SYNTHESIS AND STRUCTURE OF THE TRIMOLYBDENUM CLUSTER [(CPMOCL)3(MU-CL)4(MU-3-O)]

The title compound is obtained from CpMoCl3 is warm THF. The source of the oxygen atom is the solvent, the byproduct being 1,4-dichlorobutane. The structure shows a triangular array of molybdenum atoms without direct metal-metal bonds. Each atom bears one cyclopentadienyl group and a terminal Cl ligand, and four additional Cl atoms edge-bridge the triangular unit, two on one edge and the others one each on the two remaining edges. The oxygen atom is bonded to all three Mo atoms to complete a pseudooctahedral geometry for two metals and a four-legged piano stool geometry for the other metal. Crystal data: monoclinic, P2(1)/m, a = 7.950 (2) angstrom, b = 13.442 (4) angstrom, c = 10.049 (4) angstrom, beta = 97.87 (3)-degrees, V = 1063.7 (6) angstrom 3, Z = 2, and R = 2.98%. The solid-state structure is consistent with the magnetic susceptibility and with the H-1-NMR spectrum of the compound. These indicate that two unpaired electrons are localized on the electronically unsaturated unique metal.