Addition of Alkynes to High Nuclearity Platinum–Ruthenium Carbonyl Cluster Complexes

Abstract

The reactions of the mixed metal cluster complexes PtRu5(CO)16(μ6-C)[Pt(PBu \(^{{\rm t}}_3\))], 5 and PtRu5(CO)16(μ6-C)[Pt(PBu \(^{\rm t}_{3})\)]2, 6 with selected alkynes have been investigated. Compound 5 adds one and two equivalents of PhC2H to yield the new compounds PtRu5(CO)15(μ6-C)(μ3-PhC2H)[Pt(PBu \(^{{\rm t}}_3\))], 8 and PtRu5(CO) \(_{13}(\mu_6\)-C)( \(\mu_3\)-PhC2H)2[Pt(PBu \(^{{\rm t}}_3\))], 9 at 40 and 68°C, respectively. Compound 6 was found to react with PhC2H at 40°C to yield the new compound PtRu5(CO) \(_{16}(\mu_{6}\)-C)( \(\mu_3\)-PhC2H)[Pt(PBu \(^{{\rm t}}_3\))]2, 10. The reaction of 6 with PhC2Ph at 97°C yielded the new compound PtRu5(CO) \(_{12}(\mu_{6}\)-C)( \(\mu_3\)-PhC2Ph)2[Pt(PBu \(^{{\rm t}}_{3}\))]2, 11. All products were characterized crystallographically by single crystal X-ray diffraction techniques. The structure of 8 consists of a pseudo-octahedral PtRu5 cluster with a second platinum atom bridging a basal edge of the Ru5 square pyramid. A triply bridging PhC2H ligand is bonded to the two platinum atoms and one of the ruthenium atoms. The structure of 9 consists of a nido-dodecahedral Pt2Ru5 cluster with a carbido ligand in the interior that is not bonded to all seven of the metal atoms. It also contains two triply bridging PhC2H ligands. The structure of 10 consists of a central octahedral cluster of five ruthenium atoms and one platinum atom. Two additional platinum atoms are bonded to the platinum atom in this cluster but these atoms are not bonded to any other metal atoms of the PtRu5 cluster. A triply bridging PhC2H ligand is coordinated to the group of three platinum atoms. The structure of 11 consists of an octahedral PtRu5 cluster with two additional platinum atoms capping two PtRu2 triangular faces. There are two PhC2Ph ligands bridging two Ru3 triangular faces of the central octahedron.