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 cap** two PtRu₂ triangular faces. There are two PhC₂Ph ligands bridging two Ru₃ triangular faces of the central octahedron.