THE REACTION OF [OS-3(CO)(10)(CH3CN)(2)] WITH CARBOXYLIC-ACIDS - THE CRYSTAL AND MOLECULAR-STRUCTURES OF [OS3H(CO)(10)(C6H4(OH)CO2)] AND [OS3H(CO)(10)(C6H5COS)]

The triosmium cluster, [Os-3(CO)(10)(CH3CN)(2)], undergoes reaction wi th carboxylic acids to form clusters containing a chelating mu,eta(2)- carboxylate ligand and a hydride bridge across one edge of the triangl e via an intermediate species postulated, from IR and NMR studies, to contain a coordinated mu,eta(1)-carboxylate ion. The structure of the cluster, [Os3H(CO)(10)(C6H4(OH)CO2)] (1), has been determined by singl e-crystal X-ray diffraction and contains the 2-hydroxobenzoate ligand bound via the carboxylate oxygens in the mu,eta(2)-mode. A thiocarboxy late analogue of the postulated intermediate, viz. [Os3H(CO)(10)(C6H5C O2)] (2), has been obtained and its structure determined by single cry stal X-ray diffraction. The C6H5COS- ion, which is bound in the mu,eta (1)-mode through the sulfur atom, bridges two of the osmium atoms of t he triangle. (C) 1998 Elsevier Science S.A. All rights reserved.