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Durham E-Theses Some co-ordination complexes of beryllium organoaluminium-silyl and -germyl complexes Straord, R. G. How to cite: Straord, R. G. (1970) Some co-ordination complexes of beryllium organoaluminium-silyl and -germyl complexes, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/8807/ Use policy The full-text may be used and/or reproduced, and given to third parties in any format or medium, without prior permission or charge, for personal research or study, educational, or not-for-prot purposes provided that: • a full bibliographic reference is made to the original source • a link is made to the metadata record in Durham E-Theses • the full-text is not changed in any way The full-text must not be sold in any format or medium without the formal permission of the copyright holders. Please consult the full Durham E-Theses policy for further details. Academic Support Oce, Durham University, University Oce, Old Elvet, Durham DH1 3HP e-mail: [email protected] Tel: +44 0191 334 6107 http://etheses.dur.ac.uk 2 SOME CO-ORDINATION COMPLEXES OF BERYLLIUM ORGANOALUMINIUM-SILYL AND -6ERMYL COMPLEXES by R.G. Strafford, B.Sc. (Grey College) A Thesis submitted for the Degree of Doctor of Philosophy in the University of Durham September 1970 •> • v_> • oinx.1 SUMMARY This thesis can conveniently be divided into three parts. Part 1 This part is concerned with attempts to synthesise and isolate complexes containing either aluminium-silicon or -germanium bonds. In no case has a stable complex been isolated. Some experiments, e.g. between Me^Al and Me^GeH, produced, rather surprisingly, no reaction while other approaches give products which can be accounted for if reactive aluminium-silicon or -germanium complexes are produced as reactive intermediates. In a few cases evidence (not entirely convincing) has been obtained for impure complexes e.g. (Me^SiAlMeg T.H.F.) and (Me^Ge)^Al. Part 2 This part of the thesis is concerned with some co-ordination com• plexes of organoberyllium compounds. No reaction was detected between tetramethyl-di-arsine and dimethylberyllium. Dimethylberyllium reacts step-wise with tertbutylamine at ambient temperature to form the methyltertbutylaminoberyllium trimer and then the bis-tertbutylaminoberyIlium dimer. Dimethyl- and diethylberyllium etherates react with pyridine-2- . aldehydephenylhydrazone with elimination of alkane to give the interesting coloured aminoberyllium compounds: (MeBeCinH. _N_) and EtBeC. ,H--N, 11 ll 3 n 11 11 3 Part 3 This part of the thesis is concerned with an investigation of the vapour phase association and fragmentation of the group III metal alkyls, MeoM (M = B, Ga, In and Tl), and trivinylgallium, under electron impact. Only in the case of trimethylgallium is there any evidence of low abundant (<0.1%) associated species although certain low abundant fragment ions in the mass spectrum of trivinylgalliuin could possibly be derived from higher oligomers. Variation of the abundances of the ions of all the aIkyIs with increasing source temperature and decreasing eV is discussed. Tiie appearance potentials of the major ions in triraethylgallium were obtained, and the gallium-carbon mean bond strength is estimated. (ii) ACKNOWLEDGEMENTS It is a pleasure to thank Professor G.E. Coates and Professor F. Glockling for their help and constant encouragement throughout the work described in this thesis. I am indebted to the Science Research Council for a maintenance grant, and to all those members of the Chemistry Departments of the Universities of Durham and Belfast who so readily gave advice and assistance. (iii) NOTE The work described in this thesis was carried out in the University of Durham between September 1967 and August 1969 and in the Queen's University of Belfast between September 1969 and August 1970. This work has not been submitted for any other degree and is the original work of the author except where acknowledged by reference. (iv) PUBLICATIONS Part of the work described in this Thesis has been included in the following publication: "Alkylpolygermanes" J. Chem. Soc.(A), 1970, 426 (with F. Glockling and J.R.C. Light) The author also gave a lecture "Catenated organo- germanes" at the Joint Annual Meeting of the Chemical Society and the Royal Institute of Chemistry, Edinburgh April, 1970. (with F. Glockling and J.R.C. Light) (v) CONTENTS Summary Page No. CHAPTER 1 - Organoaluminium-silyl and -Germyl Complexes 1.1 Introduction Synthesis and properties of alkyl-polysilanes 1 Synthesis 1 Physical properties 4 Spectral studies 4 Chemical studies 5 Synthesis and properties of alkylpolygermanes 6 Physical properties 9 Spectroscopic properties 10 Chemical studies 11 Suspected organo-silyl and -germyl-aluminium complexes as intermediates 12 Known organo-silyl and -germyl main group complexes 20 1.2 Discussion Reactions of the type RjAlR' and R^MH 29 Reactions involving anionic silicon/germanium species 33 Reactions involving germyl- and silylmercury compounds 36 Alkylation of triphenylphosphine-germanium diiodide using trialkylaluminium compounds 39 1.3 Experimental General handling techniques 42 Preparation and purification of starting materials 43 (vi) Page No. Other experimental data 45 Reactions using RgAIR1 and R^'MH 47 Reactions involving anionic silicon/germanium species 52 Reactions involving germyl- and silylmercury compounds 5.6 Reactions between triphenylphosphine-germanium di-iodide and trimethyl- and triethylaluminium 58 CHAPTER 2 - Some Co-ordination Complexes of Beryllium 2.1 Introduction 62 Structure, synthesis and some general reactions of organoberyllium compounds 62 Co-ordination Complexes 64 Co-ordination complexes with donors containing active hydrogen 66 2.2 Discussion Reactions between Me2Be and Me^A&2 70 Reaction between Me^Be and ^BuNH^ 70 Reactions with pyridine-2-aldehydephenylhydrazone 73 2.3 Experimental General handling and analyses 76 Preparation and purification of starting materials 78 Me2Be and Me^As2 79 t . MegBe and BuNH2 79 Reactions with pyridine-2-aldehydephenylhydrazone 82 (vii) Page No. CHAPTER 3 - Mass Spectroscopic Studies on the Group III Alkyla 3.1 Introduction 85 Trends within the group 85 Trimethylboron: structure and properties 87 Trimethylaluminium:structure and properties 89 Trimethylgallium:structure and properties 92 Trimethylindium: structure and properties 94 Trimethylthallium:structure and properties 96 Mass spectra of main group organometallics 99 Appearance potentials and thermodynamic data 108 3.2 Experimental 113 Preparation and purification of starting materials 113 Recording mass spectra 115 Sample handling systems 115 Obtaining spectra for abundance measurements 116 Measurement of appearance potentials 117 3.3 Calculation of Results 119 Identification of ions 119 Calculation of abundances 120 Assignment of metastable peaks 121 3.4 Discussion Associated species 124 General features of the mass spectra of the group III alkyls 128 (viii) Page No Modes of decomposition 131 Appearance potential measurements 133 The mass spectrum of trivinylgallium 134 Appendix 1 Accurate mass measurements on Me^M (M = Ga,In,Tl) 137 Appendix 2 Ion abundance measurements at 70, 50, 20, 12 and lOeV and high and low source temperatures for Me^M (M = B, Ga, In, Tl). 143 Appendix 3 Accurate mass measurements and ion abundance measurements for trivinylgallium 167 References 175 (ix) SUMMARY This thesis can conveniently be divided into three parts. Part 1 This part is concerned with attempts to synthesise and isolate complexes containing either aluminium-silicon or -germanium bonds. In no case has a stable complex been isolated. Some experiments, e.g. between Me^Al and Me^GeH, produced, rather surprisingly, no reaction while other approaches give products which can be accounted for if reactive aluminiumrsilicon or -germanium complexes are produced as reactive intermediates. In a few cases evidence (not entirely convincing) has been obtained for impure complexes e.g. (Me^SiAlM^ T.H.F.) and (Me^Ge)^Al. Part 2 This part of the thesis is concerned with some co-ordination com• plexes of organoberyllium compounds. No reaction was detected between tetramethylT-di-arsine and dimethylberyllium. DimethylberyIlium reacts step-wise with tertbutylamine at ambient temperature to form the methyltertbutylaminoberyllium trimer and then the bis-tertbutylaminoberyllium dimer. Dimethyl- and diethylberyllium etherates react with pyridine-2- aldehydephenylhydrazone with elimination of alkane to give the interesting coloured aminoberyIlium compounds: (MeBeC11H11N3)n and EtBeCj^Hj^Ng Part 3 This part of the thesis is concerned with an investigation of the vapour phase association and fragmentation of the group III metal alkyls, Me^M (M m B, Ga, In and Tl), and trivinylgallium, under electron impact. Cx) Only in the case of trimethylgallium is there any evidence of low abundant (<0.1%) associated species although certain low abundant fragment ions in the mass spectrum of trivinylgallium could possibly be derived from higher oligomers. Variation of the abundances of the ions of all the alkyls with increasing source temperature and decreasing eV is discussed. The appearance potentials of the major ions in trimethylgallium were obtained, and the gallium-carbon mean bond strength is estimated. C H A P T E R 1 ORGANOGERMYL AND-SILYL COMPLEXES OF ALUMINIUM - 1 - 1.1 INTRODUCTION In the alkylation of germanium halides by organoaluminium compounds, 12 3 appreciable yields of catenated organogermanes are obtained ' ' . The mechanism