Reaction of PtRu5(CO)(15)(PBU3t)(C), 3, with hydrogen at 97 degrees C yielded the new dihydride-containing cluster compound PtRu5(CO)(14)(PBU3t)(mu-H)(2)(mu(6)-C), 5. Compound 5 was characterized crystallographically and was shown to contain an octahedral cluster consisting of one platinum and five ruthenium atoms with a carbido ligand in the center. Two hydrido ligands bridge two oppositely positioned PtRu bonds. Compound 5 reacts with Pt(PBU3t)(2) to yield Pt2Ru5(CO)(14)(PBUt(3))(2)(mu-H)(2)(mu(6)-C), 6, a Pt(PBUt(3)) adduct of 5, by adding a Pt(PBu3t) group as a bridge across one of the Ru-Ru bonds in the square base of the RU5 portion of the cluster. Compound 6 is dynamically active on the NMR time scale by a mechanism that appears to involve a shifting of the Pt(PBU3t) group from one Ru-Ru bond to another. Two new complexes, PtRu5(CO)(13)(PBu3t)(mu-H)(3)(GePh3)(mu(5)-C), 7, and PtRu5(CO)(13)(PBu3t)(mu-H)(2)(mu-GePh2)-(U-6-C), 8, were obtained from the reaction of 5 with HGePh3, The cluster of 7 has an open structure in which the Pt(PBu3t) group bridges an edge of the square base of the square pyramidal RU5 cluster. Compound 7 also has three bridging hydrido ligands and one terminal GePh3 ligand. When heated to 97 degrees C, 7 is slowly converted to 8 by cleavage of a phenyl group from the GePh3 ligand and elimination of benzene by its combination with one of the hydrido ligands. The PtRU5 metal cluster of 8 has a closed octahedral shape with a GePh2 ligand bridging one of the Ru-Ru bonds. Two tin-containing compounds, PtRU5(CO)(13)(PBU3t)(mu-H)(3)(SnPh3)(mu(5)-C), 9, and PtRU5(CO)(13)-(PBu3t)(mu-H)(2)(mu-SnPh2)(mu(6)-C), 10, which are analogous to 7 and 8 were obtained from the reaction of 5 with HSnPh3.