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The Chemistry of Group 6 and 7 Transition

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The Chemistry of Group 6 and 7 Transition THE CHEMISTRY OF GROUP 6 AND 7 TRANSITION METAL ORGANOMETALLIC NITROSYL COMPLEXES by BRIAN WILLIAM STIRLING KOLTHAMMER B.Sc. (Honours), University of British Columbia, 1975 A THESIS SUBMITTED IN PARTIAL. FULFILLMENT OF THE REQUIREMENTS FOR THE DEGREE OF DOCTOR OF PHILOSOPHY THE FACULTY OF GRADUATE STUDIES in the Department of Chemistry We accept this thesis as conforming to the required standard THE UNIVERSITY OF BRITISH COLUMBIA February, 1979 (c) Brian William Stirling Kolthammer, 197 9 In presenting this thesis in partial fulfilment of the requirements for an advanced degree at the University of British Columbia, I agree that the Library shall make it freely available for reference and study. I further agree that permission for extensive copying of this thesis for scholarly purposes may be granted by the Head of my Department or by his representatives. It is understood that copying or publication of this thesis for financial gain shall not be allowed without my written permission. Department of The University of British Columbia 2075 Wesbrook Place Vancouver, Canada V6T 1W5 Date H&AcL M Jill ABSTRACT Nitrosyl chloride exhibits a number of different reaction modes in its reactions with monomeric and dimeric neutral carbonyl complexes of transition metals. From its reaction with [CpCr(CO)3]2 under controlled conditions, the organometallic compounds CpCr (CO) 2 (NO) , CpCr(NO)2Cl, [CpCrCl2]2,, and [CpCr (NO) Cl]2 can be obtained. In contrast.,, the analogous [CpM(CO)3]2 (M — Mo or W) compounds react with C1N0 to produce CpM(CO)3Cl and CpM(NO)2Cl in comparable yields. The (arene)M(CO)3 (M = Mo or W) compounds form the C1 polymeric [M(NO)2Cl2]n species via labile M (CO) 2 (NO) 2 2 intermediates under identical experimental conditions. Poss ible pathways leading to the formation of all products are presented. Trithiazyl trichloride, N^S^Cl^, introduces the thionitrosyl group onto a metal centre during the reaction. Na[CpCr (CO) ] + 3"3N3S3C13 • CpCr (CO) 2 (NS) An x-ray crystallographic analysis of this complex shows that the thionitrosyl group coordinates essentially linearly to the chromium via the nitrogen atom. A second product formed in this reaction, Cp2Cr2(CO)^S, possesses a novel Cr-S-Cr linkage which is linear, short, and chemically inert The cations, [ (RC^H^)Mn (CO)''2 (NO) ] * (R = H or Me) react with I in acetone at room temperature to produce (RC5H4)Mn(CO)(NO)I. These species have very labile CO ligand which are readily displaced by Lewis bases to produce (RC^H4) Mn(L) (NO) I [R = H, L = PPh3 or P(OPh)3; R = Me, L = PPh3, - P(OPh)3, or P(C6H1:L)3]. The reactions of Br , Clo, and N02~ + with [(RC^H^)Mn(CO)2(NO)] produce the unusual bimetallic compounds (RC5H4)2 Mn2 (NO)3 X (R == H or Me; X = Cl, Br, or N02) The compound [CpCr(NO)2]2 abstracts all of the chlorine ligands from SnCl4, MC12 (M = Hg, Sn, or Pb), CpFe- (CO)2Cl, and Mn(CO)5Cl in. refluxing thf to form CpCr(NO)2Cl. The other products are the metals (M), [CpFe(CO)»]„, and Mn2(CO)^Q, respectively. The chromium dimer also abstracts halogen from vic-dihaloalkanes to produce the corresponding alkenes in good yields. - iv - ACKNOWLEDGEMENTS I wish to thank the faculty and technical staff of the Chemistry department for their assistance and guidance throughout this study. In particular, I wish to thank Prof. N.L. Paddock who read this thesis and offered suggestions for improvements I am indebted to the people of Room 325 for providing a pleasant atmosphere for work and especially I acknowledge Dr. J.T. Malito, D.T. Martin and B.W. Hames. The work of Jen Kolthammer, who typed this thesis, is greatly appreciated. Finally, I wish to express my gratitude to Peter Legzdins whose perseverence and encouragement are the foundations of this work. - v - TABLE OF CONTENTS Page ABSTRACT ii ACKNOWLEDGEMENTS iiv TABLE OF CONTENTS V LIST OF TABLES vii LIST OF FIGURES . ix ABBREVIATIONS AND COMMON NAMES x CHAPTER I INTRODUCTION 1 CHAPTER II SOME REACTIONS OF NITROSYL CHLORIDE WITH NEUTRAL CARBONYL COMPLEXES ... 7 Experimental 9 Results and Discussion 19 Reactions of Nitrosyl Chloride with [CpM(CO) -J2 (M = Cr, Mo, or W) and [CpMn(COr (NO) ]2 19 Reactions of Nitrosyl Chloride with Other Neutral Carbonyl Complexes .. 28 Reactions of Nitrosyl Chloride with CpMn(CO)3 33 Reactions of Nitrosyl Chloride Attributable to Cl2 and NO 34 CHAPTER III REACTIONS OF TRITHIAZYL TRICHLORIDE WITH TRANSITION METAL CARBONYL COMPOUNDS 36 Experimental 37 Results and Discussion 42 CHAPTER IV REACTIONS OF DICARBONYL(n5-CYCLO- PENTADIENYL)NITROSYLMANGANESE HEXA- FLUOROPHOSPHATE WITH HALIDE IONS .. 5 9 Experimental 61 - vi - Page Results and Discussion 73 CHAPTER V SOME ASPECTS OF THE CHEMISTRY OF BIS[ (n 5-CYCLOPENTADIENYL)DINITROSYL- CHROMIUM] 99 Experimental 99 Results and Discussion 105 Selective Removal of Halogen from Organic Halides 115 REFERENCES 119 - vii - LIST OF TABLES Table Page I Low-Resolution Mass Spectral Data for [CpCrCl2]2 and [CpCr(NO)Cl2]2 22 II Nitrosyl Stretching Frequencies of the Complexes ML2(NO)2C12 31 III Reactions of N^S Cl^ with some Tran• sition Metal Compounds 39 5 IV Physical Properties of (n-C5H[-) Cr- (CO)2(NX) Complexes 44 V Low-Resolution Mass Spectral Data for (C5H5) Cr (CO) 2 (NX). Complexes 4 6 VI Low-Resolution Mass Spectral Data for [(C5H5).Cr(CO)2]2S 53 VII Mass Spectral Data for (RC5H.)Mn(CO)- (NO) I Complexes 63 VIII Physical Properties of the Complexes (RC5H5)Mn.(L) (NO) I 66 Mn IX Elemental Analyses for (RC^H.)2 2~ (NO)3 X Complexes 71 X Physical Properties of (RC5H4)2Mn2~ (NO)3 X Complexes 72 XI Mass Spectral Data for (RCj-H .) Mn(NO) - (PPh3)I ..7 78 XII Mass Spectral Data for (RC-H.) Mn (NO) - . [P(0Ph)o]I and (CcH_)Mn(N07TP (CCH, ,) , 3 3 [P(C6Hl )3]I ....S.H. 79 XIII Mass Spectral Data for (C,H7)Fe(CO)- (PPh3)I v :.. 80 XIV 13C NMR Spectral Data of Some (MeCp)Mn Compounds 86 XV Mass Spectral Data for (C^H-)Re(CO)- (NO) I 89 - viii - Table Page XVI Mass Spectral Data for (RCVH.)„Mn„- (NO)3I 92 XVII Mass Spectral Data for (RC-HJ9Mn0- (NO)3Br 93 XVIII Mass Spectral Data for (RCr-H.) 9Mn~- (NO)3 C1 94 XIX Mass Spectral Data for (C-H-)-Mn-- (NO)3R 95 XX *H NMR Spectral Data for (RCRH.)9Mn0- (NO)3X 97 XXI Reactions of j^CpCr(NO)2 ]2 with some Halogen-Containing Compounds 101 XXII High-Resolution Mass Spectral.Data for [(C5H5)Cr(NO)2]2 107 - ix - LIST.OF FIGURES Figure Page + 1 Structure of [.Ru(PPh3>2 (NO) 2C1] 3 2 Apparatus for Purifying Nitrosyl Chloride 11 3 Molecular structure of (n5 -Cj-H,.) Cr- (CO)2(NS) 48 4 Molecular structure of [ (ri 5-CJ-HJ. ) Cr- (CO)2]2S 55 5 The *H NMR Spectra of (MeCp) Mn (CO) , (MeCp) Mn (CO) _ (PPh^) , [.(MeCp) Mn (CO) - (NO)(PPh3)]PFfi, and (MeCp)Mn(NO)- (PPh3)I . 83 6 Infrared Spectral changes accompany• ing the reactions of [CpCr(NO)0]0 ... 110 - x - ABBREVIATIONS AND COMMON NAMES The abbreviations used in this thesis are those recommended in the Handbook for Authors of Papers in American Chemical Society Publications (ACS 1978). o A Angstrom atm atmospheres Bu butyl calcd calculated cm 1 wave numbers in reciprocal centimeters Cp pentahapto-cyclopentadienyl d day(s) dec decomposes Et ethyl h hour(s) Hz Hertz, cycles per second IR infrared J magnetic resonance coupling constant m/z mass to charge ratio Me methyl MeCp pentahapto-methylcyclopentadienyl min minute (s) mm millimeters of mercury mmol millimole NMR nuclear magnetic resonance Ph phenyl thf tetrahydrofuran 6 NMR chemical shift n5 pentahapto v IR stretching frequency - 1 CHAPTER I INTRODUCTION A distinguishing trait of the d-block elements is their ability to form complexes with neutral molecules such as isocyanides, phosphines, amines, carbon monoxide, and ni• trogen monoxide. The most important of these ligands is car• bon monoxide, and volumes of information1 have been published not only on the preparation of transition metal carbonyls but also on the use of these complexes in organic synthesis and catalysis. The chemistry of transition metal nitrogen mono• xide compounds is less well developed. However, the extent of the chemistry that may be exhibited by these nitrosyl compounds and their derivatives is potentially as broad as that of the carbonyl complexes. Although nitrogen monoxide and carbon monoxide are known to bond to transition metals in an analogous fashion, the NO ligand contains one more electron ins.a TT* orbital. The presence of this extra electron also allows a nitrosyl group to behave in a fashion unobserved for a carbonyl ligand, ive. to form a bent M-N-0 bond. The two different bonding modes may be described as follows: (1) Linear The nitrosonium ion, NO , is lsoelec- tronic with carbon monoxide and, thus, it has three bonding electron pairs between the atoms and a lone electron pair on - 2 - both the nitrogen and oxygen. Both atoms are sp hybridized and both are potential donors. However, the.nitrogen coordinates preferentially, thereby avoiding a large formal positive charge on the more electronegative element. The nitrosyl ion can be considered as a a-donor and the resulting M-NEO .is linear. Occupied metal dTT orbitals provide some degree of MTT-^-NOTT* overlap estab• lishing a synergistic bonding relationship. (Alternatively, the linear group may be considered as a bond between nitrogen monoxide.and a.metal.containing an empty a-orbital and a half- filled Tr-orbital which-interacts with the ir* electron of the NO).
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