Cluster synthesis. 43. New layer-segregated platinum-ruthenium cluster complexes and their reactions with diphenylacetylene

Article abstract of DOI:10.1021/om00018a030

The new complex Pt₃Ru₆(CO)₂₁(μ-H)₃(μ ₃-H) (1) was obtained in 83% yield from the reaction of Ru₄Pt₂(CO)₁₈ with hydrogen (1 atm) at 97°C. The molecular structure was found to consist of three triangular layers of nine metal atoms arranged in the form of a face-shared bioctahedron. The central shared layer consists of three platinum atoms, while the outer layers consist of ruthenium triangles. Three hydride ligands bridge each edge of one Ru₃ triangle, while the fourth hydride ligand is a triple bridge across the other Ru₃ triangle. Compound 1 was converted to the alkyne complex Pt₃Ru₆(CO)₂₀(μ₃-PhC ₂Ph)(μ₃-H)(μ-H) (2) by reaction with PhC₂Ph. This complex contains a layered structure of Pt₃ and Ru₃ triangles similar to 1 but also has a triply bridging PhC₂Ph ligand coordinated to one of the ruthenium triangles. Compound 2 slowly adds 1 equiv of CO to form the complex Pt₃Ru₆(CO)₂₁[μ-PhCC(H)Ph](μ-H) (3) which contains an edge bridging σ-π coordinated diphenylvinyl ligand formed by the transfer of one of the hydride ligands in 2 to the diphenylacetylene ligand. Treatment of 3 with CO yields (Z)-stilbene by transfer of the remaining hydride ligand to the diphenylvinyl ligand, and the cluster is then degraded to Ru₃(CO)₁₂ and Pt₂Ru₄(CO)₁₈. Crystal Data: for 1, space group = P2₁/c, a = 18.157(3) A?, 6 = 11.701(4) A?, c = 17.580(4) A?, β = 101.03(2)°, Z = 4, 2657 reflections, R = 0.033; for 2, space group Pccn, a = 10.848(2) A?, b = 45.507(4) A?, c = 17.169(2) A?, Z = 8, 4441 reflections, R = 0.043; for 3, space group P2₁/c, a = 12.360(6) A?, b = 11.521(4) A?, c = 16.628(8) A?, β = 106.10(4)°, Z = 2, 2061 reflections, R = 0.041.