Chemistry of cyclopentadienyl tricarbonylchromium dimer. Cleavage of bis(thiophosphinyl)disulfanes and bis(thiophosphoryl)disulfanes. Syntheses of CpCr(CO)(2)(S2PPh2) and CpCr(S2PPh2)(2). X-ray crystal structure of CpCr(S2PPh2)(2)

The facile reaction of [CpCr(CO)(3)](2) with one mole equivalent of bis(dip henylthiophosphinyl)disulfane, Ph2P(S)SSP(S)PPh2, led to the isolation of d ark purplish brown solids of CpCr(CO)(2)(S2PPh2) (2) and blue solids of CpC r(S2PPh2)(2) (3) in 50 and 10% yields, respectively. Proton NMR spectral st udies demonstrated that 3 is derived from 2, the primary product. IR spectr al data indicated that 2 possesses cis CO ligands and a bidentate SP(S)Ph-2 ligand, whilst 3 contains both a unidentate and a bidentate ligand, as con firmed by its X-ray diffraction analysis. Variable temperature H-1 and P-31 spectral studies showed the occurrence of very rapid unidentate-bidentate exchange between the ligands in 3 in the temperature range - 80-60 degrees C. (C) 2000 Elsevier Science S.A. All rights reserved.