Bis(dimethylamido) Complexes of Alkyl- and Phenylgallium. Useful Precursors to the RGa2+ Synthon

Alkyl- and phenylbis(dimethylamido)gallium, [RGa(NMe2)2]2 [R = Me (1), Et (2), n Bu (3), n Hx (4), and Ph (5)], were synthesized by reactions of LiNMe2 with (RGaCl2)2. The crystal structure of compound 1 was a disordered mixture of anti and syn isomers, with the ratio of anti/syn being 64:36, which was consistent with the ratio (57:43) found in the 1H NMR spectrum. The Ga2N2 cores of the anti and syn structures were nonplanar. 1H NMR spectra indicated the presence of both anti and syn isomers for all of the other substituents. 1H NMR and mass spectra indicated that a species with the general formula of R3Ga2(NMe2)3 was formed when these compounds were heated at high temperatures.