The syntheses and structures of some main group complexes of the sterically hindered N,N'-bis(2,6-diisopropylphenyl)-4-toluamidinate ligand

Abstract

The stoichiometric reaction of the bulky benzamidine N,N’-bis(2,6-diisopropylphenyl)-4-toluamidine (HDippAm) with the metal alkyls BunLi (1 : 1 in THF), Bu₂Mg (2 : 1 in THF) and Me₂Al (1 : 1 in Et₂O) is presented. This provides the mononuclear dihapto benzamidinate compounds [Li(DippAm)(THF)2] (1), [Mg(DippAm)₂] (2) and [Al(DippAm)Me₂] (3), respectively. Compound 3 was also obtained by salt elimination using dimethylaluminium chloride and 1. All three compounds exhibit sterically strained geometries that are maintained in solution at increased temperatures. Compound 3 displays exceptional thermal and aerobic stability, while 2 constitutes a rare example of non-porphyrin supported square planar magnesium.