Transformations of Triphenylgermyl Ligands in Iridium-Ruthenium Carbonyl Cluster Complexes

The new compound IrRu3(CO)(11)(GePh3)(3)(mu-H)(4), 1, was obtained in 64% yield from the reaction of IrRu3(CO)(13)(mu-H) with HGePh3 at room temperature. Compound 1 has a butterfly structure for the four metal atoms with three GePh3 ligands and four bridging hydride ligands around the periphery of the cluster. When the reaction was performed at hexane reflux for 10 min, a second, minor compound, Ir2Ru2(CO)(11-)(GePh3)(mu-H)(3), 2, was formed. Compound 2 contains a closed cluster having two iridium and two ruthenium atoms, one GePh3 ligand, and three bridging hydride ligands. When compound 1 was heated to 68 degrees C for 6 h, two new compounds, IrRu3(CO)(10)(mu-eta(2)-C6H5)(mu-GePh)(2), 3, and IrRu3(CO)(9)(mu-eta(2)-C6H5)(mu(4)-GePh)(2)(mu-GePh2), 4, were formed by cleavage of phenyl rings from the GePh3 ligands. Compounds 3 and 4 contain square IrRu3 clusters of the metal atoms with quadruply bridging GePh germylyne ligands on opposite sides of the cluster. Both compounds also contain a rare eta(2)-bridging phenyl ligand. Compound 4 was found to react with dimethylacetylenedicarboxylate (DMAD) to yield the new compound IrRu3(CO)(9)([mu(4)-Ge(Ph)C(CO2Me)C(CO2Me)](mu-GePh2)(2), 5, by addition of DMAD to one of the bridging germylyne ligands. In the process the bridging phenyl ligand was transferred to the other bridging germylyne ligand to form a bridging germylene ligand.