Studies on some unsaturated organonitrogen metal systems

Abstract

This thesis describes studies on the coordination chemistry and reactions with metal halides of some unsaturated organonitrogen compounds. The systems studied included various ketimines, R(^1)R(^2) C = NH, and derivatives thereof, R(^1)R(^2) C = NH, MX(_n) or R(^1)R(^2) C = NMX(_n-1) containing antimony or tin atoms attached to the imino-nitrogen atoms. Aspects of the coordination chemistry of acrylonitrile CH(_2) : CHC : N and its methyl derivatives, CH(_2) : CMe C : N and MeCH : CH C : N have also been studied as well as their reactions with ether/SnCℓ(_2)/HCℓ systems. The main feature studied in the imine work was the tendency of compounds (4-XC(_6)H(_4))(_2)C = NSbCℓ(_n) (X = H or Me, n = 2 or 4) to undergo cyclometallation reaction forming a new type of antimony ring compound; 2 - SbCℓ(_n) – 4 – XC(_6)H(_3)C(4 – XC(_6)H(_4)) – NH. Related cyclometallation reactions are surveyed in chapter 1. During attempts to prepare other diarylketimino antimony tetrachlorides such as o-tolyl, ph C = NSbCℓ(_4); m-tolyl, ph C = NSbCℓ(_4) and (4 – FC(_6)H(_4))(_2) C = NSbCℓ(_4), no analogous cyclometallated products were obtained. Instead two different products were isolated: Aryℓ(_2)CNH(^+)(_2)SbCℓ(^-)(_4) and Aryℓ(_2)CNH(^+)(_2)SbCℓ(^-)(_6). Attempts to prepare t-butyl derivatives of general formula Ar, Bu(^t) C = NSbCℓ(_4) (Ar = o-tolyl, p-tolyl; m-tolyl) afforded arylnitrile, HCℓ and SbCℓ(_3), probably by elimination of Me(_2)C = CH(_2). Chloroform solutions of diphenylketimine and antimony penta- or tri- chloride deposited ph(_2)CNH(^+)(_2) SbCℓ(^-)(_6) or (ph(_2)CNH(^+)(_2))(_2) SbCℓ(_5)(^2-) respectively. In the nitrile work, using ether/SnCℓ(_2)/HCℓ systems which contain R(_2)OH(^+). SnCℓ(_3)(^-) and (R(_2)O(^+)H)(_2) ∙ SnCℓ(_4)(^2-), addition to the C = C bond of the acrylonitrile yielded Cℓ(_3)Sn.CK(_2).CH(_2).CN. Methacrylonitrile and crotononitrile gave more complicated reactions with ether/SnCℓ(_2)/HCℓ systems, apparently undergoing dimerization to form amidinium cations containing C = N - CR = NH(_2)(^+) units. Finally, several complexes were isolated from reactions between acrylonitrile or its methyl derivatives and the metal chlorides TiCℓ(_4), SnCℓ(_4), SbCℓ(_5), BCℓ(_3) CoCℓ(_2), ZnCℓ(_2), TiBr(_4), TaCℓ(_5), NiCℓ(_2)/2SbCℓ(_5) and NiCℓ(_2)/2ZnCℓ(_2). Spectroscopic and conductivity studies of these complexes were carried out, and used to deduce their probable structures.