HETERODINUCLEAR BIS(DIPHENYLPHOSPHINO)METHANE-BRIDGED MOLYBDENUM (D6)-GOLD (D10) COMPLEXES - METAL METAL INTERACTIONS AND LIGAND OXIDATION

Reinvestigation of the reaction between Ph3PAuCl and mer-Mo(dpm-PP')(dpm-P)(CO)3 (dpm = bis(diphenylphosphino)methane has shown it to be solvent dependent. The reaction in benzene yields orange {(OC)3ClMo-(mu-dpm)2Au} as reported before. Crystallization from benzene/diethyl ether gives {(OC)3ClMo(mu-dpm)2Au}.2-(C2H5)2O, which forms in the triclinic space group P1BAR with a = 13.699 (3) angstrom, b = 14.159 (4) angstrom, c = 16.187 (3) angstrom, alpha = 90.84 (2)-degrees, beta = 112.11 (2)-degrees, and gamma = 103.34 (2)-degrees at 130 K with Z = 2. Refinement of 9985 reflections and 658 parameters yielded R = 0.051 and R(w) = 0.049. The structure consists of trans-P2Mo(CO)Cl and trans-P2Au units with a long, nonbonded Mo...Au separation of 3.302 (1) angstrom. In dichloromethane solution the same reaction produces yellow [(dpm-0)2Mo(CO)2AuPPh3](PF6) after the addition of ammonium hexafluorophosphate. Some gold metal precipitates and the dpm ligand is oxidized to Ph2P(O)CH2PPh2 (dpm-0). [(dpm-O)2Mo-(CO)2AuPPh3](PF6)-CH2Cl2.0.25CH3OH.0.25H2O crystallizes in the monoclinic space group P2(1)/c with a = 27.489 (8) angstrom, b = 24.472 (5) angstrom, c = 22.085 (11) angstrom, and beta = 102.07 (3)-degrees at 130 K with Z = 8. Refinement of 9202 reflections and 576 parameters yielded R = 0.092 and R(w) = 0.091. The structure consists of a seven-coordinate molybdenum that is coordinated by two chelating dpm-0 ligands, two terminal carbon monoxide ligands, and the AuPPh3 unit. The Mo-Au distances (2.691 (3), 2.709 (3) angstrom) in the two independent cations found in the asymmetric unit are consistent with the presence of a single bond between these atoms.