Azomethine derivatives. Part XII. Alkylideneamino-beryllium chlorides and bis(alkylideneamino)-derivatives of beryllium

Abstract

The compounds [(p-tolyl)₂C:NBeCl]₂, [({p-tolyl)₂C:N}₂Be]₃, [(p-tolyl)Bu^tC:NBeCl]₂, and [{(p-tolyl)Bu^tC:N}₂Be]₂ have been prepared by reacting BeCl₂ with one or two moles of R¹R²C:NLi. BeCl₂ with 2Ph₂C:NLi apparently similarly gives [(Ph₂C:N)₂Be]_n; with Ph₂C:NSiMe₃ it gives (Ph₂C:NBeCl)₂. Four-membered (BeN)₂ rings are believed to feature in the structures of all these compounds. In their i.r. spectra the colourless alkylideneaminoberyllium chlorides have ν(CN) in the region 1608–1614 cm.^–1; the yellow bis(alkylideneamino)-derivatives at ca. 1630 cm.^–1. [ν(CN,bridging)] and at ca. 1735 cm.^–1. This last absorption, assigned ν(CNBe), is taken as evidence of linear CNBe groupings whereby terminal alkylideneamino groups are attached to three co-ordinate beryllium atoms. ¹H n.m.r. spectroscopic details for [{(p-tolyl)₂C:N}₂Be]₃ and [{(p-tolyl)Bu^tC:N}₂Be]₂ are given.