A novel ligand modification and diamond-core molybdenum(IV) 2,6-bis(2,2-diphenyl-2-thioethyl)pyridinate(2-) complex

The reaction of Mo(VI)O(2)(L-NS(2)) [L-NS(2) = 2,6-bis(2,2-diphenyl-2-thioethyl)pyridinate(2-)] or Mo(V)(2)O(3)(L-NS(2))(2) with excess PPh(3) in N,N-dimethylformamide at 70 degrees C results in the formation of gray-green (L-NOS)Mo(IV)(mu-O)(mu-S)Mo(IV)(L-NS(2)) [L-NOS = 2-(2,2-diphenyl-2-thioethyl)-6-(2,2-diphenyl-2-oxoethyl)pyridinate(2-)] (1). The crystal structure of 1 revealed a dinuclear complex comprised of two trigonal bipyramidal Mo centers bridged along an axial-equatorial edge (the mu-O-mu-S vector) such that the Mo-N bonds are trans to the bridging atoms and are anti with respect to the Mo-Mo bond (d(Mo-Mo) = 2.5535(5) A); the remaining coordination sites are occupied by the S- and O-donor atoms of the L-NOS and L-NS(2) ligands. The diamond core is asymmetric, with Mo(1/2)-O(1) distances of 1.845(2) and 2.009(2) A and Mo(1/2)-S(1) distances of 2.374(1) and 2.230(1) A. Compound 1 is unique in possessing a planar, diamond-core unit devoid of terminal oxo ligation and a new tridentate L-NOS ligand formed via a novel intramolecular modification of the original L-NS(2) ligand.