Phenylethynylberyllium complexes

Abstract

Complexes of bis(phenylethynyl)beryllium of the type (PhC⋮C)₂Be,2L have been described, in which L is pyridine, tetrahydrofuran, methyl-, dimethyl- and trimethyl-amine, and aniline, and in which L₂ is one of the chelate bases tetramethylethylenediamine, 2,2-bipyridyl, and 1,2-dimethoxyethane. The complex (PhC⋮C)₂Be,NEt₃ is monomeric in benzene and hence contains three-co-ordinate beryllium, whereas (PhC⋮C)₂Be,OEt₂ is somewhat associated, possibly by means of acetylenic bridging groups.

The lithium complex of approximate composition Li₂Be(C⋮CPh)₄ is insoluble in hydrocarbons. The reactions between bis(phenylethynyl)beryllium complexes and t-butyl alcohol, phenol, and 2-methylpropane-2-thiol give products exemplified by (PhC⋮CBeOPh,THF)_n(n between 1 and 2 in benzene) and (PhC⋮CBeSBu^t,THF)₂. The butoxide, (PhC⋮C)₂Be₃(OBu^t)₄, prepared by two methods, is a member of a new series of alkoxides of the type R₂Be₃(OBu^t)₄.

Reactions between alkynes and complexes of diethylberyllium or of methyl- or ethyl-beryllium hydride generally are slow and give mixtures of products.