Monomeric magnesium 1-azaallyl and beta-diketiminato complexes derived from the bis(trimethylsilyl)methyl ligand: The X-ray structure of the four-coordinate planar magnesium complex [Mg{N(R)C(Bu-t)C(H)R}(2)] and of [Mg({N(R)C(Ph)}(2)CH)(2)]

Reaction of [K{N(R)C(Bu-t)C(H)R}](n) {[K(LL')](n)} or [Li({N(R)C(Ph)}(2)CH) ](2) {= [Li(LL)](2)} with magnesium bromide yielded the monomeric, crystall ine magnesium complexes [Mg(LL')(2)] 1 or [Mg(LL)(2)] 2, which have been st ructurally characterised; 1 has the magnesium atom in an unusual planar env ironment.