Syntheses and reactivity of the diselenido molybdenum-manganese complex CpMoMn(CO)5(μ-Se2)

Reaction of CpMoMn(CO)(8) with elemental selenium and Me3NO in the absence of light yielded the diselenido complex CpMoMn(CO)(5)(mu-Se-2), 2. Compound 2 contains a bridging diselenido ligand lying perpendicular to the Mo-Mn bond, Mo-Mn = 2.8421(10) Angstrom. In the presence of room light, the reaction yielded the tetranuclear metal complex Cp2Mo2Mn2(CO)(7)(mu(3)-Se)(4), 3 (36% yield), and 2 (7% yield). Compound 2 reacted with ethylene to yield the ethanediselenato complex CpMoMn(CO)(5)(mu-SeCH2CH2Se), 4, by insertion of ethylene into the Se-Se bond. Compound 2 also reacted with (PPh3)(2)Pt(PhC2Ph) and CpCo(CO)(2) to yield the complexes CpMoMnPt(PPh3)(2)-(CO)(5)(mu(3)-Se)(2), 5, and Cp2CoMoMn(CO)(5)(mu(3)-Se)(2), 6, respectively, by insertion of the metal groupings CpCo and Pt(PPh3)(2) into the Se-Se bond of 2. The oxo compound Cp2CoMo(O)Mn(CO)(5)(mu(3)-Se)(2), 7, was obtained from 6 by decarbonylation at molybdenum by using Me3NO. The molecular structures of the complexes 2-7 were established by single-crystal X-ray diffraction analyses.