TOPOLOGICAL REORGANIZATION OF GALLIUM SULFIDO CLUSTERS

The prolonged thermolysis of [((t)Bu)GaS]4 in hexane results in the formation of the heptamer [((t)Bu)GaS]7 (1), while in pentane the octamer [((t)Bu)GaS]8 is formed in low yield. Dissolution of [((t)Bu)GaS]x (x = 4, 7, 8) in pyridine yields the trimeric pyridine complex [((t)Bu)Ga(S)PY]3 (2). Sublimation of 2 regenerates the tetramer, while thermolysis in the solid state yields the hexamer [((t)Bu)GaS]6 (3), which is reconverted to 2 on addition of pyridine. While compound 1 sublimes intact under vacuum, at atmospheric pressure compounds 1 and 3 sublime to yield the tetramer. The synthesis of the first gallium oxide cage compound, the nonameric [((t)Bu)GaO]9 (4), is reported. The molecular structures of 1-3 have been determined by X-ray crystallography. The relationship between [((t)Bu)GaS]x, the analogous iron-sulfide clusters [(L)FeS]x, and the iminoalanes [RAl(NR')]x is discussed. Crystal data for 1: monoclinic, P2(1)/n, a = 10.491 (2) angstrom, b = 21.697 (5) angstrom, c = 41.383 (7) angstrom, beta = 95.34 (2)-degrees, Z = 8, R = 0.059, R(w) = 0.071. Crystal data for 2: monoclinic, P2(1)/c, a = 9.377 (5) angstrom, b = 15.832 (4) angstrom, c = 22.471 (7) angstrom, beta = 98.42 (3)-degrees, Z = 4, R = 0.047, R(w) = 0.059. Crystal data for 3: orthorhombic, Cmca, a = 20.67 (1) angstrom, b = 9.116 (5) angstrom, c = 20.90 (1) angstrom, Z = 4, R = 0.058, R(w) = 0.072.