Preparation and properties of methylaluminium tetrahydroborates and their reactions with some Lewis bases

Abstract

The methylaluminium tetrahydroborates Al(BH₄)₂Me and Al(BH₄)Me₂ have been prepared from AlMe₃+ 2 or ½Al(BH₄)₃, and from AlMe_nCl_3–n and (3 –n)Li[BH₄](n= 1 or 2). They are volatile compounds which inflame in air, vaporise as the monomers, and form the following adducts: Al(BH₄)₂Me·L (L = NMe₃, NMe₂H, PMe₃, AsMe₃, OMe₂, OEt₂, and SMe₂) and Al(BH₄)Me₂·L (L = NMe₃, PMe₃, and OEt₂). Features of the i.r. and n.m.r. spectra of these compounds are reported and discussed.