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Durham E-Theses Durham E-Theses Studies on some azomethine derivatives Summerford, C. How to cite: Summerford, C. (1969) Studies on some azomethine derivatives, Durham theses, Durham University. Available at Durham E-Theses Online: http://etheses.dur.ac.uk/8636/ 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 STUDIES ON SOME AZOMETHINE DERIVATIVES by C. SUMMERFORD, B.Sc. A thesis submitted for the degree of Doctor of Philosophy in the University of Durham June 1969 C 0 NT EKI S Acknowledgements (i) Memorandum (ii) Summary (iii) INTRODUCTION Page Survey of Azomethine Derivatives of the Electropositive Elements • • 1 General Preparative Aspects 2 Group I 3 Group II 6 Group III - Boron 10 Aluminium 23 Gallium 28 Group IV - Silicon 29 Cyclic iminosilanes 38 Germanium, Tin and Lead 40 N-Metal substituted ketenimines and carbodiimides .. .. 43 Ketenimine derivatives (a) Silicon 43 (b) Tin and Lead 44 Carbodiimide derivatives 46 Tabular survey of azomethine derivatives of the electropositive elements 48 EXPERIMENTAL General Techniques 64 Nitrogen Supply 64 G-love Box 64 Spectra 65 Analyses 66 Molecular Weights 66 Solvents 67 Preparation of starting materials 67 EXPERIMENTAL RESULTS Reactions of diphenylketiminolithium with chlorosilanes Reaction of diphenylketiminolithium with: trimethylchlorsilane 75 triethylchlorsilane 75 triphenylchlorsilane 76 silicon tetrachloride 77 Reactions of diphenylketimine with chlorosilanes Reaction of diphenylketimine with: trimethylchlorsilane 77 triphenylchlorsilane 78 Reactions of 1.1>3?3-tetramethylsuanidyl-lithium with chlorosilanes Reaction of 1,1,3,3-tetramethylguanidyl-lithium with: trimethylchlorsilane 78 triethylchlorsilane 79 triphenylchlorsilane 79 Reactions of diphenylketiminotrimethylsilane with boron halides Reaction of diphenylketiminotrimethylsilane with: boron trifluoride etherate (1:1) 81 boron trichloride (1:1) 81 boron tribromide (1:1) 82 2-chloro-1,3>2-benzodioxaborole 82 phenylboron dichloride (1:1) 83 diphenylboron chloride 84 dimesitylboron fluoride 84 2,2'-biphenylylboron fluoride 85 boron trifluoride etherate (2:1) 86 boron trichloride (2:1) .. .. 86 boron tribromide (2:1) 87 phenylboron dichloride (2:1) 88 boron trichloride (3:1) 88 • Reaction of fluorenoneiminotrimethylsilane with diphenylboron chloride 89 Reaction of benzaldiminotrimethylsilane with: phenylboron dichloride (1:1) 89 diphenylboron chloride 90 dimesitylboron fluoride 91 Reactions of diphenylketiminolithium with boron halides Reaction of diphenylketiminolithium with: diphenylboron chloride .. .. .. 92 dimesitylboron fluoride 92 2-chloro-1,3»2-benzodioxaborole .. 93 phenylboron dichloride (2:1) 93 boron trichloride (2:1) 94 Reaction of di-p-tolylketiminolithium with diphenylboron chloride 94 Reactions of diphenylboron chloride with ketimines Reaction of diphenylboron chloride with: diphenylketimine (1:1) 96 diphenylketinline (1:2) 96 di(p-chlorophenyl)ketimine (1:2) 97 di-p-tolylketimine (1:2) 97 (p-bromophenyl)phenylketimine (1:2) 98 Reaction o f diphenylketiminoboron dibromide with phenyl-lithium 99 Reaction of diphenylketimine hydrochloride with sodium tetraphenylborate 99 Reaction of di-p-tolylketimine hydrochloride with sodium tetraphenylborate 100 Reaction of 1,1j3>3-tetramethylguanidyl-lithium with diphenylboron chloride 101 Reactions of ketiminolithiums with beryllium chloride Reaction of di-p-tolylketiminolithium with beryllium chloride (1:1) 102 Reaction of (p-tolyl)t-butylketiminolithium with beryllium chloride (1:1) 102 Reaction of (p-tolyl)t-butylketiminolithium with beryllium chloride (2:1) 103 DISCUSSION Reactions of diphenylketiminolithium with chlorosilanes .. 105 Reactions of 1 ,1 ,3 >3-te"tramethylguanidyl-lithium with chlorosilanes 114 Reactions of diphenylketiminotrimethylsilane with boron halides 118 Alternative routes to iminoboranes 126 Reactions of diphenylketiminolithium with boron halides 126 Reactions of ketimines with diphenylboron chloride 127 Reaction of diphenylketiminoboron dibromide with phenyl-lithium 129 Reactions of ketimine hydrochlorides with sodium tetraphenylborate • • 130 Monomeric iminoboranes .. 133 1»1»3»3-tetramethylguanidyldiphenylborane 143 Associated iminoboranes 146 Factors affecting the degree of association of iminoboranes .. 151 Ketimino derivatives of beryllium 154 Appendix 161 RKD'KRErCES 165 (i) ACKNOWLEDGEMENTS The author wishes to express his sincere thanks to Dr. K. Wade, under whose direction this research was carried out, for his encouragement and valuable advice given throughout the course of the work. The author is also indebted to the Science Research Council for a maintenance grant. (ii) MEMORA NDUM The work described in this thesis was carried out in the University of Durham between September 1966 and June 19&9* This work has not been submitted for any other degree and is the original work of the author except where acknowledged by reference. Parts of the work described in this thesis have been the subject of the following publications: Monomeric Diphenylketiminodiphenylborane, a Boron-Nitrogen Analogue of an Allene. By J.R. JenningSj I.Pattison, C.Summerford, K.Wade and B.K.Wyatt. Chem.Comm., 1968, 250. Infrared Spectroscopic Evidence of Dative Beryllium-Nitrogen w-Bonding in Bis(ketimino) Derivatives of Beryllium. By C. Summerford, K.Wade and B.K. Wyatt. Chem.Comm., 1969i 61. Azomethine Derivatives. Part VIII. The Preparation of Some Diphenylketimino- silanes, and the Use of Diphenylketiminotrimethylsilane to prepare Diphenylketiminoboranes. By C. Summerford and K. Wade. J.Chem.Soc. (A), 1969- (iii) SUMMARY This thesis describes the preparation of some azomethine derivatives of silicon, boron and beryllium. The structural implications of their infrared, and in some cases, proton magnetic resonance and mass spectra are discussed. As a background to this work the literature on azomethine derivatives of the more electropositive elements is surveyed. Diphenylketiminolithium reacts with chlorosilanes giving the diphenylketiminosilanes, PhgCiNSiR^ (R=Me, Et or Ph) and (ph2C:N)^Si. 1 >1 >3»3-"tetramethylguanidyl-lithium reacts with chlorosilanes in a similar fashion giving the 1,1,3>3-tetramethylguanidylsilanes, (Me^NjgCsNSiR^ (R=Me, Et or Ph). Reactions between diphenylketiminotrimethylsilane and boron trihalides or organoboron halides in toluene provide convenient routes to diphenylketiminoboranes; one, two or three ketimino groups being transferred to boron under mild conditions. Bis(diphenylketimino)boron halides could not be isolated, apparently disproportionating into diphenylketiminoboron dihalides and tris(diphenylketimino)borane. 12 3 4 Iminoboranes, R R C:KBR R , have also been obtained by reaction of organoboron halides with ketiminolithium compounds and with two moles of imine. Reaction of diphenylketimine hydrochloride with sodium tetra- phenylborate at 109~ gives the ketiminoborane, Ph^CiNBPh^; di-p-tolyl- ketimine hydrochloride gives the adduct, p-tolylgCiNHjBPh^, under the same conditions. Some of the iminoboranes prepared were monomeric, a state of (iv) association previously unknown for this type of compound. The evidence available supports a linear, pseudo-allenic structure involving significant pw-pyr interaction between nitrogen and boron. The factors affecting the degree of association of the iminoboranes are discussed. Reactions of beryllium chloride with one or two moles of ketiminolithium compounds give dimeric ketiminoberyIlium chlorides or bis(ketimino)beryllium derivatives respectively. Infrared spectroscopic eyidence suggests significant pTr-pw interaction between nitrogen and beryllium in the latter compounds. Features of the infrared spectra of boron trifluoride adducts and 1 2 3 hydrochloride salts of a series of imines, R R C:KR » are discussed in an appendix. INTRODUCTION - 1 - The reaction between a nitrile and a Grignard reagent followed by hydrolysis of the reaction mixture has been used for many years as 1 2 a route to ketones and ketimines. Subsequent work showed that this reaction could be extended to organolithium^ and organoaluminium 4 4 compounds. For example, Gilman and Marple obtained phenyl p-tolyl ketone in T}% yield on hydrolysis of the product from the reaction of phenyl cyanide and tri-p-tolylaluminium at about 130-140°. PhC:N + (p-tolyl)ya * [p-tolylC(Ph):NAl(p-tolyl)2] H20 p-tolylCPh II 0 Similarly the reduction of nitriles to amines by excess lithium 5 6 aluminium hydride can be stopped at the C=N stage by limiting the 7 amount of lithium aluminium hydride. However until recently very little effort has been made to isolate and characterise the metal-containing azomethine derivatives, RR C:NMXn, of the type which must constitute the intermediates in these reactions. Thus in 1934 Smith and Bergstrom isolated apparently impure diphenylketirainosodium, Ph2C:NNa, from the reaction between diphenyl- g ketimine and sodamide in liquid ammonia,
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