Syntheses and reactivity studies of the carbido-alkylidyne cluster complexes LWRu4(μ5-C)(μ-CPh)(CO)12 and LWRu5(μ6-C)(μ-CPh)(CO)14, L = Cp and Cp, obtained from reversible scission of acetylide ligand

Treatment of a 1:1 mixture of Rus(CO)(12) and the acetylide cluster LWRu2(CO)(8)(C2Ph) (1, L = Cp and Cp*) in hydrocarbon solvents afforded two carbido-alkylidyne cluster complexes, LWRu4(mu (5)-C)(CO)(12)(mu -CPh) (2) and LWRu5(mu (6)-C)(CO)(14)(mu -CPh) (3). Complexes 2 contain a square pyramidal cluster skeleton with a mu (5)-carbide and an accompanying bridging alkylidyne ligand, while WRu5 complexes 3 possess a distorted octahedral WRu5(L(G-C) framework. The transformation from 1 to 2 and 3 illustrates a reversible cleavage of an acetylide carbon-carbon bond induced by the cluster-building reaction. Moreover, the hydrogenation of complexes 2 and 3 was found to depend on the ancillary ligand on the W atom, showing selective formation of only two hydride complexes, CpWRu4(mu5-C)(mu -CPh)(mu -H)(2)(CO)(11) (4) and Cp*WRu5(mu -C)(mu -CPh)(mu -H)(2)(CO)(13) (5), respectively. Single-crystal X-ray analysis on complex 4 indicated that the hydrides resided near the apical Ru atom, while the hydrides in complex 5 were associated with the unique W metal atom. Finally, treatment of 2 with thiophenol has led to formation of the wingtip-bridged butterfly complexes LWRu4(mu (5)-C)(mu -CPh)(mu -H)(mu -SPh)(CO)(11) (7a, L = Cp; 7b, L = Cp*), in which the thiolate ligand is bonded to the Ru atoms separated by a nonbonding distance of 3.4186(8) Angstrom.