SYNTHESIS AND PHOTOCHEMICAL REACTIVITY OF PHENYLTHIOUREATOTRIOSMIUM CLUSTER COMPLEXES - CRYSTAL-STRUCTURES OF [OS3H(CO)10(MU-SC(NPH)(NHPH))] AND [OS3H(CO)9(MU-3-SC(NPH)(NHPH))]

The reaction of [Os3(CO)10(MeCN)2] with phenylthiourea (HL1) and N,N'- diphenylthiourea (HL2) yielded the thioureatotriosmium cluster complex es [OsH(CO)10(mu-L)] (L = L1 or L2) in which the thioureate moiety L b ridges two osmium atoms via the sulfur atom. The complexes underwent p hotochemical reactions with a nitrogen atom of the thioureate ligand d isplacing a carbonyl on the third osmium atom to give [Os3H(CO)9(mu3-L )] (L = L1 or L 2) . These reactions proceed cleanly and the quantum y ields and apparent activation energies have been determined. The clust er complexes have been characterized by spectroscopic means and the st ructures of [Os3H(CO)10(mu-L2)] and [Os3H(CO)9(mu3-L2) have been deter mined by X-ray diffraction: [Os3H(CO)10(mu-L2)], triclinic, space grou p P1BAR, a = 11.607(3), b = 14.341(3), c = 9.520(3) angstrom, alpha = 104.92(2), beta = 112.62(2), gamma = 94.02(2)-degrees, and Z = 2, [Os3 H(CO)9(mu3-L2)]. monoclinic, space group P2(1)/m, a = 9.583(3), b = 14 .249(3), c = 9.969(3) angstrom, beta = 103.53(2)-degrees, and Z = 2. T he structures were refined to R = 0.035 and 0.046 for 3791 and 3987 un ique diffraction data respectively. In both clusters one edge of the o smium triangle is bridged by a sulfur atom and in [Os3H(CO)9(mu3-L2)] one of the nitrogen atoms of the thioureate ligand has displaced a car bonyl from the third osmium of the cluster.