SYNTHESIS AND STRUCTURAL CHARACTERIZATION OF HOMOLEPTIC GALLIUM AMIDES

The homoleptic Ga(III) amides [(t-Bu(H)N)2Ga(mu-N(H)t-Bu)]2 (1) and Ga(N(t-Bu)SiMe3)3 (2) have been synthesized via the reaction of GaCl3 with 3 equiv of the appropriate lithium amide. A third tris(amide), Ga(tmp)3 (3) (tmp = 2,2,6,6-tetramethylpiperidide), was prepared by the thermal reaction of GaCl3 with 3 equiv of Htmp. The structures of 1 and Ga(N(SiMe3)2)3 (4) have been determined by single-crystal X-ray diffraction methods. Compound 1 crystallizes in the monoclinic space group C2/m (No. 12) with a = 9.879(2) angstrom, b = 17.427(7) angstrom, c = 19.742(1) angstrom, beta = 101.38(3)-degrees, V = 3332(23) angstrom3, and Z = 4. Compound 4 crystallizes in the trigonal space group P31cBAR (No. 163) with a = 16.050(1) angstrom, c = 8.6063(7) angstrom, V = 1920(5) angstrom3, and Z = 2. Compound 1 exists in the crystalline state as discrete dimeric units with two bridging and four terminal amido groups. The crystalline state of 4 comprises discrete monomers with D3 symmetry. The structure of 2 is disordered.