SYNTHESIS AND CHARACTERIZATION OF BINUCLEAR DERIVATIVES OF MOLYBDENUM-MANGANESE, TUNGSTEN-MANGANESE, AND RHENIUM-MANGANESE CONTAINING THE BRIDGING ETA-5-ETA-1-CYCLOPENTADIENYL GROUP .14.

The treatment of (η5-C5H5)MH2 (M = Mo or W) with CH3Mn(CO)5 gives as principal products respectively the binuclear complexes [formula ommited]where M = Mo (la) and M = W (lb), each accompanied by the evolution of methane and hydrogen; from (η5-C5H5)2ReH and CH3Mn(CO)5 one obtains (η5-C5H5)(H)Re(μ-(η5:n1-C5H4)) Mn(CO)4 (2), with evolution of methane and carbon monoxide. Studies with deuterium-labeled starting materials confirm that the methane in these reactions is formed from a hydrogen atom of a cyclopentadienyl ring of the metallocene hydride and the methyl group of CH3Mn(CO)5. The deuterium atom remaining in a sample of 2-d1 obtained from (η5-C5H5)2ReD and CD3Mn(CO)5, is found to be randomly distributed over all positions indicating an intramolecular hydrogen tautomerism in this bimolecular metalation product. With H2 at ambient temperatures, lb yields an unstable intermediate (η5-C5H5)2(H)W-Mn(CO)5 which is converted at 80 °C in the presence of H2 to (η5-C5H5)2WH2 and Mn2(CO)10; with D2 at 80 °C, the metallocene hydride obtained is found to contain extensive exchange of deuterium for hydrogen. The binuclear complex 2 is stable toward H2 up to 80 °C but shows exchange of deuterium for hydrogen when treated with D2 at that temperature. Treatment of lb with phosphorus-containing ligands gives substitution products with evolution of CO and no evidence of the formation of any acyl complexes. © 1979, American Chemical Society. All rights reserved.