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

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(Pr-i)C2Me2N(Pr-i) afforded the carbene-metal trihydride complexes [MH3{CN(Pr-i)C2Me2N(Pr-i)}], 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(Pr-i)C2Me2N(Pr-i). Variable temperature H-1 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.