Synthesis, structure, and reactivities of the Ru–Co heterobimetallic complex. Molecular structures of Cp*Ru(CO)2(μ2-CO)Co(CO)3, Cp*Ru(μ2-CO)2(μ2-dppm)Co(CO)2, Cp*Ru(CNBut)(CO)(μ2-CO)Co(CO)3, and Cp*(CO)Ru{η2:η4–μ2–C(Tol)CHC(Tol)CH}Co(CO)2 (Cp*=η5-C5Me5, d

Treatment of Cp*Ru(CO)2Cl (Cp*=η5-C5Me5) with NaCo(CO)4 produces the metal–metal bonded heterobimetallic complex Cp*Ru(CO)2(μ2-CO)Co(CO)3 (2b). Substitution of the CO ligands by the Ph2PCH2PPh2 (dppm) leads to the isolation of Cp*Ru(μ2-CO)2(μ2-dppm)Co(CO)2 (3) whereas that by ButNC gives Cp*Ru(CO)(CNBut)(μ2-CO)Co(CO)3 (4). Stoichiometric head-to-tail dimerization of p-tolylacetylene at the bimetallic site of 2b proceeds to form the dinuclear metallacyclopentadiene complex Cp*(CO)Ru{η2:η4-μ2-C(Tol)CHC(Tol)CH}Co(CO)2 (5) in which two alkyne molecules are coupled to form a ruthenacyclopentadiene core which coordinates to the Co(CO)2 fragment. On the other hand, catalytic head-to-head coupling of methyl propiolate in the presence of 2b yields (E)-(MeO2C)CHCH(CCCO2Me) (6). The molecular structures of 2b, 3, 4, and 5 have been determined by X-ray crystallography.