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.