Studies on imino, amidino and related derivatives of some main group elements

Abstract

This thesis describes studies on the co-ordination chemistry of Group II elements, magnesium and zinc, and Group IV elements silicon, germanium and tin. Attention is focussed principally on systems with ligands containing multiple-bonded nitrigen attached t, these Groups II and IV elements viz., Ketimino and amidin, derivatives containing R(_2)C=N and R(^1)NC(R)=NR(^1) ligands respectively. After an introductory survey of the relevant chemistry, Chapter 2 describes studies on fifteen ketiminomagnesium derivatives of formula types (R(_2)C=NMgBr)(_2)(L)(_x), [(R(_2)C=N)(_2)Mg](_n)(THF)(_x), (R(_2)C=NMgX)(_n)L(_m) and includes an X-ray crystal structure of (Ph(_2)C=NMgBr)(_2)(THF)(_3). All compounds described are associated species, often dimeric, and are believed to co-ordinate via bridging methyleneamino ligands with additional bridging ligands (OEt(_2), THF and TMED) in some cases. Where compounds also contain terminally attached methyleneamino ligands, their infrared spectra are consistent with linear C=N-Mg units. Chapter 3 describes related studies on ten methylene- aminozinc compounds of formula types (R(_2)C=NH)(_x)ZnX(_2), R = Ph, p-tolyl, X=C1, X = 2; R=Bu(^t), X = 1, x = 1; R= p-tolyl, X = Ph, X = 1; RCN.ZnPh(_2) (R = p-tolyl); (R(_1)R(_2)C=NZnX)(_n),= R(_2) = p-tolyl, X = Ph, n = 2; R(_2) = Eg = p-tolyl, X = Ph, n = 2; R(_1) = Ph, R(_2) = p-tolyl, X = Ph, n = 2; R(_1) = R(_2) = p-tolyl, X = (p-tolyl)(_2)C=N, The associated species are thought to have bridging methyleneamino units with three-co-ordinate zinc.