Synthesis and Characterization of Mixed Ruthenium/Platinum μ₄-Phosphinidene, Phosphorus Monoxide, and Related Clusters

The mixed-metal cluster complexes [Ru₄(CO)₁₂Pt(CO)PPh₃(μ₄-PR)] [R = NⁱPr₂ (1), F (3)] were formed by capping the Ru₃P face of the nido clusters [Ru₄(CO)₁₃(μ₃-PR)] with the labile Pt(0) reagent [(η²-C₂H₄)Pt(PPh₃)₂]. The aminophosphinidene complex 1 undergoes acid hydrolysis to yield the PO complex [Ru₄(CO)₁₂Pt(CO)PPh₃(μ₄-PO)][H₂NⁱPr₂] (4). The fluorophosphinidene cluster 3 reacts with ethanol to form the alkoxyphosphinidene complex [Ru₄(CO)₁₂Pt(CO)PPh₃(μ₄-POEt)] (5). Comparison of spectroscopic and structural data for clusters 1, 3, 4, and 5 reveals the remarkable effects of the μ₄-phosphinidene and phosphorus monoxide ligands on cluster bonding.