Open Collections

UBC Theses and Dissertations

UBC Theses Logo

UBC Theses and Dissertations

The chemistry of group 6 and 7 transition metal organometallic nitrosyl complexes Kolthamer, Brian William Stirling 1979

Your browser doesn't seem to have a PDF viewer, please download the PDF to view this item.

Item Metadata

Download

Media
831-UBC_1979_A1 K64.pdf [ 6.35MB ]
Metadata
JSON: 831-1.0060827.json
JSON-LD: 831-1.0060827-ld.json
RDF/XML (Pretty): 831-1.0060827-rdf.xml
RDF/JSON: 831-1.0060827-rdf.json
Turtle: 831-1.0060827-turtle.txt
N-Triples: 831-1.0060827-rdf-ntriples.txt
Original Record: 831-1.0060827-source.json
Full Text
831-1.0060827-fulltext.txt
Citation
831-1.0060827.ris

Full Text

THE CHEMISTRY OF GROUP 6 AND 7 TRANSITION METAL ORGANOMETALLIC NITROSYL COMPLEXES by BRIAN WILLIAM STIRLING KOLTHAMMER B.Sc. (Honours), U n i v e r s i t y of B r i t i s h Columbia, 1975 A THESIS SUBMITTED IN PARTIAL. FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY THE FACULTY OF GRADUATE STUDIES i n the Department of Chemistry We accept t h i s t h e s i s as conforming t o the r e q u i r e d standard THE UNIVERSITY OF BRITISH COLUMBIA February, 1979 (c) B r i a n W i l l i a m S t i r l i n g Kolthammer, 197 9 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 o f the r e q u i r e m e n t s f o r an advanced degree at the U n i v e r s i t y o f B r i t i s h C o l u m b i a , I ag r ee tha t the L i b r a r y s h a l l make i t f r e e l y a v a i l a b l e f o r r e f e r e n c e and s t u d y . I f u r t h e r ag ree t h a t p e r m i s s i o n f o r e x t e n s i v e c o p y i n g o f t h i s t h e s i s f o r s c h o l a r l y p u r p o s e s may be g r a n t e d by the Head o f my Department o r by h i s r e p r e s e n t a t i v e s . I t i s u n d e r s t o o d t h a t c o p y i n g o r p u b l i c a t i o n o f t h i s t h e s i s f o r f i n a n c i a l g a i n s h a l l not be a l l o w e d w i t h o u t my w r i t t e n p e r m i s s i o n . Department o f The U n i v e r s i t y o f B r i t i s h C o l u m b i a 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date H&AcL M J i l l ABSTRACT N i t r o s y l c h l o r i d e e x h i b i t s a number of d i f f e r e n t r e a c t i o n modes i n i t s r e a c t i o n s w i t h monomeric and d i m e r i c n e u t r a l c a r b o n y l complexes of t r a n s i t i o n metals. From i t s r e a c t i o n w i t h [ C p C r ( C O ) 3 ] 2 under c o n t r o l l e d c o n d i t i o n s , the o r g a n o m e t a l l i c compounds CpCr (CO) 2 (NO) , CpCr(NO) 2Cl, [ C p C r C l 2 ] 2 , , and [CpCr (NO) Cl] 2 can be o b t a i n e d . In contrast.,, the analogous [CpM(CO) 3] 2 (M — Mo or W) compounds r e a c t w i t h C1N0 to produce CpM(CO) 3Cl and CpM(NO) 2Cl i n comparable y i e l d s . The (arene)M(CO) 3 (M = Mo or W) compounds form the polymeric [ M ( N O ) 2 C l 2 ] n s p e c i e s v i a l a b i l e M (CO) 2 (NO) 2 C 1 2 i n t e r m e d i a t e s under i d e n t i c a l experimental c o n d i t i o n s . Poss i b l e pathways l e a d i n g t o the f o r m a t i o n of a l l products are presented. T r i t h i a z y l t r i c h l o r i d e , N^S^Cl^, i n t r o d u c e s the t h i o n i t r o s y l group onto a metal c e n t r e d u r i n g the r e a c t i o n . Na[CpCr (CO) ] + 3" 3N 3S 3C1 3 • CpCr (CO) 2 (NS) An x-ray c r y s t a l l o g r a p h i c a n a l y s i s of t h i s complex shows t h a t the t h i o n i t r o s y l group c o o r d i n a t e s e s s e n t i a l l y l i n e a r l y to the chromium v i a the n i t r o g e n atom. A second product formed i n t h i s r e a c t i o n , C p 2 C r 2 ( C O ) ^ S , possesses a n o v e l Cr-S-Cr l i n k a g e which i s l i n e a r , s h o r t , and c h e m i c a l l y i n e r t The c a t i o n s , [ (RC^H^)Mn (CO)''2 (NO) ] * (R = H or Me) r e a c t with I i n acetone a t room temperature to produce (RC 5H 4)Mn(CO)(NO)I. These species have very l a b i l e CO l i g a n d which are r e a d i l y d i s p l a c e d by Lewis bases to produce (RC^H4) Mn(L) (NO) I [R = H, L = PPh 3 or P(OPh) 3; R = Me, L = PPh 3, P(OPh) 3, or P ( C 6 H 1 : L ) 3 ] . The r e a c t i o n s of B r - , Clo, and N0 2~ wit h [(RC^H^)Mn(CO) 2(NO)] + produce the unusual b i m e t a l l i c compounds (RC 5H 4) 2Mn 2 (NO) 3X (R == H or Me; X = C l , Br, or N0 2) The compound [CpCr(NO) 2] 2 a b s t r a c t s a l l of the c h l o r i n e ligands from S n C l 4 , MC12 (M = Hg, Sn, or Pb), CpFe-(CO) 2Cl, and Mn(CO) 5Cl in. r e f l u x i n g t h f to form CpCr(NO) 2Cl. The other products are the metals (M), [CpFe(CO)»]„, and Mn2(CO)^Q, r e s p e c t i v e l y . The chromium dimer a l s o a b s t r a c t s halogen from v i c - d i h a l o a l k a n e s to produce the corresponding alkenes i n good y i e l d s . - i v -ACKNOWLEDGEMENTS I wish t o thank the f a c u l t y and t e c h n i c a l s t a f f o f the Chemistry department f o r t h e i r a s s i s t a n c e and guidance throughout t h i s study. In p a r t i c u l a r , I wish to thank P r o f . N.L. Paddock who read t h i s t h e s i s and o f f e r e d suggestions f o r improvements I am indebted to the people o f Room 325 f o r p r o v i d i n g a p l e a s a n t atmosphere f o r work and e s p e c i a l l y I acknowledge Dr. J.T. M a l i t o , D.T. M a r t i n and B.W. Hames. The work of Jen Kolthammer, who typed t h i s t h e s i s , i s g r e a t l y a p p r e c i a t e d . F i n a l l y , I wish to express my g r a t i t u d e to Pe t e r Legzdins whose perseverence and encouragement are the foundations of t h i s work. - v -TABLE OF CONTENTS Page ABSTRACT i i ACKNOWLEDGEMENTS i i v TABLE OF CONTENTS V LIST OF TABLES v i i LIST OF FIGURES . . i x ABBREVIATIONS AND COMMON NAMES x CHAPTER I INTRODUCTION 1 CHAPTER I I SOME REACTIONS OF NITROSYL CHLORIDE WITH NEUTRAL CARBONYL COMPLEXES ... 7 Experimental 9 Re s u l t s and D i s c u s s i o n 19 Reactions of N i t r o s y l C h l o r i d e w i t h [CpM(CO) -J 2 (M = Cr, Mo, or W) and [CpMn(COr (NO) ] 2 19 Reactions o f N i t r o s y l C h l o r i d e w i t h Other N e u t r a l Carbonyl Complexes .. 28 Reactions of N i t r o s y l C h l o r i d e w i t h CpMn(CO) 3 33 Reactions of N i t r o s y l C h l o r i d e A t t r i b u t a b l e to C l 2 and NO 34 CHAPTER I I I REACTIONS OF TRITHIAZYL TRICHLORIDE WITH TRANSITION METAL CARBONYL COMPOUNDS 36 Experimental 37 Re s u l t s and D i s c u s s i o n 42 CHAPTER IV REACTIONS OF DICARBONYL(n 5-CYCLO-PENTADIENYL)NITROSYLMANGANESE HEXA-FLUOROPHOSPHATE WITH HALIDE IONS .. 5 9 Experimental 61 - v i -Page Re s u l t s and D i s c u s s i o n 73 CHAPTER V SOME ASPECTS OF THE CHEMISTRY OF BIS[ (n 5-CYCLOPENTADIENYL)DINITROSYL-CHROMIUM] 99 Experimental 99 Res u l t s and D i s c u s s i o n 105 S e l e c t i v e Removal of Halogen from Organic H a l i d e s 115 REFERENCES 119 - v i i -LIST OF TABLES Table Page I Low-Resolution Mass S p e c t r a l Data f o r [ C p C r C l 2 ] 2 and [ C p C r ( N O ) C l 2 ] 2 22 II N i t r o s y l S t r e t c h i n g Frequencies o f the Complexes ML 2(NO) 2C1 2 31 I I I Reactions of N^S C l ^ with some Tran-s i t i o n Metal Compounds 39 IV P h y s i c a l P r o p e r t i e s o f (n 5-C5H[-) Cr-(CO) 2(NX) Complexes 44 V Low-Resolution Mass S p e c t r a l Data f o r (C 5H 5) Cr (CO) 2 (NX). Complexes 4 6 VI Low-Resolution Mass S p e c t r a l Data f o r [( C 5 H 5 ) . C r ( C O ) 2 ] 2 S 53 VII Mass S p e c t r a l Data f o r (RC 5H.)Mn(CO)-(NO) I Complexes 63 VII I P h y s i c a l P r o p e r t i e s o f the Complexes (RC 5H 5)Mn.(L) (NO) I 66 IX Elemental Analyses f o r ( R C ^ H . ) 2 M n 2 ~ (NO) 3X Complexes 71 X P h y s i c a l P r o p e r t i e s o f (RC 5H 4) 2Mn 2~ (NO) 3X Complexes 72 XI Mass S p e c t r a l Data f o r (RCj-H .) Mn(NO) -(PPh 3)I ..7 78 XII Mass S p e c t r a l Data f o r (RC-H.) Mn (NO) -. [ P ( 0 P h ) o ] I and (C cH_)Mn( N 0 7 T P (C CH, ,) , [ P ( C 6 H l 3 ) 3 ] I ....S.H.3 79 XI I I Mass S p e c t r a l Data f o r (C,H 7)Fe(CO)-(PPh 3)I v :.. 80 XIV 1 3 C NMR S p e c t r a l Data o f Some (MeCp)Mn Compounds 86 XV Mass S p e c t r a l Data f o r (C^H-)Re(CO)-(NO) I 89 - v i i i -Table Page XVI Mass S p e c t r a l Data f o r (RCVH.)„Mn„-(NO) 3I 92 XVII Mass S p e c t r a l Data f o r (RC-HJ 9Mn 0-(NO) 3Br 93 XVIII Mass S p e c t r a l Data f o r (RCr-H.) 9Mn~-(NO) 3C1 94 XIX Mass S p e c t r a l Data f o r (C-H-)-Mn--(NO) 3R 95 XX *H NMR S p e c t r a l Data f o r (RC RH.) 9Mn 0-(NO) 3X 97 XXI Reactions of j^CpCr(NO) 2 ] 2 w i t h some Halogen-Containing Compounds 101 XXII H i g h - R e s o l u t i o n Mass S p e c t r a l . D a t a f o r [ ( C 5 H 5 ) C r ( N O ) 2 ] 2 107 - i x -LIST.OF FIGURES Figure Page 1 Structure of [.Ru(PPh3> 2 (NO) 2 C 1 ] + 3 2 Apparatus for Pu r i f y i n g N i t r o s y l Chloride 1 1 3 Molecular structure of (n 5-Cj - H , .) Cr-( C O ) 2 ( N S ) 4 8 4 Molecular structure of [ (ri 5 - C J - H J . ) Cr-(CO) 2] 2S 5 5 5 The * H NMR Spectra of (MeCp) Mn (CO) , (MeCp) Mn (CO) _ (PPh^) , [.(MeCp) Mn (CO) -(NO)(PPh 3)]PF f i, and (MeCp)Mn(NO)-(PPh 3)I . 8 3 6 Infrared Spectral changes accompany-ing the reactions of [CpCr(NO) 0] 0 ... 1 1 0 - x -ABBREVIATIONS AND COMMON NAMES The a b b r e v i a t i o n s used i n t h i s t h e s i s are those recommended i n the Handbook f o r Authors of Papers i n  American Chemical S o c i e t y P u b l i c a t i o n s (ACS 1978). o A Angstrom atm atmospheres Bu b u t y l c a l c d c a l c u l a t e d cm 1 wave numbers i n r e c i p r o c a l c entimeters Cp p e n t a h a p t o - c y c l o p e n t a d i e n y l d day(s) dec decomposes E t e t h y l h hour(s) Hz H e r t z , c y c l e s per second IR i n f r a r e d J magnetic resonance c o u p l i n g constant m/z mass to charge r a t i o Me methyl MeCp pentahapto-methylcyclopentadienyl min minute (s) mm m i l l i m e t e r s o f mercury mmol m i l l i m o l e NMR n u c l e a r magnetic resonance Ph phenyl t h f t e t r a h y d r o f u r a n 6 NMR chemical s h i f t n 5 pentahapto v IR s t r e t c h i n g frequency - 1 CHAPTER I INTRODUCTION A d i s t i n g u i s h i n g t r a i t of the d-block elements i s t h e i r a b i l i t y to form complexes wi t h n e u t r a l molecules such as i s o c y a n i d e s , phosphines, amines, carbon monoxide, and n i -trogen monoxide. The most important of these l i g a n d s i s c a r -bon monoxide, and volumes of i n f o r m a t i o n 1 have been p u b l i s h e d not only on the p r e p a r a t i o n of t r a n s i t i o n metal c a r b o n y l s but a l s o on the use of these complexes i n o r g a n i c s y n t h e s i s and c a t a l y s i s . The chemistry of t r a n s i t i o n metal n i t r o g e n mono-xi d e compounds i s l e s s w e l l developed. However, the extent of the chemistry t h a t may be e x h i b i t e d by these n i t r o s y l compounds and t h e i r d e r i v a t i v e s i s p o t e n t i a l l y as broad as t h a t of the c a r b o n y l complexes. Although n i t r o g e n monoxide and carbon monoxide are known to bond to t r a n s i t i o n metals i n an analogous f a s h i o n , the NO l i g a n d c o n t a i n s one more e l e c t r o n ins.a T T* o r b i t a l . The presence of t h i s e x t r a e l e c t r o n a l s o allows a n i t r o s y l group t o behave i n a f a s h i o n unobserved f o r a c a r b o n y l l i g a n d , i v e . to form a bent M-N-0 bond. The two d i f f e r e n t bonding modes may be d e s c r i b e d as f o l l o w s : (1) L i n e a r The n i t r o s o n i u m i o n , NO , i s l s o e l e c -t r o n i c with carbon monoxide and, thus, i t has three bonding e l e c t r o n p a i r s between the atoms and a lone e l e c t r o n p a i r on - 2 -both the n i t r o g e n and oxygen. Both atoms are sp h y b r i d i z e d and both are p o t e n t i a l donors. However, t h e . n i t r o g e n c o o r d i n a t e s p r e f e r e n t i a l l y , thereby a v o i d i n g a l a r g e formal p o s i t i v e charge on the more e l e c t r o n e g a t i v e element. The n i t r o s y l i o n can be co n s i d e r e d as a a-donor and the r e s u l t i n g M-NEO .is l i n e a r . Occupied metal dTT o r b i t a l s p r o v i d e some degree of MTT-^-NOTT* o v e r l a p e s t a b -l i s h i n g a s y n e r g i s t i c bonding r e l a t i o n s h i p . ( A l t e r n a t i v e l y , the l i n e a r group may be con s i d e r e d as a bond between n i t r o g e n monoxide.and a.m e t a l . c o n t a i n i n g an empty a - o r b i t a l and a h a l f -f i l l e d T r - o r b i t a l w h i c h - i n t e r a c t s w i t h the i r * e l e c t r o n of the N O ) . When bonding i n t h i s way, the n i t r o s y l l i g a n d i s a f o r -mal t h r e e - e l e c t r o n donor. (2) Bent A bent n i t r o s y l l i g a n d i s an analogue of an o r g a n i c n i t r o s o group or the NO group i n C1N0. The M-N-0 l i n k a g e c o n s i s t s of a doubly bonded.NO group, a s i n g l e a-bond between the n i t r o g e n and the metal, and a lone p a i r o f e l e c -t r o n s on the n i t r o g e n atom. The n i t r o g e n atom i n t h i s case i s s p 2 h y b r i d i z e d and the r e s u l t i n g M-N-0 system i s bent. When bonding i n t h i s way, the n i t r o s y l l i g a n d i s a formal o n e - e l e c t r o n donor. The r e s o l u t i o n to the b e n t / l i n e a r d u a l i t y of the l i g a n d . l i e s i n whether the p a i r o f e l e c t r o n s i n ques-t i o n w i l l be f o r c e d to r e s i d e i n an atomic o r b i t a l on the n i t r o g e n atom or whether there i s a l o w - l y i n g m o l e c u l a r o r -b i t a l a v a i l a b l e to i t . An i d e a l c h a r a c t e r i z a t i o n of these two types of bonding i s pr e s e n t i n the molecular s t r u c t u r e of the d i n i t r o -- 3 -s y l c a t i o n , [ Ru(PPh 3) 2(NO) 2C1] +, shown i n Figure l 2 . The b a s a l n i t r o s y l l i g a n d forms a l i n e a r M-N-0 l i n k and the short M-N bond di s t a n c e i s i n d i c a t i v e of the m u l t i p l e bond-in g described above. The a x i a l l i g a n d contains a longer M-N distance and a d i s t i n c t l y bent M-N-0 group w i t h an angle of 136°. Although the i d e a l bond angle f o r the bent system i s 120°, d i f f e r i n g amounts of i n t e r a c t i o n between the lone p a i r on the l i g a n d and the metal o r b i t a l s produce M-N-0 groups w i t h bond angles ranging from 120° to 180° 2. The a b i l i t y of the l i g a n d to be a v a r i a b l e 1+3 e l e c t r o n donor to a metal centre w i l l g r e a t l y a f f e c t the chemistry of such complexes. In f a c t , tautomerism between the two p o s s i b l e forms can convert a c o o r d i n a t i v e l y saturated compound to a r e a c t i v e unsaturated species without the customary r e q u i r e -ment of the d i s s o c i a t i o n of a l i g a n d . I t i s therefore reasonable to expect that n i t r o s y l complexes should e x h i b i t d i f f e r e n t chemical and c a t a l y t i c p r o p e r t i e s from t h e i r i s o -- 4 -e l e c t r o n i c c a r b o n y l analogues. One of the f i r s t r e p o r t s o f t h i s unique chemistry was the e x t r a o r d i n a r y s p e c i f i c i t y shown by F e ( C O ) 2 ( N O ) 2 t o -wards o l e f i n d i m e r i z a t i o n 3 . When butadiene was t r e a t e d w i t h 1% by weight of the i r o n n i t r o s y l , 4 - v i n y l c y c l o h e x - l - e n e was formed as the s o l e product. Even the presence of other r e a c t a n t s or a d d i t i v e s l i k e E t ^ A l , PPh^, and p y r i d i n e had no i n f l u e n c e on r e a c t i v i t y or s p e c i f i c i t y . The presence of the n i t r o s y l l i g a n d s was e s s e n t i a l f o r t h i s r e a c t i o n s i n c e a v a r i e t y . o f i r o n c a r b o n y l d e r i v a t i v e s e x h i b i t e d no c a t a l y t i c a c t i v i t y . More r e c e n t l y i t has been shown1* t h a t s p e c i e s l i k e F e ( N O ) 2 ( L ) 2 (L = donor s o l v e n t ) , which may w e l l be interme-d i a t e s i n the above d i m e r i z a t i o n , are a l s o e q u a l l y s p e c i f i c f o r the formation o f the CgH^ 2 product. H i s t o r i c a l l y , the f i r s t o r g a n o m e t a l l i c complexes c o n t a i n i n g n i t r o g e n monoxide were formed by metal compounds r e q u i r i n g an odd number of e l e c t r o n s to s a t i s f y the e f f e c t i v e atomic number r u l e . Examples 5' 6 of these are: CHC1,. CO- (CO) 0 + 2N0 =»• 2Co (CO) 0 (NO) RT 3 CfiHfi [CpCr (CO) -] 7 + 2N0 » 2CpCr(CO)„(NO) RT pentane C p 9 N i + NO • CpNi (NO) RT A number of other syntheses of t r a n s i t i o n metal n i t r o s y l s i n v o l v e d unique r o u t e s 7 - I n some c a s e s 8 the formation of n i t r o s y l complexes was t o t a l l y . u n e x p e c t e d , e.g. - 5 -Et?0 Mn(CO) H + MNTS — • Mn(CO).(NO) RT (MNTS - N-methyl-N-nitroso-p-toluenesulphonamide) [CpMo(CO) 3 (NH 3) ] + + NaN0 3 d l 1 - a 3 • HCl,, CpMo(NO) 2Cl More g e n e r a l p r e p a r a t i v e routes have been s t u d i e d 9 o n l y i n more re c e n t y e a r s . At the o u t s e t o f t h i s r e s e a r c h , the o b j e c t i v e s were t h r e e f o l d , namely (1) the p r e p a r a t i o n of o r g a n o m e t a l l i c n i t r o s y l com-ple x e s , (2) the study o f t h e i r c h a r a c t e r i s t i c chemistry p a r t i c u l a r l y w i t h r e s p e c t to t h a t e x h i b i t e d by t h e i r i s o s t r u c -t u r a l and i s o e l e c t r o n i c c a r b o n y l analogues, and (3) the e v e n t u a l use of o r g a n o m e t a l l i c n i t r o s y l com-plexes as s p e c i f i c r e a c t a n t s or s e l e c t i v e c a t a l y s t s i n o r g a n i c s y n t h e s i s . In t h i s context, Chapter I I d e s c r i b e s the r e a c -t i o n s of a number of n e u t r a l metal c a r b o n y l complexes wi t h n i t r o s y l c h l o r i d e and the d i f f e r e n t r e a c t i o n modes of t h i s reagent. The p r o p e r t i e s o f the c h l o r o n i t r o s y l products from these r e a c t i o n s are a l s o d i s c u s s e d . Chapter IV d e s c r i b e s the s u c c e s s f u l attempt to prepare CpMn(CO)(NO)I and d i s c u s s e s the b a s i c f e a t u r e s which dominate i t s chemistry. These f i n d i n g s are then r e a d i l y compared with the chemistry of the known analogues CpCr(NO) 2I and CpFe(CO) 2I. In the f i n a l chapter, some chemistry of [ C p C r ( N O ) 2 ] 2 i s presented and c o n t r a s t e d w i t h t h a t of[CpMn(CO)(NO)], and the e x t e n s i v e l y - 6 -s t u d i e d [ C p F e ( C O ) 2 ] 2 . T h i s chapter concludes w i t h an account of the d i s c o v e r y of the unique s e l e c t i v i t y of [ C p C r ( N O ) 2 ] 2 i n the dehalogenation of o r g a n i c h a l i d e s . CHAPTER I I SOME REACTIONS OF NITROSYL CHLORIDE WITH NEUTRAL CARBONYL  COMPLEXES There was no g e n e r a l p r e p a r a t i v e route to t r a n s i t i o n metal n i t r o s y l compounds bef o r e 1970. A l s o , many of the then e x i s t i n g methods produced the d e s i r e d products i n low y i e l d s and/or w i t h much expenditure of e f f o r t . .Recently, s e v e r a l more, g e n e r a l l y u s e f u l procedures have been r e p o r t e d and these i n c l u d e : (1) the photo-induced r e a c t i o n of metal c a r b o n y l complexes wi t h n i t r o g e n monoxide 1 0, hv C r ( C O ) 6 + NO ** Cr(NO) 4 (1) hexanes hv CpCr (CO) 0 (NO) + NO »* C p C r ( N 0 ) o C l (2) CHC1 3 (2) the r e a c t i o n of n i t r o g e n monoxide wi t h r e a c t i v e t r a n s i t i o n metal c o m p l e x e s 1 1 , hexanes Cp~Cr + 2NO • CpCr (NO) 9 (Cc-H ) (3) ^ RT t h f CpCr (CO)((NO) (thf) +NO CpCr (NO) 9 (N0 o) (4) RT and (3) the r e a c t i o n . o f n i t r o s y l c h l o r i d e w i t h t r a n s i -t i o n metal c a r b o n y l c o m p l e x e s 1 2 . - 8 -(Ph 2P) 2N[W(CO) 5 B r ] +C1N0 » W (C0)-4 (NO) Br (5) F e ( C O ) 2 ( N O ) 2 + C1NO F e ( N O ) 3 C l (6) In t h i s l a t t e r category, two types of r e a c t i o n s are i l l u s -t r a t e d . The f i r s t i s the r e a c t i o n . o f C1N0 w i t h t r a n s i t i o n metal c a r b o n y l anions,.a route r e c e n t l y s t u d i e d as a g e n e r a l s y n t h e t i c approach to metal n i t r o s y l complexes 9. I t was shown t h a t the s t o i c h i o m e t r i c r e a c t i o n of n i t r o s y l c h l o r i d e w i t h weakly n u c l e o p h i l i c anions p r o v i d e d a convenient means of p r e p a r i n g n e u t r a l complexes such as CpM(CO) 2(NO) (M = Cr, Mo, or W), Mn(CO) 4(NO), and F e ( C O ) 2 ( N O ) 2 . The second type of r e a c t i o n , between C1N0 and n e u t r a l c a r b o n y l - c o n t a i n i n g compounds, r e a d i l y a f f o r d s n e u t r a l c h l o r o n i t r o s y l complexes i n most i n s t a n c e s . However, i n some cases unexpected pro-ducts r e s u l t . As an example, when CpMo(CO) 2(NO) i s t r e a t e d w i t h C1N0, a minor product i s [CpMo(NO)Cl 2] 2 whose occurrence, i t i s b e l i e v e d 1 2 , r e f l e c t s the f a c t t h a t C1N0 e x i s t s i n s o l u -t i o n as p a r t of the e q u i l i b r i u m 2C1N0 ,, 2N0 + C l 2 (7) I n o t h e r words, s o l u t i o n s of n i t r o s y l c h l o r i d e may e x h i b i t r e a c t i o n s t h a t can be a t t r i b u t e d to any of the chemical e n t i t i e s p r e s e n t i n the above e q u i l i b r i u m . Even when n i t r o -s y l c h l o r i d e r e a c t s as such w i t h n e u t r a l c a r b o n y l complexes, a number of d i f f e r e n t r e a c t i o n modes can be envisaged f o r i t . Among these a r e : (1) displacement of l i g a n d s capable of donating a t o t a l of four e l e c t r o n s to a metal centr e i n a c o o r d i n a t i v e l y - 9 -s a t u r a t e d complex, (2) complete displacement o f a hydrocarbon l i g a n d r e g a r d l e s s of the number,of e l e c t r o n s t h a t i t f o r m a l l y donates to the metal, and (3) formal r e a c t i o n as a n i t r o s o n i u m s a l t w i t h only Not being c o o r d i n a t e d t o the metal c e n t r e . T h i s chapterc;.e d e s c r i b e s new r e a c t i o n s between C1N0 and [CpM(CO)^] 2 (M = Cr, Mo, or W), [CpMn(CO)(NO)] 2, (arene)M(CO) 3 (M = Cr, Mo, or W), (C^H,-) Fe (CO) 2 (NO) , and CpMn(CO) 3, r e a c t i o n s which t y p i f y these reaction.modes. Experimental A l l chemicals used were of reagent grade or compar-able p u r i t y and were e i t h e r purchased (from commercial s u p p l i -ers) or prepared a c c o r d i n g to r e p o r t e d procedures. T h e i r p u r i t y was a s c e r t a i n e d from elemental analyses and/or m e l t i n g p o i n t d e t e r m i n a t i o n s . A l l m e l t i n g p o i n t s are u n c o r r e c t e d and were taken i n c a p i l l a r i e s under p r e p u r i f i e d n i t r o g e n . u s i n g a Gallenkamp M e l t i n g P o i n t Apparatus. N i t r o g e n monox-i d e (Matheson C P . grade, 99.0% min.) was f u r t h e r p u r i f i e d by p a s s i n g i t through a column of a c t i v a t e d s i l i c a g e l maintained a t -78° C. I t s p u r i t y was confirmed by mass s p e c t r a l a n a l y s i s . A l l s o l v e n t s were d r i e d a c c o r d i n g t o standard p r o c e d u r e s 1 3 and thoroughly purged w i t h p r e p u r i f i e d n i t r o g e n p r i o r to use. A l l m a n i p u l a t i o n s , u n l e s s otherwise s t a t e d , were performed on the bench u s i n g c o n v e n t i o n a l t e c h -niques f o r the m a n i p u l a t i o n of a i r s e n s i t i v e compounds 1 4 or - 1 0 -i n a Vacuum Atmospheres C o r p o r a t i o n D r i - L a b model HE-43-2 dry box f i l l e d w ith p r e p u r i f i e d n i t r o g e n . I n f r a r e d s p e c t r a were recorded on P e r k i n Elmer 457 or 710A spectrophotometers and c a l i b r a t e d w i t h the 16 01 cm 1 a b s o r p t i o n band of a p o l y s t y r e n e f i l m . Proton magnetic r e s -onance 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 T-60 spectrometer u s i n g t e t r a m e t h y l s i l a n e as an i n t e r n a l standard. 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 spectrometer w i t h r e f e r e n c e to the s o l v e n t used. A l l 1 3 C chemical s h i f t s are r e p o r t e d i n ppm d o w n f i e l d from Me^Si. The l o w - r e s o l u t i o n mass s p e c t r a were taken at 70 eV on an A t l a s CH4B spectrometer and the h i g h - r e s o l u t i o n mass s p e c t r a l data were o b t a i n e d on an A s s o c i a t e d E l e c t r i c a l I n d u s t r i e s MS9 02 spectrometer w i t h the a s s i s t a n c e of Dr. G. E i g e n d o r f and Mr. J.W. Nip. Elemental analyses were performed by Mr. P. Borda and.x-ray s t r u c t u r a l determinations were c a r r i e d out by.Dr. T.J. Greenhough. P r e p a r a t i o n of N i t r o s y l C h l o r i d e N i t r o s y l chloride.was prepared i n the f o l l o w i n g man-ner. A 100 mL three-necked f l a s k was equipped w i t h a n i t r o -gen i n l e t , a dropping f u n n e l , and a d r y i n g tower (2 x 20 cm) packed from top to bottom wi t h equal volumes o f anhydrous C a C l 2 , KC1, and NaN0 2. The top o f the tower was f i t t e d w i t h a 5 mL graduated c o l d t r a p equipped w i t h a stopcock on the t r a p i n l e t , as shown i n F i g u r e 2. The t r a p o u t l e t was con-nected to a 100 mL two-necked f l a s k equipped w i t h a n i t r o g e n FROM CINO GENERATOR FIG 2 APPARATUS FOR PURIFYING NITROSYL CHLORIDE - 12 -i n l e t secured w i t h a s i l i c a g e l d r y i n g tube. A f t e r f l u s h i n g the e n t i r e apparatus w i t h n i t r o g e n , the r e a c t i o n f l a s k was charged w i t h c o n c e n t r a t e d aqueous HCl (32 mL). An aqueous s o l u t i o n (10)mL) of NaN0 2 (5.54 g) was added dropwise to the r a p i d l y s t i r r e d a c i d s o l u t i o n . a t room temperature. The gaseous C1NO which formed i n s t a n t l y was c a r r i e d by a slow stream o f N 2 i n t o the c o l d t r a p h e l d at -78° C. In t h i s man-ner, 2.5 mL (50 mmol) of C1N0 were generated. T h i s was d i s -t i l l e d under vacuum i n t o the 100.mL f l a s k and 30 mL CH 2C1 2 were added to'the c o l d C1NO to y i e l d a deep•red s o l u t i o n . ' A l l subsequent r e a c t i o n s i n v o l v i n g C1NO were performed by the dropwise a d d i t i o n of the CH 2C1 2 s o l u t i o n to the a p p r o p r i a t e r e a c t i o n mixture w h i l e m o n i t o r i n g the course of the r e a c t i o n by i n f r a r e d spectroscopy. Reaction of N i t r o s y l -Chloride with. [CpCr (CO) 0^2' T o a s ^ r r e < ^ -s o l u t i o n o f . [ C p C r ( C O ) 3 ] 2 1 5 (2.0 g, 5.0 mmol) i n d i c h l o r o -methane (60 mL) was added.dropwise a s o l u t i o n of C1NO at room temperature. 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 yellow-green i n colour.. The progress of the r e a c t i o n was monitored by i n f r a r e d spectroscopy, and the C1NO s o l u t i o n was added u n t i l the c a r b o n y l a b s o r p t i o n s due to the i n i t i a l r e a c t a n t had disappeared. The.solvent was removed from the s o l u t i o n i n vacuo, l e a v i n g a green r e s i d u e . T h i s r e s i d u e was e x t r a c t e d w i t h hexanes to o b t a i n an orange s o l u t i o n . The hexanes were removed from the e x t r a c t s under reduced p r e s s u r e , and the r e s u l t i n g orange s o l i d was sublimed at 40° C - 13 -(5 x 10 3 mm) onto a water-cooled prober The orange sub-l i m a t e (^0.70 g) was i d e n t i f i e d by i t s i n f r a r e d spectrum as CpCr(CO) 2(NO) 1 6• The h e x a n e - i n s o l u b l e r e s i d u e was d i s s o l v e d i n dichloromethane (25 mL). The a d d i t i o n of hexanes (50 mL) to t h i s s o l u t i o n p r e c i p i t a t e d a dark green s o l i d which was c o l l e c t e d by f i l t r a t i o n . The f i l t r a t e was taken to dryness under reduced p r e s s u r e , and the r e s i d u e was r e d i s s o l v e d i n CH 2C1 2 (10 mL). The r e s u l t i n g s o l u t i o n was f i l t e r e d through a s h o r t ( 2 x 5 cm) F l o r i s i l column. The s o l v e n t was removed from the f i l t r a t e i n vacuo to o b t a i n 0.80 g of a g o l d s o l i d i d e n t i f i e d by i t s IR spectrum as C p C r ( N O ) 2 C 1 1 5 . The dark green s o l i d c o l l e c t e d p r e v i o u s l y was t r e a t e d i n the f o l l o w i n g manner. V o l a t i l e compounds were removed.at 60° C and 5 x 10 3 mm, and then the r e s i d u e was d i s s o l v e d i n dichloromethane (30 mL). T h i s s o l u t i o n was f i l t e r e d and a d d i t i o n of hexanes (60 mL) p r e c i p i t a t e d ^0.30 g of a dark green s o l i d i d e n t i f i e d by i t s mass spectrum as [ C p C r C l 2 ] 2 ' T n e f i n a l f i l t r a t e c o n t a i n e d a s m a l l amount ('vO.l g) o f [CpCr (NO) C l ] 2 as ev-idenced by i t s IR spectrum. However, t h i s l a t t e r complex c o u l d not be s a t i s f a c t o r i l y p u r i f i e d because i t s s o l u b i l i t y p r o p e r t i e s were i d e n t i c a l t o those e x h i b i t e d by [ C p C r C ^ ^ -The y i e l d s of a l l product complexes depend markedly on the amount of n i t r o s y l c h l o r i d e added. Reactions of [CpCr (NO) C l ] 2 and [ C p C r C ^ J o with NO. These r e -a c t i o n s were c a r r i e d out i n a . s i m i l a r manner. For example, [ C p C r ( N 0 ) C 1 ] 9 1 7 (0.10 g, 0.29 mmol) was d i s s o l v e d i n d i c h l o r o -- 14 -methane (40 mL) and a stream o f p r e p u r i f i e d n i t r o g e n monoxide was bubbled through the s o l u t i o n . Immediately the green s o l u t i o n became green-brown, and.the.NO flow was.stopped a f t e r s e v e r a l minutes. The s o l u t i o n was then f i l t e r e d through a s h o r t ( 3 x 2 cm) F l o r i s i l column and the s o l v e n t was removed from the f i l t r a t e i n vacuo to o b t a i n a q u a n t i t a -t i v e y i e l d o f CpCr(NO) 2Cl. In the case o f [ C p C r C l 2 ] 2 , a much lower y i e l d of CpCr (NO) 2 C l was obt a i n e d . Reaction of CpCr(CO) 2(NO) wi t h C l 2 o r I 2 . A s a t u r a t e d C H 2 C l 2 s o l u t i o n o f C l 2 was added dropwise a t room temperature to a s t i r r e d orange s o l u t i o n of C p C r ( C O ) 2 ( N O ) 1 6 (0.60 g, 3.0 mmol) i n dichloromethane (.30 mL) . Gas e v o l u t i o n o c c u r r e d and a green s o l i d p r e c i p i t a t e d . a s the s o l u t i o n became yellow-green i n c o l o u r . J u s t enough c h l o r i n e was added to r e a c t w i t h a l l of the CpCr(CO) 2(NO) as monitored.by IR spectroscopy. The f i n a l r e a c t i o n mixture was f i l t e r e d and ..the s o l v e n t was r e -moved from the f i l t r a t e i n vacuo to o b t a i n 0.26 g (41% y i e l d based on Cr) of a green-golden s o l i d i d e n t i f i e d by i t s i n f r a r e d spectrum as Cp C r ( N O ) 2 C l . The r e a c t i o n . o f CpCr(CO) 2(NO) wi t h I 2 was c a r r i e d out s i m i l a r l y . However, an IR. a b s o r p t i o n due to an i n t e r -mediate n i t r o s y l complex was observed, d u r i n g the r e a c t i o n . The i n t e r m e d i a t e slowly decomposes to the only i s o l a b l e n i t r o s y l s p e c i e s , CpCr(NO) 2I. Decomposition of [C p C r ( N O ) C l ] 2 . A s o l u t i o n . o f [ C p C r ( N O ) C l ] 2 (0.37 g, 1.0 mmol) i n benzene (40 mL) was s t i r r e d a t room - 15 -temperature f o r 20 h, du r i n g which time a blue-green p r e c i p -i t a t e formed. . The mixture was f i l t e r e d through 2 cm of F l o r -i s i l producing a golden f i l t r a t e . The benzene was removed i n vacuo and the r e s i d u e d r i e d f o r 1 h a t 25° C (5 x 10 3mm). The gold-brown s o l i d was i d e n t i f i e d as CpCr(NO) 2Cl (0.19 g, 45%) b y . i t s c h a r a c t e r i s t i c s p e c t r a l p r o p e r t i e s . Reactions o f [CpM(CO),]^ (M = Mo or W) w i t h CINQ. To a s t i r r e d dichloromethane s o l u t i o n (50 mL) of [CpMo(CO) 3] 2 (0.74 g, 2.0 mmol) a t room temperature was added dropwise a dichloromethane s o l u t i o n o f C1N0. The r e a c t i o n mixture became green-brown immediately and gas was evolved. Again, j u s t enough n i t r o s y l • c h l o r i d e was added to r e a c t w i t h a l l o f the i n i t i a l c a r b o n y l dimer. The f i n a l s o l u t i o n was concen-t r a t e d at-reduced pressure .to ^15.mL and s y r i n g e d onto a 2 x 20 cm F l o r i s i l column.. E l u t i o n of the column w i t h CH 2C1 2 developed two bands. T h e . f i r s t band, orange i n c o l o u r , was c o l l e c t e d and co n c e n t r a t e d i n vacuo to 10 mL. The a d d i t i o n of hexane (30 mL) t o t h i s s o l u t i o n 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 o f a n a l y t i c a l l y pure CpMo^Oj^Cl. An a l , c a l c d . f o r • C 8 H 5 M o 0 3 C l : C, 34.25; H, 1.80. Found: C, 33.89; H, 1.9 3. v c o cm"1 (CH-2C'l2)".: 205 7, 19 76. E l u t i o n o f the second band from the column pro-duced a green s o l u t i o n which c o n t a i n e d CpMo(NO) 2C1, i d e n -t i f i e d by i t s IR s p e c t r u m 1 2 ' 1 6 . T h i s product was c r y s t a l -l i z e d from the e l u a t e by the a d d i t i o n of hexanes. The y i e l d s of both o r g a n o m e t a l l i c products were t y p i c a l l y 35% and were - 16 -g r e a t l y dependent on the amount, of C1N0 added s i n c e both complexes r e a c t e d f u r t h e r w i t h t h i s reagent. The r e a c t i o n of [CpW(CO) 3] 2 w i t h n i t r o s y l c h l o r i d e produced CpW(NO) 2Cl and CpW ( G O ^ C l i n an analogous manner. Reaction o f [CpMn (CO) (NO) ] 2 w i t h CINQ. A dichloromethane s o l u t i o n (30 mL) c o n t a i n i n g 0.36 g (1.0 mmol) of [CpMn(CO)-( N O ) ] 2 1 8 was t r e a t e d dropwise at room temperature w i t h a s o l u t i o n . o f C1NO i n the same s o l v e n t . Gas e v o l u t i o n was observed and an o f f - w h i t e s o l i d p r e c i p i t a t e d . J u s t enough C1NO was added.to r e a c t w i t h a l l of the s t a r t i n g m a t e r i a l . The mixture was c o n c e n t r a t e d to ^15 mL and f i l t e r e d through 2 cm of C e l i t e . Hexanes (10 mL) were added to the red-black f i l t r a t e and slow c o n c e n t r a t i o n o f t h i s s o l u t i o n i n vacuo produced m i c r o c r y s t a l l i n e Cp 2Mn 2(NO) 3C1 (0.12 g, 30% y i e l d ) (vide i n f r a ) . R e a ction of (o-xylene) Mo (CO) w i t h CINQ. The compound (o-x y l e n e ) M o ( C O ) 3 1 9 (0.74 g, 2:6 mmol) was d i s s o l v e d i n d i -chloromethane (4 0 mL) and the s t i r r e d s o l u t i o n was t r e a t e d dropwise at room temperature w i t h a s o l u t i o n of C1N0 i n dichloromethane. Gas e v o l u t i o n was immediate, the y e l l o w s o l u t i o n became orange-brown, and a green s o l i d p r e c i p i t a t e d . J u s t enough C1NO was added to r e a c t completely with the i n -i t i a l c a r b o n y l complex. A f t e r a d d i t i o n of C1NO was completed, an i n f r a r e d spectrum of the supernatant s o l u t i o n i n d i c a t e d the presence of a c a r b o n y l n i t r o s y l compound. However, con-t i n u e d s t i r r i n g of the r e a c t i o n mixture f o r s e v e r a l minutes - 17 -caused.more green s o l i d to form. Hence, s t i r r i n g was main-t a i n e d u n t i l the supernatant was c o l o u r l e s s . The s o l v e n t was then removed i n vacuo and the green r e s i d u e d i s s o l v e d i n t e t r a h y d r o f u r a n to o b t a i n a c l e a r green s o l u t i o n . An i n f r a -r e d spectrum of t h i s s o l u t i o n r e v e a l e d t h a t s o l v a t e d [Mo-I N O ) 2 C I 2 ] R 2 0 was the o n l y n i t r o s y l complex p r e s e n t . Reaction of [Mo(NO)^Cl^] n w i t h Ph-,P. The polymeric [Mo-( N O ) 2 C l 2 ] n produced i n the p r e v i o u s r e a c t i o n ( 0 . 5 9 g) was s t i r r e d i n a r e f l u x i n g benzene s o l u t i o n (60 mL) of Ph 3P ( 2 . 0 g, 7.6 mmol). A f t e r 1 h the i n i t i a l mixture had become a c l e a r green s o l u t i o n , thereby i n d i c a t i n g t h a t adduct f o r -mation was complete. The s o l v e n t was removed i n vacuo and the yellow-green r e s i d u e was e x t r a c t e d w i t h dichloromethane (40 mL). Slow a d d i t i o n of hexanes ( 1 0 0 mL) p r e c i p i t a t e d the w e l l known yellow-green M o ( N O ) 2 C 1 2 ( P P h 3 ) 2 2 ° • Reactions of (arene)W(CO) 3 [arene = C 6H £, CH.,C6H5, or  (CH^j^C^H^] wi t h CINQ. The r e a c t i o n s of n i t r o s y l c h l o r i d e w i t h ( a r e n e ) W ( C O ) 3 2 1 complexes were c a r r i e d out i n a manner i d e n t i c a l to t h a t d e s c r i b e d p r e v i o u s l y f o r the molybdenum analogue. However, the p rogress of these r e a c t i o n s was s l i g h t -l y d i f f e r e n t . For example, when j u s t enough C 1 N O to consume the tungsten r e a c t a n t had been added, very l i t t l e [ W ( N 0 ) 2 ~ C l 2 ] n had p r e c i p i t a t e d . An i n f r a r e d spectrum of the r e a c -t i o n mixture r e v e a l e d the presence of a c a r b o n y l n i t r o s y l complex which was not a f f e c t e d by the a d d i t i o n of an excess of n i t r o s y l c h l o r i d e . T h i s complex was i s o l a t e d by - 18 -f i l t e r i n g the f i n a l r e a c t i o n mixture and t a k i n g the f i l t r a t e t o dryness i n vacuo. The r e s u l t i n g red-brown s o l i d was s o l u b l e i n t e t r a h y d r o f u r a n , dichloromethane, and benzene, and s l i g h t l y s o l u b l e i n hexane. Pure samples of t h i s compound c o u l d not be obtained because.of i t s tendency t o t r a n s f o r m sl o w l y to [ W ( N O ) 2 C 1 2 ] n 2 0 i n s o l u t i o n . a t room temperature. In f a c t , s t i r r i n g a dichloromethane s o l u t i o n o f t h i s compound f o r 48 h p r e c i p i t a t e d [ W ( N O ) 2 C l 2 ] n q u a n t i t a t i v e l y . The r e d -brown complex was t e n t a t i v e l y formulated as W(CO) 2(NO) 2C1 2 by v i r t u e o f i t s i n f r a r e d spectrum [ v C Q cm 1 (CH 2C1 2) 2145, 2070. v N Q cm - 1 (CH 2C1 2) 1815, 1725]. R e a c t i o n of ( C p 5 ) Fe (CO) 2 (NO) with CINQ. A pentane s o l u t i o n (30 mL) of ( C 3 H 5 ) F e ( C O ) 2 ( N O ) 2 2 c o o l e d to 0° C was t r e a t e d w i t h a s o l u t i o n o f C1NO i n dichloromethane. The red s o l u -t i o n immediately darkened and gas was evo l v e d . When the r e a c t i o n was complete, the s o l v e n t s were removed i n vacuo l e a v i n g a red-brown s o l i d . S u b l i m a t i o n of t h i s r e s i d u e a t 40° C (5 x 10 3 mm) onto a water-cooled probe produced [Fe ( I J O i ) ' ^ C l ] 2 as evidenced by i t s IR and mass s p e c t r a . R e a c t i o n o f CpMn(C0) 3 w i t h CINQ. To a s t i r r e d s o l u t i o n of CpMn(CO) 3 (0.41 g, 2.0 mmol) i n dichloromethane (40 mL) a t room temperature was added dropwise a s o l u t i o n o f C1NO i n C H 2 C I 2 . A f t e r a few minutes, gas was evolved and the s o l u -t i o n became cloudy. The r e a c t i o n was exothermic and a l a r g e amount of C1NO was consumed. When the i n i t i a l complex had completely r e a c t e d (as i n d i c a t e d by IR s p e c t r o s c o p y ) , the - 19 -r e a c t i o n mixture was taken t o dryness i n vacuo. The r e s u l t i n g r e s i d u e was e x t r a c t e d w i t h e t h a n o l (95%) and the e x t r a c t s were t r e a t e d w i t h a s a t u r a t e d aqueous s o l u t i o n of NH^PF^, thereby p r e c i p i t a t i n g a b r i g h t y e l l o w s o l i d . T h i s s o l i d (0.38 g, 54% y i e l d ) was i d e n t i f i e d as [CpMn(CO) 2(NO)]PF g by i t s c h a r a c t e r i s t i c i n f r a r e d spectrum 2 3 . Reaction of Mn^(CO)^Q w i t h CINQ. A s t i r r e d dichloromethane s o l u t i o n (100 mL) of Mn 2(CO)^Q (1.0 g, 2.6 mmol) was t r e a t e d a t room temperature with an excess of C1NO. The y e l l o w s o l u -t i o n became orange i n i t i a l l y , but no gas was e v o l v e d . The r e a c t i o n mixture was s t i r r e d f o r 3 h, d u r i n g which time a y e l l o w s o l i d p r e c i p i t a t e d and some gas e v o l u t i o n o c c u r r e d . The s o l v e n t was then removed i n vacuo, and the y e l l o w r e s i d u e was sublimed a t 50° C (5 x 10 3 mm) onto a water-cooled probe to o b t a i n 0.23 g (38% y i e l d ) of Mn(CO) 5Cl. An a l , c a l c d f o r C 50 5MnCl: C, 26.06. Found: C, 25 .99. R e s u l t s and D i s c u s s i o n Reactions of N i t r o s y l C h l o r i d e w i t h [CpM(CO ) . J 2 (M = Cr,  Mo, o r W) and [CpMn(CO)(NO)] 2. The a b i l i t y o f n i t r o s y l c h l o r i d e to r e a c t by v a r i o u s modes i s c l e a r l y i l l u s t r a t e d by i t s r e a c t i o n w i t h .[CpCr-( C O ) 3 ] 2 . I f an excess of C1NO i s employed, CpCr(NO) 2C1 i s the major o r g a n o m e t a l l i c product obtained. However, i f o n l y s u f f i c i e n t C1NO to consume the o r i g i n a l dimer i s added, the - 20 -p r i n c i p a l o r g a n o m e t a l l i c products are C p C r ( N 0 ) 2 C l and [CpCr-C l 2 ] 2 ' Although both o f these compounds are w e l l known, t h e i r p r o d u c t i o n i n t h i s r e a c t i o n i s unique. The formation o f C p C r ( N 0 ) 2 C l can be r e a d i l y understood i f one c o n s i d e r s the i n i t i a l s p e c i e s produced i n t h i s r e a c t i o n . When only a sm a l l amount of n i t r o s y l c h l o r i d e i s mixed w i t h [CpCr (CO) ^ ] 2 , the presence o f a c a r b o n y l n i t r o s y l complex i s i n d i c a t e d by the i n f r a r e d spectrum o f the r e a c t i o n mixture. T h i s complex can be e a s i l y i s o l a t e d and i d e n t i f i e d as CpCr(CO) 2(NO). I t has been p r e v i o u s l y e s t a b l i s h e d 1 2 ' 1 6 t h a t t h i s complex i s smoothly converted to CpCr(N O ) 2 C l by treatment w i t h C1NO. The formation o f the d i c a r b o n y l n i t r o s y l i n t e r m e d i a t e thus resembles the cleavage o f the s t a r t i n g c a r b o n y l dimer by n i t r o g e n monoxide 2 1* which a l s o produced CpCr (CO) 2 (NO) . Th e r e f o r e , 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 product i s probably formed by the f o l l o w i n g s e q u e n t i a l r e a c t i o n s : [ C p C r ( C O ) 3 ] 2 + 2C1NO • 2CpCr (CO) 2 (NO) + 2CO + C l 2 (8) CpCr (CO) 2 (NO) + C1NO • CpCr(NO) 2Cl + 2CO (9) The o t h e r product, [ C p C r C l 2 ] 2 , i s r a t h e r unexpected. I t i s not produced i n the r e a c t i o n s of C l 2 with [ C p C r ( C O ) 3 ] 2 , CpCr(CO) 2(NO), or CpCr ( N O ) 2 C l , nor i s i t formed i n the r e -a c t i o n s of the l a t t e r two compounds wit h n i t r o s y l c h l o r i d e . I t thus appears t h a t a novel r e a c t i o n mode of n i t r o s y l c h l o r i d e w i t h [ C p C r ( C O ) 3 ] 2 leads t o t h i s s u r p r i s i n g product, i . e . - 21 -[ C p C r ( C O ) 3 ] 2 C 1 N ° » . [ C p C r C l 2 ] 2 (10) Th i s r e a c t i o n p a r a l l e l s t h a t d e s c r i b e d p r e v i o u s l y 2 5 f o r the c a r b o n y l dimer wi t h CH 2=CHCH 2X (X = Br or I ) , i . e . XCHCH=CH0 [ C p C r ( C O ) 3 ] 2 [CpCrX 2] (11) i n which c a r b o n y l - or a l l y l - c o n f c a i n i n g i n t e r m e d i a t e s were not observed. The complex CpCr(NO) 2Cl has been w e l l c h a r a c t e r -i z e d 2 6 , and [ C p C r C l 2 ] 2 has been p r e v i o u s l y prepared by sever-a l other m e t h ods 2 7. The l a t t e r compound has a l s o been sug-g e s t e d 2 3 as an in t e r m e d i a t e i n the p r e p a r a t i o n of C p C r ( N 0 ) 2 C l from C r C l 3 , NaCj-H,. , and NO, although i t was not i s o l a t e d . A s i m i l a r complex has been r e p o r t e d 2 8 to r e s u l t from the r e -a c t i o n of chromocene wit h H C l ( g ) . Most of these r e p o r t s , however, are probably d e a l i n g w i t h a s o l v a t e d s p e c i e s such as C p G r C l 2 • t h f 2 5 s i n c e the p r e p a r a t i v e r e a c t i o n s are c a r r i e d out i n t e t r a h y d r o f u r a n . D e s o l v a t i o n of t h i s s p e c i e s a f f o r d s " C p C r C l 2 " as a blue-green amorphous powder which i s not very s o l u b l e i n common o r g a n i c s o l v e n t s . In c o n t r a s t , the green [ C p C r C l 2 l 2 t h a t i s i s o l a t e d here i s very s o l u b l e , even i n dichloromethane. Although the p r e v i o u s l y r e p o r t e d observa-t i o n s may p e r t a i n to v a r i o u s c h l o r o complexes, the exact f o r m u l a t i o n of our compound i s confirmed by i t s mass spectrum which i s summarized i n Table I. The spectrum e x h i b i t s the parent i o n and the expected fragmentation p a t t e r n of d i m e r i c [CpCrCl 9]„, namely the s e q u e n t i a l l o s s of c y c l o p e n t a d i e n y l - 22 -Table I. Low-Resolution Mass S p e c t r a l Data f o r [CpCrCl 2] and [CpCr (N0)C1] 9 m/z Rel abund Assignment 3 m/z Rel abund Assignment 3 374 5 ( C 5 H 5 ) 2 C r 2 C l 4 + 364 4 ( C 5 H 5 ) 2 C r 2 C l 2 ( N O ) 2 + 339 43 ( C 5 H 5 ) 2 C r 2 C l 3 + 334 33 ( C 5 H 5 ) 2 C r 2 C l 2 ( N O ) + 304 5 ( C 5 H 5 ) 2 C r 2 C l 2 + 304 34 ( C 5 H 5 ) 2 C r 2 C l 2 + 274 7 C 5 H 5 C r 2 C l 3 + 182 100 ( C 5 H 5 ) 2 C r + 187 7 C 5 H 5 C r C l 2 + 15 2 29 C 5 H 5 C r C l + 182 22 ( C 5 H 5 ) 2 C r + 117 31 C 5 H 5 C r + 152 100 C 5 H 5 C r C l + 65 24 C 5 H 5 + 117 10 C c H c C r + 5 5 52 23 C r+ 65 16 C | H 5 + 52 7 r 20 Cr+ The assignments i n v o l v e the most abundant n a t u r a l l y 5 2 35 o c c u r r i n g i s o t o p e s , i . e . Cr and C l , i n each fragment. - 23 -and c h l o r i n e l i g a n d s . The m o l e c u l a r s t r u c t u r e o f t h i s com-pound probably c o n t a i n s e i t h e r two or four c h l o r i n e b r i d g e s between the metal atoms. Since the completion of t h i s work, two f u r t h e r r e p o r t s of t h i s compound have appeared. The p h o t o l y s i s of C pCr(CO) 3Me 2 9, [ C p C r ( C O ) 3 ] 2 , or [ C p C r ( C O ) 2 ] 2 1 0 i n halogenated s o l v e n t s (commonly CHC13) leads to the forma-t i o n of l a r g e amounts of [ C p C r C l 2 ] 2 / In these r e a c t i o n s i t appears the p h o t o d e c a r b o n y l a t i o n produces a r a d i c a l i n t e r m e d i -ate which a b s t r a c t s c h l o r i n e from the s o l v e n t to produce, e v e n t u a l l y , the c h l o r o - b r i d g e d s p e c i e s . When [ C p C r C l 2 ] 2 , d i s s o l v e d i n dichloromethane, i s t r e a t e d w i t h n i t r o g e n monoxide, t h i s d i m e r i c s t r u c t u r e i s d i s r u p t e d and C p C r ( N O ) 2 C l i s produced. The y i e l d s of t h i s l a t t e r c o n v e r s i o n are q u i t e low, and t h i s may account f o r the low y i e l d s o b t a i n e d i n the o r i g i n a l p r e p a r a t i o n of C p Cr(NO) 2C1 2 3. A t h i r d , a l b e i t minor, product of the r e a c t i o n of [ C p C r ( C O ) 3 ] 2 w i t h C1N0 i s [CpCr (NO) C l ] 2 . 'In view o f the known r e a c t i o n of C l 2 ( g ) w i t h CpMo(CO) 2(NO) to y i e l d [CpMo-( N O ) C l 2 ] 2 3 0 , i t i s not unreasonable to expect t h a t the a n a l -ogous r e a c t i o n between CpCr(CO) 2(NO) and C l 2 ( g ) c o u l d produce [CpCr(NO)Cl] 2. However, we f i n d t h a t t h i s r e a c t i o n r e s u l t s i n an unusual d i s p r o p o r t i o n a t i o n which leads to the forma-t i o n of C pCr(NO) 2Cl i n high y i e l d s (with r e s p e c t to the n i t r o s y l . l i g a n d ) . Furthermore, no r e a c t i o n between CpCr-(NO) 2C1 and C l 2 or C1N0 occurs i n s o l u t i o n , thereby e x c l u d i n g these as pathways l e a d i n g to the p r o d u c t i o n of [ C p C r ( N O ) C l ] 2 . A f o u r t h p o s s i b i l i t y might be the r e a c t i o n of n i t r o s y l - 24 -c h l o r i d e w i t h an i n t e r m e d i a t e c a r b o n y l complex, but no a b s o r p t i o n s a t t r i b u t a b l e to c a r b o n y l - c o n t a i n i n g s p e c i e s other than CpCr(CO)2(NO) are observed i n the i n f r a r e d spectrum of the r e a c t i o n mixture. Hence, the [CpCr(NO)Cl] 2 i s probably formed d i r e c t l y from [ C p C r ( C O ) 3 ] 2 / b y the r e a c t i o n [ C p C r ( C O ) 3 ] 2 + 2C1N0 [CpCr (CO) (NO) C l ] 2 + 4C0 (12) f o l l o w e d immediately by [CpCr (CO) (NO) C l ] 2 +• [CpCr (NO) C l ] 2 + 2C0 (13) as c h l o r i n e . b r i d g e s are formed.in the f i n a l product. The displacement of two c a r b o n y l l i g a n d s by each C1N0 added i n r e a c t i o n (12) r e p r e s e n t s a very common r e a c t i o n mode of n i t r o s y l c h l o r i d e and has numerous precedents. One example which i s very s i m i l a r to t h i s i s the c o n v e r s i o n of [Re(CO) 4~ C l ] 2 to [ R e ( C O ) 2 ( N O ) C l 2 ] 2 by the process d e p i c t e d i n equation ( 1 4 ) 3 1 . The spontaneous l i b e r a t i o n of carbon [ R e ( C O ) 4 C l ] 2 + 2C1N0 *> [Re (CO) 2 (NO) C l 2 ] 2 " + 4C0 (14) monoxide invoked i n r e a c t i o n (13) appears to be a g e n e r a l p r o p e r t y of a number of c a r b o n y l h a l o n i t r o s y l complexes, and some v e r i f i e d examples of such t r a n s f o r m a t i o n s are d i s c u s s e d i n subsequent paragraphs. The p r e v i o u s l y unknown d i m e r i c complex, [ C p C r ( N O ) C l ] 2 has s i n c e been prepared by another method 1 7. When CpCr(NO) 2Cl i s t r e a t e d w i t h NaOEt i n t e t r a h y d r o f u r a n a t room temperature, - 25 -a m e t a t h e t i c a l r e a c t i o n occurs and CpCr(N0)20Et i s formed as an unstable red o i l . Upon exposure to h i g h vacuum at room temperature, the ethoxide d e r i v a t i v e spontaneously l o s e s n i t r o g e n monoxide t o y i e l d [CpCr(NO)(OEt)] 2. Treatment of a benzene s o l u t i o n o f the ethoxo dimer w i t h HCl(g) a f f o r d s [CpCr(NO)Cl] 2 q u a n t i t a t i v e l y . The c h l o r o compound e x h i b i t s a mass spectrum (Table I) which i s c o n s i s t e n t w i t h t h i s d i m e r i c f o r m u l a t i o n and i t e x h i b i t s a s i n g l e a b s o r p t i o n i n the IR spectrum at 16 78 cm 1 a t t r i b u t a b l e to a t e r m i n a l n i t r o s y l group. I t s molecular s t r u c t u r e i s , presumably, s i m i l a r t o those possessed by the complexes [ C p C r ( N O ) L ] 2 3 2 ' 3 3 (L = SMe, SPh, or NMe2) i n which L groups b r i d g e two CpCr(NO) m o i e t i e s . In s o l u t i o n i n benzene [CpCr(NO)Cl] 2 i s s l o w l y con-v e r t e d (^ 72 h) to CpCr(NO) 2Cl and a blue-green, n o n - 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 . T h i s t r a n s f o r m a t i o n can be i n h i b -i t e d by the a d d i t i o n of PPh^ and does not occur i n donor s o l v e n t s such as t e t r a h y d r o f u r a n . T h i s i s due to the forma-t i o n of CpCr(NO) ( P P h 3 ) C l 3 1 f w i t h the former and the probable formation o f CpCr(NO)Cl•thf i n t e t r a h y d r o f u r a n . T h i s forma-t i o n of CpCr(NO) 2Cl, t h e r e f o r e , probably r e f l e c t s some form of i n t e r m e t a l l i c t r a n s f e r of the n i t r o s y l l i g a n d i n the dimer o n l y . The analogous compound [CpCr(NO)I] 2 (vNQ A T 168 0 cm 1) i s formed i n the r e a c t i o n of I 2 w i t h CpCr(CO) 2(NO) but t h i s i n t e r m e d i a t e decomposes i n hours to CpCr(NO) 2I. (Again, i f PPh^ i s present, t h i s decomposition does not occur and CpCr (NO) (PPh-.)I i s formed) . T h i s may a l s o be the pathway - 26 -by which C l 2 ( g ) converts CpCr(CO) 2(NO) to C p C r ( N O ) 2 C l a l -though -no i n t e r m e d i a t e [CpCr(NO)Cl] 2 i s observed d u r i n g t h i s r e a c t i o n . The c h l o r o dimer i s a l s o c l e a v e d by n i t r o g e n mon-oxide, a q u a n t i t a t i v e c o n v e r s i o n to CpCr(NO) 2Cl being observed. In c o n t r a s t to [CpCr(CO)^] 2, the analogous molyb-denum and tungsten compounds [CpM(CO) 3] 2 (M.= Mo or W) r e a c t with an excess o f n i t r o s y l c h l o r i d e to produce i n t r a c t a b l e brown-black s o l i d s . However, i f the progress of the r e a c t i o n i s monitored by i n f r a r e d spectroscopy and the a d d i t i o n of ClNO i s stopped.at the a p p r o p r i a t e time, the f o l l o w i n g r e a c -t i o n can be e f f e c t e d : [CpM(CO) 3] 2 + 2C1N0 • CpM(NO) 2C1. + CpM(CO) 3Cl + 3C0 (15) U n l i k e the chromium case, n o . c a r b o n y l n i t r o s y l i n t e r m e d i a t e which can account f o r the formation of the CpM(NO) 2Cl com-plexes i s observed d u r i n g the course of t h i s r e a c t i o n . Thus, although i t has been e s t a b l i s h e d t h a t the CpM(NO) 2Cl com-plexes are c o n v e n i e n t l y produced by the r e a c t i o n of ClNO w i t h CpM(CO) 2(NO) 1 2, these l a t t e r compounds are not d e t e c t a b l e a t any time d u r i n g the course of r e a c t i o n (15). T h i s i s not s u r p r i s i n g i n view of the l a c k of r e a c t i o n between [CpM-( C O ) 3 ] 2 (M = Mo or W) and NO at room temperature 2 **. The d e r i v a t i o n of the c h l o r o d i n i t r o s y l complexes from the parent dimers i s t h e r e f o r e somewhat enigm a t i c . The CpM(CO) 3C1 (M = Mo or W) products may r e s u l t from the cleavage o f the c a r b o n y l dimers by ClNO i n a manner s i m i l a r to t h a t d e s c r i b e d f o r [ C p F e ( C O ) 0 ] 0 1 2 . However, - 27 -s i n c e a second complex i s also.formed i n r e a c t i o n (15), i t i s more probable t h a t both CpM(CO) 3Cl and CpM(NO) 2C1 are produced from the same d i m e r i c molecule. Support f o r t h i s • i n f e r e n c e comes from the f a c t t h a t the i n f r a r e d a b s o r p t i o n s due t o the two product complexes i n c r e a s e i n i n t e n s i t y a t s i m i l a r r a t e s as r e a c t i o n (15) p rogresses and t h a t the p r o-ducts are formed i n comparable y i e l d s . A l s o , the r e a c t i o n between C1N0 and CpM(CO) 3Cl does not produce CpM(NO) 2Cl. Hence, r e a c t i o n (15) appears to f o l l o w a unique m e c h a n i s t i c pathway which i n v o l v e s C1N0 and. the dimers [CpM(CO) 3] 2 (M = Mo or W) . Since both CpM(NO) 2C1 and CpM(CO) 3Cl r e a c t f u r t h e r w i t h C1N0, t h e i r y i e l d s from r e a c t i o n (15) are d r a s t i c a l l y reduced i f an excess o f n i t r o s y l c h l o r i d e i s used. When the d i m e r i c [CpMn(CO)(NO)] 2 i s t r e a t e d w i t h n i t r o s y l c h l o r i d e , an unusual type of s u b s t i t u t i o n product r e s u l t s . C o n s i d e r i n g the above s t u d i e s , i t would seem prob-able t h a t the b i m e t a l l i c system would be c l e a v e d producing s p e c i e s l i k e CpMn(NO) 2 and.CpMnXNO)(CO)Cl. Inst e a d , C1N0 d i s p l a c e s the customary two c a r b o n y l l i g a n d s even though i t i s removing one from each manganese c e n t r e , i . e . [CpMn(CO) ( N 0 ) ] 2 + C1N0 • Cp(NO)2MnMn(NO) (Cl)Cp + 2C0 (16) The product i n t h i s r e a c t i o n i s an a i r s t a b l e , diamagnetic, red-brown s o l i d whose s t r u c t u r e probably c o n s i s t s of one CpMn(NO) group and one CpMnCl group j o i n e d by two NO b r i d g e s and a metal-metal bond. In order to s a t i s f y the e f f e c t i v e - 28 -atomic number r u l e , the b r i d g i n g n i t r o s y l l i g a n d s must a c t as two e l e c t r o n donors t o the CpMnCl u n i t and onl y s i n g l e e l e c t r o n donors to the CpMn(NO) group. .This asymmetry of the b r i d g i n g u n i t i s demonstrated i n the s t r u c t u r e s o f the a n a l -ogous compounds C p 2 M n 2 ( N O ) 3 ( N 0 2 ) 3 s and C p 2 M n 2 ( N O ) 3 ( C 5 H 5 ) 3 6 . T h i s complex has been prepared i n another context and i t s f u l l c h a r a c t e r i z a t i o n i s pr e s e n t e d i n Chapter IV. Reactions o f N i t r o s y l C h l o r i d e w i t h Other N e u t r a l Carbonyl  Complexes. N i t r o s y l c h l o r i d e r e a c t s r a p i d l y w i t h (arene)M-(CO) 3 complexes (M = Mo or W) at room temperature to even-t u a l l y produce the po l y m e r i c [M(NO) 2 C l 2 ] n , , compounds . A l -though these complexes have been p r e v i o u s l y prepared by another r o u t e 2 0 , the f a c t t h a t they are formed i n t h i s r e -a c t i o n r e f l e c t s an unprecedented r e a c t i o n mode o f ClNO. The displacement o f o l e f i n i c l i g a n d s by n i t r o s y l c h l o r i d e has been r e p o r t e d 3 7 , but the displacement o f the arene l i g a n d has not been p r e v i o u s l y r e p o r t e d . The r e a c t i o n o f (arene)-C r ( C O ) 3 complexes w i t h ClNO a t room temperature produces - 29 -s p e c i e s of the type [ C r ( N O ) 2 ( C l ) 2 ] n and [ C r ( N O ) C l 3 l n which were not r e a d i l y s e p a r a b l e . A r e c e n t r e p o r t 3 8 i n d i c a t e s t h a t ClNO r e a c t s w i t h these ( arene) Cr (CO) 3 compounds i n t e t r a h y d r o f u r a n or dichloromethane below -30° C to form i n -tense red s o l u t i o n s which contain, r e a c t i v e complex fragments of the type [CICr (CO) 2 (NO).] . These fragments decompose on warming to room temperature. The a l l y l l i g a n d of (C 3H 5)Fe(CO) 2(NO) i s a l s o d i s -p l a c e d by ClNO, the r e a c t i o n l e a d i n g u l t i m a t e l y t o the p r o -d u c t i o n of [ F e ( N O ) 2 C l ] 2 . During the course of the r e a c t i o n , the formation of F e ( N O ) 3 C l was observed and t h i s l a t t e r com-p l e x r e a d i l y decomposes t o g i v e the d i n i t r o s y l p r o d u c t 9 . ' 1 0 . In q u i t e s i m i l a r r e a c t i o n s , CpCo(CO) 2 and CpRe(CO) 3 r e a c t 1 7 with n i t r o s y l c h l o r i d e a t -78° C to produce [Co(NO) 2C1] 2 and [ R e ( C O ) 2 ( N O ) C l 2 ] 2 , r e s p e c t i v e l y . The c y c l o p e n t a d i e n y 1 l i g a n d i s a p parently removed by ClNO i n these conversions i n a man-ner completely analogous to the displacement of the arene group d e s c r i b e d above. During the r e a c t i o n s i n v o l v i n g the (arene)W(CO) 3 compounds, an i n 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 i s formed and t h i s p e r s i s t s i n s o l u t i o n f o r s e v e r a l hours a t room tern-, p e r a t u r e . T h i s i n t e r m e d i a t e i s formulated as W(CO) 2(NO) 2 C 12 on the b a s i s o f the i n f r a r e d spectrum which i t e x h i b i t s i n dichloromethane s o l u t i o n , i . e . c a r b o n y l - s t r e t c h i n g a b s o r p t i o n s at 2145 and 2070 cm 1 and 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 at 1815 and 1725 cm 1 . C o n s i s t e n t w i t h t h i s f o r m u l a t i o n , these - 30 -n i t r o s y l a b sorptions occur at h i g h e r f r e q u e n c i e s than those r e p o r t e d f o r the r e l a t e d complexes W ( N O ) 2 C 1 2 L 2 2 0 (Table I I ) , an expected o b s e r v a t i o n s i n c e the c a r b o n y l l i g a n d i s a b e t t e r T T-acid. Dichloromethane s o l u t i o n s of W (CO) 2 (NO) 2 C l 2 are red i n c o l o u r , are a i r s e n s i t i v e , and s l o w l y d e p o s i t [ W ( N O ) 2 C l 2 ] n while being s t i r r e d a t room temperature under an i n e r t atmosphere. Hence, although W ( CO) 2 (NO) 2 C 1 2 i s s t a b l e i n s o l u t i o n f o r s h o r t p e r i o d s . o f time a t ambient temperature, the c a r b o n y l l i g a n d s i n the complex are q u i t e l a b i l e and are e v e n t u a l l y r e p l a c e d by c h l o r i n e b r i d g e s i n an a s s o c i a t e d complex as i n d i c a t e d i n e q u a t i o n (17). nW(CO) 2 (NO) 2 C 1 2 • [ W ( N O ) 2 C l 2 ] n + 2nCO (17) During the r e a c t i o n s i n v o l v i n g the (arene)Mo(CO)^ compounds, the i n t e r m e d i a t e Mo (CO) 2 (NO) 2 C 1 2 s p e c i e s can be d e t e c t e d by IR spectroscopy (Table I I ) , but i t i s s t a b l e i n s o l u t i o n f o r o n l y a few minutes at room temperature. L i k e i t s tungsten analogue, Mo(CO) 2(NO) 2C1 2 s P ° n t a n e o u s l y evolves gas and forms [Mo(NO) 2 C l2-' n w n ; " - c h c a n b e c h a r a c t e r i z e d as i t s t r i p h e n y l -phosphine adduct 2 0 . T h i s l a b i l i t y o f c a r b o n y l l i g a n d s appears to be an i n t r i n s i c p r o p e r t y o f t r a n s i t i o n metal c a r b o n y l n i t r o s y l ha-l i d e s and s e v e r a l o t h e r examples have been observed i n our l a b o r a t o r y . F o r i n s t a n c e 1 7 , W(CO) 4(NO)Cl r e a d i l y evolves carbon monoxide when d i s s o l v e d i n t e t r a h y d r o f u r a n at room tem-perature and transforms to [ W ( C O ) 9 ( N O ) ( t h f ) C l ] 0 , i . e . Table I I . 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 3 of the Complexes ML 2 (NO) 2 C 1 2 Compound v C Q ( c m M v N Q ( c m M Mo (CO) 2 (NO) 2 C 1 2 2160, 2080 1840, 1750 M o ( P P h 3 ) 2 ( N O ) 2 C 1 2 1790, 1670 b Mo(AsPh 3) 2:(N0)- 2C1 2 1765, 1645 b W(CO) 2 (NO) 2 C 1 2 2145, 2070 1815, 1725 W ( P P h 3 ) 2 ( N O ) 2 C 1 2 1790, 1670 b W(AsPh 3) 2 (N0). 2C1 2 1765, 1645 b i n dichloromethane s o l u t i o n d ata taken from r e f e r e n c e 20 - 32 -2W(C0) (N0)C1 t h f [W(CO) 2 (NO) (thf) C l ] 2 + 4CO (18) The m o l e c u l a r s t r u c t u r e of t h i s dimer i n a l l l i k e l i h o o d con-t a i n s two W(CO)2(NO)(thf) groups l i n k e d by c h l o r i n e b r i d g e s so t h a t the valence e l e c t r o n c o n f i g u r a t i o n of the metal s a t -i s f i e s the i n e r t gas formalism. S i m i l a r l y , when CpWtCO^CNO) i s t r e a t e d w i t h I 2 i n dichloromethane, an i n 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 s p e c i e s i s formed which s l o w l y decomposes (1 h) to [ C p W ( N O ) I 2 ] 2 3 9 • T h i s r e a c t i o n occurs as f o l l o w s : CpW(CO)-2(NO) + I 2 • CpW(CO) (NO) I 2 + CO (19) CpW(CO) (NO) I • [CpW(NO)I 2] 2 + CO (20) T h i s l a t t e r r e a c t i o n i s completely r e v e r s i b l e under an atmos-phere of carbon monoxide. Another t r a n s f o r m a t i o n which f o l l o w s a s i m i l a r p a t -t e r n i s the formation of [ C o ^ O ^ C l ^ by the r e a c t i o n of Co(CO) 3(NO) wi t h n i t r o s y l c h l o r i d e 1 7 . Although an interme-d i a t e s p e c i e s i s not d e t e c t e d i n t h i s i n s t a n c e , t h i s conver-s i o n l i k e l y o ccurs v i a the s e q u e n t i a l r e a c t i o n s (21). and (2 2) , Co(CO) 3(NO) + ClNO • Co(CO) (NO) 2C1 + 2CO (21) both of which, as shown above, have pr e c e d e n t s . T h i s p r o -p e n s i t y of c a r b o n y l h a l o n i t r o s y l complexes t o l o s e c a r b o n y l l i g a n d s and form d i m e r i c or p o l y m e r i c compounds by the con-comitant formation of h a l i d e b r i d g e s can a l s o be invoked to 2Co(CO) (NO) 2C1 #> [Co (NO) 2C1] 2 + 2CO (22) - 33 -r a t i o n a l i z e the products o b t a i n e d from other r e a c t i o n s i n -v o l v i n g n i t r o s y l c h l o r i d e and a n e u t r a l c a r b o n y l complex. For example, [ M ( C 0 ) 4 C 1 2 ] 2 (M = Mo or W) complexes are converted by ClNO to [ M ( N O ) C l 3 ] n and s m a l l amounts o f [ M ( N O ) 2 C l 2 ] " * 0 . The t r i c h l o r o - p o l y m e r may w e l l r e s u l t from the r e a c t i o n s [ M ( C 0 ) 4 C 1 2 ] 2 + 2C1N0 » [M(CO) 2 ( N 0 ) C 1 3 ] 2 + 4C0 (23) n[M(CO) 2 ( N 0 ) C 1 3 ] 2 • [M(NO) Clg] 2 . + .4nC0 (24) which i n v o l v e the same modes o f t r a n s f o r m a t i o n d e s c r i b e d above f o r Co(CO) 3(NO) w i t h ClNO. (The d i n i t r o s y l complexes may w e l l r e s u l t from some i n t e r m e t a l l i c NO t r a n s f e r as d i s -cussed p r e v i o u s l y ) . Reactions o f N i t r o s y l C h l o r i d e w i t h CpMn(CO) 3. U n l i k e i t s rhenium analogue, CpMn(CO) 3 r e a c t s s l o w l y at room temperature w i t h ClNO and the c y c l o p e n t a d i e n y l group i s not d i s p l a c e d from the metal d u r i n g the r e a c t i o n . I n -stead, ClNO appears t o behave analogously t o a n i t r o s o n i u m s a l t as the product o b t a i n e d . i s the w e l l known c a t i o n [CpMn(CO) 2 (NO) ] + l f 1 . The y i e l d s o f t h i s r e a c t i o n , though, are c o n s i d e r a b l y l e s s than those observed when NOPF^ i t s e l f i s u s e d 4 2 . T h i s c a t i o n does not r e a c t f u r t h e r even when t r e a t e d w i t h an excess of ClNO f o r s e v e r a l hours, thereby r e f l e c t i n g i t s i n h e r e n t s t a b i l i t y . A few oth e r examples o f t h i s type o f behaviour o f ClNO have been r e p o r t e d . For ex-amp l e 4 3 , both ClNO and BrNO r e a c t with F e ( C O ) 3 ( P P h 3 ) 2 i n a c e t o n i t r i l e to gi v e [Fe (CO) 9 (NO) (PPh-J ] + X - . - 34 -Reactions o f . N i t r o s y l Chloride attributable to C l ^ and NO. As mentioned b r i e f l y i n the introduction to this chapter, the reactions of C1N0 i n certain instances may be more readily viewed as reactions of either chlorine or n i -trogen monoxide. The more common of these reactions involves the C l 2 part of the equilibrium (7). The following reac-tions show c h a r a c t e r i s t i c s of only t h i s species i n the reac-tant solution, e l g l M 2(CO) 1 Q + 2C1N0 •> 2M(C0)5C1 + 2N0 (25) (M = Mn or Re) [CpFe(CO) 2] 2 + 2C1N0 2CpFe(CO) 2Cl + 2N0 (26) [CpCr(NO) 2l 2 + 2C1N0 • 2CpCr(NO) 2Cl + 2N0 (27) and no nitrosyl-containing species are observed at a l l i n reactions (25) and (26). I t thus appears that none of these species react with n i t r o s y l chloride i t s e l f . Also, i t i s known that Mn2(CO) 1 ( ) l t \ [CpFe (CO) 2] 2 h 5 , and [CpCr (NO) 2] 2 1 1 a l l require more forcing conditions to react with nitrogen monoxide. So i t seems probable that i t i s simply the C l 2 part of the reactant solution which e f f e c t s the above trans-formations. During the following reaction, CpM(CO)2(NO) + C1N0 • CpM(NO) 2Cl + 2C0 (28) (M = Cr, Mo, or W) minor but s i g n i f i c a n t amounts of a by-product are formed. In - 35 -the molybdenum.case, i t has been i d e n t i f i e d as.[CpMo(NO)-CI2] 2 a n c* this same product has been observed for the reac-ti o n of CpMo (CO) 2 (NO) a n d C l 2 ( g ) 3 0 . However, for. CpW (CO) 2 ~ (NO), since the reaction i s normally car r i e d out at -78° C, only a very small amount of a red by-product i s formed. The IR spectrum of this s o l i d i s consistent with i t s formulation as [CpW(NO) CI2] 2 i - n comparison with that of the recently prepared [CpW(NO)I 2 1 2 3 9• During the reaction of CpCr(CO) 2-(NO) with C1N0, the blue-green by-product i s most l i k e l y some [ C p C r C l x ] n species s i m i l a r to those described e a r l i e r . More important, though, i s the fact that C1N0 i t s e l f reacts read i l y with the CpM(CO)2(NO)-complexes to give the desired products i n excellent y i e l d s . There are no examples as yet showing the reaction of only the nitrogen monoxide part of the equilibrium except for the reaction discussed e a r l i e r involving [CpCr(CO)^]^• The problem which arises here, of course, i s the fact that the product of thi s reaction, CpCr(CO)^ (NO), reacts further with C1N0. Therefore, unlike the previous reactions i n v o l -ving C ^ , the product observed.for the reaction [CpCr(CO) 3] 2 + 2N0 • 2CpCr(CO)2(NO) + 2C0 (29) i s not the f i n a l product i n the reaction of thi s dimer with n i t r o s y l chloride. CHAPTER I I I REACTIONS.OF TRITHIAZYL TRICHLORIDE WITH TRANSITION METAL  CARBONYL COMPOUNDS A n a t u r a l e x t e n s i o n of the study of the p r e p a r a -t i o n and p r o p e r t i e s of t r a n s i t i o n metal n i t r o s y l complexes i s the i n v e s t i g a t i o n of t r a n s i t i o n metal t h i o n i t r o s y l (NS) complexes. A comparison of the p h y s i c a l p r o p e r t i e s of these f a m i l i a l compounds should l e a d to a b e t t e r understanding of both the n i t r o s y l and t h i o n i t r o s y l l i g a n d . At the p r e s e n t time there i s a s t r i k i n g p a u c i t y of t h i o n i t r o s y l complexes and the few such c o o r d i n a t i o n compounds t h a t are known**6 r e s u l t from the r e a c t i o n of elemental sulphur, propylene s u l p h i d e , or d i s u l p h u r d i c h l o r i d e w i t h c o o r d i n a t e d h i t r i d o l i g a n d s i n the p r e c u r s o r s , e.g. Mo(N) (S 2CNR 2) • + S g Mo(NS) (S 2CNR 2) 3 (30) [Re(NBr 2) ( P R 3 ) 3 ] 2 + S 2 C l 2 • [Re(NS) (Cl) (Br) (PR 3>3] (31) In r e a c t i o n s resembling the procedures used to s y n t h e s i z e v a r i o u s o r g a n o m e t a l l i c n i t r o s y l complexes, namely the t r e a t -ment o f . o r g a n o m e t a l l i c c a r b o n y l compounds wit h n i t r o s y l c h l o r i d e (Chapter I I ) , t h i s chapter d e s c r i b e s attempts to d i r e c t l y i n t r o d u c e the t h i o n i t r o s y l f u n c t i o n a l i t y u s i n g t r i -t h i a z y l t r i c h l o r i d e , N^S^C!-,. - 37 -Experimental A l l e x perimental procedures d e s c r i b e d here were per-formed under the same gen e r a l c o n d i t i o n s o u t l i n e d i n Chapter I I . T r i t h i a z y l t r i c h l o r i d e was prepared by the l i t e r a t u r e method h 7 and r e c r y s t a l l i z e d from carbon t e t r a c h l o r i d e . R e action of Na [CpCr (CO) ^] w i t h C l ^ ^ N ^ . To a s t i r r e d t e t r a -hydrof uran s o l u t i o n (60 mL) c o n t a i n i n g 2.24 g (10.0 mmol) of N a [ C p C r ( C O ) 3 ] 1 6 c o o l e d to -78° C was added dropwise a t h f s o l u t i o n of Cl^S^N^ (0.82 g, 3.35 mmol). Gas e v o l u t i o n oc-c u r r e d , a p r e c i p i t a t e formed, and the r e a c t i o n mixture developed a red-brown c o l o u r a t i o n . A f t e r the a d d i t i o n of the Cl^S^N^ was complete (30 min), the mixture was allowed to warm slow l y to room temperature. The t e t r a h y d r o f u r a n was removed i n vacuo l e a v i n g a green-brown r e s i d u e . T h i s s o l i d was suspended i n toluene (30 mL) and t r a n s f e r r e d to the top of a 3 x 10 cm F l o r i s i l column. E l u t i o n of the column w i t h t o l -uene produced two bands (red and green i n colour) which were c o l l e c t e d together and taken to dryness under reduced p r e s -sure. S u b l i m a t i o n a t 30° C ( 5 x 1 0 3 mm) onto a d r y - i c e c o o l e d probe produced 0.9 2 g (4.2 mmol, 21% y i e l d ) of red c r y s t a l l i n e CpCr(CO) 2(NS). A n a l , c a l c d f o r C_,H cCr0 oNS: C, 38.36; H, 2.30; N, 6.39. Found: C, 38.64; H, 2.20; N, 6.37. Mp 68-69° C. The r e s i d u e from the s u b l i m a t i o n was e x t r a c t e d w i t h dichloromethane and the r e s u l t i n g o l i v e green s o l u t i o n was t r e a t e d w i t h hexanes and s l o w l y c o n c e n t r a t e d i n vacuo. In - 38 -t h i s manner, c r y s t a l s o f [ C p C r ( C O ) 2 ] 2 S (0.65 g, 34% y i e l d based on Cr) were produced. Anal, c a l c d f o r C 1 4 H 1 Q C r 2 0 4 S : C, 44.45; H, 2.67; S, 8.48. Found: C, 44.47; H, 2.64; S, 8.19. Mp ( i n a i r ) 112-113° C dec. Reactions o f Cl.,S^N 3 w i t h o t h e r T r a n s i t i o n Metal Carbonyl  Complexes. The r e a c t i o n s of Cl^S^N^ w i t h other complexes were performed s i m i l a r l y and the experimental d e t a i l s are summarized i n Table I I I . •Reaction of CpCr (CO) 2;('NS) w i t h n i t r o s y l c h l o r i d e . A d i -chloromethane s o l u t i o n .(60 mL); c o n t a i n i n g 0.88 g (4.0 mmol) CpCr(CO) 2(NS) was t r e a t e d dropwise a t room temperature w i t h a s o l u t i o n o f ClNO i n the same s o l v e n t . Gas e v o l u t i o n oc-c u r r e d and a green-brown s o l i d p r e c i p i t a t e d . J u s t enough ClNO was added t o r e a c t with a l l the t h i o n i t r o s y l complex (monitored by i n f r a r e d s p e c t r o s c o p y ) . The mixture was then c o n c e n t r a t e d t o 15 mL and t r a n s f e r r e d to a 3 x 8 cm F l o r i s i l column. E l u t i o n of the column wi t h dichloromethane produced three components: (1) a f a s t moving yellow-orange band c o n t a i n i n g ^0.05 g of m a t e r i a l , (2) a golden-brown band.containing C p C r ( N O ) 2 C l . The t o t a l amount i s o l a t e d was 0.23 g (27%), (3) a blue-green band which c o u l d not be e l u t e d from the column with CH 0C1 0. Table I I I . Reactions o f N 3 S 3 C 1 3 with some T r a n s i t i o n Metal Compounds T r a n s i t i o n metal cmpd. (mmol) Amt. of N 3 S 3 C 1 3 (mmol) So l v e n t (mL) Temp. P r o d u c t s ( y i e l d s ) I s o l a t i o n and I d e n t i f i c a t i o n Na[CpW(CO) 3] (5.0) 1.7 thf(150) -78° [CpW(CO) 3] 2(20%) CpW(CO) 3 c i ( i o % ) Chromatography on F l o r i s i l ; i n f r a r e d cl spectrum Na[CpMo(CO) ] (6.2) 2.4 t h f (120) -7( [CpMo(CO) ] 2(25%) CpMo(CO) Cl(15%) Chromatography on F l o r i s i l ; i n f r a r e d spectrum 3 Na[Mn(CO)J (5.6) 2.0 thf(100) 2 0° Mn 2(CO) 1 Q(25%) Sublima t i o n a t 40° (5 x 1 0 _ 3 mm); i n f r a r e d s p e c t r u m 3 CpCr(CO) 2 (NO) (3.0) CpMo (CO) (NO) (5.0) 1.0 thf(lOO) 1.6 20° CH 2C1 2 (100) CpCr(NO) 2C1(35%) 20° [CpMo(NO)Cl] (<5%) Chromatography on F l o r i s i l ; i n f r a r e d s pectrum 3 I n f r a r e d s p e c t r u m 3 By comparison with the i n f r a r e d spectrum of the a u t h e n t i c compound. - 40 -Reaction o f N i t r o s y l C h l o r i d e w i t h [ C p C r ( C O ) ^ ] a n d  [CpCr(CO)2^2' A dichloromethane s o l u t i o n of G1NO was added dropwise to a s t i r r e d , room temperature s o l u t i o n of [CpCr-( C O ) 2 ] 2 s (0.38 g, 1.0 mmol) i n the same s o l v e n t (40 mL). Gas e v o l u t i o n occurred, the s o l u t i o n turned b r i g h t green, and a f i n e y e l l o w s o l i d p r e c i p i t a t e d . When a l l the sulphur complex had r e a c t e d , the mixture was reduced i n volume t o 10 mL and t r a n s f e r r e d to the top of a 2 x 5.. cm F l o r i s i l column. Washing the column w i t h C E ^ C ^ produced a golden - s o l u t i o n • w h i c h was taken to dryness i n vacuo. The r e s i d u e was i d e n t i f i e d as C p C r ( N O ) 2 C l (0.26 g, 60% y i e l d ) . The r e a c t i o n o f [CpCr(CO) 2]2 w i t h C1NO proceeded s i m i l a r l y p r o d u c i n g CpCr-(NO) 2C1 i n 42% y i e l d . R e a c t i o n of CpCr(CO) 2(NS) w i t h PPh.,. Two d i f f e r e n t experiments were performed i n an attempt to produce CpCr(CO)(PPh^)(NS). In the f i r s t , a toluene s o l u t i o n (30 mL) c o n t a i n i n g CpCr-(CO) 2(NS) (0.22 g, 1.0 mmol) was t r e a t e d w i t h PPh 3 (0.52 g, 2.0 mmol) and the mixture h e l d a t r e f l u x f o r 70 h. At the end o f t h i s time, an IR spectrum of the s o l u t i o n i n d i c a t e d that.no r e a c t i o n had oc c u r r e d . The toluene was removed i n vacuo and the remaining r e s i d u e sublimed onto a d r y - i c e c o o l e d probe (30° C, 5 x 10~ 3 mm) to recover-.CpCr (CO) 2 (NS) almost q u a n t i t a t i v e l y . The second experiment i n v o l v e d p h o t o l y s i s o f a hexanes s o l u t i o n (200 mL) c o n t a i n i n g CpCr(CO) 2(NS) (0.22 g, 1.0 mmol) u s i n g a 140 W medium pr e s s u r e mercury lamp. A f t e r - 41 -6 h, complete d e s t r u c t i o n o f the o r g a n o m e t a l l i c t h i o n i t r o s y l complex had o c c u r r e d and no new complexes c o n t a i n i n g the NS l i g a n d were d e t e c t e d . Reaction o f CpCr(CO) 2(NS) wi t h NOPF £. The r e a c t i o n between CpCr (CO) 2 (NS) and NOPF g was c a r r i e d out i n C r ^ C ^ / C t ^ C N at T78° C i n a s i m i l a r f a s h i o n t o t h a t r e p o r t e d 5 5 f o r the r e a c -t i o n o f CpM(CO) 2(NO) (M = Mo or W) with NOPFg. The r e s u l t i n g blue-green product was very r e a c t i v e and c o u l d not be p u r i f i e d . I t was t e n t a t i v e l y i d e n t i f i e d as-=>-[CpCrr(eo,), (NO) :(NS) ] P F r based on i t s IRb spectrum: (2122, itLJ90 , and 1243 cm" 1). Reac t i o n . o f [CpCr(CO)(NO)(NS)]PF £ with Iodide Ion. A s t i r r e d acetone s o l u t i o n (40 mL) c o n t a i n i n g Nal (0.30 g, 2.0 mmol) was t r e a t e d w i t h the s o l i d t h i o n i t r o s y l s a l t (0.50 g) and the r e s u l t i n g green s o l u t i o n slowly turned green-brown. Gas e v o l u t i o n was observed and a green s o l i d p r e c i p i t a t e d . The mixture was s t i r r e d f o r 2 h and then the acetone was removed i n vacuo. The blue-green r e s i d u e was e x t r a c t e d w i t h C E ^ C ^ and the e x t r a c t s f i l t e r e d through 2 cm of F l o r i s i l producing a golden-brown f i l t r a t e which was found t o c o n t a i n C p C r ( N O ) 2 I 9 (0.14 g, ^25% y i e l d ) . R eaction o f [ C p C r C C O ^ K w i t h N i t r o g e n Monoxide. P r e p u r i f i e d n i t r o g e n monoxide was bubbled s l o w l y through a toluene s o l u -t i o n (25 mL) c o n t a i n i n g 0.45 g (1.30 mmol) o f [CpCr(CO) 2 1 2 8 f o r 12 h. During t h i s p e r i o d , the green s o l u t i o n developed an orange c o l o u r a t i o n . The r e s u l t i n g s o l u t i o n was concen-- 42 -t r a t e d to ^ 10 mL i n vacuo and then t r a n s f e r r e d to the top o f a 3 x 5 c m o F l o r i s i l column made up i n dichloromethane. E l u -t i o n o f the column w i t h dichloromethane developed an orange band t h a t was c o l l e c t e d and taken t o dryness under reduced p r e s s u r e . . S u b l i m a t i o n of the r e s i d u e a t room temperature (5 x 10. 3 mm) onto a d r y - i c e c o o l e d probe a f f o r d e d 0.23 g (1.1 mmol; 43% y i e l d ) of C p C r ( C O ) 2 ( N O ) 1 2 ' 1 6 . The F l o r i s i l column.was then e l u t e d w i t h t e t r a h y d r o -f u r a n t o produce a dark green band which a l s o was c o l l e c t e d and taken to d r y n e s s . i n vacuo. C r y s t a l l i z a t i o n of the r e s u l t i n g s o l i d from Ct^C^-hexanes y i e l d e d green c r y s t a l s o f C p C r ( N O ) 2 ( N 0 2 ) 1 1 (0.20 g, 35% y i e l d ) 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 . 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 r i t h i a z y l t r i c h l o r i d e , w i t h Na-[CpCr(CO) 3] produces CpCr(CO) 2(NS), the f i r s t o r g a n o m e t a l l i c t h i o n i t r o s y l complex, i n 21% y i e l d . t h f Na [CpCr ( C O ) + %N S C l CpCr (CO) , (NS) + NaCl + CO J 3 3 3 _ 7 g o c £ (32) The success o f t h i s r e a c t i o n r e f l e c t s the f a c t t h a t i n donor s o l v e n t s , t r i t h i a ; z y l - t r i c h l o r i d e ^ probably e x i s t s . as • a s o l v a -ted monomer, i . e . N S C K t h f ) ^ . (This i s based on the observa-t i o n t h a t i n s o l v e n t s such.as t h f or CH^CN, N^S^Cl.^ forms green s o l u t i o n s which e x h i b i t a v N g i n t h e i r IR spectrum at 1220 cm - 1 where as i n CC1. s o l u t i o n o r as a N u j o l mull t h i s - 43 -same a b s o r p t i o n occurs at ^ 1000 cm 1 ) . A comparison of the p h y s i c a l p r o p e r t i e s o f the new t h i o n i t r o s y l product (I) w i t h those e x h i b i t e d by i t s n i t r o s y l analogue (II) allows, f o r the f i r s t time, a d i r e c t c o n t r a s t o f , t h e bonding p r o p e r t i e s of the NO and NS l i g a n d . D i c a r b o n y l ( n 5 - c y c l o p e n t a d i e n y l ) thionitrosylchromium.; ,i i s a dark r e d - v i o l e t , diamagnetic s o l i d which d i s s o l v e s i n common or g a n i c s o l v e n t s to g i v e b l o o d - r e d s o l u t i o n s t h a t even-t u a l l y d e p o s i t some decomposition products when exposed to a i r f o r s e v e r a l hours. The pure s o l i d i s reasonably s t a b l e i n a i r but i s bes t s t o r e d under d i n i t r o g e n . I t s i n f r a r e d spectrum i n hexanes (Table IV) e x h i b i t s the expected three s t r o n g bands a t t r i b u t a b l e to t e r m i n a l CO and NS groups. The v N S band occurs i n the frequency range found 1* 6 f o r oth e r t h i o n i t r o s y l complexes. The v n bands of I appear a t s l i g h t -- 44 -Table IV.. P h y s i c a l P r o p e r t i e s o f ( n 5-C^H,_) Cr (CO) 0(NX) Complexes X 0 c o l o u r mp, °C v C Q , cm v (in.hexane) 1 NX' C m ( i n hexane) 1E NMR, 6 ppm ( i n C D C 1 3 ) 1 3 C NMR, 6 ppm ( i n C D C 1 3 ) r e d - v i o l e t 6 8 . 0 - 6 9 . 0 2 0 3 3 s, 1 9 6 2 s 1 1 8 0 s. 5 . 0 8 9 2 . 75 (CCH[.) 2 3 9 . 4 3 (CO) orange-red 6 9 i 5 - 7 0 . 5 2 0 2 8 s, 1 9 5 5 s 1 7 1 3 s 5 . 0 3 9 0 . 7 6 (C 5H 5) 2 3 7 . 6 3 (CO) - 45 -l y h i g h e r f r e q u e n c i e s t h a t those o f I I , thereby s u g g e s t i n g t h a t the NS l i g a n d i s more e f f e c t i v e at removing e l e c t r o n d e n s i t y from the c e n t r a l metal than i s the NO l i g a n d . The Cr-N bond i n I a l s o appears to be somewhat s t r o n g e r than the Cr-N bond i n I I , as evidenced by the mass s p e c t r a l data d i s -p l a y e d i n Table V. While both complexes e x h i b i t fragmentation p a t t e r n s corresponding to the s e q u e n t i a l l o s s o f l i g a n d s and the common base peak can be ass i g n e d to the Cj-H,_Cr+ i o n , the C^H,-CrNS + i o n i s markedly more abundant i n the mass spectrum of I than i s the C^H,-CrNO+ i o n i n the spectrum o f I I . The NMR s p e c t r a l data o f compounds I and I I (Table IV) p r o v i d e an i n t e r e s t i n g c o n t r a s t . The *H NMR spectrum of I c o n s i s t s o f a s i n g l e sharp peak which occurs at a s l i g h t l y lower f i e l d than the corresponding a b s o r p t i o n due to the c y c l o p e n t a d i e n y l protons of I I . S i m i l a r l y , the 1 3 C NMR chem-i c a l s h i f t s o f the c y c l o p e n t a d i e n y l and ca r b o n y l carbons are f u r t h e r d o w n f i e l d from Me^Si f o r complex I . A comparable do w n f i e l d s h i f t f o r 5 ( 1 3C^H^) has p r e v i o u s l y been observed 1* 9 when a CO group i n CpMn(CO) 3 ( i s o e l e c t r o n i c with II) has been r e p l a c e d by a CS group to gi v e CpMn(CO) 2(CS) ( i s o e l e c -t r o n i c with I ) . However such a s u b s t i t u t i o n a l s o r e s u l t s i n an u p f i e l d s h i f t o f 6 ( 1 3C0) which i s e x a c t l y o p p o s i t e t o the e f f e c t t h a t i s observed i n going from I I to I. Down-f i e l d s h i f t s o f 1 3C0 resonances are normally a s s o c i a t e d w i t h the replacement o f a c a r b o n y l l i g a n d by a donor l i g a n d on the c a r b o n y l complex [e.g. CpMo(CO)„(NO) e x h i b i t s 6 ( 1 3C0) Table V. Low-Resolution Mass S p e c t r a l Data f o r (Cj-H^Cr-(CO) 0(NX) Complexes X = S X = 0 m/ z Rel abund Assignment3 Rel abund m/z 219 191 163 117 52 36 8 74 100 63 C 5 H 5 C r ( C O ) 2 ( N X ) + C 5 H 5 C r ( C O ) ( N X ) + C c H c C r ( N X ) + C 5 H 5 C r + C r + 26 21 13 100 37 203 175 147 117 52 The assignments i n v o l v e the most abundant n a t u r a l l y occur-r i n g i s o t o p e s i n each fragment. - 47 -at 226.72 wh i l e CpMo(CO)(NO)(PPh^) e x h i b i t s 6 ( 1 3C0) at 2 4 4 . 8 6 ] 5 0 and the observed d o w n f i e l d s h i f t i n the above i n -stance ^ may.ybe due to a l a r g e i n c r e a s e i n donor s t r e n g t h o f the NS l i g a n d vs. the NO l i g a n d w i t h only a s m a l l i n c r e a s e i n . Lewis a c i d s t r e n g t h . I t i s obvious t h a t more work i s r e -q u i r e d to i n t e r p r e t the d i f f e r e n t e l e c t r o n - d o n a t i n g and 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 two l i g a n d s . The m o l e c u l a r s t r u c t u r e of CpCr(CO) 2(NS) i s shown i n F i g u r e 3, w i t h important bond lengths and bond angles being summarized t h e r e . G e n e r a l l y , the molecular geometry i s s i m i l a r to t h a t e x h i b i t e d by o t h e r "piano s t o o l " molecules [e.g. CpMn(CO) 3 5 1 and C p C r ( C O ) 2 ( N O ) 5 2 ] . The Cr-C-0 l i n k a g e s are i n h e r e n t l y l i n e a r , and the Cr-C(Cp), Cr-C(O), and C-0 bond lengths are comparable to those found i n other c y c l o -pentadienylchromium c a r b o n y l s 2 7 • 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 of the s t r u c t u r e i s the f a c t t h a t the t h i o -n i t r o s y l l i g a n d c o o r d i n a t e s e s s e n t i a l l y l i n e a r l y to the metal o v i a the n i t r o g e n atom. The Cr-N bond l e n g t h o f .1.694 A f a l l s i n the range of values r e p o r t e d 2 7 f o r Cr-N bonds formed by l i n e a r , t e r m i n a l n i t r o s y l l i g a n d s . Hence i n a formal sense, the t h i o n i t r o s y l group (an o v e r a l l t h r e e -e l e c t r o n donor) can be c o n s i d e r e d . to be bonded as NS +, a mode of c o o r d i n a t i o n t h a t i s d i r e c t l y analogous to metal-t h i o c a r b o n y l bonding and i n v o l v e s the s y n e r g i s t i c c o u p l i n g of a and TT bonding components. C o n s i s t e n t w i t h t h i s view of back-donation from Cr TT o r b i t a l s t o NS T T* o r b i t a l s i s the - 48 -Figure 3. Molecular s t r u c t u r e of ( n 5 - C 5 H 5 ) C r ( C O ) 2 ( N S ) . o S e l e c t e d average bond lengths (A) and angles (°): Cr-N, 1.694; Cr-C(O), 1.883; C-0, 1.131; N-S, 1.551; Cr-N-S, 176.8; Cr-C-O, 178.1; C(0)-Cr-C(0), 92.4; C(0)-Cr-N, 94.8. - 49 -f a c t t h a t the N-S d i s t a n c e o f 1.551 A ..in the complex i s longer than the NS e q u i l i b r i u m bond l e n g t h o f 1.440 A d e t e r -mined s p e c t r o s c o p i c a l l y i n the vapour s t a t e . 5 3 . C o n s i d e r i n g the above s p e c t r o s c o p i c comparison of CpCr(CO) 2(NS) and CpCr(CO) 2(NO), i t would be expected t h a t the Cr-N(S) bond l e n g t h would be s h o r t e r than the Cr-N(O) bond l e n g t h i n the r e s p e c t i v e molecules. R e g r e t t a b l y , an e f f e c t i v e comparison o f these d i s t a n c e s i s precluded.by c r y s t a l l o g r a p h i c d i s o r d e r among the CO and NO groups i n the s o l i d s t a t e s t r u c t u r e o f C pCr(CO) 2(NO)! 2. The presence of the t h i o n i t r o s y l l i g a n d i s expected to have on l y a minor e f f e c t on the chemical r e a c t i v i t y o f CpCr(CO) 2(NS) compared to t h a t o f the n i t r o s y l d e r i v a t i v e . Since the i n f r a r e d a b s o r p t i o n s f o r the c a r b o n y l l i g a n d s are of only s l i g h t l y higher energy, there should not be a s i g -n i f i c a n t i n c r e a s e i n the l a b i l i t y . Indeed, t h i s i s found to be true as the t h i o n i t r o s y l . c o m p l e x does not r e a c t w i t h PPh 3 even at r e f l u x i n t o l u e n e . A f t e r s e v e r a l days, no r e a c t i o n has o c c u r r e d and the CpCr(CO) 2(NS) can be recovered u n a l t e r e d . T h i s i s comparable to the n i t r o s y l complex where c o n d i t i o n s of 160° i n neat t r i p h e n y l p h o s p h i n e are r e q u i r e d to produce CpCr(CO)(PPh^)(NO) 5 4. T h i s l a t t e r phosphine complex can a l s o be prepared p h o t o c h e m i c a l l y but p h o t o l y s i s of CpCr(CO) 2(NS) i n the presence of p p h 3 leads t o the removal of the c a r b o n y l and t h i o n i t r o s y l l i g a n d s from the s t a r t i n g m a t e r i a l . A p p a r e n t l y , a more s e l e c t i v e p h o t o d e c a r b o n y l a t i o n - 50 -method i s r e q u i r e d which w i l l probably depend on an a n a l y s i s o f the e l e c t r o n i c s t r u c t u r e of the molecule. I t may then be p o s s i b l e to s e l e c t i v e l y i r r a d i a t e . a s o l u t i o n o f CpCr(CO) 2(NS) to achieve t h i s r e s u l t . F u r t h e r s u b s t i t u t i o n r e a c t i o n s of the t h i o n i t r o s y l complex a l s o g i v e unusual r e s u l t s . The displacement of the two!* c a r b o n y l l i g a n d s w i t h n i t r o s y l c h l o r i d e t o g i v e CpCr(NO)-(NS)Cl does not occur under the same c o n d i t i o n s t h a t t r a n s -form CpCr(CO) 2(NO) to the d i n i t r o s y l analogue. I n s t e a d , the r e a c t i o n of C1NO with CpCr(CO) 2(NS) a l s o produces C p C r ( N O ) 2 C l as the only i s o l a b l e n i t r o s y l - c o n t a i n i n g product. There are no new t h i o n i t r o s y l complexes d e t e c t e d d u r i n g the r e a c t i o n . C a r e f u l m o n i t o r i n g o f the r e a c t i o n by i n f r a r e d spectroscopy does suggest, though, the formation o f an i n t e r m e d i a t e . I t i s p o s s i b l e t h a t CpCr(CO) 2(NO) i s formed s i n c e a s m a l l shoulder appears on the low energy s i d e of the 1711 cm 1 band of the product. However, both c a r b o n y l a b s o r p t i o n s o f t h i s i n t e r m e d i a t e would be masked by those due to the s t a r t i n g d i c a r b o n y l t h i o n i t r o s y l compound. A l s o , C p C r t C O ^ -(NO) r e a c t s much f a s t e r w i t h n i t r o s y l c h l o r i d e than does CpCr(CO)2(NS), thereby making i t extremely d i f f i c u l t t o i s o l a t e any o f the former i f i t i s indeed formed d u r i n g the r e a c t i o n o f the t h i o n i t r o s y l complex w i t h C1N0. The p r o -d u c t i o n of CpCr(CO)2(NO) by t h i s r e a c t i o n would not be unusual i n the l i g h t of the d i s c u s s i o n of the r e a c t i v i t y of C1NO.in the p r e v i o u s chapter. One p o s s i b i l i t y i s the r e a c -t i o n of the n i t r o g e n monoxide p a r t of the C1NO s o l u t i o n - 51 -e q u i l i b r i u m (equation 7) with CpCr(CO) 2(NS) to produce the d i c a r b o n y l n i t r o s y l s p e c i e s . However no r e a c t i o n occurs be-tween NO and a s o l u t i o n of CpCr(CO) 2(NS) a t room temperature. Thus CpCr (CO) 2 (NO) must be formed .by some other r e a c t i o n pathway. The r e a c t i o n o f ClNO with CpCr(CO) 2(NS) a l s o p r o -duces s m a l l amounts of a y e l l o w and an orange-yellow s o l i d . Because of the l i m i t e d q u a n t i t i e s of these products, exact i d e n t i f i c a t i o n c o u l d not be made. At present, no oth e r f u l l y c h a r a c t e r i z e d s u b s t i t u -t i o n product c o n t a i n i n g an i n t a c t Cr-NS group has been p r e -pared. However, one r e a c t i o n which appears t o produce a new t h i o n i t r o s y l s p e c i e s i s "•" • CH ?C1 9/CH CN CpCr (CO) 0 (NS) + NOPF, - - — > [CpCr(CO)(NO)(NS)]PF, A b -78° C + CO (33) T h i s r e a c t i o n p a r a l l e l s e x a c t l y t h a t o f CpM(CO) 2(NO) (M = Cr, Mo, o r W) w i t h t h i s same n i t r o s o n i u m s a l t 5 5 . The p r o -duct o f r e a c t i o n (33) i s a w a t e r - s e n s i t i v e , green-black pow-der which i s i n s o l u b l e i n a l l but those s o l v e n t s w i t h which i t r e a c t s . . I t was assigned the composition [CpCr(CO)(NO)-(NS)]PFg on the b a s i s o f i t s i n f r a r e d spectrum (Nujol mull) which e x h i b i t s bands a s s i g n a b l e to a v C Q at 2122 cm 1, a v N Q at 1790 cm - 1, and a v N g a t 1243 cm"1 and by analogy to other r e a c t i o n s o f n i t r o s o n i u m s a l t s w i t h complexes l i k e CpCr(CO) 2(NS). The ca r b o n y l and n i t r o s y l s t r e t c h i n g f r e -quencies are i n the range p r e v i o u s l y observed f o r c a r b o n y l -n i t r o s y l c a t i o n s 5 5 ' 5 6 . A l s o , the t h i o n i t r o s y l s t r e t c h i n g - 52 -frequency i s at h i g h e r energy i n t h i s c a t i o n than i n the n e u t r a l CpCr(CO) 2(NS). T h i s i s c o n s i s t e n t w i t h a decrease i n e l e c t r o n d e n s i t y at the metal centre which manifests i t s e l f i n l e s s back donation from the metal to the IT* o r -b i t a l s of the NS l i g a n d . S e v e r a l attempts to prepare more s t a b l e s u b s t i t u t e d products of the type [CpCr(NO)(NS)(L)]-P F 6 [L = PPh 3, P(OPh) 3, o r P(n-Bu) 3] were u n s u c c e s s f u l . A l s o , n u c l e o p h i l i c a t t a c k of the i o d i d e i o n on the c a t i o n l e d to displacement of both the c a r b o n y l and t h i o n i t r o s y l l i g a n d producing [CpCr(NO)I] 2 i n s t e a d of the d e s i r e d CpCr(NO)(NS)I. The f i n a l p roduct i s o l a t e d from the r e a c t i o n of [CpCr(CO)(NO)-(NS)]PF, with KI was CpCr(N0) oI which was probably formed by O Z the d i s p r o p o r t i o n a t i o n o f [CpCr(NO)I] 2 d i s c u s s e d i n Chapter I I . The second product of the r e a c t i o n of Na[CpCr(CO) 3] w i t h N 3 S 3 C 1 3 i s C p 2 C r 2 ( C O ) 4 S . T h i s sulphur complex i s an a i r s t a b l e , diamagnetic s o l i d . w h i c h i s f r e e l y s o l u b l e i n common o r g a n i c s o l v e n t s except p a r a f f i n hydrocarbons and sublimes without attendant decomposition a t 80° C (5 x 10 3 mm) i n a dynamic vacuum. I t s low r e s o l u t i o n mass spectrum (Table VI) confirms i t s b i m e t a l l i c nature and e x h i b i t s a fragmentation p a t t e r n which i n d i c a t e s t h a t the C r 2 S grouping i s q u i t e r e s i s t a n t to cleavage. I t e x h i b i t s i n f r a r e d ab-s o r p t i o n s due t o c a r b o n y l l i g a n d s a t 2000, 1960, 1932, and 1924.cm 1 i n hexanes and resonances i n i t s 1H NMR a t 6 4.87 (s) and i n i t s 1 3C NMR at 5 245.9 (s, CO) and 6 89 .0 - 53 -Table VI. Low-Resolution Mass S p e c t r a l Data f o r [(C 5H 5)Cr(CO) 2 ] 2 S m/z Rel abund Assignment3 378 20 ( C 5 H 5 ) 2 C r 2 ( C O ) 4 S + 322 14 ( C 5 H 5 ) 2 C r 2 ( C O ) 2 S + 294 25 ( C 5 H 5 ) 2 C r 2 ( C O ) S + 266 100 ( C 5 H 5 ) 2 C r 2 S + 201 18 ( C 5 H 5 ) C r 2 S + 182 96 ( C 5 H 5 ) 2 C r + 136 28 C r 2 S + 133 18 ( C 5 H 5 ) 2 C r 2 S 2 + 117 30 ( C 5 H 5 ) C r + 52 75 C r + The assignments i n v o l v e the most abundant n a t u r a l l y o c c u r -r i n g i s o t o p e s i n each fragment. - 54 -(s, C 5H 5) i n CDC1 3. The NMR r e s u l t s show t h a t the c a r b o n y l (and c y c l o p e n t a d i e n y l ) l i g a n d s a r e . m a g n e t i c a l l y e q u i v a l e n t on the time s c a l e of the experiment-at room temperature. The IR data suggest t h a t a v a r i a b l e temperature NMR study of t h i s complex would i n d i c a t e t h a t a low energy process such as r o t a t i o n around the Cr-S bond - allows t h i s averaging. 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 have been observed 5 7 f o r the complexes Cp 2Mo 2(CO) 4(RCECR) (R = H, E t , or Ph) which have been shown to c o n t a i n a d i s c r e t e [CpMo(CO) 2] 2 u n i t b r i d g e d by the acetylene l i g a n d . S t u d i e s 5 7 have p r o v i d e d evidence f o r rearrangement processes which average the environment of the CO l i g a n d s at room temperature s u f f i c i e n t l y f a s t t o r e s u l t i n only, one 1 3C NMR resonance due to these l i g a n d s while the IR spectrum s t i l l e x h i b i t s - f o u r bands. The m o l e c u l a r s t r u c t u r e of [CpCr(CO) 23 2S i s shown i n F i g u r e .4. . The p e r i p h e r a l dimensions o f the molecule are comparable to those found i n other cyclopentadienylchromium c a r b o n y l s 2 7 . The most s t r i k i n g aspect of the s t r u c t u r e i s the c e n t r a l , e s s e n t i a l l y l i n e a r Cr-S-Cr l i n k a g e . The o average Cr-S bond l e n g t h of 2.075 A i s markedly s h o r t e r than any such d i s t a n c e y e t r e p o r t e d , and i t implies, .the e x i s -tence of m u l t i p l e bonding between the three atoms. T h i s i n f e r e n c e draws support from two p r e v i o u s s t r u c t u r a l d e t e r -o minations. A bond l e n g t h of 2.510 A i n (CO) 5Cr(SPMe^) has been r e p o r t e d 5 8 and assigned to a Cr-S s i n g l e bond. The o o b s e r v a t i o n 5 9 of a Cr-S d i s t a n c e of 2.351 A i n F i g u r e 4. M o l e c u l a r s t r u c t u r e of [-.(fi 5—C5H5) Cr (CO) 2] 2 S . S e l e c t e d average bond lengths (A) and angles (°): Cr-S, 2.075; Cr-C(O), 1.858; C r - C ( c p ) , 2.198; C-O, 1.143; Cr-S-Cr, 174.34; S-Cr-C(O), 94.7; S-Cr-Cp ( c e n t r o i d ) , 129.0; C(0)-Cr-C(0), 89.8. - 56 -(CO) j-CrSFeCc^ (CO) g has been i n t e r p r e t e d i n terms of s y n e r g i c a and IT bonding between the two atoms. To account f o r the extreme shortness of the Cr-S bond and the diamagnetism of Cp 2Cr 2(CO) 4S and to provide each chromium wi t h the favoured 18-electron c o n f i g u r a t i o n , the bonding i n the c e n t r a l u n i t i s best represented as CrESECr i n which chromium o r b i t a l s ( p r i n c i p a l l y 3d) overlap w i t h appropriate s u l f u r o r b i t a l s . There has been one previous r e p o r t 6 0 of a s h o r t e r metal-s u l f u r bond; th a t i n the complex i o n { [ ( P h 2 P C H 2 ) 3 C C H 3 ] 2 ~ N i 2 S } 2 + which contains a l i n e a r Ni-S-Ni group w i t h a Ni-S o bond distance of 2.034 A/ I t i s i n t e r e s t i n g to note t h a t i n -t h i s c a t i o n (and an analogous CO species) the L^M moieties are i n i n i t i a l 15-electron c o n f i g u r a t i o n s and therefore a MES5M bonding r a t i o n a l e a l s o accounts f o r the documented p h y s i c a l p r o p e r t i e s of these complexes. The r e a c t i v i t y of the complex [CpCr(CO) 2] 2S and the Cr 2S u n i t can be r e a d i l y compared to the r e a c t i v i t y of the chromium-chromium - t r i p l e bond i n [CpCr (CO) 2 ] 2 . Both of these compounds are reasonably s t a b l e towards a i r 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 . Both r e a c t w i t h C1NO to produce the expected CpCr(NO) 2C1. The s t r e n g t h of the Cr-S-Cr linkage i s demonstrated by the i n e r t n e s s of Cp 2Cr 2(CO) 4S to s e v e r a l other reagents. A toluene s o l u t i o n of the s u l f u r complex maintained under 10 4 atm pressure of carbon monoxide showed no change a f t e r 18 h and the s t a r t i n g m a t e r i a l could be recovered u n a l t e r e d . However, under i d e n t i c a l c o n d i t i o n s , - 5 7 -the d i c a r b o n y l dimer i n c o r p o r a t e s two molecules o f carbon monoxide to become [ C p C r ( C O ) 3 ] 2 6 1 • I n t h e i r r e a c t i o n s w i t h n i t r o g e n monoxide, [C p C r ( C O ) 2 ] 2 S again shows no r e a c t i v i t y while the n o n - s u l f u r c o n t a i n i n g s p e c i e s i s converted to a mixture of CpCr(CO) 2(NO) ( 4 3 % ) and C p C r ( N O ) 2 ( N 0 2 ) ( 3 5 % ) a t room temperature. Attempts at p r e p a r i n g o t h e r t r a n s i t i o n metal t h i o -n i t r o s y l complexes were not as s u c c e s s f u l as the p r e v i o u s example. Reactions of t e t r a h y d r o f u r a n s o l u t i o n s of N^S^Cl^ w i t h the anions shown i n Table I I I l e a d mostly to o x i d a t i o n products, i . e . LnM~ + N 3 S 3 C 1 3 (LnM) 2 + "-S=N-" In the case o f [CpM(CO) 3] (M = Mo or W), a second product of the r e a c t i o n i s CpM(CO) 3C1 which probably i n d i c a t e s t h a t at l e a s t two types of r e a c t i o n s are o c c u r r i n g . The products from the r e a c t i o n s o f t r i t h i a z y l t r i c h l o r i d e w i t h CpM(CO) 2(NO) (M = Cr or Mo) are t o t a l l y i n e x p l i c a b l e on the b a s i s o f the p r e s e n t l y a v a i l a b l e i n f o r m a t i o n on the r e a c t i v i t i e s of N 3 S 3 C 1 3 . The success o f t h i s method i n p r e p a r i n g the f i r s t o r g a n o m e t a l l i c t h i o n i t r o s y l complex i s q u i t e s u r p r i s i n g i n view.of the complexity o f the r e a c t a n t , ( N S C l ) 3 . The f a i l u r e o f the r e a c t i o n w i t h n e u t r a l compounds to produce the s p e c i e s CpM(NO)(NS)Cl i s not unexpected s i n c e the c o n d i t i o n s used to prepare the analogous CpM(NO) 9C1 complexes are much l e s s - 5 8 -i n v o l v e d . - I t i s known 6 2 t h a t (NSC1) 3 can be t h e r m a l l y de-polymerized to produce the monomeric t h i a z y l c h l o r i d e . The use of t h i s s i m p l e r r e a c t a n t may w e l l l e a d to d e s i r e d conversions i n a s i m i l a r manner t o the use of n i t r o s y l c h l o r i d e t o prepare c h l o r o n i t r o s y 1 compounds. - 59 -CHAPTER IV REACTIONS OF DICARBONYL(n5-CYCLOPENTADIENYL)NITROSYLMANGANESE  HEXAFLUOROPHOSPHATE WITH HALIDE IONS Since a r e i n v e s t i g a t i o n of the t i t l e c a t i o n was c a r r i e d out i n 1964 1 8, a g r e a t d e a l of i n t e r e s t has a r i s e n i n i t s r e a c t i o n s with a wide v a r i e t y of n u c l e o p h i l e s . In t h a t same r e p o r t , the r e a c t i o n of [CpMn(CO) 2(NO)]PF^ wi t h the t e t r a h y d r i d o b o r a t e anion i n a two phase water-benzene system was found to produce [CpMn(CO)(N0)] 2. T h i s compound probably r e s u l t e d from the f o l l o w i n g sequence of r e a c t i o n s , [CpMn(CO) 2(N0) ] + + H - CpMn(CO) (NO) H-+-VC0. (34) 2CpMn(C0)(NO)H > [CpMn(CO)(NO)] 2 + H 2 (35) The d i m e r i z a t i o n step (equation 35) i s a common r e a c t i o n o f th e r m a l l y unstable metal c a r b o n y l h y d r i d e s . More i m p o r t a n t l y , the f i r s t o f these r e a c t i o n s r e p r e s e n t s hydride attack on the metal centre (with displacement of a CO lig a n d ) and i s a common mode of n u c l e o p h i l i c a t t a c k on the manganese c a t i o n . Other examples of n u c l e o p h i l e s which show t h i s type of be-hav i o u r i n c l u d e S C ( C H 3 ) 3 ~ 6 3 , S 2CSC (CH 3) 3 _ , and S^NR^ 6 1* (R = Me o r Et) and t h e i r mode o f r e a c t i o n i s summarized i n equ a t i o n (36). Loss o f the second c a r b o n y l l i g a n d i n t h i s - 60 -[CpMn(CO) 2 (NO) ] + S^NP^ CpMn(NO) (S^NF^) + 2 C O (36) example i s i n d i c a t i v e of the l a b i l i t y of t h i s l i g a n d i n s p e c i e s l i k e CpMn(CO)(NO)(S 2CNR 2) which may w e l l be the i n i t i a l product o f n u c l e o p h i l i c a t t a c k . A second s i t e f o r t h i s type of r e a c t i o n to occur i s shown i n the next e q u a t i o n . Here, the methoxide i o n a t t a c k s [CpMn(CO) 2(NO)] + + MeO~ * CpMn(CO) (NO) [C(O) (OMe)] (37) the c a r b o n y l l i g a n d producing the carbomethoxy d e r i v a t i v e , 5 . Other n u c l e o p h i l e s have a l s o been observedj'to r e a c t a t the l i g a n d s r a t h e r than the metal c e n t r e . V a r i o u s a l k y l and a r y l amines r e a c t w i t h the c a t i o n a t room temperature to y i e l d the amido d e r i v a t i v e s CpMn(CO)(NO)[C(0)NHR] 6 6. Methyl-l i t h i u m and p h e h y l l i t h i u m e r e a c t w i t h [CpMn (CO) 2 (NO) ] P F g to give the r i n g a d d i t i o n products (5-exo-R-C^H,-)Mn(CO)^(NO) as w e l l as the c a r b o n y l a d d i t i o n products CpMn(CO)(NO)[C(0)R] (R = Me or Ph) 6 7 . In an e f f o r t to extend the comparative chemistry of the c a r b o n y l and n i t r o s y l l i g a n d s , i t was hoped t h a t the above r e s u l t s i n d i c a t e d t h a t the r e a c t i o n of h a l i d e ions w i t h the [CpMn(CO)2(NO)] + c a t i o n would produce the complexes CpMn(CO)(NO)X (X = C l , Br, or I ) . Then the chemistry of these s p e c i e s c o u l d be c o n t r a s t e d d i r e c t l y w i t h t h a t of the known i s o e l e c t r o n i c CpCr (NO) 2% a n d CpFetCO^X complexes. There was one b r i e f r e p o r t on t h i s r e a c t i o n which appeared d u r i n g the course of t h i s work 6 8 . The a t t a c k of the I i o n - 61 -on the t h i o c a r b o n y l d e r i v a t i v e , [CpMn(CO)(CS)(NO)] was found to produce CpMn(CS)(NO)I as an a i r s t a b l e s o l i d . Fur-thermore i t was s t a t e d t h a t the r e a c t i o n of the d i c a r b o n y l c a t i o n w i t h I " r e s u l t e d i n the formation o f c a r b o n y l - and n i t r o s y l - f r e e decomposition products o f an unknown nature." T h i s chapter p r e s e n t s evidence t h a t CpMn(CO)(NO)I and i t s m e t h y c y c l o p e n t a d i e n y l congener can indeed be s y n t h e s i z e d by t h i s type o f r e a c t i o n . These complexes are a l s o formed by d i r e c t i o d i n a t i o n of the dimers, [(RC 5H 4)Mn(CO)(NO)] 2 (R = H o r Me). The r e a c t i o n s o f the c a t i o n w i t h C l , Br , and N0 2 are a l s o d i s c u s s e d . Experimental A l l e x perimental procedures d e s c r i b e d were performed under the g e n e r a l c o n d i t i o n s d e t a i l e d i n Chapter I I . P r e p a r a t i o n of ( R C ^ ) Mn(CO) (NO)I (R = H or Me). Method A. S o l i d KI (2.20 g, 13.3 mmol) was added to a s t i r r e d y e l l o w s o l u t i o n of [CpMn(CO) 2(NO)]PF 6 1 8 (4.50 g, 12.8 mmol) i n acetone (100 mL) a t room temperature. A r e a c t i o n o c c u r r e d immediately as evidenced by a change i n c o l o u r t o gray-brown, e v o l u t i o n of a gas, and formation o f an o f f - w h i t e p r e c i p i t a t e . The r e a c t i o n mixture was s t i r r e d f o r 5 min du r i n g which time gas e v o l u t i o n ceased. The s o l v e n t was removed under reduced p r e s s u r e , the r e s u l t i n g gray r e s i d u e was e x t r a c t e d w i t h 3 x 25 mL p o r t i o n s o f CH 2C1 2, and the e x t r a c t s were taken to dryness i n vacuo to o b t a i n a green-brown s o l i d . T h i s s o l i d was formulated as s l i g h t l y impure - 62 -CpMn(CO)(NO)I by v i r t u e of i t s IR spectrum i n C H 2 C 1 2 (which e x h i b i t e d s t r o n g a b s o r p t i o n s a t 2030 and 1776 cm" 1), i t s 1E NMR spectrum i n CDC1 3 (which showed a s t r o n g , sharp peak at 6 5.30), and i t s ambient temperature mass spectrum, which i s summarized i n Table V I I . / A n a l y t i c a l l y pure samples o f t h i s compound c o u l d not be o b t a i n e d because i t decomposed both i n s o l u t i o n and i n . t h e s o l i d , s t a t e . For i n s t a n c e , a s t i r r e d . d i c h l o r o m e t h a n e s o l u t i o n (20 mL) c o n t a i n i n g ^0.2 g of CpMn(CO)(NO)I slowly d e p o s i t e d a green s o l i d which was i n s o l u b l e i n a l l common o r g a n i c s o l v e n t s ; a f t e r 72 h complete decomposition had o c c u r r e d . As a s o l i d , the complex decom-posed s i m i l a r l y but over a longer p e r i o d of time (^8 days). An acetone s o l u t i o n of [(MeCp)Mn(CO) 2(NO)]PF g r e a c t e d w i t h KI to a f f o r d impure (MeCp)Mn(CO)(NO)I i n an i d e n t i c a l manner as demonstrated by the i n f r a r e d spectrum of the product i n C H 2 C 1 2 which showed s t r o n g a b s o r p t i o n s a t 2050 and 1772 cm 1 . Furthermore, the elemental composition of t h i s product was confirmed by a m o l e c u l a r weight d e t e r -mination u s i n g an A.E.I. MS 5 0 h i g h - r e s o l u t i o n mass s p e c t r o -meter (Ca l c d : 318.8902. Found: 318.8908). T h i s method of p r e p a r i n g the (RCr-H,^) Mn(CO) (NO) I complexes c o u l d a l s o be e f f e c t e d i n t e t r a h y d r o f u r a n , as both conversions went to completion w i t h i n , 1 0 min. However, IR m o n i t o r i n g of the f i n a l r e a c t i o n mixtures i n d i c a t e d t h a t both of the d e s i r e d products decomposed more r a p i d l y i n t h i s s o l v e n t . T h i s decomposition was complete a f t e r 6 h. - 63 -Table V I I . Mass Complexes S p e c t r a l Data f o r (RC 5H 4)Mn(CO)(NO)I R = H R = Me ' abund Assignment Rel , abund m / z 305 57 (RC 5H 4)Mn(CO) (NO) I + 31 319 277 69 (RC CH.)Mn(NO)I + o 4 58 291 275 12 (RC 5H 4)Mn(CO) I + 8 289 247 80 (RCCH.)MnI + 100 261 186 0 H(RC5H4) 2Mn + 33 214 185 0 (RC 5H 4) 2Mn + 29 213 192 45 RC 5H 4I + 29 206 182 60 M n l + 63 182 130 34 ( RC 5H 4) 2 + 38 15 8 120 100 (RC 5H 4)Mn + 71 134 65 (150) RC 5H 4 t (158) 79 55 29 Mn + 50 55 - 64 -Method B. To a s t i r r e d s o l u t i o n of [CpMn(CO)(NO)] 2 1 8 (0.36 g, 1.0 mmol) i n dichloromethane (50 mL) a t room temperature was added s o l i d I 2 (0.26 g, 1.0 mmol). The o r i g i n a l r e d - v i o l e t s o l u t i o n r a p i d l y turned green-brown and a dark green s o l i d p r e c i p i t a t e d . A f t e r 3 min the r e a c t i o n mixture was f i l t e r e d and the f i l t r a t e taken to dryness .in.vacuo t o o b t a i n ^0.5 g of a green-brown s o l i d which e x h i b i t e d the s p e c t r o s c o p i c c h a r a c t e r i s t i c s o f CpMn(CO)(NO)I (vide s u p r a ) . The r e a c t i o n between [ (MeCp)?Mn(CO) (NO) ]' 2 6' 9 and I 2 proceeded analogously. Benzene c o u l d a l s o be employed as a s o l v e n t f o r both t r a n s f o r m a t i o n s . P r e p a r a t i o n o f CpMn(NO)(PPhg) I. A s o l u t i o n of CpMn(CO)(NO)I was prepared a c c o r d i n g t o Method A u s i n g 1.05 g (3.0 mmol) of [CpMn(CO) 2(NO)]PF g and 0.50 g (3.3 mmol) o f Nal i n acetone. The r e a c t i o n mixture was f i l t e r e d t o remove the NaPF^ by-product, and the s t i r r e d green-brown f i l t r a t e was t r e a t e d with 0.80 g (3.0 mmol) of s o l i d PPh 3. Vigorous gas e v o l u -t i o n o c c u r r e d immediately and the s o l u t i o n developed a brown c o l o u r a t i o n . A f t e r 5 min a brown, c r y s t a l l i n e s o l i d began to p r e c i p i t a t e and c r y s t a l l i z a t i o n was complete a f t e r 15 min. The s o l i d was c o l l e c t e d , washed w i t h hexanes (2 x 10 mL), and d r i e d i n vacuo t o o b t a i n 0.93 g (58% y i e l d ) o f pure CpMn(NO) ( P P h 3 ) I . A n a l , c a l c d f o r C 2 3H 2 QMnNOPI: C, 51.23; H, 3.74; N, 2.60. Found: C, 51.33; H, 3.50; N, 2.65. v N Q (CH 2C1 2) 1720 cm - 1.  1H NMR (CDClg) 6 7.38 (15H,. m),, 4.72 (5H, s) . - 65 -Mp 15 6° C dec. P r e p a r a t i o n of (MeCp)Mn(NO)(PPh,)I. A s t i r r e d d i c h l o r o -methane s o l u t i o n (50 mL) o f (MeCpMn(CO) (NO) I prepared by-Method B from 0.77 g (2.0 mmol) of [(MeCp)Mn(CO)(NO)] 2 and 0.51 g (2.0 mmol) o f I 2 was t r e a t e d w i t h 0.90 g (3.5 mmol) of s o l i d PPh^ at room temperature. The s o l u t i o n became brown and vigorous gas e v o l u t i o n o c c u r r e d . A f t e r 15 min, hexanes (20 mL) were added and the f i n a l r e a c t i o n mixture was f i l -t e r e d . Slow c o n c e n t r a t i o n o f the f i l t r a t e under reduced pressure a f f o r d e d 1.64 g (74% y i e l d ) of (MeCp)Mn(PPh 3)(NO)I as a brown, m i c r o c r y s t a l l i n e s o l i d . A n a l , c a l c d f o r C 2 4H 2 9MnNOPI: C, 52.10; H, 4.01; N, 2.53. Found: C, 51.77; H, 3.81; N, 2.63. V N Q (CH 2C1 2) 1720 cm - 1. XH NMR (CDClg) 6 7.33 (15H, m), 4.93 (2H, b ) , 4.40 (IH, b) , 3.84 (IE), b) , 1.90 (3H, s) . Mp 132-133° C. Reaction o f (RC^H^)Mn(CO)(NO)I w i t h Other Phosphines and  Phos p h i t e s . The r e a c t i o n s of the c a r b o n y l . - n i t r o s y l i o d i d e s w i t h other phosphorus-containing l i g a n d s were c a r r i e d out as d e s c r i b e d above. The p h y s i c a l p r o p e r t i e s of the products are d e s c r i b e d i n Table V I I I . R eaction of (RC^H^)Mn(CO)(NO)I wi t h Other Lewis Bases. S o l u -t i o n s o f (RCj-H^) Mn(CO) (NO) I i n dichloromethane when t r e a t e d w i t h a s l i g h t excess of such Lewis bases as C^H^N, (CH^^SO, H N ( C 6 H 1 3 ) 2 , (CH 3) 2NC(0)H, or C^H^N, slowly (^ 6 h) produce v a r i a b l e y i e l d s (10 - 25%) of the complexes (RC^H^) 2Mn 2(NO) 3I Table V I I I . P h y s i c a l P r o p e r t i e s o f the Complexes (RC 5H 5)Mn(L)(NO)I fR = H, L = P ( O C 6 H 5 ) 3 ; R = Me, L = P ( O C 6 H 5 ) 3 o r p ( C 6 H 1 ] L ) 3 ] Mp A n a l y s i s : C a l c d (Found) I R ( v N Q ) H N 1E NMR( RCnHj.) (C CH C)MnP(OC,H c) _(NO) I D O D b j (CgH 7)MnP(OC 6H 5) 3 (NO) I 126° dec 84-85° (CgH 7)MnP(C 6H 1 1) 3(NO)I 121-122° 47.04 (46.90) 47.94 (47.86) 3.43 (3.26) 3.69 (3.51) 2.39 (2.36) 2. 33 (2.41) 50.54 7.06 2.45 (50.36) (7.09) (2.45) 1748 cm - 1 1740 cm - 1 1707 cm 1 4.48 (5H, s) 4.70 (2H, b ) , 4.33 (IH, b ) , 3.66 (IH, b), 1.60 (3H, s) 5.47 (IH, b ) , 5.17 (IH, b ) , 4.92 (IH, b ) , 3.85 (IH, b), c ci b c i n CH 2C1 2 s o l u t i o n 6 , i n CDC1 3 s o l u t i o n covered by resonances due to L - 67 -(R = H or Me). The products c o u l d be p u r i f i e d by removal of the s o l v e n t i n vacuo and 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. An a l , c a l c d f o r C 1 0H 1 0Mn 2N 3C> 3I: C, 26.29; H, 2.21; N, 9.19. Found: C, 26.46; H, 2.47; N, 9.23. . v N Q ( C H 2 C l 2 ) 1748, 1526 cm" 1. Mp 182° C dec. Ana l , c a l c d f o r C 1 2 H 1 4 M n 2 N 3 0 3 I : C, 29772; H, 2.91; N, 8.66. Found: C, 30.31; H, 3.33; N, 8.44. v N Q (CH 2C1 2) 1734, 1520 cm" 1. Mp 146-147° C. Reac t i o n o f CpMn (CO) (NO) I wit h Na[ ( g ^ O C ^ O ) 2 A 1 H 2 ^ • A s t i r -red benzene s o l u t i o n (30 mL) c o n t a i n i n g CpMn(CO)(NO)I (^ 2 mmol) was t r e a t e d dropwise at room temperature w i t h a benzene s o l u t i o n o f sodium dihydridobis(2-methoxyethoxy)-aluminate. The green-brown r e a c t i o n mixture s l o w l y turned r r e d - v i o l e t and a s o l i d p r e c i p i t a t e d . The r e a c t i o n was monitored by IR spectroscopy and the a d d i t i o n o f the r e -ducing, agent stopped when a l l of the s t a r t i n g m a t e r i a l had reacted.- A t t h i s p o i n t the mixture was concentrated i n vacuo to 10 mL and then t r a n s f e r r e d by s y r i n g e t o the top of a 2 x 5 cm column of alumina (Woelm n e u t r a l grade 1). E l u t i o n o f the column w i t h benzene produced a r e d - v i o l e t band which was c o l l e c t e d and taken to dryness under reduced p r e s s u r e . The r e s i d u e was i d e n t i f i e d as [CpMn(CO)(NO)] 2 1 8 on the b a s i s of i t s IR, NMR, and mass s p e c t r a . ( Y i e l d ^52%) . Reaction o f (MeCp)Mn(CO)(NO)I with Zn/Hg. To a s t i r r e d z i n c - 68 -amalgam (2%) was added a t e t r a h y d r o f u r a n s o l u t i o n (30 mL) c o n t a i n i n g (MeCp)Mn(CO)(NO)I (^1 mmol). A gray s o l i d s l o w l y d e s p o s i t e d as the supernatant turned red-brown. A f t e r 3 h the r e a c t i o n was complete. The supernatant was removed by s y r i n g e , . f i l t e r e d , and the r e s u l t i n g s o l u t i o n taken to dry-ness in.vacuo. The red-brown r e s i d u e was p u r i f i e d as des-c r i b e d i n the p r e v i o u s s e c t i o n and [ (MeCp) Mn (CO) (NO)] 2 6. 9 was i s o l a t e d i n moderate y i e l d (0.13 g, ^65%). P r e p a r a t i o n of [CpCr ( C O ) ( N O ) J P F 6 • The.complex, CpCr(CO) 2(NO) (0.61 g, 3.0 mmol) was d i s s o l v e d i n a mixture o f CH 2Cl2 (15 mL) and CH^CN (5 mL) and the orange s o l u t i o n was cooled to -78° C. S o l i d NOPFg (0.54 g, 3.1 mmol) was added and the mixture was s t i r r e d f o r 2 h. During t h i s time the s o l u t i o n turned green and a s i m i l a r l y c o l o u r e d s o l i d formed. The ad-d i t i o n o f c o l d F t 2 0 (25 mL) p r e c i p i t a t e d more s o l i d and the product was c o l l e c t e d on a f r i t t e , washed w i t h E t 2 0 , and d r i e d i n vacuo. The product, [CpCr(CO)(NO) 2]PF^, 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 . Y i e l d = 0.97 g (93%) . Reaction of [CpCr(CO)(NO) 2]PF^ w i t h KI. To an acetone s o l u -t i o n (30 mL) c o n t a i n i n g 0.35 g (1.0 mmol) [CpCr(CO)(NO) 2]PF g was added 0.20 g (1.2 mmol) o f s o l i d KI. The mixture was s t i r r e d at room temperature f o r 2 h du r i n g which time i t turned yellow-brown and a gray p r e c i p i t a t e formed. The ace-tone was removed i n vacuo and the r e s i d u e was e x t r a c t e d w i t h - 69 -CE^C]^. The e x t r a c t s were f i l t e r e d through a 2 x 3 cm column o f F l o r i s i l and the f i l t r a t e was taken to dryness under reduced p r e s s u r e t o produce CpCr (NO) 2 I (0.21 g, 77% y i e l d ) 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 9 . P r e p a r a t i o n o f (MeCp)Fe(CO) ( P P h 3 ) I . A benzene s o l u t i o n (100 mL) c o n t a i n i n g 2.82 g (8.9 mmol) o f (MeCp) Fe (CO) 2 I (prepared by the r e a c t i o n o f [ (MeCp) Fe (CO) 2 ] 2 w i t h I ^ 1 ) and 2.36 g (9.0 mmol) of p p h 3 was s t i r r e d at r e f l u x f o r 18 h. The s o l u t i o n was f i l t e r e d hot and the s o l v e n t was removed i n V V , G vacuo. The re s i d u e was r e c r y s t a l l i z e d from CH 2 c l 2/hexanes to o b t a i n a n e a r l y q u a n t i t a t i v e y i e l d o f (MeCp)Fe(CO)(PPh 3)I. Anal, c a l c d f o r C 2 5 H 2 2 O F e I P : C, 54.38; H, 4.02. Found: C, 54.15; H, 4.01. v c o ( C H 2 C l 2 ) 1945 cm" 1.  1H NMR (CDC1 3)•6 7.33 (15H, m), 4.78 (IH, b ) , 4.33 (1H, b ) , 3.80 (1H, b ) , 3.63 (IH, b), 2.12 (3H, s ) . Mp 146° C. P r e p a r a t i o n o f CpRe (CO) (NO) I . A CH 3CN s o l u t i o n of CpRe(CO) 3 was t r e a t e d w i t h a s l i g h t excess o f s o l i d NOPF^ to produce [CpRe(CO) 2(NO)]PF 6 completely analogously t o the formation of the manganese c a t i o n r e c e n t l y r e p o r t e d 1 * 2 . The rhenium c a t i o n was then reduced w i t h NaBH^ i n t h f ac c o r d i n g to the pub-l i s h e d p r o c e d u r e 7 0 . The product o f t h i s r e a c t i o n , CpRe(CO)-(NO)Me (0.22 g, 0.7 mmol), was d i s s o l v e d i n dichloromethane (25 mL) and the s o l u t i o n was t r e a t e d dropwise at room temper-ature w i t h a dichloromethane s o l u t i o n c o n t a i n i n g I 2 (0.19 g ) . The s o l u t i o n darkened and no gas e v o l u t i o n was observed. The - 70 -s o l u t i o n was s t i r r e d . f o r 1 h and was then c o n c e n t r a t e d to 10 mL and f i l t e r e d . Hexanes (10 mL) were added to the f i l -t r a t e and the s o l u t i o n c o n c e n t r a t e d to 3 mL as 0.23 g (75% y i e l d ) of c r y s t a l l i n e CpRe(CO)(NO)I separated. The product was c o l l e c t e d by f i l t r a t i o n and d r i e d i n vacuo. A n a l , c a l c d f o r C 6H 5ReN0 2I: C, 16.52; H, 1.66; N, 3.21. Found: C, 15.78; H, 1.12; N, 3.07. v C 0 ( C H 2 C l 2 ) 1992 cm" 1. v N Q (CH 2C1 2) 1733 cm" 1. *H NMR (CDC1 3) 6 5.78 (5H, s ) . Mp 135° C dec. R e a c t i o n .of [CpMn (CO) 2 (NO) ] P F £ w i t h NaBr. To a s t i r r e d ace-tone s o l u t i o n (100 mL).containing [CpMn(CO) 2 (NO) ] P F g (2.5 g, 7.1 mmol) was added s o l i d NaBr (0.80 g, 7.8 mmol) . The o r -ange s o l u t i o n g r a d u a l l y darkened and gas e v o l u t i o n was observed. The mixture was s t i r r e d f o r 1 h and then the s o l -vent was removed i n vacuo. The gray r e s i d u e was care f u l l y e x t r a c t e d w i t h 3 x 30 mL p o r t i o n s of CH 2C1 2 and the r e s i d u e washed a f i n a l time w i t h 40 mL of t h i s s o l v e n t . The com-bined CH 2C1 2 s o l u t i o n s were co n c e n t r a t e d to 40 mL and hexanes (40 mL) were added. Slow removal of the s o l v e n t under reduced pressure produced 0.43 g (44% y i e l d based on the NO ligand) o f Cp 2Mn 2(NO) 3Br. The r e a c t i o n s o f the [ (RCr-H .) Mn(CO) ~ (NO) ] PF, (R = D 4 2 o H o r Me) complexes wi t h NaBr, NaCl, and NaN0 2 were c a r r i e d out s i m i l a r l y . The p h y s i c a l p r o p e r t i e s and analyses of the products are recorded i n Tables IX and X. - 71 -Table IX. Elemental Analyses f o r (RC 5H 4) 2Mn 2(NO) 3X Complexes C a l c d Found C H N C H N R = H Br 29.30 2.46 10.25 29.53 2.72 10.02 N0 2 31.94 2.68 14 .90 31.75 2.60 14 .79 C 5 H 5 45 .59 3.83 10.63 44. 87 3.79 10. 71 CH 3 38.28 3.80 12.18 38.39 3. 83 12.18 CH 3 Br 32.90 3.22 9.59 33.20 3.24 9.41 N0 2 35 .66 3. 49 13.86 35.30 3.49 13.54 - 72 -Table X. P h y s i c a l P r o p e r t i e s o f (RC 5H 4) 2Mn 2(NO) 3X Complexes Colour Mp a 2 C 1 2 ) cm - 1 R = H X = Br red-black 15 0° dec 1745 , 1527 C l red-black b 1746, 1529 N0 2 red-brown 134° dec 1757, 1544 C 5 H 5 r e d - v i o l e t 153° dec 1730, 1510 CH 3 dark red 163° dec 1723, 1501 R = CH3 X = Br red-black 144° dec 1734, 1522 C l r e d-black b 1737, 1522 N0 2 red-brown 135° dec 1745, 1539 " A l l complexes explode v i o l e n t l y on decomposition. A n a l y t i c a l l y pure samples c o u l d not be ob t a i n e d but data o b t a i n e d on impure samples: R = H, 145° dec; R = CH 3, 141° dec. - 73 -Reactions of Cp^Mn^(NO)^Br with NaC 5H 5 or LiMe. The reac-tions were carried out s i m i l a r l y except that the methyl-lithium reaction was done at -78° C. A 0.15 M solution of NaC^Hj- i n tetrahydrof uran was added dropwise to a s t i r r e d room temperature solution of Cp 2Mn 2(NO) 3Br (0.41 g, 1.0 mmol). The reaction occurred immediately as evidenced by a colour change to dark red and the formation of a fine p r e c i p i t a t e . The progress of the reaction was monitored by IR and the addition of the NaC<-H,- stopped when the bands due to the s t a r t i n g material had disappeared. The thf was removed under reduced pressure and the gray residue was extracted with 4 x 20 mL portions of dichloromethane. The r e s u l t i n g solution was concentrated i n vacuo to 30 mL and hexanes (35 mL) were added. The t o t a l volume was reduced to 15 mL during which time e s s e n t i a l l y complete c r y s t a l l i z a t i o n occurred. The red - v i o l e t c r y s t a l s were collected, washed with hexanes, and dried i n vacuo. Y i e l d = 0.30 g (76%). The physical properties and a n a l y t i c a l data f o r the complexes Cp 0Mn«(NO)_R (R = Me or C rH r) are summarized i n 2 2 3 b o Tables IX and X. Results and.Discussion Contrary to the claims of other i n v e s t i g a t o r s 1 8 ' 6 8 , the previously unknown complex, CpMn(CO)(NO)I, and i t s methylcyclopentadieny1 analogue can be e a s i l y prepared by either of the reactions [ (RC5H4)Mn(CO) (NO) ] 2 + I • 2(RC5H4)Mn(CO) (NO)I (38) - 74 -[ (RC 5H 4)Mn(CO) 2(N0) ] + I * ( R C ^ ) Mn (CO) (NO) I + CO (39) both o f which p r o c e e d - r a p i d l y - t o completion at room tempera^ t u r e . T h i s i s not s u r p r i s i n g s i n c e these r e a c t i o n s are a n a l -ogous to the formation of the i s o e l e c t r o n i c CpFe(CO) 2I o r CpCr (NO) 2 I e i t h e r by the d i r e c t i o d i n a t i o n of the d i m e r s 1 8 ' 1 * 1 or from i o d i d e a t t a c k on t h e i r r e s p e c t i v e c a t i o n s , i . e . [ C p F e ( C O ) 3 ] + 7 1 and [ C p C r ( C O ) ( N O ) 2 ] + . The (RC 5H 4)Mn(CO)(NO)I complexes are a i r - s e n s i t i v e , green-brown s o l i d s t h a t d i s -s o l v e f r e e l y i n common o r g a n i c s o l v e n t s except p a r a f f i n hydrocarbons. They decompose slo w l y both i n s o l u t i o n and i n the s o l i d s t a t e even when maintained under an atmosphere of p r e p u r i f i e d n i t r o g e n . T h i s behaviour i s c o n s i s t e n t w i t h t h a t p o s t u l a t e d i n Chapter II i n which the thermal i n s t a b i l i t y of t r a n s i t i o n metal ca r b o n y l n i t r o s y l h a l i d e s o f t e n leads to the formation of p o l y m e r i c halogen-bridged s p e c i e s . The IR s p e c t r a of the (RC^H^)Mn(CO)(NO)I compounds e x h i b i t the cus-tomary absorptions due to t e r m i n a l c a r b o n y l and n i t r o s y l l i g a n d s , and t h e i r 1H NMR s p e c t r a d i s p l a y resonances char-a c t e r i s t i c of a pentahapto RC^H 4 l i g a n d . The presence of the p a rent ions and fragments showing the s e q u e n t i a l l o s s o f l i g a n d s from the metal centre i n t h e i r mass s p e c t r a (Table VII) are c o n s i s t e n t w i t h the above f o r m u l a t i o n . In order to c h a r a c t e r i z e these complexes f u r t h e r , s e v e r a l t y p i c a l t r a n s f o r m a t i o n s o f (RC 5H 4)Mn(CO)(NO)X s p e c i e s were c a r r i e d out. Z i n c amalgam was used i n a Wurtz c o u p l i n g . r e a c t i o n (equation 4 0) to produce the known dimers, - 75 -2(RC 5H 4)Mn(CO) (NO) I + Zn/Hg t h f » [ (RC 5H 4) Mn ( CO) (NO) ] 2 (40). [(RC 5H 4)Mn(CO)(NO)] 2. A s i m i l a r r e a c t i o n has been r e p o r t e d which y i e l d s [CpCr (NO) 2J 2 from CpCr (NO) 2 C 1 7 2 . The iodo s p e c i e s can a l s o be reduced u s i n g a hy d r i d o - r e a g e n t ( N a [ ( C H 3 O C 2 H 4 0 ) 2 A 1 H 2 ] ) , thereby again producing the d i m e r i c [(RC 5H 4)Mn(CO)(NO)] 2 p r o b a b l y - v i a a sequence of r e a c t i o n s s i m i l a r to equations 34 and 35 i n v o l v i n g the intermediacy o f (RC 5H 4)Mn(CO)(NO)H. (The formation of such hydrides from r e a c t i o n s o f t h i s r e d u c i n g agent w i t h o r g a n o m e t a l l i c n i t r o -s y l h a l i d e s i s the s u b j e c t of a r e c e n t p a p e r 7 3 ) . The forma-b t i o n o f a product c o n t a i n i n g both c a r b o n y l and n i t r o s y l l i g a n d s confirms the f o r m u l a t i o n o f the s t a r t i n g m a t e r i a l as a c a r b o n y l n i t r o s y l complex. Furthermore, r e g a r d l e s s o f the method by which s o l u t i o n s o f (RC^H 4)Mn(CO)(NO)I are generated, they r e a d i l y evolve carbon monoxide when t r e a t e d w i t h t r i -phenylphosphine, i . e . (RC 5H 4)Mn(CO) (NO) I + PPh-3 • ( R C ^ ) M n ( P P h 3 ) (NO) I + CO (41) and the new c r y s t a l l i n e complexes, (RCj-H,-)Mn(PPh 3)(NO)I, can be i s o l a t e d i n good y i e l d s . T h i s r a p i d displacement of a c a r b o n y l l i g a n d i s a l s o observed f o r W(CO) 4(NO)I which forms the monosubstituted d e r i v a t i v e mer-W(CO) 3 (NO) (PPhp) I when t r e a t e d w i t h P p h 3 at room t e m p e r a t u r e 7 4 . The p r e p a r a -t i o n of s e v e r a l other d e r i v a t i v e s o f the type (RC^H 4)Mn-(L)(NO)I [R = H, L = P(OPh) 3; R = Me, L = P(OPh) 3 or P(CgH^^) 3] can be c a r r i e d out by analogous r e a c t i o n s and - 76 -along w i t h the above chemical and s p e c t r o s c o p i c evidence supports the hypothesis t h a t the complexes (RC^H^) Mn (CO)(NO)I do i n f a c t e x i s t and.are s t a b l e at room temperature f o r a reasonable p e r i o d of time. The chemistry o f these complexes i s dominated by the l a b i l i t y o f the c a r b o n y l group and the thermal i n s t a b i l i t y o f the compounds themseives. Because of t h i s , p r e l i m i n a r y attempts.at p r e p a r i n g a l k y l o r a r y l d e r i v a t i v e s by meta-t h e s i s f a i l e d . In c o n t r a s t , the i s o e l e c t r o n i c CpFe (CO) 2 I and CpCr(NO) 2I are s t a b l e almost i n d e f i n i t e l y (under N 2) and compounds of the type CpM(L 2XR (M = Fe, L = CO; M = Cr, L = NO) can be r e a d i l y p r e p a r e d 2 6 ' 7 2 . A l s o , s u b s t i t u t i o n a o f a CO or NO l i g a n d i n the l a t t e r compounds r e q u i r e s the presence of an excess of PPh^ i n r e f l u x i n g benzene f o r 18 h. I t t h e r e f o r e appears t h a t i t i s not simply the presence of a n i t r o s y l l i g a n d but the presence of a mixture of the two l i g a n d s (CO and NO) which.confers t h i s odd thermal i n s t a b -i l i t y on CpMn(CO)(NO)I. The compounds (RC^H^)Mn(NO)(L)I [R = CH 3 or H; L = P(OPh) 3, p p h 3 , or p ( 0 g H n ) 3 ] a r e green to brown a i r - s t a b l e s o l i d s which are s o l u b l e i n dichloromethane and c h l o r o f o r m , but l e s s s o l u b l e i n benzene, t e t r a h y d r o f u r a n , o r acetone. T h e i r IR s p e c t r a d i s p l a y s i n g l e n i t r o s y 1 - s t r e t c h i n g absorp-t i o n s i n the range 1707 - 1748 cm"1 which are 30 - 70 cm"1 lower than those e x h i b i t e d by the (RC^H^)Mn(CO)(NO)I com-p l e x e s . The decrease i n frequency as L v a r i e s i n the o r d er - 7 7 -CO > P(OPh) 3 > PPh 3 > p ( c 6 H 1 1 ) 3 h a s been previously observed i n other systems and i s consistent with the replacement of a carbonyl ligand by a better electron donating phosphine l i -gand and the reported v a r i a t i o n i n a-donor, •re-acceptor a b i l -i t i e s of the d i f f e r e n t phosphines 7 5. The mass spectra of the two triphenylphosphine complexes (Table XI) reveal fragmen-tati o n patterns attributable to (RC^H^)Mn(NO)I+ and p p h 3 + ions. Parent ion peaks are not detectable even at such low exci t a t i o n potentials as 20 eV. A.similar pattern i s obser-ved for the other (RC 5H 4)Mn(L)(NO)I complexes (Table XII). In contrast, the mass spectrum of the iron analogue, (MeCp)-Fe(PPh 3)(CO)I, (Table XIII) exhibits several fragments which maintain the metal-phosphine l i n k (including the parent i o n ) . The difference i n behaviour of these two i s o e l e c t r o n i c com-plexes i s surprising. I t i s expected, since NO i s thought to be a better Tr-aeid, that the n i t r o s y l ligand should better s t a b i l i z e an electron donating group attached to the metal. Therefore, one would expect the manganese derivative to be more stable. This i s not observed. Also, the t r i c y c l o -hexylphosphine derivatives, which should be the most stable, are observed to be quite unstable. Both complexes tend to decompose slowly i n a solution not containing an excess of P(CgH^^) 3 and.this p r o c l i v i t y to form free phosphine and aa species l i k e [CpMn(NO)I] has made the i s o l a t i o n of pure CpMnIP(C gH 1 1) 3](NO)I extremely d i f f i c u l t . Obviously, the presence of a strongly electron-donating phosphine i s not - 78 -Table XI. Mass S p e c t r a l Data f o r (RC 5H 4) Mn (NO) (PPh 3) I* R = H R = Me m/z Rel abund Assignments Rel abund m/z 277 3 (RC 5H 4)Mn(NO)I + 9 291 262 100 P ( C 6 H 5 ) 3 + 100 262 247 8 (RC 5H 4)MnI + 0 261 185 22 ( R C 5 H 4 ) 2 M n + 14 213 185 P ( C 5 H 5 ) 2 + 5 185 182 6 Mnl + 9 182 120 26 (RC 5H 4) Mn + 14 134 65 8 R C 5 H 4 + 9 79 55 10 Mn + 9 55 ^ a s s s p e c t r a l data i n c l u d e s o n l y P ( C g H 5 ) 3 , p ( c , g H 5 ) 2 ' a n d fragments c o n t a i n i n g Mn. A l l s p e c t r a a l s o i n c l u d e d the c h a r a c t e r i s t i c fragmentation p a t t e r n s of P(C,H[-)-.. - 79 -Table X I I . Mass S p e c t r a l Data f o r (RC^H ) Mn (NO) [P (OPh) ,] I a R = H R = Me m/z Rel abund Assignment Rel abund m/z 310 100 P ( O C 6 H 5 ) 3 + 100 310 277 8 (RC 5H 4)Mn(NO) I + 3 291 247 13 (RC 5H 4)MnI + 6 261 185 0 ( R C 5 H 4 ) 2 M n + 5 213 182 5 M n l + 6 182 120 17 (RC 5H 4)Mn + 11 134 65 34 R C 5 H 4 + 26 79 55 7 Mn + 7 55 Mass S p e c t r a l Data f o r (C 6H 7) Mn(NO) [P (C gH 1 ] L) 3 ] I a (C 6H 7)Mn(NO) I + , 291 (18); P t C g H . ^ ) ^ , 280 (80); ( C g H 7 ) M n I + , 261 (42); ( C 6 H 7 ) 2 M n + , 213 (21); M n l + , 182 (37); (C 6H ?)Mn +, 134 (26); C,H*, 79 (88); Mn +, 55 (100). b / ^ a s s . s p e c t r a l data i n c l u d e only L + [L = P(OPh) 3 or p ( C 6 H l i ) 3 l and fragments c o n t a i n i n g Mn. A l l s p e c t r a a l s o i n c l u d e d the c h a r a c t e r i s t i c fragmentation p a t t e r n s o f L. - 80 -Table X I I I . Mass S p e c t r a l Data f o r (CH-) Fe (CO) (PPh_) I a m/ z .Rel "abund Assignment 552 1 (C 6H 7) Fe [P(C 6H 5) 3 ] ( C O ) I + 524 8 ( C 6 H 7 ) F e [ P ( C 6 H 5 ) 445 1 F e [ P ( C 6 H 5 ) 3 ] I + 397 2 ( C 6 H ? ) F e [P(C 6H 5) 3 = + 290 2 ( C 6 H ? ) F e ( C O ) I + 262 100 P ( C 6 H 5 ) 3 + 214 40 ( C 6 H 7 ) 2 F e + 183 36 F e l + 79 11 C 6 H 7 + 56 10 F e + a + Mass s p e c t r a l data i n c l u d e s o n l y p(CgH,-) 3 and fragments c o n t a i n i n g Fe. A l l s p e c t r a a l s o i n c l u d e d the c h a r a c t e r i s t i c fragmentation pa t t e r n s , o f P(C (-H C.) 7. - 81 -s t a b i l i z e d , by the n i t r o s y l l i g a n d and i t thus seems t h a t NO may not be as s t r o n g a i r - a c i d as i s commonly b e l i e v e d . I t i s a l s o reasonable.to conclude: t h a t . t h e , a - d o n o r . e f f e c t s of the n i t r o s y l l i g a n d are f a r more important than i t s 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 i n these complexes. The *H NMR spectrum o f CpMn(PPh 3) (NO) I c o n s i s t s o f a m u l t i p l e t centered at. 6 7.32 and a s i n g l e t at 5 4. 72 of r e l a t i v e i n t e n s i t y 3:1, and these resonances can be as s i g n e d to the phenyl and c y c l o p e n t a d i e n y l protons r e s p e c t i v e l y . The spectrum of the t r i p h e n y l p h o s p h i t e d e r i v a t i v e i s s i m i l a r and can be assig n e d analogously. The 1H NMR s p e c t r a o f the m e t h y l 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 a l s o show resonances corresponding t o the ph o s p h i n e s l i g a n d s as w e l l as a s i n g l e t at ^ 6.2 a s s i g n a b l e to the methyl group attached to the r i n g . However, u n l i k e the p a r e n t . c a r b o n y l , (MeCp)Mn(CO) 3, the f o u r protons on the m e t h y l c y c l o p e n t a d i e n y l r i n g are not magnet-i c a l l y e q u i v a l e n t . Instead, three resonances ( f o u r i n the case of the P ( C , H n n ) _ d e r i v a t i v e ) are observed which are due 6 11 3 to the a , a ' , 3 * 3 ' s p i n system. These resonances are a s s i g -nable t o the protons on the d i a s t e r e o t o p i c s i d e s of the meth-y l c y c l o p e n t a d i e n y l group and t h i s magnetic non-equivalence confirms the presence of the asymmetric metal c e n t r e . I t was p r e v i o u s l y r e p o r t e d 7 6 t h a t the c a r b o n y l and n i t r o s y l groups i n the complex CpMo(CO)(NO)(PPhMe 2) were s u f f i c i e n t l y d i f f -e r e n t t o induce the magnetic non-equivalence of the two methyl groups even though these two l i g a n d s are s i m i l a r i n - 82 -both s t r u c t u r e and charge d i s t r i b u t i o n . However, the induced inequivalence i n t h i s compound i s extremely s m a l l compared to t h a t observed i n the manganese cases presented above. I t i s t h e r e f o r e of i n t e r e s t t o compare the *H NMR s p e c t r a of the s e r i e s o f r e l a t e d compounds (MeCp)Mn(CO) 3, (MeCp) Mn (CO) 2~ (PPh 3) , [ (MeCp)Mn(CO) (NO) ( P P h 3 ) ] P F g , and (MeCp) Mn(PPh 3) (NO) I . The s p e c t r a are reproduced i n Figure 5. The spectrum of the parent carbonyl (5a) e x h i b i t s the expected resonances at 6 4.51 (4H, s) and 1.89 (3H, s) and the spectrum of the t r i -phenylphosphihe d e r i v a t i v e (5b) shows the i n e q u i v a l e n t protons at the a and 3 p o s i t i o n s . I n t e r e s t i n g l y , although the a and 6 proton resonances appear b e t t e r r e s o l v e d i n the spectrum of the c a t i o n ( 5 c ) , there s t i l l does not appear to be any observed magnetic inequivalence between the two sides of the methylcyclopentadienyl r i n g . This compound d i f f e r s from the molybdenum complex c i t e d p r e v i o u s l y i n t h a t i t s carbonyl and n i t r o s y l ligands are not s u f f i c i e n t l y d i f f e r e n t - 83 -F i g u r e 5 . The 1H NMR S p e c t r a o f (a) (MeCp)Mn(CO) 3, (b) (MeCp) Mn(CO) 2 (PPh 3) , (c) [ (MeCp)Mn(CO) (NO) (PPh 3) ] P F 6 , and (d) (MeCp)Mn(NO) (PPh 3) I - 85 -i n t h i s compound to induce the.magnetic i n e q u i v a l e n c e i n the r i n g . The f i n a l spectrum i n the f i g u r e i s t h a t o f the com-p l e x (MeCp) Mn (PPh^) (NO) I and i t e x h i b i t s the resonances p r e -v i o u s l y d e s c r i b e d . The d i r e c t assignment of these resonances i s not p o s s i b l e a t t h i s time. In o r d e r . t o f i n d a more s e n s i t i v e probe of the asym-metry at the metal centre o r , at l e a s t , the magnetic i n e q u i v -alence on the r i n g , a study of the 1 3 C NMR of these complexes was undertaken. The data o b t a i n e d are summarized i n Table XIV. The assignments o f the c a r b o n y l and t r i p h e n y l p h o s p h i n e l i g a n d s are based on p r e v i o u s l y r e p o r t e d r e s u l t s 7 7 and the expected chemical s h i f t s o f . t h e s e two l i g a n d s . The i n d i r e c t c o u p l i n g constants J ( 3 i p . j ^ - i 3^) °f r b 2 4 H z between the 1 3C0 and 3 1 P P h 3 n u c l e i are common f o r a c i s - l i g a n d arrangement. The d i r e c t . c o u p l i n g constants J ( 3 i p _ i 3 C ) f o r t n e t r i p h e n y l -phosphine l i g a n d s are.reported.as w e l l as the assignment of the i n d i r e c t c o u p l i n g c o n s t a n t s , J ^ 3 i p _ i 3 C j and ^ ( 3 i p _ i 3 c ^ based on p r e v i o u s l y r e p o r t e d data. The l a c k o f i n t e r a c t i o n between the phosphorus and C-4 i s not uncommon. The a s s i g n -ment of the resonance f o r the .methyl carbon o f the MeCj-H4 l i g a n d i s unambiguous as i s t h a t of the carbon adjacent to the methyl group. In the case o f the o t h e r f o u r r i n g c a r -bons, the a n t i c i p a t e d r e s u l t s are indeed observed. Although the s p e c t r a f o r (MeCp)Mn(CO) 3 and (MeCp)Mn(CO) (PPh 3) ex-h i b i t only two resonances f o r these carbon atoms, the c a t -i o n i c complex [(MeC 5H 4)Mn(CO)(NO)(PPh 3)]PF g has f o u r d i s t i n c t Table XIV. 1 3 C NMR S p e c t r a l Data o f Some (MeCp)Mn Compounds Compound 6 CO 6 PPh 3 6 C(Cp) 6 C(CH 3) (MeCp)Mn(CO) 225 . ,10 102. ,4 2 13. ,30 82. ,21 81. ,72 (MeCp)Mn(CO) 2 P P h3 232. .82 C l 138. ,21 ( J P . -c 40. ,0 Hz) 98. ,76 " 13. .60 JP-C 24.4 Hz C 2 132. ,77 ( J P . -C 13. ,2 Hz) 82. ,91 C 3 127. ,90 <JP- -c 8. ,6 Hz) 81. ,72 C4 129. ,22 (MeCp)Mn(CO) (NO) ( P P h 3 ) P F g 213. .91 C l 131. ,38 ( J P . -c 59 . 2 Hz) 115. ,23 11, .99 JP-C 24.0 C2 132. ,87 (JP--c 20. .4 Hz) 98. .11 C 3 129. ,91 (JP--c 11. .4 Hz) 95. .49 C4 132. ,86 93. .87 93, .36 (MeCp)Mn(NO) (PPhg) I C l 134. .71 <JP--c 30, .2 Hz) 106, .51 12, .82 C2 133. .29 (JP--c 9, . 8 Hz) 97, .02 C 3 127. .96 (JP--c 9, . 4 Hz) 95, .61 C4 129, .89 91. .43 86.47 - 87 -resonances i n i t s spectrum. Of course, t h i s e f f e c t i s amp-l i f i e d f o r the n e u t r a l complex (MeCp)Mn(NO)(PPh^)I, where the four l i g a n d s d i f f e r to a l a r g e r e x t e n t i n s i z e and e l e c -t r o n i c p r o p e r t i e s and t h e r e f o r e induce g r e a t e r magnetic non-equivalence. However, t h i s does c o n f i r m t h a t 1 3 C NMR spectroscopy i s a m o r e . s e n s i t i v e probe of the asymmetry i n these complexes. S i m i l a r d e r i v a t i v e s of manganese c o n t a i n i n g f o u r d i f f e r e n t l i g a n d s have been prepared p r e v i o u s l y and separated i n t o o p t i c a l isomers. When the t r i p h e n y l p h o s p h i n e c a t i o n , [CpMn(CO)(PPh 3)(NO)]PF g, i s t r e a t e d w i t h sodium L-menth-oxide, diastereomers of the type CpMn(PPh 3)(NO)[C(0)0-menthyl] r e s u l t ! 8 . By d i f f e r e n t i a l c r y s t a l l i z a t i o n , e s s e n t i a l l y o p t i c a l l y pure isomers are ob t a i n e d . These d i a -stereomers can then be a c i d i f i e d and the r e s u l t i n g s o l u t i o n t r e a t e d w i t h NH^PFg to produce the o p t i c a l l y a c t i v e (+) and (-) [CpMn(CO) (PPh 3) (NO)] + c a t i o n s . These c a t i o n s are con-f i g u r a t i o n a l l y s t a b l e 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 . I n t e r e s t i n g l y , the menthoxide d e r i v a t i v e s slowly racemize i n s o l u t i o n ( v i a a phosphine d i s s o c i a t i o n pathway) and a f t e r s e v e r a l hours o p t i c a l a c t i v i t y due to the metal c e n t r e i s no longer observed. The success of the p r e s e n t study i n p r e p a r i n g the new complexes (RC 5H 4)Mn(L)(NO)I [L = PPh 3, P ( 0 P h ) 3 , and P ( C g H ^ ) 3 ] i n i t i a t e d attempts t o prepare (i) these same com-ple x e s by a d i f f e r e n t r o u te, and ( i i ) the analogous rhenium - 8 8 -complexes by the same or d i f f e r e n t routes. The f i r s t of these endeavours f a i l e d when i t was observed that the cation [(MeCp)Mn(CO)(PPh 3)(N0)] + did not react with any NaX (X = C l , Br, or I) i n refluxing acetone. After f i v e days, a majority of the s t a r t i n g material had decomposed. Attempts to pre-pare CpRe(CO) (NO)I by a method .analogous to the formation of the manganese derivative (equation 39) f a i l e d . The s t a r t -ing cationic complex [CpRe (CO) 2 (NO) ] PF g. could be recovered unaltered after several days reflu x i n g i n an acetone solu-t i o n containing an excess of Nal. However, since this com-pound i s of considerable i n t e r e s t for comparison, another preparative route was examined. A common reaction of t r a n s i t i o n metal a l k y l bonds involves the cleavage of t h i s linkage by I 2 to give the a l k y l iodide and the metal iodide. Since the compound CpRe (CO) -(NO)Me had been previously r e p o r t e d 7 0 i n the l i t e r a t u r e , the reaction C H 2 C l 2 CpRe (CO) (NO) Me + I CpRe (CO) (NO) I + Mel (42) was attempted and was found to produce the desired product i n good y i e l d s . The IR, 'HJMR and mass spectral data (Table XV) are consistent with the above formulation. The complex i s a i r stable i n the s o l i d state and i n solution and, i n contrast to the manganese analogue, the carbonyl ligand i s i n e r t to s u bstitution. CpRe(CO)(NO)I does not react with triphenylphosphine even when held .at reflux i n a toluene solution containing an excess of t h i s reagent. The unusual - 89 -Table XV. Mass S p e c t r a l Data of (CVHj.) Re (CO). (NO) I m/z ;Rel abund Assignment 3 437 79 (C 5H 5)Re(CO)(NO)I + 409 86 (CCH[-) Re (NO) I + b b 379 100 ( C 5 H 5 ) R e l + 35 3 29 (C 3H 3) R e l + 314 6 R e l + 218.5 6 ( C 5 H 5 ) R e ( C O ) ( N O ) I 2 + 204.5 8 (C 5H 5) Re (NO) I 2 + 189 .5 10 ( C 5 H 5 ) R e l 2 + 187 6 Re + Assignments are based on the 8 7Re isotope. - 90 -s t a b i l i t y o f t h i s complex r e p r e s e n t s the only known example of a mixed c a r b o n y l n i t r o s y l h a l i d e o f a t r a n s i t i o n metal wi t h an i n e r t c a r b o n y l l i g a n d . In the course o f s t u d y i n g the chemical r e a c t i v i t y of the (RCj-H^) Mn (CO) (NO) I (R = H or Me) complexes, attempts to prepare d e r i v a t i v e s c o n t a i n i n g N-donor l i g a n d s r e s u l t e d i n the o b s e r v a t i o n of a unique d i s p r o p o r t i o n a t i o n r e a c t i o n (RC 5H 4)Mn(CO) (NO) I + C ^ N • (RC 5H 4) 2Mn 2 (NO) 3 I (43) which produced the s p e c i e s (RC,-H4) 2Mn 2 (NO) ^I as the only i s o l a b l e n i t r o s y l complexes. Although no r e a c t i o n pathway i s r e a d i l y apparent, two o b s e r v a t i o n s should be noted. F i r s t l y , the r e a c t i o n s are r e l a t i v e l y slow (^ 6 h) and c a r e -f u l m o n i t o r i n g of these conversions by IR spectroscopy does not show any evidence f o r the formation o f an i n t e r m e d i a t e (RCj-H4) Mn(L) (NO) I s p e c i e s . Secondly, a s m a l l amount of NO(g) i s p r e s e n t i n the atmosphere above the r e a c t i o n mix-ture and i t s presence may i n d i c a t e t h a t n i t r o s y l l i g a n d t r a n s f e r occurs v i a f r e e . n i t r o g e n monoxide. A l s o , d u r i n g the p r e p a r a t i o n o f (RC^H 4)Mn(CO)(NO)I i n t h f . o r acetone, s m a l l amounts of these b i m e t a l l i c complexes are formed i n d i c a t i n g t h a t O-donor l i g a n d s a l s o f a c i l i t a t e these con-v e r s i o n s . C o n s i s t e n t w i t h t h i s i n f e r e n c e i s the f a c t t h a t dimethylsulphoxide i s as e f f e c t i v e a s . p y r i d i n e or p y r r o l -i d i n e i n producing the complexes (RC 5H 4) 2Mn 2(NO)^I from the parent c a r b o n y l n i t r o s y l i o d i d e s . - 91 -The r e a c t i o n s of the c a t i o n s , [(RC^H^)Mn(CO) 2(NO)] +, with the n u c l e o p h i l e s Br , C l , or N0 2 a l s o produce com-pounds of the formula (RC 5H 4) 2Mn 2(NO) 3X (X = Br, C l , or N 0 2 ) . A l l of the b i m e t a l l i c complexes are red-brown to r e d -b l a c k , r e l a t i v e l y a i r s t a b l e compounds t h a t are s o l u b l e i n p o l a r o r g a n i c s o l v e n t s , s p a r i n g l y s o l u b l e i n benzene, and i n -s o l u b l e i n hexanes. T h e i r s o l u t i o n s d i s p l a y IR ab s o r p t i o n s (Table X) a t ^1745 and /^1525 cm"1 a t t r i b u t a b l e to t e r m i n a l and b r i d g i n g n i t r o s y l l i g a n d s r e s p e c t i v e l y . . The mass s p e c t r a (Table XVI) of the i o d o - d e r i v a t i v e s e x h i b i t peaks due to the parent, P +, and the ions [P-NO] +, [P-2N0] +, and [P-3N0] +, as w e l l as those a r i s i n g from cleavage of the b i m e t a l l i c s p e c i e s , i . e . [ ( R C 5 H 4 ) M n ( N O ) 2 ] + and [ ( R C 5 H 4 ) M n l ] + . The mass s p e c t r a o f a l l o f the d e r i v a t i v e s are pre s e n t e d i n Tables XVII t o XIX and they e x h i b i t fragmentation p a t t e r n s s i m i l a r to the iodo complexes. I t i s i n t e r e s t i n g to note t h a t un-der c e r t a i n c o n d i t i o n s ions due to the s p e c i e s (RC,-H 4) 3~ Mn 2(NO) 3 may be observed i n the mass s p e c t r a of these d e r i v a t i v e s . Ion-molecule r e a c t i o n s , of the type shown i n equa t i o n (44), have p r e v i o u s l y been observed i n the mass s p e c t r a ( R C 5H 4) 2Mn 2(NO) 3Br + ( R C 5 H 4 ) + • ( R C ^ ) 3Mn 2 (NO) 3 + B r + (44) of other n i t r o s y l compounds 7 9. These complexes apparently belong to the g e n e r a l c l a s s of compounds (RC^H 4) 2Mn 2(NO) 3X of which the members w i t h - 92 -Table XVI. Mass S p e c t r a l Data f o r ( R C 5 H 4 ) 2 M n 2 ( N O ) 3 I ( R = H or Me) R = H e R = Me m/z Rel abund Assignment Rel , , , m/z abund ' 457 6 ( R C 5 H 4 ) 2 M n 2 ( N O ) 3 I + 17 485 427 17 ( R C 5 H 4 ) 2 M n 2 ( N O ) 2 I + 43 455 397 8 ( R C 5 H 4 ) 2Mn 2(NO) I + 14 425 367 29 ( R C 5 H 4 ) 2 M n 2 I + 71 395 24 7 4 ( R C 5H 4) Mnl + 7 261 237 3 M n 2 I + 9 237 191 3 ( R C 5 H 4 ) Mn 20 + 0 205 185 22 ( R C 5 H 4 ) 2Mn + 25 213 180 40 ( R C 5H 4) Mn(NO) 2 + 69 194 182 6 M n l + 12 182 15 0 15 ( R C 5 H 4 ] Mn(NO) + i 22 164 120 100 ( R C 5H 4) Mn + 100 134 65 34 R C 5 H 4 + 57 79 55 40 Mn + 50 55 - 93 -Table XVII. Mass S p e c t r a l Data f o r (RC 5H 4) 2Mn 2(NO) 3 B r (R = H o r Me) R = H R = Me m/ z Rel abund Assignment3 Rel abund m/ z 409 1 (RC^H 4) 2Mn 2 (NO) 3 B r + 5 437 379 3 ( R C 5 H 4 ) 2 M n 2 ( N O ) 2 B r + 15 407 349 2 (RC 5H 4) 2Mn 2(NO)Br + 6 377 330 3 ( R C 5 H 4 ) 2 M n 2 ( N O ) 3 + 0 35 8 319 8 ( R C 5 H 4 ) 2 M n 2 B r + 45 347 300 3 ( R C 5 H 4 ) 2 M n 2 ( N O ) 2 + 0 328 270 3 ( R C 5 H 4 ) 2 M n 2 ( N O ) + 0 298 199 1 (RC 5H 4)MnBr + 0 214 191 11 (RC 5H 4)Mn 20 + 0 205 185 40 ( R C 5 H 4 ) 2 M n + 25 213 180 20 (RC 5H 4)Mn(NO) 2 + 55 19 4 15 0 8 (RC 5H 4)Mn(NO) + 14 164 134 3 MnBr + 0 134 120 110 0 (RC 5H 4)Mn + 100 134 65 60 R G 5 H 4 + 86 79 55 53 Mn + 30 55 aAssignments are based on the 7 9 B r i s o t o p e . - 94 -Table XVIII. Mass S p e c t r a l Data f o r (RC 5H 4) 2Mn 2(NO) 3 c i (R = H o r Me) R = H R = Me m/z Re l abund Assignment3 R e l abund m/z 365 5 ( R C 5 H 4 ) 2 M n 2 ( N O ) 3 C 1 + 6 393 335 3 ( R C 5 H 4 ) 2 M n 2 ( N O ) 2 C 1 + 16 363 330 7 ( R C 5 H 4 ) 2 M n 2 ( N O ) 3 + 7 358 305 4 ( R C 5 H 4 ) 2 M n 2 ( N O ) C l + 10 333 300 . 10 ( R C 5 H 4 ) 2 M n 2 ( N O ) 2 + 328 275 10 ( R C 5 H 4 ) 2 M n 2 C l + 61 303 270 9 (RC 5H 4) 2Mn 2(NO) + 3 298 191 41 (RC 5H 4)Mn 20 + 0 205 185 35 (RC 5H 4) 2Mn + 40 213 180 28 (RC 5H 4)Mn(NO) 2 + 50 194 150 15 (RC 5H 4) Mn (NO) + 18 164 120 48 (RC 5H 4)Mn + 100 134 65 100 R C 5 H 4 + 90 79 55 41 Mn + 44 55 Assignments are based on the 3 5 C 1 isotope. - 95 -Table XIX. Mass S p e c t r a l Data f o r (Cj-H,-) 2Mn 2(NO) 3R (R = CH. or C,HJ 3 b b R = C 5 H 5 R = CH 3 m/z Rel abund Assignment Rel abund m/z 395 1 (C 5H 5) 2Mn 2(NO) 3 R + 26 345 365 2 ( C 5 H 5 ) 2 M n 2 ( N O ) 2 R + 11 315 335 1 (C 5H 5) 2Mn 2(NO) R + 11 2 85 330 6 ( C 5 H 5 ) 2 M n 2 ( N O ) 3 + 3 330 305 2 ( C 5 H 5 ) 2 M n 2 R + 82 255 300 8 ( C 5 H 5 ) 2 M n 2 ( N O ) 2 + 6 300 270 8 ( C 5 H 5 ) 2 M n 2 ( N O ) + 14 270 191 37 ( C 5 H 5 ) M n 2 0 + 55 191 185 75 ( C 5 H 5 ) 2 M n + 45 185 180 7 (C cH c)Mn(NO) ~ + b b 2. 36 180 150 6 (CcH[-)Mn(NO) + b b 12 15 0 120 100 (C CH C)Mn + b b 100 120 66 67 C 5 H 6 + 11 66 65 50 C 5 H 5 + 6 65 55 38 Mn + 45 55 - 96 -R = H and X = C 5 H 5 2 6 , N 0 2 3 5 , and C g H 5 7 9 have been p r e v i o u s l y c h a r a c t e r i z e d . In f a c t , the C^H^ d e r i v a t i v e can be r e a d i l y prepared by t r e a t i n g any of the s p e c i e s Cp 2Mn 2(NO) 3X (X = C l , Br, I, or N0 2) w i t h NaC5H,-. A l s o , other a l k y l or a r y l d e r i v a t i v e s may be o b t a i n e d by u s i n g the a p p r o p r i a t e l i t h i u m reagent, e.g. t h f Cp 2Mn 2 (NO) 3 B r + MeLi Cp 2Mn 2 (NO) 3Me + L i B r (45) — 78 °C The *H NMR s p e c t r a l data o f the b i m e t a l l i c com-plexes are compiled i n Table XX. The spectrum of Cp 2Mn 2-(NO) 3 I i n CDC1 3 c o n s i s t s o f one p a i r of resonances o f e q u a l i n t e n s i t y a t 6 5.53 and 5.34 and a second p a i r o f d i f f e r e n t , y e t e q u a l , i n t e n s i t y at <5 5.30 and 5.20. These two p a i r s of s i g n a l s are probably due to the c i s and trans isomers r e s p e c t i v e l y 7 9 . The *H NMR spectrum of Cp 2Mn 2(NO) 3(C 5H 5) a l s o e x h i b i t s resonances due to c i s and t r a n s isomers. Furthermore, the r a t i o o f c i s to t r a n s isomers appears to be very dependent on the s o l v e n t i n which the spectrum i s r e -corded and the data obtained a t room temperature i n acetone-dg i n d i c a t e s t h a t a complex i n t r a m o l e c u l a r rearrangement pro-cess occurs i n s o l u t i o n . (This process may w e l l i n v o l v e i n t e r c o n v e r s i o n o f the a- and TT-bonded c y c l o p e n t a d i e n y l - 97 -Table XX. 1H NMR S p e c t r a l Data f o r (RCVH .) 0Mn 0 (NO) ->Xa O 4 z 2 6 (R = H, X = C l , Br, I , N0 2, CH 3, o r C 5H 5; R = Me, X = C l , Br, I, or N0 o) R = H C l 5 .50 (5H, s) / 5 . 30 (5H, s) Br 5 .53 (5H, S) / 5. 33 (5H, s) I 5 .53 (5H, s) 7 5 . 34 (5H, s) 5 .30 (5H, s) / 5 . 20 (5H, s) N0 2 5 .43 (5H, s) / 5 . 32 (5H, s) CH 3 5 .17 (5H, s) / 5 . 10 (5H, s) , -0.60 (3H , s) C 5 H 5 5 .33 (5H, s) 1 5 . 27 (5H, s) , 4 . 43 (5H, s) , 5 .47 (5H, s) t 5 . 40 (5H, s) , 4 .50 (5H, s) C l 5 .07 (6H, b) 1 4 . 77 (2H, b) , 1 .77 (3H, s) r 1. 53 (3H, s) Br 5 .23 (6H, b) t 4. 83 (2H, b) , 1 .98 (3H, s) i 1. 77 (3H, s) I 5 . 47 (2H, b) i 5 . 33 (4H, b) , 4 .90 (2H, b) , 2 . 10 (3H, s) i 1. 87 (3H, s) N0 2 5 . 30 (2H, b). i 5. 10 (4H, b) , 4 .90 (2H, b) , 2 .03 (3H, s) r 1. 77 (3H, s) a6, i n CDC1-. s o l u t i o n - 98 -ri n g s ) . Studies to elucidate the mechanism of this process are currently i n progress. The 1H NMR spectra of the Cp^ Mn.,-(NO)3X (X = Br, C l , N0 2, or Me) derivatives e x h i b i t only two resonances i n the Tr-cyclopentadienyl proton region and there-fore probably e x i s t mainly, or excl u s i v e l y , as trans isomers. The spectrum of the methyl derivative also displays a single resonance at 6 -0.6 assignable to the methyl group. The spectra of the methylcyclopentadienyl derivatives are somewhat more complicated. F i r s t of a l l , the iodo-derivative does not appear to e x i s t as a mixture of c i s and trans isomers (but rather exclusively trans) i n thi s case. Also, although one of the methylcyclopentadienyl ligand's protons on each complex appears as two resonances i n the r a t i o of 4:3 [ i d e n t i c a l to the case of (MeCp)Mn(CO)^], the second such set of protons appears as three resonances in the r a t i o of 2:2:3 as i n the case of (MeCp)Mn(CO) 2(PPh 3). I t seems l i k e l y that the f i r s t MeCp ligand i s attached to the manganese centre bonded to the terminal n i t r o s y l ligand while the second ligand of thi s type i s probably bound to the metal atom attached to the X-group. C H 3 - 99 -CHAPTER V SOME ASPECTS OF THE CHEMISTRY OF BIS[(n 5-CYCLOPENTADIENYL)- DINITROSYLCHROMIUM] The compound b i s [ ( n 5 - c y c l o p e n t a d i e n y l ) d i n i t r o s y l -chromium],.[CpCr(NO) 2]2' w a s f i r s t o b t a i n e d 1 8 i n 1964 by the sodium t e t r a h y d r i d o b o r a t e r e d u c t i o n o f CpCr(NO)2CI i n an aqueous medium. U n f o r t u n a t e l y , only r e l a t i v e l y s m a l l quan-t i t i e s o f the r e d - v i o l e t compound were a v a i l a b l e due to the 5% y i e l d o f the o r i g i n a l p r e p a r a t i o n , and an e x t e n s i v e study of i t s c h a r a c t e r i s t i c r e a c t i o n s c o u l d not be made. I t has been r e c e n t l y s hown 9' 7 2 t h a t [ C p C r ( N O ) 2 ] 2 c a n b e very conven-i e n t l y s y n t h e s i z e d i n h i g h e r y i e l d s (55 - 75%) by r e d u c i n g CpCr(NO) 2Cl with e i t h e r z i n c amalgam i n t e t r a h y d r o f u r a n or sodium amalgam i n benzene. In t h i s manner, a s u f f i c i e n t amount.of the dimer has become a v a i l a b l e t o enable an i n v e s -t i g a t i o n of i t s p h y s i c a l and chemical p r o p e r t i e s more f u l l y than was p r e v i o u s l y p o s s i b l e . T h i s chapter p r e s e n t s the r e s u l t s o f these i n v e s t i g a t i o n s and c o n t r a s t s the chemistry o f [CpCr(NO)2]2 w i t h t h a t e x h i b i t e d by i t s i s o e l e c t r o n i c c a r b o n y l analogue, [CpFe (CO) 2 ] 2 • Experimental A l l e xperimental procedures d e s c r i b e d here were performed under the same g e n e r a l c o n d i t i o n s d e t a i l e d i n - 100 -Chapter I I . Reaction.: o f [CpCr(NO) o w i t h H C l ( a q ) . To a s t i r r e d s o l u -t i o n o f [ C p C r ( N O ) 2 ] 2 (0.17 g, 0.50 mmol) i n e t h a n o l (25 mL) and dichloromethane (5 mL) was added 12 M HCl (1 mL, 12 mmol) at room temperature. The r e a c t i o n mixture r e t a i n e d i t s o r i g i n a l r e d - v i o l e t c o l o u r u n t i l a i r was bubbled through i t f o r about 10 min, whereupon i t became green-brown. At the\ end o f t h i s time the f i n a l mixture was taken to dryness i n vacuo and the r e s i d u e was e x t r a c t e d w i t h dichloromethane (30 mL). The e x t r a c t was f i l t e r e d and an IR spectrum of the filtrate.'showed i t t o c o n t a i n CpCr (NO) 2 C 1 J 2 . The o r -gan o m e t a l l i c product (0.11 g, 52%) was o b t a i n e d by removing the s o l v e n t from the f i l t r a t e i n vacuo. Reaction of [ C p C r ( N O ) 2 ] 2 w i t h I,,. To a s t i r r e d d i c h l o r o m e t h -ane s o l u t i o n (40 mL) o f [ C p C r ( N 0 ) 2 ] 2 (0.35 g, 1.0 mmol) a t room temperature was added I 2 (0.28 g, 1.1 mmol). The r e a c t i o n mixture immediately changed c o l o u r from r e d - v i o l e t to yellow-brown. I t was s t i r r e d f o r 1 h, at which time, an IR spectrum r e v e a l e d CpCr(NO) 2 I 9 'to8 as the only organometal-l i c product. The product c o u l d be i s o l a t e d v i r t u a l l y q u a n t i t a t i v e l y by t a k i n g the f i n a l s o l u t i o n t o dryness i n vacuo. The r e a c t i o n s o f [ C p C r ( N O ) 2 ] 2 w i t h other i n o r g a n i c h a l o g e n - c o n t a i n i n g compounds were performed s i m i l a r l y , and they are summarized i n Table XXI. Table XXI. Reactions o f [ C p C r ( N O ) 2 ] 2 with some Halogen-Containing Compounds Reactant (mmol) Dimer (mmol) S o l v e n t (mL) Reaction C o n d i t i o n s Products ( y i e l d ) Method of I s o l a t i o n C1N0 0.23 CH 2C1 2 (35) Immediate at 25° CpCr(NO) 2C1 (>95%) Removal of s o l v e n t i n vacuo S n C l 4 (0.90) 1.5 t h f (50) Reflux 17 h CpCr(NO) 2C1 (69%) Chromatography on F l o r i s i l w i t h CH 2C1 2 as e l u a n t H g C l 2 (1.0) 1.0 t h f (60) Reflux 24 h CpCr(NO) 2Cl (>95%) Chromatography on F l o r i s i l S n C l 2 (1.0) 1.0 t h f (60) Reflux 24 h CpCr (NO) 2C1 (>95%) Chromatography on F l o r i s i l P b C l 2 (1.0) 1.0 t h f (60) Reflux 24 h CpCr(NO) 2C1 (>95%) Chromatography on F l o r i s i l p r epared as d e s c r i b e d i n Chapter I I - 102 -Reaction o f [CpCr(NO) 2 ] 2 w i t h C p F e ( C O ) 2 C l . A mixture o f [ C p C r ( N O ) 2 ] 2 (0.18 g, 0.50 mmol) and CpFe (CO) 2Clk 1 (0.21 g, 1.0 mmol) i n t h f (40 mL) was heated under r e f l u x f o r 4.5 h, dur i n g which time the r e a c t i o n mixture developed a y e l l o w i s h t i n g e to i t s v i o l e t c o l o u r a t i o n . An IR spectrum.of the f i n a l r e a c t i o n mixture at room t e m p e r a t u r e . i n d i c a t e d t h a t i t con-t a i n e d some o f the o r i g i n a l r e a c t a n t [ C p C r ( N O ) 2 ] 2 as w e l l as the products CpCr(NO) 2Cl and [ C p F e ( C O ) 2 ] 2 . In o r d e r to con-f i r m the presence o f t h i s l a t t e r p r oduct, the f i n a l r e a c t i o n mixture was chromatographed on.alumina w i t h dichloromethane as e l u a n t . The f i r s t r e d - v i o l e t band to separate was c o l l e c t e d and the s o l v e n t removed from the e l u a t e under reduced p r e s s u r e . The r e s i d u e was i d e n t i f i e d as [ C p F e ( C O ) 2 ] 2 by comparison o f i t s IR (CH 2C1 2) and NMR (C^Dg) s p e c t r a with s p e c t r a o f an a u t h e n t i c sample of the compound. Reaction o f [ C p C r ( N O ) 2 ] 2 w i t h Mn(CO) 5Cl. To a s o l u t i o n of [ C p C r ( N O ) 2 ] 2 (0.18 g, 0.50 mmol) i n t h f (40 mL) was added M n ( C O ) 5 C l 8 0 (0 . 23 g, 1.0 mmol). The r e s u l t i n g r e d - v i o l e t s o l u t i o n was s t i r r e d a t r e f l u x f o r 70 h whereupon i t became yellow-brown. The s o l u t i o n was allowed to c o o l to room temperature when an IR spectrum i n d i c a t e d the formation of M n 2 ( C O ) 1 0 as w e l l as the expected CpCr(NO) 2Cl. The products were i s o l a t e d i n the f o l l o w i n g manner. The t h f was removed i n vacuo and the r e s i d u e e x t r a c t e d w i t h 10 mL of d i c h l o r o -methane. The r e s u l t i n g s o l u t i o n was t r a n s f e r r e d to a 2 x 8 cm F l o r i s i l column and e l u t i o n of the column w i t h d i c h l o r o -- 103 -methane produced - two bands. The f i r s t band, y e l l o w i n c o l o u r , was c o l l e c t e d . a n d found to c o n t a i n Mn 2(CO)^Q. The second slow-moving band was golden-brown i n c o l o u r and the IR spectrum of the e l u t e d s o l u t i o n showed i t to c o n t a i n CpCr-(NO) 2C1. P y r o l y s i s o f [CpCr (NO) 2 ] 2» 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 o f [CpCr(NO) 2] 2.(0.75 g, 2.1 mmol) i n toluene (100 mL) was heated under g e n t l e r e f l u x f o r 24.h. During t h i s time the s o l u t i o n darkened and a b l a c k s o l i d p r e c i p i t a t e d . The s o l -vent was removed from the f i n a l c o o l e d r e a c t i o n mixture i n vacuo, and the r e s i d u e r e d i s s o l v e d i n .dichloromethane. The dichloromethane s o l u t i o n was then s y r i n g e d onto a 2 x 10 cm F l o r i s i l column and a green band was e l u t e d w i t h t h i s same s o l v e n t . The e l u a t e was taken to dryness i n vacuo and the res i d u e was r e c r y s t a l l i z e d from.CH 2Cl 2/hexanes t o o b t a i n dark green c r y s t a l s (0.11 g, 15%) o f C p 2 C r 2 ( N O ) 3 ( N H 2 ) . Anal, c a l c d f o r C 1 0 H 1 2 C r 2 N 4 O 3 : C, 35.30; H, 3.55; N, 16.50. Found: C, 3 4.70; H, 3.60; N, 16.20. An i n t e n s e brown band was next e l u t e d from the F l o r i s i l column w i t h t h f as s o l v e n t , and the e l u a t e was taken to dryness i n vacuo. The re s i d u e c r y s t a l l i z e d from CH 2C1 2/ hexanes as a red-brown m i c r o c r y s t a l l i n e s o l i d (0.30 g) (Found:.C, 45.20; H, 4.00; N, 10.80))which d i s p l a y e d a parent peak i n i t s mass spectrum at m/z 531.899. P y r o l y s i s o f [(MeCp)Mn(CO)(NO)] 0. A r e d - v i o l e t s o l u t i o n of - 104 -[ (MeCp) Mn(CO) (NO) ] 2 6 9 (0 .97 g, 2.5 mmol) i n t h f (50 mL) was heated.under r e f l u x w i t h s t i r r i n g f o r 20 h. At the end of t h i s time the r e a c t i o n mixture had, d e p o s i t e d some black-brown i n s o l u b l e m a t e r i a l and.the supernatant l i q u i d had a dark-green t i n g e . - An IR spectrum o f the supernatant a t room temperature d i d . not e x h i b i t the ..carbonyl and n i t r o s y l ab-s o r p t i o n s o f the s t a r t i n g compound. The f i n a l r e a c t i o n mix-ture was taken to dryness i n vacuo. Dichloromethane (15 mL) was added t o the r e s i d u e , and the mixture (a green-black s o l u t i o n and r u s t - c o l o u r e d s o l i d ) was t r a n s f e r r e d to the top of a 2 x 13 c m . F l o r i s i l column f o r subsequent chromatography. E l u t i o n o f the column w i t h C H 2 C l 2 r e s u l t e d . i n the development of.two d i s t i n c t bands. The f i r s t p a l e orange band, which c a r r i e d q u i c k l y down the column, was c o l l e c t e d and compara-t i v e IR spectroscopy of t h i s f r a c t i o n i n d i c a t e d t h a t i t cont a i n e d a very s m a l l amount of (MeCp)Mn(CO) 3. The second f r a c t i o n t o be e l u t e d from the column was a very broad green-b l a c k band which r e q u i r e d ^300 mL of s o l v e n t f o r complete e l u t i o n . . T h i s e l u a t e was co n c e n t r a t e d i n vacuo to a volume of 25 mL, and s u f f i c i e n t hexane was then added t o induce the c r y s t a l l i z a t i o n of (MeCp) 3Mn 3(NO) 4 (0.09 g, 10%). Ana l , c a l c d f o r c 1 8 H 2 i M n 3 N 4 ° 4 : c ' 415.4 0 ; H, 4.05; N, 10.70. Found: C, 41.40; H, 4.00; N, 10.90. Reaction o f [ C p C r ( N O ) 2 ] 2 w i t h 5,6-dibromocholestery1 bromide. A t h f s o l u t i o n (40 mL) c o n t a i n i n g [GpCr(NO) 2] 2 (0.35 g, 1.0 mmol) and 5,6-d i b r o m o c h o l e s t e r y l bromide (0.61 g, 1.0 - 105 -mmol) was s t i r r e d at r e f l u x f o r 6 h. At the end of t h i s time, an i n f r a r e d spectrum of the r e a c t i o n s o l u t i o n i n d i c a t e d complete c o n v e r s i o n o f the s t a r t i n g n i t r o s y l dimer t o CpCr-(NO) 2 B r * T n e s o l v e n t was removed under reduced p r e s s u r e and the remaining green-brown r e s i d u e was d i s s o l v e d i n benzene. F i l t r a t i o n of t h i s s o l u t i o n through a 2 x 5 cm column of alum-i n a removed the o r g a n o m e t a l l i c product and the f i l t r a t e was taken to dryness under reduced p r e s s u r e to i s o l a t e pure c h o l e s t e r y l bromide i n 89% y i e l d . A l l halogen a b s t r a c t i o n r e a c t i o n s were performed s i m i l a r l y u s i n g a v a r i e t y o f v i c - d i h a l o a l k a n e s ( i n c l u d i n g 1,2-dibromocyclohexane, 1,2,5,6-tetrabromocyclooctane, 1,2-dipheny1-1,2-dibromoethane, and 5,6-dibromocholesterol) and the o r g a n i c products were i s o l a t e d i n an i d e n t i c a l man-ner. Results.and D i s c u s s i o n The compound [ C p C r ( N O ) 2 ] 2 bears a remarkable resem-blance t o i t s i s o e l e c t r o n i c c a r b o n y l analogue [ C p F e ( C O ) 2 ] 2 • Both compounds are red-purple s o l i d s which are i n s o l u b l e i n water, s p a r i n g l y s o l u b l e i n non-polar o r g a n i c s o l v e n t s , and s o l u b l e i n p o l a r o r g a n i c s o l v e n t s to g i v e s o l u t i o n s which o x i d i z e g r a d u a l l y i n a i r . In the s o l i d s t a t e both dimers e x h i b i t t r a n s l i g a n d - b r i d g e d s t r u c t u r e s 8 1 , but the i r o n com-pound can a l s o be i s o l a t e d i n a c i s b r i d g e d form under c e r -t a i n c o n d i t i o n s ? 2 . Both molecules a l s o undergo r a p i d i n t r a -m o l e c u l a r rearrangement at room t e m p e r a t u r e 8 3 , e x i s t i n g i n - 106 -solution as an e q u i l i b r a t i n g mixture of a l l possible isomeric structures. some of t h e i r physical properties. The 70 eV mass spectral data of both dimers are shown i n Table XXII. In contrast to the reported spectrum of [CpFe(CO) 2] 2 8 1*, t n e high-resolution mass spectrum of the chromium dimer reveals sequential loss of n i t r o s y l groups, but the most abundant species present i s the b i m e t a l l i c Cp 2Cr 2(NO) + ion. Indeed, ions containing two metal atoms are generally much more abundant for the chromium compound. Migration of the cyclopentadienyl group between metal atoms occurs much less readily than for the iron com-pound as evidenced by the markedly less abundant chromocinium ion. F i s s i o n of the chromium dimer also occurs i n a sym-metrical manner ( i . e . no ions of the type CpCr(NO) 3 + are detectable) , but various ions (such as the r e l a t i v e l y abun-dant CpCr 20 +and Cr 20 +) i n the mass spectrum of the chromium compound have no counterparts in the fragmentation pattern of the i r o n compound. L - C O , N O The two compounds e x h i b i t s t r i k i n g s i m i l a r i t i e s i n - 107 -Table XXII. H i g h - R e s o l u t i o n Mass S p e c t r a l Data f o r t(C 5H 5)Cr(NO) 2 ] 2 m/z Me asd m/z C a l c d Rel abund Assignment' R e l abund (Fe) b 35 3 .952 353 .951 45 ( C 5 H 5 ) 2 C r 2 ( N O ) 4 + 9 323 .953 323 .953 34 ( C 5 H 5 ) 2 C r 2 ( N O ) 3 + 6 293 .955 293 .955 10 ( C 5 H 5 ) 2 C r 2 ( N O ) 2 + 10 263 .957 263 .957 100 ( C 5 H 5 ) 2 C r 2 ( N O ) + 4 198 .919 198 .918 13 ( C 5 H 5 ) C r 2 ( N O ) + 0 184 .915 184 . 915 74 ( C 5 H 5 ) C r 2 0 + /0 182 .018 182 .019 10 ( C 5 H 5 ) 2 C r 70 176 .976 176 .976 14 ( C 5 H 5 ) C r ( N O ) 2 + 19 146 .978 146 .978 12 ( C 5 H 5 ) C r ( N O ) + 19 133 .879 133 .879 15 C r 2 ( N O ) + 0 119 .876 119 . 876 44 C r 2 0 + 0 116 .980 116 .980 24 ( C 5 H 5 ) C r + 100 103 .881 103 .881 2 C r 2 + 2 66 .048 66 .047 5 C 5 H 6 + 6 65 .040 65 .039 5 C 5 H 5 + 6 51 .942 51 .941 48 C r + 41 Assignments are based on the 5 2 C r isotope. ^Data from reference 84, assignments are for the analogous fragments of [ (C^H,-) Fe (CO) 2 ] 2 • - 108 -The two compounds e x h i b i t some chemical s i m i l -a r i t i e s , and these are summarized i n equations (46) - (48) CH C l 9 [CpM(L0)p] o + I 9 2CpM(LO) I (46) o r CHC1 3 ^ EtOH [CpM(LO) 2J 2 + 2HC1 * 2CpM(LO) 2C1 (47) °2 CH 9 C l 9 [CpM(LO) 2] 2 + 2C1NO - 2CpM(LO) 2Cl (48) (M = Fe o r Cr, L = C o r N, r e s p e c t i v e l y ) . Thus, [ C p C r ( N O ) 2 ] 2 i s c l eaved by i o d i n e , h y d r o c h l o r i c a c i d , o r n i t r o s y l c h l o r i d e a t ambient temperature with - concurrent c o n v e r s i o n of the b r i d g i n g n i t r o s y l l i g a n d s i n t o 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 a manner i d e n t i c a l t o t h a t r e p o r t e d 1 l&l 6 ' 4 1 f o r [CpFe (CO) 2] 2 , the compounds CpCr(NO) 2X (X = C l or I) being the f i n a l p r o d u c t s . However, i n other aspects of t h e i r chemistry, the two dimers are s i g n i f i c a n t l y d i f f e r e n t . Reduction o f [ C p F e ( C O ) 2 ] 2 by sodium amalgam i n t h f proceeds r e a d i l y at room temperature, and 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 of the [CpFe(CO) 2] anion can be ob-t a i n e d . In c o n t r a s t , the r e d u c t i o n of [ C p C r ( N O ) 2 ] 2 under i d e n t i c a l c o n d i t i o n s leads r a p i d l y to complete decomposition of the compound. The n i t r o s y l dimer i s found t o be s t a b l e under l e s s v igorous c o n d i t i o n s and i s u n a f f e c t e d by z i n c amalgam i n t h f or benzene. The f a i l u r e of a l a r g e number o f r e d u c i n g agents to produce the anion [CpCr(NO) 2] 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 such an anion should be s t a b i l i z e d by the presence of s t r o n g TT-acid l i g a n d s . - 109 -However, i t i s i n t h e i r r e a c t i o n s w i t h halogen-c o n t a i n i n g s p e c i e s t h a t the two dimers most c l e a r l y show t h e i r chemical d i f f e r e n c e s . For example, the chromium dimer a b s t r a c t s a l l the c h l o r i n e l i g a n d s from t i n t e t r a c h l o r i d e under the c o n d i t i o n s i n d i c a t e d i n e q u a t i o n (4'9) whereas the i r o n dimer r e a c t s w i t h SnCl^ i n i n e r t s o l v e n t s to form a compound c o n t a i n i n g a h e t e r o n u c l e a r metal-metal bond and the compound CpFe(CO) 2Cl (equation 5 0 ) 8 5 . The progress of t h f 2 [CpCr (NO) 2 ] 2 + S n C l 4 • 4CpCr(NO) 2Cl + Sn (49) r e f l u x JCA:'<: [CpFeCCO) 2 ] 2 + S n C l 4 »> CpFe (CO) 2 S n C l 3 + C p F e ( C O ) 2 C l r e f l u x (50) r e a c t i o n s such as (4 9) can be monitored very c o n v e n i e n t l y by i n f r a r e d spectroscopy s i n c e 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 due to n i t r o s y l groups of the r e a c t a n t [ C p C r ( N O ) 2 ] 2 occur at 1667 (terminal) and 1512 cm 1 (bridging) whereas those due to the two t e r m i n a l n i t r o s y l groups of the product CpCr-(NO) 2C1 occur at 1815 and 1710 cm"1 (Figure 6). The p r o p e n s i t y of the n i t r o s y l dimer to a b s t r a c t halogen atoms dominates i t s r e a c t i o n s w i t h i n o r g a n i c and o r g a n o m e t a l l i c halides.. Hence, treatment o f [ C p C r ( N O ) 2 ] 2 with the c h l o r i d e s o f . b i v a l e n t mercury, t i n , or l e a d r e s u l t s i n the formation of the elemental metals and the customary CpC r ( N O ) 2 C l , i . e . as i n e q u a t i o n (51) (M = Hg, Sn, o r Pb) . [ C p C r ( N O ) 2 ] 2 + MC1 2 • 2CpCr(NO) 2Cl + M (51) r e f l u x - 110 -I n f r a r e d s p e c t r a l c h a n g e s a c c o m p a n y i n g t h e r e a c t i o n s [ C p C r ( N O ) 2 ] 2 + R X J f e * Frequency (cm - 1) 2000 1800 1600 1400 I I I I I I I Initial Final Figure 6 - I l l -The i r o n c a r b o n y l dimer, on the other hand, undergoes an o x i d a t i v e - a d d i t i o n r e a c t i o n w i t h S n C l 2 under, comparable ex-p e r i m e n t a l c o n d i t i o n s (equation 52) to y i e l d a p r o d u c t which n-BuOH [CpFe(CO) 2 ] 2 + S n C l 2 • [CpFe (CO) ] 2 S n C 1 2 ( 5 2 ) r e f l u x c o n t a i n s c o v a l e n t i r o n - t i n b o n d s 8 5 , and i t a p p a r e n t l y does not r e a c t w i t h P b C l 2 8 2 . Furthermore, [ C p C r ( N O ) 2 ] 2 f u n c t i o n s as a Wurtz c o u p l i n g reagent when t r e a t e d w i t h a p p r o p r i a t e o r g a n o m e t a l l i c h a l i d e s , as i l l u s t r a t e d i n equations (5 3) t h f [ C p C r ( N O ) 2 l 2 + 2CpFe(CO) 2Cl • 2CpCr(NO) 2Cl + r e f l u x [ C p F e ( C O ) 2 ] 2 (53) and (54). Both conversions proceed smoothly i n r e f l u x i n g t h f [ C p C r ( N O ) 2 ] 2 + 2Mn(CO) 5Cl * 2CpCr(N0) 2C1 + r e f l u x M n 2 ( C O ) 1 Q (54) t e t r a h y d r o f u r a n , but r e a c t i o n (5 3) i s hampered by the f a c t t h a t CpFe(CO) 2Cl i s not p a r t i c u l a r l y s t a b l e under the exper-im e n t a l c o n d i t i o n s employed. I n t e r e s t i n g l y , i f CpFe(CO) 2I i s used i n p l a c e o f i t s chloro-analogue i n r e a c t i o n (53), o r i f r e a c t i o n (5 3) i s allowed to proceed a t room temper-ature f o r 8 d, d e t e c t a b l e amounts of [ C p F e ( C O ) 2 ] 2 are not formed d e s p i t e the f a c t t h a t halogen a b s t r a c t i o n by the chromium n i t r o s y l dimer s t i l l o c c u r s . Attempts to extend t h i s r e a c t i o n to the p r e p a r a t i o n of the unknown dimers [CpM(NO) 2] 2 (M = Mo or W) met w i t h l i t t l e s u c c e s s . Hence, - 112 -when CpW(NO) 2Cl i s t r e a t e d w i t h [ C p C r ( N O ) 2 ] 2 i n t h f at r e f l u x i n the u s u a l 2:1 s t o i c h i o m e t r y the expected CpCr(NO) 2Cl i s formed i n good y i e l d s , but no n i t r o s y 1 - c o n t a i n i n g complexes of tungsten can be d e t e c t e d i n the f i n a l r e a c t i o n mixture. S i m i l a r r e a c t i o n s c a r r i e d out i n benzene at r e f l u x or i n t h f or benzene at. ambient temperature^.also l e a d to the formation o f CpCr(NO) 2C1 as the o n l y n i t r o s y 1 - c o n t a i n i n g p r o d u c t and no new o r g a n o m e t a l l i c products c o n t a i n i n g molybdenum or tungsten are i s o l a t e d . The r e a c t i o n between the chromium dimer and Ph^SnCl i n r e f l u x i n g t h f (equation 55) has been r e c e n t l y r e p o r t e d 8 7 . [CpCr(N0) 9] + Ph^SnCl "CpCr(NO) „C1 + z 1 J r e f l u x 8 d ^ C p 2 C r 2 ( N O ) 3 ( N H 2 ) (55) The two chromium-containing products are formed i n approx-imately equal amounts, a n d . i t i s c l e a r . t h a t halogen a b s t r a c -t i o n by the n i t r o s y l reagent has again o c c u r r e d . (The e x a c t nature o f the t i n product was not a s c e r t a i n e d , but i t was not hexaphenyldistannane). The o r i g i n of the b i m e t a l l i c amido compound i n r e a c t i o n (55) remains u n c e r t a i n at the p r e s e n t time, but i t i s of i n t e r e s t t o note t h a t the same compound can be obtained i n 15% y i e l d by h e a t i n g a toluene s o l u t i o n of [ C p C r ( N O ) 2 l 2 under g e n t l e r e f l u x f o r 24 h. T h i s amido . complex was f i r s t i s o l a t e d as a b y - p r o d u c t 9 2 , d u r i n g the p r e p a r a t i o n of [ C p C r ( N O ) 2 ] 2 , and i t was presumed to be formed by the unusual r e d u c t i o n of a Cr-NO l i n k a g e i n the - 113 -l a t t e r compound to a Cr-NH 2 group by the reducing agent employed. Consequently, even though [ C p C r ( N O ) 2 ] 2 i - s n o t d e t e c t a b l y changed by r e f l u x i n g i n t h f f o r 24 h, i t i s p o s s i b l e t h a t d u r i n g the prolonged time (8 d) r e q u i r e d to e f f e c t completion of r e a c t i o n (55) some thermal c o n v e r s i o n ( i n v o l v i n g the r e d u c t i o n of a Cr-NO group by e i t h e r t h f o r Ph^SnCl) i n t o C p 2 C r 2 ( N O ) 3 ( N H 2 ) may have occu r r e d . The p r i n c i p a l p r o d u c t from the p y r o l y s i s o f [CpCr-( N O ) 2 ] 2 i s a red-brown c l u s t e r compound whose ex a c t formula-t i o n has y e t to be determined. I t i s s o l u b l e i n p o l a r o r g a n i c s o l v e n t s and s l i g h t l y s o l u b l e i n toluene. I t s s o l u -t i o n s e x h i b i t one t e r m i n a l n i t r o s y l a b s o r p t i o n (at 1670 cm 1) i n t h e i r i n f r a r e d s p e c t r a and there are no a b s o r p t i o n s observed due to b r i d g i n g n i t r o s y l l i g a n d s e i t h e r i n s o l u t i o n , m u l l , or KBr d i s c s p e c t r a . The mass s p e c t r a l data c o l l e c t e d a t 270° C e x h i b i t fragments o f the type ( C 5 H 5 ) 3 C r 2 ( N O ) 3 + , ( C 5 H 5 ) 2 C r 2 0 + , and ( C 5 H 5 ) 2 C r + . The XH NMR spectrum of the compound i n CDC1 3 c o n s i s t s o f a broad complex peak i n the r e g i o n normally a s s o c i a t e d w i t h T r-cyclopentadieny 1 p r o t o n s . A l l o f t h i s evidence p o i n t s to a c l u s t e r c o n t a i n i n g three o r f o u r chromium centres surrounded by c y c l o p e n t a d i e n y l and t e r m i n a l n i t r o s y l l i g a n d s . With the o b s e r v a t i o n of the f o r -mation of the b r i d g i n g amido-complex i n the same r e a c t i o n which produces t h i s p o l y m e t a l l i c compound, i t i s not u n l i k e l y t h a t amido b r i d g e s may a l s o be p r e s e n t and necessary f o r the s t a b i l i t y o f the c l u s t e r complex. I t i s , however, q u i t e apparent t h a t t h i s product i s not a simple oligomer of - 114 -[CpCr(NO)]. ( P y r o l y s i s of [ C p F e ( C O ) 2 ] 2 leads to the form-a t i o n o f [CpFe(CO)] i n low y i e l d s 8 8 ) . In view o f the r e a c t i o n s of [ C p C r ( N O ) 2 J 2 and [ C p F e ( C O ) 2 ] 2 c o n s i d e r e d p r e v i o u s l y i n t h i s chapter, i t was of i n t e r e s t to determine how the related.manganese dimer, [(MeCp)Mn(CO)(NO)3 2, r e a c t s w i t h h a l o g e n - c o n t a i n i n g r e a c t a n t s under comparable experimental c o n d i t i o n s . U n f o r t u n a t e l y , the manganese compound i s q u i t e t h e r m a l l y l a b i l e and r e a c t s with S n C l 2 i n r e f l u x i n g t h f to produce on l y i n t r a c t a b l e decomposition products which do not c o n t a i n c a r b o n y l o r n i t r o s y l l i g a n d s . In f a c t , the dimer i t s e l f r e a d i l y decom-poses i n r e f l u x i n g t h f and i s converted i n low y i e l d s i n t o (MeCp)Mn(CO) 3 and (MeCp) 3Mn 3(NO) 4 as the onl y d e t e c t a b l e o r g a n o m e t a l l i c c a r b o n y l and n i t r o s y l p r o d u c t s . The new t r i m e t a l l i c compound forms b l a c k c r y s t a l s which are f r e e l y s o l u b l e i n common o r g a n i c s o l v e n t s (except p a r a f f i n hydrocarbons) to give a i r - s t a b l e green-black s o l u t i o n s . When heated i n an open c a p i l l a r y the c r y s t a l s decompose at 15 7° C. The 1H NMR spectrum of the compound c o n s i s t s o f two sharp resonances at 6 4.78 and 1.83 of r e l -a t i v e i n t e n s i t y 4:3, thereby i n d i c a t i n g the eq u i v a l e n c e of the three m e t h y l c y c l o p e n t a d i e n y l r i n g s and the diamagnetism of the.compound. The IR spectrum i n dichloromethane e x h i b i t s three s t r o n g bands a t 15 38, 1483, and 1333 cm 1 a t t r i b u -t a b l e to b r i d g i n g n i t r o s y l groups. The major peaks i n the mass spectrum of the compound are due to the ions (C^H^) 3 ~ M n 3 ( N O ) x + (x •= 4, 2, o r 1) and ( C 6 H y ) 2 M n 2 ( N O ) y + (y = 2 or 1) , - 115 -the (CgH 7) 3Mn 3(NO) i o n being the most abundant. The com-pound i s thus apparently i s o s t r u c t u r a l w i t h i t s c y c l o p e n t a -d i e n y l analogue, Cp 3Mn 3(NO) 4, which possesses three doubly b r i d g i n g n i t r o s y l groups and one t r i p l y b r i d g i n g n i t r o s y l group 8 9 . S e l e c t i v e Removal of Halogen from Organic H a l i d e s . An e x t e n s i o n of the study o f the chemical r e a c t i v i t y of [CpCr(NO)2^2' P a r t i c u l a r l y i t s halogen a b s t r a c t i o n a b i l i t y , i s an examination o f the e f f e c t i v e n e s s o f the dimer as a reagent f o r the dehalogenation o f o r g a n i c s u b s t r a t e s . The s t u d i e s can be d i v i d e d i n t o two p a r t s : (1) the r e a c t i o n o f [ C p C r ( N O ) 2 ] 2 w i t h b e n z y l i c , a l l y l i e , and a l k y l h a l i d e s , and (2) the r e a c t i o n of [ C p C r ( N O ) 2 ] 2 w i t h v i c - d i h a l o -alkanes. There are many reagents which e f f e c t i v e l y couple b e n z y l i c and a l l y l i e h a l i d e s 9 0 . S i m i l a r l y , the r e a c t i o n of the n i t r o s y l dimer w i t h d i a r y l h a l o a l k a n e s r e s u l t s i n the - 116 -formation o f the corresponding s u b s t i t u t e d ethanes (equation 56). However, u n l i k e other c o u p l i n g reagents, the n i t r o s y l R' R1 R* 1 1 1 (56) 2 R 2 C - X - R 2 C - C R 2 ( b b ) R = oryl i R'= aryl or H complex does n o t couple a l l y l or m e t h a l l y l h a l i d e s . In f a c t , [ C p C r ( N O ) 2 ] 2 does not even r e a c t w i t h a l l y l h a l i d e s or most simple a l k y l or a r y l h a l i d e s , and the o r g a n i c compounds may be recovered u n a l t e r e d . For i n s t a n c e , no halogen a b s t r a c -t i o n occurs from 3-chloropropene, 1-chloropqntane, 2-chloro-2-methylpropane, 1-bromo-2-phenylethane, 1-bromo-2-phenylethene, or iodobenzene. However, i n c o n t r a s t to t h i s , [ C p C r ( N O ) 2 ] 2 does r e a c t w i t h v i c - d i h a l o a l k a n e s i n a 1:1 r a t i o t o produce the corresponding alkenes. Some t y p i c a l t r a n s f o r m a t i o n s are shown below. T o t a l dehalpgenation occurs i n a l l r e a c t i o n s (trans) - 117 -trans-dibromide of cholesterol producing the expected CpCr(NO) 2Br and, more i m p o r t a n t l y , the o l e f i n s are i s o l a b l e i n >75% y i e l d s . Since i t was observed t h a t no r e a c t i o n occurred be-tween [CpCr(NO) 2] 2 a n d n o n - v i c i n a l non-benzylic haloalkanes, an attempt was made to perform s e l e c t i v e v i c i n a l halogen a b s t r a c t i o n from v i c - d i h a l o a l k y l h a l i d e s w i t h the hope of l e a v i n g the t h i r d halogen unperturbed. Two such r e a c t i o n s have been s t u d i e d to date and have r e s u l t e d i n the i s o l a t i o n of the d e s i r e d haloalkene products i n good y i e l d s (equations 5 7 and 5 8) . C 6 H g CHBrCHBr 2 • (^HgCH = CHBr 7 3 % <57> - 118 -(58) trans- dibromide of cholesteryl bromide Consequently, as long as the remaining h a l i d e i s n o n - b e n z y l i c , the n i t r o s y l dimer can a p p a r e n t l y be used to e f f e c t such t r a n s f o r m a t i o n s g e n e r a l l y . S i m i l a r r e a c t i v i t y i s shown only by the NaCH 2S(0)CH 3 r e a g e n t 9 1 but i t i s not widely a p p l i c -able s i n c e i t may a l s o e f f e c t dehydrohalogenation. On the o t h e r hand, [ C p C r ( N O ) 2 ] 2 i s s p e c i f i c to halogen only, can be used s t o i c h i o m e t r i c a l l y , and i s e f f e c t i v e i n very s h o r t p e r -i o d s o f time (4 - 12 h) under very m i l d c o n d i t i o n s . F i n a l l y i t should be noted t h a t the n i t r o s y l com-pl e x appears to show no p r e f e r e n c e f o r c y c l i c or e x o c y c l i c halogens. Furthermore, although o n l y t r a n s - s t i l b e n e was i s o l a t e d as a p r o d u c t from the dehalogenation o f 1,2-dibromo-1,2-diphenylethane, the s t e r e o c h e m i s t r y of these t r a n s f o r m a t i o n s has not y e t been completely s t u d i e d . - 119 -REFERENCES 1. Pino, P.; Wender, I. "Organic S y n t h e s i s v i a Metal Carbonyls", V o l I; Wiley: New York, 196 8; V o l I I ; Wiley: New York, 19 77. 2. P i e r p o n t , C.G.; Van Derveer, D.G.; Durland, W.; E i s e n -berg, R. J . Am. Chem. Soc. 1970, 9_2, 4760. G r i f f i t h s , W.P. Adv. Organomet. Chem. 19.68,,]_, 211. 3. C a n d l i n , J.P.; Janes, W.H. J . Chem. Soc. (C) 1968, 1856, 4. B a l l i v e t - T k a c h e n k o , D.; R i v e c c i e , M.; E l Murr, N. Inorg, Chim. A c t a 1978, 30, L289. 5. Mond, R.L.; W a l l i s , A.F. J . Chem. Soc. 1922, 32. 6. Fisteher ,E.O. ; P l e s s k e , K. Chem. Ber. 1961, 9_4, 93. 7. T r e i c h e l , P.M.; P i t c h e r , E.; K i n g , R.B.; Stone, F.G.A. J . Am. Chem. Soc. 1961, 83, 2593. 8. Green, M.L.H.; Sander, T.R.; Whiteley, R.N. Z. N a t u r f o r s c h . 1968, 2 3b, 106. 9. M a l i t o , J.T. Ph.D. T h e s i s , U n i v e r s i t y o f B r i t i s h C o l -umbia, 19 76. 10. Herberhold, M.; K l e i n , R.; A l t , H.G. J . I s r . Chem. 1977, 15, 206. 11. Hames, B.W.; Legzdins, P.; M a r t i n , D.T. Inorg. Chem. 1978, r 7 , 3644. 12. Legzdins, P.; M a l i t o , J.T. I b i d . 1975, 14, 1875. 13. P e r r i n , D.D.; Armego, W.L.F.; P e r r i n , D.R. " P u r i f i c a -t i o n of Laboratory Chemicals"; Pergamon P r e s s : Oxford, 19 66. 14. S h r i v e r , D.F. "The M a n i p u l a t i o n o f A i r - S e n s i t i v e Com-pounds"; McGraw-Hill: New York, 19 69. 15. Stone, F.G.A.; King, R.B. Inorg. Synth. 1963, 7, 104. 16. Hoyano, J.K.; Le g z d i n s , P.; M a l i t o , J.T. I b i d . 1978, 1£, 126. 17. Kolthammer, B.W.S.; Leg z d i n s , P.; M a l i t o , J.T. Inorg. Chem. 1977, 16^ , 3173. - 120 -18. King, R.B.; B i s n e t t e , M.B. I b i d . 1964, 6_, 791. 19. N i c h o l l s , B.; Whiting, M.C. J . Chem. Soc. 1959, 551. 20. Cotton, F.A.; Johnson, B.F.G. Inorg. Chem. 1964, 3_, 1609. 21. King, R.B.; F r o n z a g l i a , A. I b i d . 1966, 5, 1837. 22. Murdoch, H.D. Z. N a t u r f o r s c h . 19 65, 20b, 179. 23. King, R.B. "Organometallic Syntheses"; Academic P r e s s : New York, 1965; p 161-168. 24. F i s c h e r , E.O.; P l e s s k e , K. Chem. Ber. 1961, 9_4, 93. 25. F i s c h e r , E.O.; Ulm, K.; K u z e l , P. Z. Anorg. Chem. 1963, 319, 253. 26. P i p e r , T.S.; W i l k i n s o n , G. J . Inorg. N u c l . Chem. 1956, 2 , 3 8 . 27. Sneeden, R.P.A. "Organochromium Compounds"; Academic P r e s s : New York, 19 75 . 28. P i p e r , T.S.; W i l k i n s o n , G. J . Inorg. Nucl..Chem. 1956, 3, 104. 29. Rausch, M.D.; Gismondi, T.E.; A l t , H.G.; Schwarzle, J.A. Z. N a t u r f o r s c h . 19 77, 32b, 998. 30. McCleverty, J.A. ; Seddon, D. J . Chem. S o c , Da l t o n Trans., 1972, 2526. 31. Z i n g a l e s , F.; T r o v i a t i , A.; C a r i a t i , F.; U g u a g l i a t i , P. Inorg. Chem. 1971, 10, 507. 32. Ahmad, H.; Bruce, R.; Knox, G. Z. N a t u r f o r s c h . 1966, 21b, 289. 33. P r e s t o n , F.; Reed, R.L. J . Chem. S o c , Chem. Commun. 1966, 51. 34. F i s c h e r , E.O.; Strametz, H. J . Organomet. Chem. 1967, 10, 323. 35. Calderon, J.L.; C o t t o n , F.A.; DeBoer, B.G.; Mar t i n e z , N. J . Chem. S o c , Chem. Commun. 1971, 1476. 36. Calderon, J.L.; Fontana, S.; Fra u e n d o r f e r , E.; Day, V.W. ; S t u l t s , B.R. Inorg. Chim. Ac t a 1976, 17, L31. 37. Connelly, N.G. Inorg. Chim. A c t a Rev. 19 72, 6_, 47. - 121 -38. Herberhold, M.; Bernhagen, W. Angew. Chem., I n t . Ed. E n g l . 1976, 15, 617. 39. L e g z d i n s , P.; M a r t i n , D.T., p e r s o n a l communication, 1978. 40. D a v i s , R.; Johnson, B.F.G.; A l - O b a i d i , K.H. J . Chem. S o c , Dalton Trans. 1972, 508. 41. P i p e r , T.S.; Cotton, F.A.; W i l k i n s o n , G. J . Inorg. Nucl. Chem. 1955, 1, 165, 42. C o n n e l l y , N.G. Inorg. Synth. 1976, 15_, 91. 43. Crooks, G.R.; Johnson, B.F.G. J . Chem. Soc. A 1968, 1238. 44. Wawersik, H. ; Basolo, F. Inorg. Chem. 1967, 6_, 1066. 45. Brunner, H. J . Organomet. Chem. 1968, 1_4, 173. 46. Chatt, J . ; D i l w o r t h , J.R. J . Chem. S o c , Chem. Commun. 1974, 508. Bishop, M.W.; Chatt, J . ; D i l w o r t h , J.R. I b i d . 1975, 780. 47. J o l l y , W.L.; Maguire, K.D. Inorg. Synth. 1967, 9_, 102. 48. Hackett, P.; O ' N e i l l , P.S.; Manning, A.R. J . Chem. S o c , Dalton Trans. 1974, 1625. 49. B u t l e r , I.S. Acc. Chem. Res. 1977, 10_, 359. 50. B o t t o , R.E.; Kolthammer, B.W.S.; Leg z d i n s , P.; Roberts, J.D. Inorg. Chem., i n p r e s s . 51. Berndt, A.F.; Marsh, R.E. A c t a C r y s t . 1963, 16_, 118. 52. Atwood, J.L.; S h a k i r , R.; M a l i t o , J.T.; Herberhold, M.; Kremnitz, W.; Bernhagen, W.; A l t , H.G. J . Organomet. Chem. 1979, 165, 65. 53. Dyke, J.M.; M o r r i s , A.; T r i c k l e , I.R. J . Chem. S o c , Faraday II 1977, 73_, 147. 54. Brunner, H. J . Organomet. Chem. 1969 , 16^ , 119. 55. Stewart, R.P.; Moore, G.T. Inorg. Chem. 1975, 1_4, 2699. 56. F i s c h e r , E.O.; Strametz, H. Z. N a t u r f o r s c h . 1968, 23b, 278. 57. B a i l e y , W.I.; Chisholm, M.H.; Cotton, F.A.; Rankel, R.A. J. Am. Chem. Soc. 1978, 100, 5764. - 122 -58. Baker, E.N.; Reay, B.R. J . Chem. S o c , Dalton Trans. 1973, 2205. 59. R i c h t e r , F.; Vahrenkamp, H. /Angew. Chem., I n t . Ed. E n g l . 1978, 17, 444. 60. M e a l l i , C ; M i d o l l i n i , S.; S a c c o n i , L. Inorg. Chem. 1978, 17 r 632. 61. G i n l e y , D.S.; Bock, C.R.; Wrighton, M.S. Inorg. Chim. A c t a 1977, 23, 85. 62. P a t t o n , R.L.; J o l l y , W.L. Inorg. Chem. 1970, 9_, 1079 . 63. Hydes, P.; McCleverty, J.A.; Orchard, D.G. J . Chem. S o c A 1971, 3360 . 64. McCleverty, J.A.;.James, T.A.; Wharton, E . J . Inorg. Chem. 1969, 8, 1340. 65. King, R.B.; B i s n e t t e , M.B.; F r o n z a g l i a , A. J . Organomet. Chem. 1966, 5, 341. 66. B u s e t t o , L.; P a l a z z i , A.; P i e t r o p a o l o , D.; D o l c e t t i , G. J . Organomet. Chem. 19 74, 66_, 45 3. 67. Brunner, H.; Langer, M., J . Organomet. Chem. 1973, 54_, 221. 68. E f r a t y , A.; A r n i e r e , R.; Ruda, W.A. Inorg. Chem. 1977, 16, 3124. 69. James, T.A.; McCleverty, J.A. J . Chem. Soc. A 19 70, 850. 70. Stewart, R.P.; Okamoto, N.; Graham, W.A.G. J . Organomet. Chem. 1972 , 42_, C32. 71. Kochhar, R.K.; P e t i t , R. J . Organomet. Chem. 1966, 6, 272. 72. Hoyano, J.K.; Legzdins, P.; M a l i t o , J.T. J . Chem. S o c , Dalton Trans. 19 75, 102 2. 73. Legzdins, P.; M a r t i n , D.T. Inorg. Chem., i n p r e s s . 74. C o l t o n , R.; Commons, C.J. Aust. J . Chem. 1973, 1487. 75. Tolman, C A . J . Am. Chem. S o c 19 70 , 9_2, 2953. 76. S c h l o g l , K.; Gowal, H. Monatsh. Chem. 1968, 99_, 578. 77. Mann, B.E. Adv. Organomet. Chem. 1974, 12_, 1. - 123 -78. Brunner, H. TAngew. Chem., Int. Ed. Engl. 1969, 8_, 38 2. 79. Muller, J.; Schmidt, S. Z. Anorg. Allgem. Chem. 1976, 426, 77. 80. Abel, E.W.; Wilkinson, B. J. Chem. Soc. 1959, 1501. 81. Calderon, J.L.; Fontana, S.; Frauendorfer, E.; Day, V.W. J. Organomet. Chem. 19 74, 6_4, CIO. Bryan, R.F.; Greene, P.T. J. Chem. Soc. A 1970, 3064. 82. Bryan, R.F. ; Greene, P.T.; Newlands, M.J.; F i e l d , D.S. J. Chem. Soc. A 1970, 3068. 83. Kirchner, R.M.; Marks, T.J.; K r i s t o f f , J.S.; Ibers, J.A. J. Am. Chem. Soc. 1973, 95_, 6602. 84. Lewis, J.; Manning, A.R.; M i l l e r , J.R.; Wilson, J.M. J. Chem. Soc. A 1966, 1663. 85. Edmondson, R.G.; Newlands,.M.J.; Eisner, E.; Thompson, L.K. J. Organomet. Chem. 1972, 35, 119. 86. Bonati, F.; Wilkinson, G. J. Chem. Soc. 1964, 179. 87. Kolthammer, B.W.S.; Legzdins, P. J. Chem. S o c , Dalton Trans. 19 78, 31. 88. King, R.B. Inorg. Chem. 1966, 5, 2227. 89. Elder, R.C.; Cotton, F.A.; Schunn, R.P. J . Am. Chem. Soc. 1967, 89, 3645. 90. Olah, F.A.; Prakash, G.K.S. Synthesis 1976, 607. 91. Cardenas, C.G.; Khafaji, A.N.; Osborn, C.L.; Gardner, P.D. Chem. Ind. 1965, 345. 92. F l i t c r o f t , N. J. Organomet. Chem. 1968, 15, 254. PUBLICATIONS R.E. B o t t o , B.W.S. Kolthammer, P. Legzdins and J.D. Roberts. Carbon-13 and Nitrogen-15 NMR Spectroscopy o f Some ( n 5 -C y c l o p e n t a d i e n y l ) n i t r o s y l Complexes of Group 6B Elements. Inorg. Chem., i n pr e s s . T.J. Greenhough, B.W.S. Kolthammer, P. Legzdins and J . T r o t t e r . [ ( n 5 - C 5 H 5 ) C r ( C O ) 2 ] 2 s / a Novel O r g a n o m e t a l l i c Complex P o s s e s s i n g a Cr = S = Cr Linkage. .J. Am. Chem. S o c , submitted f o r p u b l i c a t i o n . T.J. Greenhough, B.W.S. Kolthammer, P. Legzdins and J . T r o t t e r . The T h i o n i t r o s y l Ligand; Molecular S t r u c t u r e of D i c a r b o n y l ( n 5 - c y c l o p e n t a d i e n y 1 ) t h i o n i t r o s y l c h r o m i u m . J . Chem. S o c , Chem. Commun., 1036-1037 (1978). B.W.S. Kolthammer and P. Leg z d i n s . O r g a n o m e t a l l i c N i t r o s y l Chemistry. 7. Evidence f o r the E x i s t e n c e o f (n 5-RC 5H4)-Mn (CO) (NO) I (R = H or CH 3) . Inorg. Chem. , 18_, 8 89-891 (1979) .. B.W.S. Kolthammer and P. Le g z d i n s . P r e p a r a t i o n of ( n 5 - C 5 H 5 ) -C r ( C O ) 2 ( N S ) . The F i r s t O r g a n o m e t a l l i c T h i o n i t r o s y l Complex. J . Am. Chem. Soc., 100, 2247-2248 (1978). B.W.S. Kolthammer, P. Legzdins and D.T. M a r t i n . S e l e c t i v e Removal of Halogen from Organic H a l i d e s Using [ ( n - C 5 H 5 ) -C r ( N O ) 2 ] 2 . Tetrahedron L e t t . , 323-326 (1978). B.W.S. Kolthammer, P. Legzdins and J.T. M a l i t o . Organo-m e t a l l i c N i t r o s y l Chemistry. 4. A d d i t i o n a l Reactions of N i t r o s y l C h l o r i d e w i t h N e u t r a l Carbonyl Complexes. Inorg. Chem., 16, 3173-3178 (1977). B.W.S. Kolthammer and P. L e g z d i n s . O r g a n o m e t a l l i c N i t r o s y l Chemistry. P a r t 3. Some Aspects of the Chemistry o f B i s [ ( n - c y c l o p e n t a d i e n y l ) d i n i t r o s y l c h r o m i u m ] . J . Chem.  S o c , Dalton Trans. , 31-35 (1978) . B.W.S. Kolthammer, P. Legzdins and J.T. M a l i t o . ( n b - C y c l o -p e n t a d i e n y l ) n i t r o s y l Chromium, Molybdenum, and Tungsten Complexes. Inorg. Synth., 19, 208-212 (1979). 

Cite

Citation Scheme:

        

Citations by CSL (citeproc-js)

Usage Statistics

Share

Embed

Customize your widget with the following options, then copy and paste the code below into the HTML of your page to embed this item in your website.
                        
                            <div id="ubcOpenCollectionsWidgetDisplay">
                            <script id="ubcOpenCollectionsWidget"
                            src="{[{embed.src}]}"
                            data-item="{[{embed.item}]}"
                            data-collection="{[{embed.collection}]}"
                            data-metadata="{[{embed.showMetadata}]}"
                            data-width="{[{embed.width}]}"
                            async >
                            </script>
                            </div>
                        
                    
IIIF logo Our image viewer uses the IIIF 2.0 standard. To load this item in other compatible viewers, use this url:
http://iiif.library.ubc.ca/presentation/dsp.831.1-0060827/manifest

Comment

Related Items