Triruthenium clusters containing mono and bidentate phosphines: Synthesis, structure, thermal reactivity and fluxional behavior

Abstract The syntheses, structures and thermal reactions of [Ru3(CO)9{P(C4H3E)3}(μ-dppe)] (2, E = S; 3, E = O; dppe = 1,2-bis(diphenylphosphino)ethane) are described. These triphosphine-substituted clusters can be easily obtained in high yield from the Me3NO initiated room temperature reaction between [Ru3(CO)10(μ-dppe)] (1) and P(C4H3E)3. Both clusters have been structurally characterized which reveals that the functionalized phosphine P(C4H3E)3 is coordinated to the remote ruthenium atom using the phosphorus atom, while the NMR spectroscopic data indicate that both clusters are fluxional in solution mainly due to the ring-flipping process involving the dppe ligand which has been probed by VT NMR spectroscopy. Thermolysis of 2 at 66 oC affords 1 via P(C4H3S)3 dissociation, whilst that of 3 under similar experimental conditions also furnishes the diruthenium σ,π-furyl complex [Ru2(CO)6(μ,η2-C4H3O){μ-P(C4H3O)2] (4) in addition to 1.