Organoindium thiolate oligomers: An X-ray structural study

The reaction of R{sub 3}In (R = methyl, tert-butyl, xylyl) with bis(tricyclohexyltin) sulfide, 2-methylpropane-2-thiol, 4,6-dimethyl-2-mercaptopyrimidine, cyclopentanethiol, cyclohexanethiol, 2,5-dimethylbenzenethiol, or 2,6-methylbenzenethiol has yielded seven new indium-sulfur complexes. These complexes have been studied by {sup 1}H and {sup 13}C NMR spectroscopy, and their structures have been determined by single-crystal X-ray diffraction techniques. Four of the complexes form dimeric species with planar (In-S){sub 2} cores, one complex forms a trimer which adopts a skew-boat conformation, one complex forms a trimer with a planar six-membered (InS){sub 3} ring with a secondary In-N interaction, giving rise to a pseudo-five-coordinate In atom, and the seventh complex forms a tetramer in an extended chair conformation, the first known indium tetramer. Several of the factors of importance to the structures of these compounds, and especially those which lead to the unusual planar derivative, will be discussed.