From the reaction of CpWIr3(CO)11 with excess diphenylacetylene in refluxing toluene, two products have been isolated as crystalline solids: brown CpWIr3(CO)7(mu3,eta2-C2Ph2)2 (1a) and red CpWIr3(CO)5(mu-CPh)(mu3-CPh){mu,eta4-C(Ph)C(Ph)C(Ph)C(Ph)} (1b) in 40% and 37% yields, respectively. Analytical and spectroscopic data in support of these formulations as well as the results of single-crystal X-ray diffraction studies of both compounds are reported. Compound la has two distinct alkyne units bonded to separate faces of the closed (tetrahedral) WIr3 cluster core. In contrast compound lb has an open (butterfly) core with the tungsten atom at a 'hinge' position, and the alkyne ligands have undergone either C=C scission to give mu2- and mu3-coordinated alkylidyne moieties or dimerization via C-C coupling to give an iridacyclopentadienyl system. The possible relationship of these transformations to the pathways involved in catalytic butane hydrogenolysis over Ir/W(Mo) cluster-derived catalysts are discussed.
