Preparation and structure of lithium bis[cis-ethene-1,2-di((t)butylamido)]gallate(III) tetrahydrofuran

The dilithium diamide reagent obtained from N,N ' -di((t)butyl)-1,4-diazabu tadiene and two equivalents of lithium metal reacts with anhydrous gallium trichloride in tetrahydrofuran / hexane, followed by treatment with metalli c potassium, to give the title compound in about 40% yield. Cyclic imides o f gallium(III) and gallium(II) are by-products of this process. The structu re of Li{[cis-C2H2((NBu)-Bu-t)(2)](2)Ga} has been determined from single cr ystals containing one mole equivalent of tetrahydrofuran. The gallium atom is chelated by two diamide ligands. One of the five-membered chelate rings is planar while the second one is folded at its nitrogen atoms. The lithium atom is eta (4)-coordinated to the 1,4-diazabutene(2) unit of this ring an d further to the oxygen atom of the solvent molecule.