SYNTHESIS AND CRYSTAL-STRUCTURE OF THE TETRABUTYLBIS(THIOPHENE GLOXYLATO) DISTANNOXANE DIMER, ([(C4H9)(2)SNO2CC(O)C4H3S]2O)(2)

Reaction of (n)Bu(2)SnO with thiophene glyoxylic acid yields the title compound which crystallizes as the centrosymmetric distannoxane dimer . Determination of the crystal structure of the compound reveals the p resence of two different environments for tin and two distinct carboxy late groups; one of the carboxylate groups bonds to the six-coordinate tin atom via a carboxylate and an cr-keto oxygen atom to form a five- membered chelate ring whereas the other carboxylate group forms a unid entate bridge (via one oxygen atom only) across the six-coordinate and five-coordinate tin centres.