.P.; D o l c e t t i , G . ; Farnham,P.H.; Ibers,J.A.; L e s t e r , J . E . ; Redd,CA. Inorg. Chem. (1 973) ,  12, 1304. 22) Beck,W.; Lottes,K. Chem. Ber. (1963), 96, 1046. 23) (a) Swanson,B.I.; Satiya,S.K. Chem. Soc. Chem. COmm.  (1973), 40. (b) Herberhold,M.; Razavi,A. Angew. Chem. I n t . Ed. E n g l . (1972), 11, 1092. (c) Herberhold,M.; Razavi,A. J_^ Organomet. Chem.  ( 1974) , 67, 81 . 24) Fi s c h e r , E . O . ; Schneider,R.J.J.; M u l l e r , J . J . Organomet.  Chem. (1968), 14, P4. 25) Fischer,E.O.; Beckert,0.; Hafner,W.; Stahl,H.O. Z.  N a t u r f o r s c h . (1955), B19, 598. 26) Brunner,H. J_;_ Organomet. Chem. (1 968 ) , 1 2 , 517. 27) (a) Hughes,W.; Zeuch,E. Inorg. Chem. ( 1973) , 12, 471. (b) Bencze,L. J_;_ Organomet. Chem. ( 1 973), 56, 303. (c) Taube,R.; Seyferth,K. Z. Chem. (1973), 13. 28) (a) Bruce,R.; Chaudhay,F.M.; Knox,G.R.; Pauson,P.L. Z.  N a t u r f o r s c h . (1965), B20, 73. 1 56 (b) Murdoch,H. N a t u r f o r s c h . (1965), B20, 179. 29) Gwost,D.U.; Caulton,K.G. Inorq. Chem. (1973) , 12, 2095. 30) Cotton,F.A.; Wilkinson,G. "Advanced Inorganic Chemistry"; 4th Ed.; Wiley I n t e r s c i e n c e : Toronto, 1980, Chapter 25. 31) Reed, C. A.; Roper, W.R. Chem. Soc. Dalton Trans.  ( 1972), 1243. 32) Lokshin,B.V.; Rusach,E.B.; Kolobova,N.E.; Makarov,Yu,V.; Ustynyk,N.A.; Zdanovich,V.I.; Zhakaeva,A. Zh.; Setkina,V.N. J_;_ Organomet. Chem.  (1976), 108, 353. 33) Crease,A.E.; Legzdins,P. J . Chem. Soc. Dal t o n Trans.  (1973), 1501. 34) Feltham,R.D.; Enemark,J.H. Topics i n Inorg. And  Organomet. Stereochem. (1981), 12, 155. 35) (a) Grundy,K.R.; Reed,C.A.; Roper,W.R. Chem. Commun.  (1970), 1501. (b) Reed,C.A.; Roper,W.R. JN Chem. Soc. (A) ( 1 970) , 3054. (c) Wison,R.D.; Ibers,J.A. Inorq. Chem. (1979),18, 336. 36) Calderon,J.L.; Fontana,S.; Fr a u e n d o r f e r , E . ; Day,V.W. J . Organomet. Chem. (1974), 64, C10. 37) (a) Elder,R.C.; Cotton,F.A.; Schunn,R.A. J_^ Am. Chem.  Soc. (1967), 89, 3645. (b) Elder,R.C. Inorq. Chem. (1974), 13, 1037. 38) Calderon,J.L.; Fontana,S.; F r a u e n d o r f e r , E . ; Day,V.W.; Iske,S.D.A. Organomet. Chem. (1 974) , 64 , C16. 39) Braga,D.; Johnson,B.F.G.; Lewis,J. Mace,J.M.; McPartlin,M.; Puga,J.; Nelson,W.J.H.; Raithby,P.R.; Whitmire,K.H. J_;_ Chem. Soc. Chem. Comm. ( 1982) , 1081. 40) Onaka,S. Inorg. Chem. (1980), 19, 2132. 41) S h r i v e r , D . F . J_;_ Organomet. Chem. (1975) , 94, 259. 42) M u l l e r , J . ; Schmitt,S. J . Organomet. Chem. (1978), 160, 109. 157 43) Hames,B.W.; Legzdins,?.; Oxley,J.C. Inorg. Chem.  (1980), 19, 1565. 44) Collman,J.P.; Hegedus,L.S. " P r i n c i p l e s and A p p l i c a t i o n s of O r g a n o t r a n s i t i o n Metal Chemistry"; U n i v e r s i t y Science Books: M i l l V a l l e y , CA, 1980. 45) Legzdins,P.; Martin,D.T. Inorg. Chem. (1979), 18, 1250. 46) (a) Calderazzo,F. Angew. Chem., I n t . Ed. E n g l . (1977),  16, 299. (b) W o j c i c k i , A . Adv. Organomet. Chem. (1973), 11, 87. (c) Parshall,G.W. "Homogeneous C a t a l y s i s " ; Wiley: New York, 1980; p 7 7 f f . 47) Weiner,W.P.; Bergman,R.G. Am. Chem. Soc. (1983),  105, 3922 and r e f e r e n c e s c i t e d t h e r e i n . 48) (a) B i b l e r , J . P . ; W o j c i c k i , A . Inorg. Chem. (1966), 5, 889. (b) Green,M.L.H.; H u r l e y , C R . Organomet. Chem. (1967), 19, 188. 49) M a l i t o , J . T . Ph.D. D i s s e r t a t i o n , The U n i v e r s i t y of B r i t i s h Columbia, 1976. 50) W o j c i c k i , A . Adv. Organomet. Chem. (1974) , 12, 31. 51) Atkins,P.W. "Quanta: A Handbook of Concepts"; Oxford U n i v e r s i t y P r e s s : Oxford, 1974. 52) For examples see: (a) Mulliken,R.S.; Ermler,W.C. "Diatomic M o l e c u l e s : R e s u l t s of ab I n i t i o C a l c u l a t i o n s " ; Academic Press: New York, 1977. (b) Brion,H.; Moser,C. Chem. Phys. (1960), 32, 1194. (c) Brion,H.; M o s e r , C ; Yamakazi,M. Chem. Phys.  (1959), 30, 673. (d) Fenske,R,F.; DeKock,R.L. Inorg. Chem. (1972), 1 1 , 437. (e) DeKock,R.L.; Sarapu,A.C; Fenske,R.F. Inorg. Chem.  (1971), 10, 38. 158 53) (a) Nesmayanov,A.N.; Anisimov,K.N.; Kolobova,N.E. ; Krasnoslobodskaya,L.L. Izu. Akad. Nauk. SSSR, Ser.  Khim. (1970), 860; B u l l . Acad. S c i . USSR Div. Chem.  S c i . ( E n g l . T r a n s l . ) (1970), 807. (b) Stewart,R.P.; Okamoto,N.; Graham,W.A.G. J .  Organomet. Chem. (1972), 42, C32. (c) Sweet,J.R.; Graham,W. A.G. Organomet. Chem.  (1979), 173, C9. (d) Casey,CP.; Andrews ,M. A.; R i n z , J . E . Am. Chem.  Soc. (1979) , 1 01, 741. (e) Tam,W.; Wong,W.; Gladysz,J.A. J_j_ Am. Chem. Soc. (1979) , 101, 1589. (f) Casey,CP.; Andrews,M.A.; McAlister,D.R. J . Am.  Chem. Soc. ( 1979), 101, 3371 . (g) Casey,CP.; Andrews,M.A.; McAlister,D.R.; R i n z , J . E . Anu Chem. Soc. (1980), 102, 1927. (h) Sweet,J.R.; Graham,W. A.G. J_;_ Am. Chem. Soc . (1 982) ,  104, 2811. 54) Hoyano,J.K.; Legzdins,P.; M a l i t o , J . T . J_;_ Chem. Soc. , Dalton Trans. (1975), 1022. 55) (a) Hames,B.W.; Martin,D.T.; Legzdins,P. " A b s t r a c t s of Papers", 10th I n t e r n a t i o n a l , Conference on Organometallic Chemistry, Toronto, Canada, Aug. 1981; 2E04. (b) Hames,B.W.; Legzdins,P. O r g a n o m e t a l l i c s ( 1 982), 1 , 116. (c) Legzdins,P.; Martin,D.T. O r g a n o m e t a l l i c s submitted f o r p u b l i c a t i o n . 56) (a) Kolthammer,B.W.S.; Legzdins,P. Chem. Soc.,  Dalton Trans. (1978), 31. (b) Kolthammer,B.W.S.; Legzdins,P.; Martin,D.T. Tetrahedron L e t t . (1978), 323. 57) Legzdins,P.; Martin,D.T.; Nurse,CR. Inorg. Chem. (1980) , 19, 1560. 58) King,R.B. Inorq. Chem. (1967) , 6j_ 30. 159 59) King,R.B. Inorg. Chem. (1968) , 7_j_ 90. 60) (a) James,T. A.; McCleverty, J.A. J_;_ Chem. Soc. (A)  (1971), 1068, 1596. (b) McCleverty, J.A. J_^ Chem. Soc . Dalton Trans. (1 972), 2588. 61) Greenhough,T.J.; Legzdins,P.; Martin,D.T.; T r o t t e r , J . Inorg. Chem. (1979), 18, 3268. 62) M a l i t o , J . T . ; Shakir,R.; Atwood,J.L. J_^ Chem. Soc. ,  Dalton Trans. (1980), 1253. 63) (a) McClevery,J.A.; Seddon,D. J ^ Chem. Soc., Dalton  Trans. (1972), 2526. (b) Seddon,D.; Kita,W.G.; Bray,J.; McCleverty,J.A. Inorg. Synth. (1976), 16, 24. 64) Kolthammer,B.W.S.; Legzdins,P.; M a l i t o , J . T . Inorg.  Chem. (1977), 16, 3173. 65) Greenhough,T.J.; Kolthammer,B.W.S.; Legzdins,P.; T r o t t e r , J . Inorg. Chem. (1979), 18, 3548. 66) Z i n g a l e s , F . ; T r o v a t i , A . ; C a v i a t i , F . ; U g u a g l i a t i , P . Inorg. Chem. (1971), 10, 507. 67) (a) Kolthammer,B.W.S.; Legzdins,P. Inorg. Chem.  (1979),18, 889. (b) Hames,B.W.; Kolthammer,B.W.S.; Legzdins,P. Inorg.  Chem. (1981), 20, 650. 68) Connelly,N.G. Inorg. Chim. A c t a . Rev. (1972), 6, 47. 69) Kolthammer,B.W.S. Ph.D. D i s s e r t a t i o n , The U n i v e r s i t y of B r i t i s h Columbia, 1979. 70) (a) Evans,D.F. J_;_ Chem. Soc. ( 1959) , 2003. (b) Bailey,R.A. J_;_ Chem. Ed. (1972) , 49, 299. 71) F i s c h e r , E . O . ; Strametz,H. J ^ Organomet. Chem. (1967),  10, 323. 72) Hardy,A.D.U.; Sim,G.A. A c t a . C r y s t a l l o g r . , Sect. B (1979), 35, 1463. 73) (a) Bush,M.A.; Sim,G.A.; Knox,G.R.; Ahmad,M.; 160 Robertson,G.G. Chem. Soc., Chem. Commun. (1969), 74. (b) Bush,M.A.; Sim,G.A. ;L Chem. Soc. (A) ( 1970) , 611. 74) (a) King,R.B.; Bisnette,M.B. J . Am. Chem. Soc. (1963),  85, 2527. (b) Ring,R.B.; Bisnette,M.B. Inorg. Chem. (1964), 3, 791 . 75) (a) Ahmad,M.; Bruce,R.; Knox,G. N a t u r f o r s c h . B (1966), 21, 289. (b) P r e s t o n , F . J . ; Reed,R.I. Chem Commun. (1966), 51. (c) McPhail, A.T.; Sim,G.A. Chem. Soc . (A) ( 1 968) , 1858. 76) R o t t , J . ; Guggolz,E.; Rettenmeier,A.; Ziegler,M.L. Z.  N a t u r f o r s c h . B (1982), 37, 13. 77) Ungermann,C.B.; Caulton,K.G. Am. Chem. Soc. (1976),  98, 3862. 78) Sacco,A.; Vasapollo,G.; Giannocarro,P. Inorg. Chim.  Ac t a . (1979), 32, 171. 79) Doyle,M.P.; Pickering,R.A.; Dykstra,R.L.; Cook,B.R. J .  Am. Chem. Soc. (1982), 104, 3392. 80) Tolman,C.A. Chem Rev. (1977), 77, 313. 81) Regina,F.J.; W o j c i c k i , A . Inorg. Chem. (1980), 19, 3803. 82) (a) Barnett,K.W.; Slocum,D.W. Organomet. Chem.  (1972), 44, 1 . (b) Adams,R.D.; C o l l i n s , D . E . ; Cotton,F.A. J ^ Am. Chem.  Soc. (1974), 96, 749. 83) Hackett,P.; O ' N e i l l , P . S . ; Manning,A.R. Chem. Soc.,  Dalton Trans. (1974), 1625. 84) Goh, L—Y.; D'Aniello,M.J.; S l a t e r , S . ; M u e t t e r t i e s , E . L . ; T a r a n a i e p o u r , I . ; Chang,M.I.; F r i e d r i c h , M . F . ; Day.V.W. Inorg. Chem. (1979), 18, 192. 85) K e l l e r , H . J . Z_;_ N a t u r f o r s c h . B (1968), 23, 133. 86) For examples, see: 161 (a) Manriquez,J.M.; McAlister,D.R.; Sanner,R.D.; Bercaw,J.E. Anu Chem. Soc. (1978) , 1 00, 271 6. (b) T h r e l k e l , R . S . ; Bercaw,J.E. Organomet. Chem. (1977) , 136, 1 and r e f e r e n c e s c i t e d t h e r e i n . (c) Thomas,J.L. J± Am. Chem. Soc. (1973), 95, 1838. (d) M a i t l i s , P . M . Acc. Chem. Res. ( 1978), 11, 301 and re f e r e n c e s c i t e d t h e r e i n . (e) Manriquez,J.M.; Fagan,P.J.; Schertz,L.D.; Marks,T.J. Inorg. Synth. (1982), 21, 181. (f) Fagan,P.J.; Manriquez,J.M.; Marks,T.J. In "Organometallics of the f—Elements", Marks,T.J.; Fischer,R.D. Eds; R e i d e l P u b l i s h i n g Co, Dordrecht, H o l l a n d , 1979, Chapter 4. 87) (a) Piper,T.S.; Wilkinson,G. J_^ Inorg. N u c l . Chem.  ( 1956) , 2j_ 38. (b) Hastings,M.C. B.Sc. D i s s e r t a t i o n , The U n i v e r s i t y of B r i t i s h Columbia, 1981. 88) Shriver,D.F. "The M a n i p u l a t i o n of A i r - S e n s i t i v e Compounds"; McGraw-Hill: New York, 1969. 89) Perrin,D.D.; Armarrego,W.L.F.; Perrin,D.R. " P u r i f i c a t i o n of Laboratory Chemicals", 2nd Ed.; Pergamon P r e s s : Oxford, 1980. 90) Mulay,L.N.; Boudreaux,E.A. "Theory and A p p l i c a t i o n s of Molecular Diamagnetism"; W i l e y — I n t e r s c i e n c e : Toronto, 1976, and r e f e r e n c e s c i t e d t h e r e i n . 91) Clark,H.C.; O'Brien,R.J. Can. J_^ Chem. (1961 ), 39, 1030. 92) Hoyano,J.K.; Legzdins,P.; M a l i t o , J . T . Inorg. Synth. (1978) , 18, 126. 93) Brunner,H. J_;_ Organomet. Chem. (1 969) , 1 6, 119. 94) Calderon,J.L.; Cotton,F.A. Organomet. Chem. (1971),  30, 377. 95) Cotton,F.A.; Legzdins,P. J_;_ Am. Chem. Soc. ( 1 968), 90, 6232. 96) Calderon,J.L.; Cotton,F.A.; Legzdins,P. J . Am. Chem. 1 62 Soc. (1969), 91, 2528. 97) Cotton,F.A.; Rusholme,G.A. J . Am. Chem. Soc. (1972),  94, 402. 98) (a) Huttner,G.; B r i n t z i n g e r ,H.H.~; B e l l , L . G . ; F r i e d r i c h , P . ; Bejenke,V.; Neugebauer,D. Organomet.  Chem. (1978), 145, 329. (b) Tang Wong,K.L.; Br i n t z i n g e r ,H.H. Jj_ Am. Chem. Soc.  (1975), 97, 5143. (c) B e l l , L . G . ; B r i n t z i n g e r , H . H . Organomet. Chem. (1977) , 135, 173. 99) Nesmayanov,A.N.; Ustynyuk,N.A.; Makarova,L.G.; Andrianov,V.G.; Struchkov,Yu.T.; S t e f f e n Andrae; Ustynyuk,Yu.A.; Malyugina,S.G. Organomet. Chem. (1978) , 159, 189. 100) (a) McCleverty,J.A.; Murray,A,J. Chem. Soc., Dalton  Trans. (1979), 1424. (b) Hunt,M.M.; Kita,W.G.; McCleverty,J.A. Chem.  Soc., Dalton Trans. (1978), 474. (c) Hunt,M.M.; McCleverty,J.A. Chem. Soc., Dalton  Trans. (1978), 480. 101) McCleverty,J.A.; Murray,A.J. T r a n s i t i o n Met. Chem. (1979) , 4j. 273. 102) F a l l e r , J . W . ; Chodosh,D.F.; Katahiva,D. Organomet.  Chem. (1980), 187, 227. 103) Beatty,R.P.; Datta,S.; Wreford,S.S. Inorg. Chem.  (1979) , 18, 3139. 104) Lee,W-S; B r i n t z i n g e r , H . H . Organomet. Chem. (1981),  209, 401 . 105) Beevor,R.G.; F r i t h , S . A . ; Spencer,J.L. Organomet.  Chem. (1981) , 221, C25. 106) (a) Hallam,B.F.; Pauson,P.L. Chem. Soc. (1958), 642. (b) Burton,R.; P r a t t , L . ; Wilkinson,G. J_;_ Chem. Soc.  (1961), 594. . (c) Preston ,H.G.Jr.; Davis, J.C. J r . J_;_ Am. Chem. Soc .  (1973), 95, 636. 163 (d) Crews,P. jh Am. Chem. Soc. ( 1973), 95, 636.. 107) Green ,M.L.H.; P r a t t , L . ; Wilkinson,G. J_^ Chem. Soc.  (1959), 3753. 108) (a) Carbonaro,A.; Greco,A. Organomet. Chem. (1970),  25, 477. (b) Von Gustorf,E.K.; Buchkremer,J.; P f a i f f e r , Z . ; Grevels,F-W. Angew. Chem. I n t . E d i t . E n g l . (1971 ) , 10, 260. (c) K r u g e r , C ; Tsay, Y—H. Angew. Chem. I n t . E d i t . E n g l . (1971) , 10, 261 . 109) (a) F a l l e r , J . W . ; Rosan,A.M. J . Am. Chem. Soc. (1977),  99, 4858. (b) F a l l e r , J . W . ; Rosan,A.M. Ann. N.Y. Acad. S c i .  (1977) , 295, 186. 110) Segal,J.A.; Green,M.L.H.; D a v i n , J . C ; Prout,K. J . Chem.  Soc. Chem. Commun. (1976), 766. 111) Von Gustorf,E.K.; Jaenicke,0.; Polansky,0.E. Angew.  Chem. I n t . E d i t . E n g l . (1972) , 1 1 , 532. 112) (a) Erker,G.; Wicher,J.; Engel,K.; R o s e n f e l d t , F . ; Dietrich,W.; Kruger,C. J_;_ Am. Chem. Soc . (1 980) , 1 02 , 6344. (b) Yasuda,H.; K a j i h a r a , Y . ; Mashima,K.; Nagasuna,K.; Lee,K.; Nakamura,A. O r q a n o m e t a l l i c s (1982), 1 , 388. (c) Dorf,U.; Engel,K.; Erker,G. O r g a n o m e t a l l i c s (1983), 2_^  462. 113) Von Sasse,H.E.; Ziegler,M.L. Z_^  Anorg. A l l g . Chem. (1972) , 392, 167. 114) (a) Tachikawa,M.; Shapley,J.R.; Haltiwanger,R.C.; Pierpont,C.G. Am. Chem. Soc. (1976), 98, 4651. (b) Pierpont,C.G. Inorg. Chem. (1978), 17, 1976. 115) Cotton,F.A. In "Dynamic Nuclear Magnetic Resonance Spectroscopy"; Jackman,L.M.; Cotton,F.A., Eds; Academic Pr e s s : New York, 1975; Chapter 10 and r e f e r e n c e s c i t e d t h e r e i n . 116) see f o r example: 164 (a) Mews,R.; Glemser,0. Angew. Chem. (1975), 87, 208; Angew. Chem. I n t . E d i t . E n g l . (1975), 14, 186. (b) Mews,R.; Angew. Chem. (1975), 87, 669; Angew. Che.  I n t . E d i t . E n g l . (1975), 14, 640. (c) Uson,R.; Riera,V.; Gimeno,J.; Laguna,M.; Gamasa,M.P. J_;_ Chem. Soc. , Dalton Trans. ( 1979) , 996. (d) Edwards,D.A.; Marshalsea,J. J ^ Organomet. Chem.  (1977), 131, 73. (e) Reger,D.L.; Coleman,C.J. J ^ Organomet. Chem.  ( 1977) , 1 31, 153. (f) Reger,D.L.; Coleman,C.J.; M c E l l i g o t t , P . J . J .  Organomet. Chem. (1979), 171, 73. (g) Reimann,R.H.; S i n g l e t o n , E . J_;_ Organomet. Chem.  (1973),59, C24. (h) Powell,P.; R u s s e l l , L . J . J ^ Organomet. Chem. (1977),  129, 415. • ( i ) W h i t e , C ; Thompson,S.J.; M a i t l i s , P . M . J . Organomet.  Chem.' (1 977) , 134, 319. ( j ) Doyle,G.; Tobias,R.S. Inorg. Chem. (1967), 6, 1111. (k) Piper,T.S.; Wilkinson,G. J ^ Inorg. N u c l . Chem.  (1956) , 2j_ 38. (1) Jennings,M.A.; Wo j c i c k i , A . J ^ Organomet. Chem.  (1968) , 14, 231. (m) King,R.B.; Welcman,N.A. Inorg. Chem. (1969), 8, 2540. (n) Klein,H.P.; Thewalt,U. J ^ Organomet. Chem. (1981) ,  206, 69. 117) Mattson,B.M.; Graham,W.A.G. Inorg. Chem. (1981), 20, 3186. 118) S c h l o t e r , K . ; Nagel,U.; Beck,W. Chem. Ber. (1980), 113, 3775. 119) Uchtman,V.A.; Dahl,L.F. J . Am. Chem. Soc. ( 1 969) , 91 , 3763. • ' 120) (a) B e r t o l u c c i , A . ; Freni,M.; Romiti,P.; C i a n i , G . ; 165 S i r o n i , A . ; Albano,V.G. J_;_ Organomet. Chem. ( 1976) , 113, C61 . (b) C i a n i , G . ; S i r o n i , A . ; Albano,V.G. Chem. Soc., Dalton Trans. (1977), 1667. 121) Mennemann,K.; Mattes,R. Angew. Chem. I n t . E d i t . E n g l .  (1976) , 15, 118. 122) Kirtley,S.W.; Chanton,J.P.; Love,R.A.; Tipton,D.L.; S o r r e l l , T . N . ; Bau,R. J_^ Anu Chem. Soc. (1980), 1 02, 3451 . 123) (a) Nakamoto,K. " I n f r a r e d Spectra of Inorganic and C o o r d i n a t i o n Compounds", 2nd Ed.; W i l e y — I n t e r s c i e n c e : Toronto, 1970. (b) Cotton,F.A. "Chemical A p p l i c a t i o n s of Group Theory", 2nd Ed.; W i l e y - I n t e r s c i e n c e : New York, 1971. 124) Lokshin,B.V.; Ginzburg,A.G.; Nazarova,E.B. Russ. Chem.  Rev, ( e n g l . T r a n s l . ) (1980) , 49, 115. 125) (a) Hackett,P.; Manning,A.R. Chem. Soc., Dalton  Trans. (1975), 1006. (b) Connelly,N.G.; Lucy,A.R.; Galas,A.M.R. Chem.  Soc., Chem. Commun. (1981 ) , 43. 126) Geary,W.J. Coord. Chem. Rev. (1971), 7, 81. 127) " C a t a l y t i c A c t i v a t i o n of Carbon Monoxide"; ACS Symposium S e r i e s ; F o r d , P . C ; Ed; American Chemical S o c i e t y : Washington, 1981; V o l 152. 128) Eisenberg,R.; Hendrikson,D.E. Adv. In C a t a l y s i s (1979),  28, 79 and r e f e r e n c e s c i t e d t h e r e i n . 129) (a) F i s c h e r , F . ; Tropsch,H. Chem. Ber. (1923), 56, 2428. (b) F i s c h e r , F . ; Tropsch,H. Chem. Ber. (1926), 59, 830, 832 and 923. (c) H e n r i c i - O l i v e , G . ; O l i v e , S . Angew, Chem. I n t . E d i t .  E n g l . (1976), 15, 136. 130) . (a) Haggin,J. Chem. Eng. News (1981), 59(8), 39. (b) Haggin,J. Chem. Eng. News (1981), 59(43), 22. 131) Parshall,G.W. "Homogeneous C a t a l y s i s " ; 166 W i l e y — I n t e r s c i e n c e : Toronto, 1980. 132) (a) Enemark,J.H.; Feltham,R.D.; R i k e r - N a p p i e r , J . ; B i z o t , K . F . Inorq. Chem. (1975), 14, 624. (b) La Monica,G.; Freni,M.; Cenine,S. J ^ Organomet.  Chem. (1974), 71, 57. 133) Ball,R.G.; Hames,B.W.; Legzdins,P.; T r o t t e r , J . Inorg.  Chem. (1980), 19, 3626. 134) Stevens,R.E.; G l a d f e l t e r , W . L . Am. Chem. Soc. (1 982) ,  104, 6454. 135) Nugent,W.A.; Haymore,B.L. Coord. Chem. Rev. (1 981 ), 31 , 123. 136) (a) Fjare,D.E.; G l a d f e l t e r ,W.L. J_;_ Am. Chem. Soc.  (1981), 103, 1572. (b) Fjare,D.E.; G l a d f e l t e r , W . L . Inorg. Chem. (1981),  20, 3533. 137) P a u l i n g , L . "The Nature of the Chemical Bond"; 3rd Ed; C o r n e l l : I thaca, NY, 1967. 138) S c h l o t e r , K . ; Beck,W. N a t u r f o r s c h . B (1980) , 35, 985. 139) Dolphin,D.; Wick,A.E. " T a b u l a t i o n of I n f r a r e d S p e c t r a l Data"; W i l e y — I n t e r s c i e n c e : Toronto, 1977. 140) (a) Drezdon,M.A.; Whitmire,K.H.; Bhat.tacharyya ,A.A, ; Hsu,W-L.; N a g e l , C . C ; Shore,S.G.; Shriver,D.F. J . Am.  Chem. Soc. (1982), 104, 5630. (b) Holt,E.M.; Whitmire,K.H.; Shriv e r , D . F . J .  Organomet. Chem. (1981), 213, 125. (c) Shr i v e r , D . F . " A c t i v a t i o n of Carbon Monoxide by Carbon and Oxygen C o o r d i n a t i o n " ; Chapter 1 of Ref. 127. (d) Whitmire,K.H.; Sh r i v e r , D . F . Am. Chem. Soc.  (1981), 103, 6754. 141) (a) Murphy,W.R.Jr.; Takeuchi,K.J.; Meyer,T.J. J . Am.  Chem. Soc. (1982), 104, 5817. (b) Thompson, M. S.; Meyer, T.J . J_j_ Am. Chem. Soc . (1 981 ) ,  103, 5577. 142) Graham,W.A.G. Personal communication. 167 143) (a) Dawson,A.; MeFarlane,W.; P r a t t , L . ; Wilkinson,G. J .  Chem. Soc. (1962), 3653. (b) Symon,D.A.; Wadding ton ,T.C. J;_ Chem. Soc. (A)  (1971), 953. (c) Harris,D.C.; Gray,H.B. Inorg. Chem. (1975), 14, 1215. 144) Legzdins,P.; Martin,D.T.; Nurse,C.R.; Wassink,B. Organometallies, i n p r e s s . 145) Connelly,N.G. Inorg. Synth. (1974) , 15, 91 . 146) Boyle,P.F.; Nicholas,K.M. J . Organomet. Chem. (1976),  114, 307. 147) Legzdins,P.; Wassink,B. Unpublished o b s e r v a t i o n s . 148) (a) Wochner,F.; K e l l e r , E . ; B r i n t z i n g e r , H . H . J .  Organomet. Chem. (1982) , 236, 267. (b) Clamp,S.; Connelly,N.G.; Payne,J.D. J . Chem. Soc.,  Chem. Comm. (1981), 897. (c) Connelly,N.G.; Payne,J.D.; Geiger,W.E. J . Chem.  Soc., Dalton Trans. (1983), 295. 168 APPENDIX 1 X-RAY DIFFRACTION DATA D i f f T a c t o m e t e r : Enraf-Nonius CAD4 R a d i a t i o n : MoK (X=0.71073 A) A l l atoms r e f i n e d , i n c l u d i n g H atoms. C r y s t a l system: Space group: a b c a I 1 Volume of u n i t c e l l : Z : Ab s o r p t i o n c o e f f i c i e n t : Scan range : R e f l e c t i o n s ( i 0 > 3 a i 0 ) : 2a M o n o c l i n i c P2 1/c 9.2096(9) A 10.0416(4) A 24.274(3) A 92.275(5)° 2243.1(3) A 3 4 16.6 cm - 1 O<20<55 3230 3b T r i c l i n i c P1 9.3505(9) A 10.1435(11) A 12.4454(11) A 84.994(7)° 83.183(7)° 89.597(6)° 1167.6(2) A 3 2 16.8 cm"1 O<20<6O 4783 R : E r r o r i n o b s e r v a t i o n : of u n i t weight. 0.039 0.039 0.046 0.050 1.794 e 2.271 e 1 70 Table A1 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 x 10', Mn x 10 5 , H X10 3) 2 a . And I s o t r o p i c Thermal Parameters (U _ X 10 3 A 2) For Atom X 1 z U /U--^eq ' — i s o Mn( 1 ) 38243( 5) 16435( 5) 36676( 2) 30 Mn(2) 15346( 6) 3619( 5) 37957( 2) 30 Mn(3) 16027( 6) 28256( 5) 39814( 2) 32 F(1) 4820 ' 3) 2788( 4) 5375( 1 ) 83 F(2) 5279 ' 5) 3020( 6) 6277( 1 ) 146 F(3) 3064< 5) 2692( 5) 5944( 2) 1 38 F(4) 41 16< , 8) 4578( 4) 581 9{ 2) 166 0( 1 ) 2785 [ 3) 97( 3) 2742( 1 ) 54 0(2) -740 [ 3) 1890( 3) 3271 ( 1 ) 56 0(3) 2940< 3) 3924( 3) 3036( 1 ) 54 0(4) 3056 3) 1047( 3) 4824( 1 ) 44 N( 1 ) 2718 ' 3) 562( 3) 3 1 98 ( 1 ) 34 N(2) 380 ' 3) 1 768 ( 3) 3539( 1 ) 37 N(3) 28071 ; 3) 3 1 03 ( 3) 3395( 1 ) 36 N(4) 2683< 3) 1 392 ( 3) 4281 ( 1 ) 30 C(1 ) 57631 , 4) 1679( 4) 3190.( 2) 43 C(2) 5732 4) 501 ( 5) 3496( 2) 51 C(3) 5763< ' 5) 828( 7) 4058( 2) 61 C(4) 5809< 5) 2224( 7) 4 1 05 ( 2) 60 C(5) 58 1 4 ( 4) 2744( 5) 3571 ( 2) 49 C(6) 76 k 5) -1256( 4) 3532( 2) 46 C(7) -338 5) -736( 4) 4053( 2) 47 C(8) 794< 5) -925( 4) 4439( 2) 48 C(9) 1 948< 5) -1542( 4) 4 1 82 ( 2) 48 C( 10) 1 502< 5) -1752( 4) 3626( 2) 46 C( 1 1 ) 233< 5) 4594( 4) 3952( 2) 51 C( 12) 1669< 5) 4946( 4) 41 1 2( 2) 50 C( 13) 2067I 6) 4315( 4) 46 1 0 ( 2) 53 C( 14) 865( 6) 3558( 5) 4766( 2) 57 C( 15) -253< 5) 371 1 ( 5) 4364( 2) 55 C( 16) 5780< 8) 1809( 8) 2575( 2) 70 C( 17) -824I 8) -1282( 6) 301 1 ( 3) 70 C( 18) -6111 8) 5053( 6) 3448( 3) 72 B 43191 i 6) 3282( 6) 5870( 2) 51 H(NO) 339( 7) 1 73 ( 6) 499( 3) 89(21) H(2) 559( 5) -48( 5) 336( 2) 72(16) H(3) 566( 4) 25( 5) 433( 2) 45(12) H(4) 576( 5) 270( 5) 440( 2) 56(13) H(5) 576( 4) 359( 4) 344( 2) 43(12) H(7) -1 21 ( 5) -26( 5) 4 1 0 < 2) 54(13) H(8) 75( 4) -11 ( 4) 479( 2) 41(11) H(9) 285( 5) -191 ( 4) 435( 2) 48(12) c o n t i n u e d * • • 171 HI 10) 209( 4) -2 1 0 { 4) 336( 2) 48(12) H( 12) 226( 6) 546( 6) 388( 2) 80(18) H( 13) 297( 5) 441 < 5) 482( 2) 54(13) H( 14) 89( 5) 301 ( 5) 51 0 ( 2) 53(13) H( 15) -116< 5) 322< 5) 436( 2) 62(14) H( 16a) 651 ( 8) 1 54 ( 6) 242( 3) 90(22) H( 16b) 51 8 ( 8) 94( 8) 243( 3) 146(31) H( 16c) 521 ( 7) 242( 7) 243( 3) 98(26) H( 17a) -13( 7) -1 58 ( 6) 272( 3) 90(21 ) H( 17b) -1 17( 7) -43( 7) 285( 3) 104(24) H( 17c) -1 57 < 12) -1 97 ( 12) 295( 5) 233(51) H( 18a) -5( 6) 527( 5) 3 1 8 ( 2) 60(18) H( 18b) -1 49 ( 7) 442( 8) 329( 3) 123(25) H( 18c) -109( 9) 578( 10) 352( 4) 161(38) U = 1/3 trace U,. —eq —diag 172 Table A2 F i n a l Ani s o t r o p i c Thermal Parameters (U ,j x 1 0 3 ; Mn x 10") For 2 a Atom y, i y 2 2 U 3 3 y, 2 y, 3 y 2 3 Mn( 1 ) 281 ( 3) 274( 3) 340( 3) -4( 2) 6( 2) 17( 2) Mn(2) 3 1 4 ( 3) 204( 3) 379( 3) -10( 2) 24( 2) -3( 2) Mn<3) 336( 3) 1 98 ( 3) 428( 3) 14( 2) 1 1 ( 2) -6( 2) F( 1 ) 80( 2) 1 1 3( 3) 55( 2) 9( 2) -4( 1 ) -26( 2) F(2) 1 05 ( 3) 275( 7) 56( 2) 47( 3) -20( 2) -32( 3) F(3) 96( 3) 1 49 ( 4) 1 72 ( 4) -52( 3) 41 ( 3) -31( 4) F(4) 3 1 0 ( 8) 46( 2) 1 43 ( 4) 9( 3) 1 3( 5) -15( 3) 0(1 ) 69( 2) 58 ( 2) 36( 2) -14( 2) 7( 1 ) - 1 K 1) 0(2) 41 ( 2) 40( 2) 86( 2) 2( 1 ) -19( 2) K 2) 0(3) 62( 2) 43( 2) 55( 2) -3( 1 ) -1 ( 1 ) 23( 2) 0(4) 62( 2) 39( 2) 31 ( 1 ) -1 ( 1 ) -6( 1 ) 5( 1) N( 1 ) 39( 2) 27( 2) 35( 2) -1 ( 1 ) 2( 1 ) 1 ( 1) N(2) 32( 2) 26( 2) 54( 2) -1 ( 1 ) -1 ( 1 ) 0( 1) N(3) 38( 2) 28( 2) 40( 2) -6( 1 ) -2( 1 ) 6( 1) N(4) 38( 2) 22( 2) 29( 1 ) 1 ( 1 ) 0( 1 ) 1 ( 1) C( 1 ) 31 ( 2) 43( 2) 54( 2) -1 ( 2) 1 1 ( 2) -2( 2) C(2) . 37( 2) 44( 3) 72( 3) 9( 2) 10( 2) 6( 2) C(3) 32( 2) 85( 4) 65( 3) 1 2( 2) -1 ( 2) 28( 3) C(4) 36( 2) 89( 4) 53( 3) -7 ( 2) -4 ( 2) -18( 3) C(5) 35( 2) 47( 3) 63( 3) -9( 2) 7( 2) -3( 2) C(6) 48( 2) 27( 2) 62( 3) -14( 2) -3 ( 2) 0( 2) C(7) 43( 2) 35( 2) 65( 3) -9( 2) 12( 2) 3( 2) C(8) 67( 3) 35( 2) 43( 2) -1 1 ( 2) 12( 2) 7( 2) C(9) 55( 3) 29( 2) 62( 3) -2( 2) -2( 2) 14( 2) C( 10) 59( 3) 17( 2) 64( 3) -5( 2) 1 3( 2) -4( 2) C( 1 1 ) 52( 3) 27 ( 2) 73( 3) 17( 2) -2( 2) -8( 2) C( 12) 58( 3) 20( 2) 72( 3) 1 ( 2) 4 ( 2) -7( 2) C( 13) 65( 3) 31 ( 2) 64( 3) 3( 2) -5( 2) -17( 2) C( 14) 85( 4) 34( 2) 54( 3) 1 1 ( 2) 22( 3) -8( 2) C( 15) 51 ( 3) 42( 3) 74( 3) 2( 2) 20( 2) -14( 2) C( 16) 67( 4) 94( 5) 51 ( 3) -1 ( 4) 23( 3) 5( 3) C( 17) 83( 4) 51 ( 3) 73( 4) -20( 3) -22( 3) 0( 3) C( 18) 72( 4) 52( 3) 92( 5) 25( 3) -16( 3) 1 ( 3) B 50( 3) 47( 3) 54( 3) -2( 2) -6( 2) -12( 2) *The a n i s o t r o p i c thermal parameters employed i n the refinement are i n the e x p r e s s i o n : f = f °exp(-2rr2Z:2:u. . h. h. a. *a. *) " ~ - i i - i - I - i " I 1 73 Table A3 Bond Lengths (A) For 2a With Estimated Standard  D e v i a t i o n s In Parentheses. Bond Length(A) Bond Length(A) Mn (1 )-Mn(2) 2.5002(7) F< 1 )-B 1.395(6) Mn : i I-Mn(3) 2.5098(7) F( 2)-B 1.326(6) Mn (1 |-N(1 ) 1.850(3) F< 3)-B 1.317(6) Mn (1 )-N(3) 1.849(3) F( 4)-B 1.321(7) Mn {i l-N(4) 1.874(3) 0< 1)-N(1) 1.206(4) Mn ; i >-co) 2.167(4) 01 2)-N(2) 1.205(4) Mn i i >-C(2) 2.153(4) 01 3)-N(3) 1.209(4) Mn (1 )-C(3) 2.149(4) 01 4)-N(4) 1.393(4) Mn (1 >-C(4) 2.156(4) C< 1)-C(2) 1.399(6) Mn (1 >-C(5) 2.161(4) CI 1)-C(5) 1.414(6) Mn (2 >"Mn(3) 2.5150(8) C 1)-C(16) 1.499(7) Mn [2 )-N(1) 1.860(3) CI 2)-C(3) 1.402(7) Mn (2 )-N(2) 1.860(3) CI 3)-C(4) 1.402(9) Mn (2 -N(4) 1.864(3) CI 4)-C(5) 1.399(7) Mn '2 -C(6) 2.187(4) CI 6)-C(7) 1.435(6) Mn (2 )-C(7) 2.159(4) c 6)-C(10) 1.415(6) Mn [2 -C(8) 2.159(4) c 6)-C(17) 1.484(7) Mn [2 >-C(9) 2.157(4) c< 7)-C(8) 1.387(6) Mn '2 -C(10) 2.162(4) CI 8)-C(9) 1.399(6) Mn 3 -N(2) 1.857(3) CI 9)-C(10) 1.411(7) Mn 3 -N(3) 1.861(3) CI 11)-C(12) 1.409(6) Mn '3 -N(4) 1.880(3) CI 11)-C(15) 1.422(7) • Mn 3 -C(1 1 ) 2.178(4) CI 11)-C(18) 1.497(7) Mn 3; -C(12) 2.153(4) CI 12)-C(13) 1.400(7) Mn 3] -C(13) 2.167(4) CI 13)-C(14) 1.408(7) Mn 3] -C(14) 2.176(5) CI 14)-C(15) 1.398(7) Mn 3 1 -C(15) 2.168(4) A l s o OU)-H(NO) 0.85(6) H(N0)-F(1) 1.91(6) 174 Table A4 Bond Angles (deg) For 2a With Estimated D e v i a t i o n s In Parentheses. Standard Bonds Angle(deg) Bonds Angle(deg) Mn ( 2)-Mn(1)-Mn(3) 60. 26(2) Mn(1)-N(3)-Mn(3) 85. 16(1 3) Mn ( 2)-Mn(1)-N(1) 47. 80(9) MnO )-N(3)-0(3) 137. 3(3) Mn ( 2)-Mn(1)-N(3) 91 . 99(9) Mn(3)-N(3)-0(3) . 1 37. 2(3) Mn ( 2)-Mn(1)-N(4) 47. 85(9) Mn(1 )-N(4)-Mn(2) 83 . 98(1 2) Mn ( 3)-Mn( 1 )-NO ) 91 . 67(10) Mn(1)-N(4)-Mn(3) 83. 92( 1 2) Mn ( 3)-Mn(1)-N(3) 47. 62(10) MnO ) - N ( 4 ) - 0 ( 4 ) 131. 3(2) Mn ( 3)-MnO )-N(4) 46. 16(9) Mn(2)-N(4)-Mn(3) 84 . 40(1 2) NO )-Mn(1)-N(3) 89. 18(13) Mn(2)-N(4)-0(4) 124. 9(2) NO )-Mn(1)-N(4) 95. 60(13) Mn(3)-N(4)-0(4) 131. 6(2 N(3 )-Mn(1)-N(4) 95. 72(13) C(2)-C(1)-C(5) 107. 0(4; Mn ( 1)-Mn(2)-Mn(3) 60. 06(2) C ( 2 ) - C O )-C( 16) 127. 2(5 Mn ( 1)-Mn(2)-N(1) 47. 47(9) C(5)-C(1)-C(16) 125. 8(5' Mn ( 1)-Mn(2)-N(2) 92. 35(10) C O )-C(2)-C(3) 108. 5(4 Mn ( 1)-Mn(2)-N(4) 48. 18(9) C ( 2 ) - C ( 3 ) - C ( 4 ) 108. 2(5 Mn ( 3)-Mn(2)-N(1 ) 91 . 27(9) C(3)-C(4)-C(5) 1 07 . 5(5 Mn ( 3)-Mn(2)-N(2) 47. 38(10) C O )-C(5)-C(4) 108. 7(5 Mn ( 3)-Mn(2)-N(4) 48. 08(9) C(7)-C(6)-C(10) 1 05. 3(4 NO )-Mn(2)-N(2) 90. 09(14) C(7)-C(6)-C(17) 1 26. 9(5 NO )-Mn(2)-N(4) 95. 61(13) C O 0 )-C(6)-C( 1 7 ) 127. 8(5 N(2 )-Mn(2)-N(4) 95. 32(13) C(6)-C(7)-C(8) 109. 1 (4 Mn ( 1)-Mn(3)-Mn(2) 59. 68(2) C(7)-C(8)-C(9) 108. 8(4 Mn ( 1)-Mn(3)-N(2) 92. 12(10) C(B)-C(9)-C(10) 1 07 . 2(4 Mn ( 1)-Mn(3)-N(3) 47. 22(9) .C(6)-C( 1 0)-C(9) 109. 6(4 Mn ( 1)-Mn(3)-N(4) 47. 93(9) C( 12)-C(11)-C(15) 1 06. 2(4 Mn ( 2)-Mn(3)-N(2) 47. 47(10) C( 12)-C( 1 1 )-C08) 126. 8(5 Mn ( 2)-Mn(3)-N(3) 91 . 24(10) C( 15)-C(1 1 )-C08) 126. 9(5 Mn ( 2)-Mn(3)-N(4) 47. 52(9) C( 1 1 )-C(12)-C(13) 1 09. 6(4 N(2 )-Mn(3)-N(3) 90. 53(14) C( 12)-C(13)-C(14) 1 07 . 1 (5 N(2 )-Mn(3)-N(4) 94. 86(13) C( 13)-C(14)-C(15) 1 08. 5(5 N(3 )-Mn(3)-N(4) 95. 09(13) C O 1 ) - C ( l 5 ) - C ( l 4 ) 108. 5(4 Mn ( 1)-N(1)-Mn(2) 84 . 73(13) F(1)-B -F(2) 109. 7(4 Mn ( 1)-N(1)-0(1 ) 1 38. 3(3) F(1)-B -F(3) 1 06. 2(4 Mn ( 2)-N(1)-0(1 ) 1 36. 7(3) F O ) - B -F(4) 1 08. 7(5; Mn ( 2)-N(2)-Mn(3) 85. 15(13) F(2)-B -F(3) 111. 9(6) Mn ( 2)-N(2)-0(2) 1 36. 4(3) F(2)-B -F(4) 110. 7(5 Mn ( 3)-N(2)-0(2) 137. 8(3) F(3)-B -F(4) 109. 5(5 A l s o N ( 4 ) - 0 ( 4 ) - H ( N O ) 0(4)-H(NO)-F(1) K(NO)-F(1)-B 107(4) 156(6) 112(2) 1 75 T a b l e A5 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 x 10", Mn And P x 10 5, H x 10 3) And I s o t r o p i c Thermal Parameters (U x 10 3 A 2) For 3b. Atom X 1 2 Ueq/Miso Mn( 1 ) 37932( 4) 25550( 4) 30364( 3) 29 Mn(2) 15444{ 4) 12799( 4) 29208( 3) 29 Mn(3) 15971( 4) 37432( 4) 25074( 3) 31 P 39485(10) 23815( 9) - 13343( 7) 50 F( 1 ) 2986 ( 6) 1615 [ 4) -413 3) 174 F(2) 4364 ( 5) 3273 i 5) -454 3) 1 53 F(3) 2883 ( 5) 341 4 [ 5) -1598 6) 206 F(4) 5040 ( 5) 3143 [ 4) -2216 ' 3) 1 39 F(5) 3476 ( 6) 1 509 [ 4) -21 63 ' 3) 172 F(6) 5148 ( 7) 1 426 [ 7) -1 1 39 7) 255 0( 1 ) 2828 ( 3) 773 2) 4894 2) 52 0(2) -755 ( 2) 2703 : 2) 4025 2) 51 0(3) 2871 ( 3) 4714 i 2) 4273 2) 57 N( 1 ) 2712 ( 2) 1 365 2) 4021 2) 33 N(2) 370 ( 2) 2625 ' 2) 3457 2) 32 N(3) 2753 ( 2) 3957 2) 3600 2) 36 N(4) 2697 ( 2) 2389 k 2) 1893 2) 32 C( 1 ) 5719 ( 3) 2521 3) 3855 3) 42 C(2) 571 4 ( 3) 1417 4) 3230 3) 46 C(3) 5729 ( 3) 1 862 4) 2139 3) 53 C(4) 5750 ( 3) 3243 i 4) 2049 3) 56 C( 5) 5738 i 3) 3654 3) 3108 k 3) 48 C(6) 169 [ 3) 307 3) 1 926 ' 3) 45 C(7) -337 ' 4) 19 ' 4) 3049 : 3) 54 C(8) 736 5) -643 3) 3559 i 3) 60 C(9) 1 940 i 5) -789 3) 2769 3) 54 C( 1 0) 1584 3) -218! 3) 1769 3) 44 C ( 1 1 ) 254 4) 5500 3) 2529 3) 50 C( 12) 1 687 < 5) 5855! 4) 21 04 5) 63 C( 1 3) 2070 5) 5227! 4) 1 167 4) 68 C( 14) 904 5) 4477! 4) 978 3) 63 C( 1 5) -202! 4) 4642! 4) 1815! 3) 52 C( 16) 5708! 5) 2497! 5) 5053! 4) 63 C( 17) -6631 5) 1016! 5) 1092! 4) 65 C( 18) -584! 6) 5949! 5) 3538! 5) 73 H(N) 287( 3) 231 ( 3) 1 25 ( 3) 37( 9) H(2) 561 ( 4) 72( 4) 342( 3) 56(13) H(3) 586( 6) 1 23 ( 6) 1 58 ( 5) 121 (20) H(4) 560( 4) 381 ( 3) 1 43 ( 3) 49( 9) H(5) 564( 3) 449( 3) 332( 2) 35( 8) H(7) -1 28 ( 5) 44( 4) 332( 3) 68(12) H(8) 71( 5) -86( 4) 429( 4) 80(14) c o n t i n u e d * • • 176 H( 9) 276( 5) -1 20 ( 5) 291 ( 4) 88(15) H( 10) 225( 5) -15( 4) 1 02 ( 3) 74(12) Hi 12) 207( 6) 623( 5) 243( 4) 78(19) H( 13) 282( 5) 529( 4) 86( 3) 60(13) H( 14) 79( 5) 398( 4) 40( 4) 76(14) H( 15) -81 ( 5) 423( 4) 1 97 ( 3) 60(14) H( 16a) 531 ( 6) 1 96 ( 5) 536( 5) 81(22) H( 16b) 648( 9) 280( 8) 540( 7) 165(31) H( 16c) 5 1 6 ( 5) 338( 5) 524( 4) 88(15) H( 17a) -109( 5) 41 ( 5) 79( 4) 90(15) H( 17b) -15( 4) 1 37( 4) 51 ( 3) 55 (11) H( 17c) -1 1B( 6) 1 88 ( 6) 1 29 ( 4) 113 (18) H< 18a) -1 45 ( 8) 539( 7) 373( 6) 161(26) H< 18b) -15( 5) 628( 5) 4 1 0 ( 4) 80(15) H( 18c) -1 04 ( 6) 651 ( 5) 334( 4) 83(17) Table A6 F i n a l A n i s o t r o p i c Thermal Parameters JUij 2L 10" h l l For 3b. Atom y, 1 y 2 2 y 3 3 2 y, 3 y 2 3 Mn( 1 ) 236( 2) 294 ( 2) 3 1 8 ( 2) -2( 1 ) -21 ( 1 ) 1 3( 1 ) Mn(2) 284( 2) 272 ( 2) 300( 2) -30( 1 ) -10( 1 ) -10( 1 ) Mn(3) 280( 2) 289 ( 2) 351 ( 2) 30( 1 ) -22( 1 ) 38( 1 ) P 605( 5) 447 ( 5) 422( 4) 23( 4) 84( 4) -1 1 ( 3) F( 1 ) 2666( 58) 1655 (38) 743( 20) -1373( 40) 606( 27) -222( 21 ) F(2) 1 950 ( 42) 1839 (40) 822( 21 ) -1001( 34) 92( 23) -440( 23) F(3) 1 562( 44) 1861 (48) 2876( 68) 9 T 9 ( 38) -925( 45) -10( 48) F(4) 1 595 ( 34) 1523 (34) 908( 23) -603( 29) 387( 22) 24( 22) F(5) 2796( 61 ) 1 522 (36) 805( 22) -1039( 40) 255( 30) -525( 23) F(6) 2 1 02 ( 66) 2440 (72) 2989( 84) 1 538 ( 59) -263( 60) 229( 64) 0( 1 ) 5 1 2 ( 13) 653 (15) 379( 1 1 ) -60( 1 1 ) -1 05 ( 10) 1 71 ( 10) 0(2) 335( 10) 530 (13) 608( 13) 23( 9) 141 ( 10) -12( 1 1 ) 0(3) 551 ( 14) 557 (14) 624( 15) -41 ( 1 1 ) -38( 1 1 ) -283( 12) N( 1 ) 306( 1 1 ) 351 (11) 325( 1 1 ) -4( 9) -12( 9) 28( 9) N(2) 282( 10) • 344 (11) 333( 1 1 ) 13( 8) -12( 8) -6( 9) N(3) 333( 1 1 ) 332 (11) 401 ( 12) -28( 9) -8( 9) -41 ( 9) N(4) 326( 1 1 ) 338 (11) 271 ( 1 1 ) -7( 9) 1 1 ( 9) -9( 9) C( 1 ) 273( 13) 463 ( 16) 522 ( 17) -45( 1 1 ) -92( 12) 33( 13) C(2) 275( 13) 400 (17) 692( 22) 53( 12) -60( 13) -3( 16) C(3) 277 ( 14) 745 (24) 563( 20) 99( 14) 50( 13) -1 32 ( 18) C(4) 293( 14) 752 (25) 566( 20) -54( 15) 61 ( 13) 1 62( 18) C(5) 307( 14) 407 (17) 707( 22) -88( 12) -55( 14) 59( 15) C(6) 367( 14) 484 (17) 533( 18) -94( 13) -48( 13) -1 94 ( 1 4 ) C(7) 482( 19) 562 (20) 566( 20) -258 ( 16) 1 09( 15) -1 60 ( 16) C(8) 862( 28) 374 (17) 531 ( 20) -286( 18) -18( 19) 34( 15) C(9) 690( 24) 262 (14) 702( 23) 9( 15) - 1 48 ( 19) -74( 14) C( 10) 429( 16) 400 ( 15) 51 1 ( 17) -38( 13) -14( 13) - 1 72 ( 13) C( 1 1 ) 459( 17) 358 (15) 664 ( 21 ) 1 3 9 ( 13) -48( 15) 58 ( 15) C( 12) ' 540( 22) 309 (17) 987( 35) 8( 15) -54( 22) 1 55( 20) C( 13) 600( 24) 590 (23) 7 1 3 ( 27) 151 ( 20) 1 12( 21 ) 372 ( 21 ) C( 14) 759( 27) 694 (25) 425( 18) 298( 21 ) -1 33( 18) 1 1 2( 1 7) C( 15) 426( 18) 484 (19 ) 631 ( 21 ) 1 29( 15) -1 43 ( 16) 94 ( 16) C( 16) 545( 22) 805 (30) 575( 22) -1 23 ( 22) -228( 18) -29( 21 ) C( 17) 553( 23) 749 (29) 709( 27) -20( 21 ) -235( 21 ) -174( 23) C( 18) 770( 31 ) 583 (25) 8 1 4 ( 32) 285( 25) 10( 25) - 1 07 ( 23) *The a n i s o t r o p i c thermal parameters employed i n the refinement are U^j i n the e x p r e s s i o n : t = f°exp(-2rr 2IIU h h a *a *) i i i j ~ i ~ i 1 78 Table A7 Bond Lengths (A) For 3b With Estimated Standard  D e v i a t i o n s In Parentheses. Bond uncorr. cor r . Bond uncorr cor r . Mn -Mn(2) 2.5015(5) 2.509 P -F(1) 1 .529( 3) 1 . 569 Mn i 1 -Mn(3) 2.5001(5) 2.509 P -F(2) 1 .565( 3) 1 .609 Mn 1 -N( 1 ) 1.856(2) 1 .862 P -F(3) 1 - 484 ( 4 ) 1 .542 Mn 11 -N( 3) 1.858(2) 1 .865 P -F(4) 1.562( 3) 1 .605 Mn 1 -N(4) 1.869(2) 1 .877 P -F(5) 1.522( 3) 1 . 562 Mn (1 -C( 1 ) 2.171(3) 2. 178 P -F(6) 1.505( 5) 1 . 566 Mn (1 -C(2) 2.154(3) 2. 164 0(1)-N(1) 1 .21 1 ( 3) 1.214 Mn (. 1 -C(3) 2.158(3) 2. 169 0(2)-N(2) 1.202( 3) 1 .205 Mn 11 -C(4) 2.163(3) 2. 174 0(3)-N(3) 1.201( 3) 1 .205 Mn {1 -C(5) 2.154(3) 2. 1 62 C( 1 )-C(2) 1 . 4 1 8 ( 5) 1 .428 Mn [2 -Mn(3) 2.5064(5) 2.515 C( 1 )-C(5) 1.412( 4 ) 1 .422 Mn [2 -N( 1 ) 1.858(2) 1 .866 C(1)-C(16) 1.488( 5) 1 .494 Mn ,2 -N(2) 1.865(2) 1 .872 C(2)-C(3) 1.392( 5) 1.401 Mn '2 -N( 4 ) 1.871(2) 1 .877 C(3)-C(4) 1.395( 6) 1 .404 Mn 2 -C(6) 2.185(3) 2. 1 90 C(4)-C(5) 1 . 4 1 5 < 6) .1.424 Mn 2 -C(7) 2.165(3) 2.173 C(6)-C(7) 1 . 427( 5) 1.436 Mn 2 -C(8) 2.148(3) 2. 1 60 C(6)-C(10) 1 .42 1 ( 4) 1.431 Mn 2 -C(9) 2.149(3) 2. 1 60 C(6)-C(17) 1.501( 6) 1 . 507 Mn 2 -C( 1 0) 2.176(3) 2.183 C(7)-C(8) 1.389( 6) 1 .398 Mn 3 -N(2) 1.861(2) 1 .867 C(8)-C(9) 1 .421 ( 6) 1 .429 Mn 3] -N(3) 1.862(2) 1 .870 C(9)-C(10) 1 . 402 ( 5) 1.410 Mn 3 1 -N(4) 1.672(2) 1 .879 C(11)-C(12) 1 . 4 1 8 ( 5) 1 .429 Mn 3 -C(11) 2.173(3) 2. 180 C(11)-C(15) 1. 4 00 ( 5) 1.413 Mn 3 -C(12) 2.157(3) 2. 170 C O 1 )-C08) 1.503( 6) 1.511 Mn 3 -C(13) 2.154(3) 2.169 C(12)-C(13) 1.386( 7 ) 1 . 397 Mn 3 -C(14 ) 2.153(3) 2. 167 C( 13)-C(14) 1.389( 7 ) 1 .400 Mn 3) -C(15) 2.143(3) 2. 1 52 C(14)-C(15) 1.398( 6) 1 .408 A l s o N(4)-H 0.81(3) H-FO) 2.24(4) Table A8 Bond Angles (deg) For 3b With Estimated Standard  D e v i a t i o n s In Parentheses. Bonds Angle(deg) Bonds Angle(deg) Mn(2) -Mn(1)-Mn(3) 60. 148(15) F ( 3 ) - P -F(4) 87. 0(3) Mn (2 ) -Mn(1)-N(1 ) 47. 70(7) F ( 3 ) - P -F(5) 91 . 9(4) Mn(2) -Mn(1)-N(3) 92. 00(7) F ( 3 ) - P -F(6) 173. 9(4) Mn(2) -Mn(1)-N(4) 48. 07(7) F ( 4 ) - P -F(5) 91 . 5(2) MnO) -Mn(1)-N(1) 92. 44(7) F ( 4 ) - P -F(6) 87. 1(3) Mn(3) -Mn(1)-N(3) 47. 84(8) F ( 5 ) - P -F(6) 89. 4(4) MnO) -Mn(1)-N(4) 48. 12(7) Mn( 1 ) -N( 1 )-Mn(2) 84. 68(9) N(1 )-Mn(1)-N(3) 90. 37(10) Mn( 1 ) -N( 1 )-0(1) 1 37. 5(2) N( 1 )-Mn(1)-N(4) 95. 65(10) Mn(2) -N( 1 )-0(1) 1 36. 9(2) N(3)- Mn(1)-N(4) 95. 88(10) Mn(2) -N(2 )-Mn(3) 84. 55(9) Mn( 1 ) -Mn(2)-Mn(3) 59. 899(15 Mn(2) -N(2 )-0(2) 1 36. 9(2) Mn ( 1 ) -Mn(2)-N(1) 47. 63(7) MnO) -N(2 )-0(2) 1 37 . 8(2) Mn ( 1 ) -Mn(2)-N(2) 92. 44(7) Mn ( 1 ) -N(3 )-Mn(3) 84 . 47(10) Mn ( 1 ) -Mn(2)-N(4) 48. 00(7) Mn ( 1 ) -NO )-0(3) 1 37. 0(2) Mn (3) -Mn(2)-N( 1 ) 92. 20(7 ) Mn (3 ) -NO )-0O) • 138. 1 (2) Mn (3) -Mn(2)-N(2) 47. 66(7 ) Mn( 1 ) -N(4 )-Mn(2) 83. 94 (9) Mr. (3) -Mn(2)-N(4) -47. 98(7) Mn ( 1 ) -N(4 )-Mn(3) 83. 86(10) N( 1 )-Mn(2)-N(2) 91 . 34(10) Mn (2) -N(4 )-Mn(3) 84 . 06(9) N( 1 )-Mn(2)-N(4) 95. 51(10) C ( 2 ) - C( 1 ) -C(5) 1 06. 0(3) N(2)- Mn(2)-N(4) 95. 50(10) C ( 2 ) - C O ) -CO 6) 127. 2(3) Mn ( 1 ) -Mn(3)-Mn(2) 59. 954(15 C ( 5 ) - C O ) -C(16) 1 26. 9(4) Mn ( 1 ) -Mn(3)-N(2) 92. 58(7) C( 1 )-C(2) -C(3) 1 09. 3(3) Mn O ) -Mn(3)-N(3) 47. 70(7) C ( 2 ) - C O ) -C(4) 1 08. 3(3) Mn ( 1 ) -Mn(3)-N(4) 48. 02(7) C ( 3 ) - C(4) -C(5) 1 07 . 6(3). Mn (2) -Mn(3)-N(2) 47. 80(7) C( 1 )-C(5) -C(4) 1 08. 8(3) Mn(2) -Mn(3)-N(3) 91 . 75(7) C ( 7 ) - C(6) -COO) 1 06. 5(3) Mn (2 ) -Mn(3)-N(4) 47. 96(7) C ( 7 ) - C(6) -C(17) 125. 7(4) N(2)- Mn(3)-N(3) 90. 59(10) C( 1 0) -C(6 )-C(l7) 127. 9(3) N(2)- Mn(3)-N(4) 95. 62(10) C ( 6 ) - C(7) -C(8) 1 08. 9(3) N(3)- Mn(3)-N(4) 95. 65(10) C ( 7 ) - C(8) -C(9) 108. 2(3) F( 1 )-P -F(2) 86. 4(2) C ( 8 ) - C(9) -COO) 107. 8(4) F(1 )-P -F(3) 96. 8(4) C ( 6 ) - C( 10)-C(9) 108. 7(3) F(1 )-P -F(4) 1 75. 1(3) C( 12) - c o 1)-C(15) 105. 4(4) F( 1 )-P -F(5) 91 . 4(2) C( 12) - c o 1)-C(18 ) 126. 9(4) F(1 )-P -F(6) 89. 1(4) C( 1 5) -CO 1 )-C0 8) 127. 7(4) F ( 2 ) - P -F(3) 86. 9(3) C( 1 1 ) - c o 2)-C(13) 1 09. 2(4) F ( 2 ) - P -F(4) 90. 7(2) C( 12) -CO 3)-C(14) 108. 3(4) F ( 2 ) - P -F(5) 177. 4(3) C( 1 3) -CO 4)-C(15) 1 07. 4(4) F ( 2 ) ~ P -F(6) 92. 1(4) C( 1 1 ) -CO 5)-C(14) 109. 7(4) A l s o N(4)-H-F(1) 165(3) APPENDIX 2 INFRA-RED, 1H-NMR, 13C-NMR AND ESR SPECTRA OF THE NEW COMPLEXES PREPARED IN THIS RESEARCH 181 [ ( T j 5 - C 5 H 5 ) C r ( N O ) l ] 2 r IR (CH 2C1 2): 1200 1000 WAVE N U M B E R I C M " ) [ (Tj 5-C 5H 5)Cr(NO) (OEt) ] 2 , IR(CH 2C1 2) : 1200 lOOu WAVlNUMMR t M " ' l [ (T ? 5-C 5H 5)Cr(NO) (OMe) ] 2 , IR (CH 2C1 2) 1200 1000 1 82 (T? 5-C 5H 5)Cr(NO) ( P P h 3 ) C l . IR ( C H 2 C 1 2 ) : i i M M : ;• ; | | j j ' | I |U I I i U 2lJv 3000 2iW) iUOO 1000 1600 WOO YJUO 1000 800 W A V E N U M 6 £ R ( C M " ' ) WAVENUMBfB I C M " I EPR (Toluene) : a < 3 1 P > 1 1 83 ( 77 5 - C s H 5 )Cr(NO) (PPh 3 ) Br, IR ( C H 2 C 1 2 ) : WAVENUMBERfCM"') :CO 1000 W A V E N U M B E R (CM" 1 ) EPR (Toluene a < 3 1 P : 20G 1 84 (T? 5-C 5H 5)Cr(NO) (PPh 3 )I . IR ( C H 2 C 1 2 ) : 3S0O 3000 2100 2ouO loOO l&OO 1400 lyOO IOOC 600 W A V E N U M B E R (CM" ' ) W A V E N U M B E R ( C M " ) EPR (Toluene) 185 ( 77 5 - C 5 H 5 )Cr(NO) {P(OPh) 3 } l . IR ( C H 2 C 1 2 ) : EPR (Toluene) : ( T ? 5 - C 5 H 5 )Cr(NO) {P(OEt) 3 } I . EPR (Toluene) 1 87 ( T;5 — C s M e 5 ) C r (NO) 2 B r . IR ( C H 2 C 1 2 ) : 00 3000 2100 2000 1800 1000 MOO 1200 1000 " " " " BOO ' ^ " ^ 0 [ W A V E N U M K R I C M " ' ) WAVtNUMBER t M " f 1H-NMR (CDC1 3): l 6 "T" 4 8 ppm ~~T~ 2 188 189 (T7 5-C 5Me 5)Cr(NO) 2I. IR ( C H 2 C 1 2 ) : WAVENUMBER (C NT') WAVENUMBER (CM"') 1H—NMR ( C D C l 3 ) : 190 [ ( T ? 5 - C 5 M e 5 ) M o ( N O ) I 2 ] 2 . IR ( C H 2 C 1 2 ) : WAVENUMKRlCM - 1 ) WAVENUMBER (CM"'I 1H—NMR ( C D C I 3 ) : 8 T" 6 n ppm 1 2 191 1 92 [ (T; 5-C 5Me 5)W(NO)I 2 3 2 , IR ( C H 2 C 1 2 ) : 'H-NMR (CDC1 3) 8 6 ppm 4 nr 2 1 93 1 94 (r? 5-C 5Me 5 )Mo(NO) (PPh 3 ) l 2 . IR ( C H 2 C 1 2 ) : 'H-NMR ( C D C l 3 ) : 195 (q»-C 5Me 5)Mo(NO)(P(OPh) 3}l 2 . IR ( C H 2 C 1 2 ) : 1H—NMR (CDC1 3): J ~r 8 ppm 4 2 4CTOO Hz 2100 1000 8 10 6 10 1 3 J I I I I I L C—NMR (CDC1 3): i i i i i i i VJ • I i I • F T >-H— J 100 ppm s'o S o i i i i > i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i i VD ( T? 5 —C 5Me5 )W (NO) (PPh 3 ) l 2 . IR ( C H 2 C 1 2 ) : V W V E N U M B H I C M - I WAVSNUMBER ICM-I 1H—NMR (CDC1 3): 1 98 199 200 (C 5H 5) 2W(NQ)I. IR ( C H 2 C 1 2 ) : .-.••..•tiiU'.-.d iC«"'i WaVENlWbER 1C*A'') 'H-NMR ( C D C l 3 ) : 8 ppm ° 8 201 ( T ? 5 - C 5 H 5 )MO(NO) ( T ? * - s - t r a n s - C 5 H , ) . IR ( C H 2 C 1 2 ) : 30GJ W A V £ N U * « H ( C M ' ' 1 IJOO 1000 WAVENUMfcfft iCM'M 'H-NMR ( C D C 1 3 ) -J J L 8 6 ppm 4 0 203 204 ( T ? 5 - C 5 H 5 )MO(NO) ( T ? " - s - t r a n s - C 6 H 1 0 ), IR ( C H 2 C 1 2 ) : iooo WAVENUMBEfUCM*') 1200 IOOO WAVENUMBER (CM"') 1H—NMR ( C D C l 3 ) : 1 r r r J r 8 6 ppm OS 205 206 ( T ? S - C 5 H 5 )MO(NO) (^"-s-trans-CfiH, „). IR ( C H 2 C 1 2 ) : ;. : : | 1 ; _ 1 . " " " " 1 — 1 — . . . t - •q_ ; 1 w -Y • ! i - \ — V J \ • . . 1... 1 •  :T '!'"'! . . . ! . . ! . .J • i | ••-•••h: — — - ;--• •• u ' ' o | !> :.;.::i.U::: •1.: ! ! ... • • ! HHf!-- -1 •• '!•": 1 .: ! : . . . 0 ' - . . . :L ._ ... . . . . . . . . j . . . . - -rj-:" •:! • : . . :L . ! . • ; : ! : : ! ; : : ' : i : : :::;BI::tTM7^ - - - - - _ .:. . ,i,!=M to 3000 2i00 3000 1600 1600 U00 1300 1000 BOO 6CX W A V E N U M B E R ( C M - M W A V E N U M B E R 1CM-') 1H-NMR ( C D C l 3 ) : JUL V J 1 i r 8 T r ppm 4 "i 1 1 r 207 [(C SH 5) 2Mo(NO)(CH 3CN)]BF t t IR (Nujol m u l l ) : 1200 1000 WAVfNUMMft CM"') 1H—NMR (CD 3N0 2): 8 I 6 ppm I 4 208 IR (CH 3CN): W A V E N U M M R I C M " ' ) W A V E N U M B E R ICM - ' ) 1H—NMR (CD 3CN): 4000Hz 2o'oo 13C-NMR (CD 3CN): 10J00 800 I 600 J I L J I L 200 150 100 50 S 0 210 [ (C 5H 5) 2Mo(NO)(CH 3CN)]SbF 6 . IR (Nujol m u l l ) : 1H—NMR (CD3NO2): 21 1 IR(CH 3CN): 1200 1000 WAVENUMBER (CM"') 1H—NMR (CD 3CN) X A-8 "T~ 6 ppm 4 2 OS [ { ( T} 5—C 5H S )Mo (NO) (OH) } 3 Q ] B F a . 2H 2Q. IR(Nujol m u l l ) : 1H—NMR ( ( C D 3 ) 2 C O ) : P P M I j I 4 0 J L 4000Hz 2000 1000 800 I 600 13C-NMR (D,0) 200 150 j • I I 1 r _T 1 100 p P m 50 8 0 I ! 1 1 , i i ; 1 i - : i 214 [{(T ? 5-C 5H 5)Mo(NO)(OH)} 30]SbF 6.(CH3) 2CO. IR (CH 3CN): 1206 1000 W A V E N U M R E R CM" ' ) 1H-NMR (CD 3CN): 215 [ { ( T ? 5 - C 5 H 5 )MO(NO) (OH) } 30]BF,, .2H 20. IR (Nujol m u l l ) : 3.0 1 , , j 4 , 1 , , , • 0 3 , ... 1 ... , •i .T .-1 i • ! /~\T . X-« • 1. • . . 1 . 1 . 1 1 i , .V.,.  i... ; : : | ; : ; ; [•••'••• .:::|!:. . 'i1 . : : ; ! : ! ; : 1 i' * •' • 1 :1 :.. .; ;-: '• •• ; / 1 / ' •Pv- •c 1 \ A - •1 ""I"!' VM ii i: : '..\: , / r: \ *c •"TV:: 1 ' t o • 1 / ! « 0 . • "'I ::H:::- m iH;r if Hi'-i 1 •::\: ;; l:: 4 r:;;i!--: 0 ::. !l!r: Wm " 1 \ .IHiiiJ: ] o * : 1 ~ r". ! I:;~ i; ~ ;:: r •:.:.{;;!: m Y:N:;;' Mini - -in i: "nji" :- | ::J;;!lllljJ:::;-:l! ;• •! ^  = = = = "! = = = A = d;:!! H; = =TTT1:; p' 1E ; )"•:'!: -4iii. Miillii; ".ni'iii 1 :):;;: . • |::: • | : :: 30 l 'J-r|i; •: 1; j 0 - •^|r^T-; :H;r|i];l WMmm — V. |:- h:: ' = = 1 =;:: m ft ' iiiiliiii : :i:'. iiil-iiiliiillii::!^ ;! :;!!:;;i!;;i;li::nnn ..: j •:::: i • i !;;i7*::! 'i;:i:Y -;::mi-H- -,: :i:::: itiirfti :::: j: i: i i 1 •:::!::: fftlriftfi-H. 00 3000 2300 2O00 IftO 1600 MOO 1200 1000 BOO V»»VINUMB£«tM-'l W»VtNUMM« tM-'l 1H—NMR (CD 3CN): 216 (C 5H 5) 2M(N0)I.AgY. (a) M=Mo, Y=BF„. IR (Nujol m u l l ) : (b) IR (CH 3CN): (c) M=Mo, Y=SbF 6. IR (Nujol m u l l ) : WAVtNUMBER ( CM" ' ) W A V E N U M E E R C M - ' ) WAVENU«IRER<CM*M W A V E N U M M R (CM* 1 ) WAVfJNUMMftlCM-'i WAVENUMBER tCW) 217 (d) M=Mo, Y=SbF 6. IR(CH 3CN): (e) M=W, Y = BFa . IR (Nujol m u l l ) : ( f ) M=W, Y=SbF 6 . I R (Nujol m u l l ) : WAVENUMBER (CM*') WAVENUMBER CM" ' ) 218 [ ( T ? 5 - C 5 H 5 ) 2Mo(NO) ]A1C1 3I . IR ( C H 2 C 1 2 ) : 1H—NMR ( ( C D 3 ) 2 C O ) : 70 60 5 0 PPM ( £ I 4 0 30 20 219 [ (T? 5-C 5H aMe) 3Mn 3 (NO) 3 (NOH) ]BF„ . IR ( N u j o l m u l l ) : ~i 1 i 1 1 1 1 1 r~ 8 6 ppm 4 2 08 220 221 UT} 5-C 5H t tMe) 3Mn 3(NO) 3(NH) ]BF a . IP (CH 2C1 2): WAVtNOMfiEftiCM'M WAVtNUMfiEB t C W ) 1H—NMR ( C D 2 C 1 2 ) : ~i 1 1 1 r 25 20 15 p p m 10 5 222 [ (T? 5-C 5H aMe) 3Mn 3(NO) 3(NH) ] P F 6 . IR ( C H 2 C 1 2 ) : WAVENUMBER ICM'') 1000 WAVE N U M B E R C M " ) 1H—NMR (C D 2 C 1 2 ) : n r 20 15 ppm I 10 5 — i 0 223 [ ( T ? 5 - C 5 H 5 ) 2Mn 2 ( N 0 ) 2 (CO) (NH 2 ) 3BPh„ . 0. 5CH 2C1 2. IR ( C H 2 C 1 2 ) : • v___. _ ' • • •_•_]'• i i i I i i i iT i i ,i 7T,'i" i i ,i " i " . ... i l , i i ,i i 1 1 1 1 1 iT 11 ilMii'i|iiilnnT . i . Y | i , " , i ; ,j,=:j,!: 1 • i i '1 / ! ----- *P 1 1 1 iV IV\ liij.;.: OJ.j. : ' : ! *\ f !-. !;•• : 1 • J 1 I j • 1 i I j • : : : j r : : •.I-;--: . . . : | . . . . t P-4;;H \ ' i P : # P ; ; - - . 1 :1 o I / .i;iiLi 4|4 •' H 7 i ' : ~ e p--:i A ,.,.,: r ! !;|..,. t P P P - : : •  I- '!' -=: -1! H i — "j p j i :;i P P J P P ; P ; : ; : p 0 i' - P ~ i 1 o ! •: «C . i-.. ;. T •' : '< :. : .^•;..^J:i||i!]..:i: - {Pprl": ii " '1: • ' •j.y': ! — P P '.'.'}..'•:.]. '•]'...-.Li': ] 0: : . ] : : ; : | : ; : i j i ! : ; ; ; ; # P ; r - p 1;. • :h •• • , :p \ : : ; : . r-i • . :! . . :::Jt-:: Nil-; :n;|--:!, P ••MM : ; : ; ! , : : ; ' i ' 3 - j .;j:ii:I|:;:;JiLiiUL;; P : : # P : "::]•;• : ! ; : ' .1 : p ; i :..a...: P i ; ; . . rlt! P ^iii:;! i p p p - j : ;p ; -^ - 1 !--iH;"-!-. 1 •:: - •]:•: •• Mr;-.] ..j. :! • u :i:;ii!M ' ; ! 1:: : iPn ; 3 3000 2AO0 2000 1600 I60O MOO 1200 1000 800 60 WAVENUMBER (CW ' I WAVENUMBER (CM - 1) 1H—NMR ( ( C D 3 ) 2 C O ) : 224 [ (T? 5-C 5Hi,Me) ?Mn 2 (NO) 7 (CO) (NH 7 ) ]BPh„ . IR ( C H 2 C 1 2 ) : W A V E N U M I I R ICM" 1 ) W A V E N U M B E R (CM•') 225 IR (CH 3CN): PUBLICATIONS Mingos, D.M.P.; Nurse. CR. Molecular O r b i t a l Calculations on n 3 - and n 5-Hexadienyl Complexes of the Platinum Metals; An Analysis of t h e i r Conformational Preferences and Fluxional C h a r a c t e r i s t i c s . J . Organomet. Chem., 1980, 184, 281. Legzdins, P.; Martin, D.T.; Nurse, C.R. Organometallic N i t r o s y l Chemistry. 12. New Cyclopentadienylnitrosyl Complexes of Tungsten. Inorg. Chem., 1980, 19, 1560. Legzdins, P.; Nurse. C.R. Organometallic N i t r o s y l Chemistry 17. Solvent Control of the Reactions of Bis(cyclopentadienyl)iodonitrosylmolybdenura with some S i l v e r (I) S a l t s . Inorg. Chem., 1982, 2j_, 3110. Legzdins, P.; Nurse, C.R.; R e t t i g , S.J. Organometallic N i t r o s y l Chemitry. 18. Ac t i v a t i o n of Coordinated Nitrogen Monoxide. Synthesis and Characterisation of novel p 3-Hydroxyimido and Ug-Imido Complexes. J . Am. Chem. Soc., 1983, 105, 3727. Legzdins, P.; Martin, D.T.; Nurse, C.R.; Wassink, B. Organometallic N i t r o s y l Chemistry, 19. Protonation vs. Oxidative Cleavage of the Isoelectronic Complexes [ ( n 5 -C 5H 1 +R)M(L0) 2] 2 (M = Cr, Mn, Fe; L = C or N; R = H or Me) by HBF^. Organometallics, i n press. 

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