Azomethine derivatives. Part 19. Di-t-butylmethyleneamino-derivatives of beryllium

Abstract

The synthesis of the new methyleneaminoberyllium compounds [BeCl(NCBu^t₂)]₂, Li[Be(NCBu^t₂)₃], [Be(NCBu^t₂)₂]₂, [BeBuⁱ(NCBu^t₂)]₂, Be(NCBu^t₂)[N(SiMe₃)₂], [BeBuⁱ(NCPh₂)]₂, and [BeBu^t(NCPh₂)]₂ is described. Features of their i.r., ¹H n.m.r., and mass spectra, and an X-ray crystallographic study of [Be(NCBu^t₂)₂]₂, are reported and discussed, with particular reference to indications of N [graphic omitted] Be (p→p) dative π bonding in these compounds. The metal–nitrogen bond lengths and angles in [Be(NCBu^t₂)₂]₂ are compared with those in related beryllium compounds to illustrate the way that Be–N bond lengths reflect the co-ordination numbers of the metal and nitrogen atoms, and to illustrate the factors that influence the geometry of (BeX)₂ four-membered ring systems.