SYNTHESIS, CRYSTAL-STRUCTURE, PHOTOPHYSICAL PROPERTIES AND THEORETICAL-STUDIES OF [CU-3(PH(2)PCH(2)PPH(2))(3)(WS4)]CLO4

The reaction of [Cu-2(dppm)(2)(MeCN)(4)](2+) [dppm = bis(diphenylphosphino)methane] with [WS4](2-) gives the cationic d(0)-d(10) complex [Cu-3(dppm)(3)(WS4)](+), the crystal structure of which has been determined. The three copper atoms and the thiotungstate ligand form a distorted 'flywheel' array with W...Cu separations of 2.790(3), 2.803(3) and 2.834(3) Angstrom. In the solid state the complex shows an intense emission with lambda(max) at 615 nm. Extended-Huckel molecular-orbital calculations reveal that the emitting state may arise from a [psi(Cu,P)-->W-VI] charge-transfer transition.