Precursors of quadruply bridging phosphorus monoxide ligands: synthesis and structural characterization of a new family of anionic fluoro and alkoxyphosphinidene clusters Ru5(CO)15(μ4-PR) (R = NiPr2, NCy2, F, OMe, OEt, OiPr): generation and structure of [

A new family of phosphorus functionalized, pentanuclear ruthenium clusters Ru5(CO)15(μ4-PR) [R = NiPr2, NCy2, F, OMe, OEt, OiPr, O−] has been synthesized and representative compounds structurally characterized. The reaction of Ru4(CO)13(μ3-PNR2) (1) (R = Cy, iPr) with Ru3(CO)12 in refluxing heptane yields H2Ru3(CO)9(μ3-PNR2) (2) and Ru5(CO)15(μ4-PNR2) (3). An alternative high-yield synthesis for 3 is the reaction of 1 with Ru(CO)5 in refluxing hexane. Treatment of 3 with HBF4·Et2O produces Ru5(CO)15(μ4-PF) (4) in high yield. In contrast, refluxing 3 with HBF4·H2O in CH2Cl2 yields 4 and [R2NH2][Ru5(CO)15(μ4-PO)] (5), a cluster containing a μ4-phosphorus monoxide (PO) ligand. The reaction of 4 with alcohols affords the series of alkoxy phosphinidene cluster complexes Ru5(CO)15(μ4-POR′) (6) (R′ = Me, Et, iPR). The structures of 2a (R = NCy2), 3a (R = NCy2), 4 (R = F), and the phosphorus monoxide cluster [H2NCy2][Ru5(CO)15(μ4-PO)] (5a and 6a) (R′ = Me) have been determined by X-ray diffraction studies.