Gallane Complexes with Amido−Amine Ligands

Gallane complexes bearing amido−amine ligands −N(R)CH2CMe2CH2NMe2 [R = H or SiMe3 (TMS)], {H2Ga[N(H)CH2CMe2CH2NMe2]}2, 1, H2Ga[N(TMS)CH2CMe2CH2NMe2], 2, {H(Cl)Ga[N(H)CH2CMe2CH2NMe2]}2, 3, {[(TMS)2N](H)Ga[N(H)CH2CMe2CH2NMe2]}2, 4, and HGa[N(TMS)CH2CMe2CH2NMe2]2, 5, were synthesized from the reactions of the quinuclidine adducts of mono- and dichlorogallane with the corresponding lithium amides. Structural determinations of compounds 1, 3, and 4 showed all were dimeric with bridging amido groups. Rather than bond to gallium the tertiary amine groups in 1 and 4 were hydrogen-bonded to the amido N−H. In the structure of compound 3 the amine group occupied an axial position in the trigonal bipyramidal geometry of the five-coordinate gallium. The results were rationalized in terms of the steric and electronic properties of gallium ligands.