Carbene complexes of Group 13 trihydrides: synthesis and characterisation of [MH3{CN(Pri)C2Me2N(Pri)}], M = Al, Ga or In

Abstract

The reaction of LiInH₄ with NMe₃·HCl yielded [InH₃(NMe₃)] which could not be isolated in the solid state. Treatment of [MH₃(NMe₃)] with either 1 or 2 equivalents of the stable carbene CN(Prⁱ)C₂Me₂N(Prⁱ) afforded the carbene–metal trihydride complexes [MH₃{CN(Prⁱ)C₂Me₂N(Prⁱ)}], M = Al, Ga or In. The aluminium and indium complexes could also be prepared by treating either LiAlH₄ or LiInH₄ with 1 or 2 equivalents of CN(Prⁱ)C₂Me₂N(Prⁱ). Variable temperature ¹H NMR studies of the carbene–MH₃ complexes revealed them to be fluxional in solution at room temperature. The crystal structures of the monomeric aluminium and gallium hydride complexes showed them to contain partially delocalised carbene ligands.