Precursors of quadruply bridging phosphorus monoxide ligands: synthesis and structural characterization of a new family of anionic fluoro and alkoxyphosphinidene clusters Ru 5(CO) 15(μ 4-PR) (R = N iPr 2, NCy 2, F, OMe, OEt, O iPr): generation and structure of [H 2NCy 2][Ru 5(CO) 15(μ 4-PO)

Abstract

A new family of phosphorus functionalized, pentanuclear ruthenium clusters Ru 5(CO) 15(μ 4-PR) [R = N i Pr 2, NCy 2, F, OMe, OEt, O i Pr, O −] has been synthesized and representative compounds structurally characterized. The reaction of Ru 4(CO) 13(μ 3-PNR 2) ( 1) (R = Cy, i Pr) with Ru 3(CO) 12 in refluxing heptane yields H 2Ru 3(CO) 9(μ 3-PNR 2) ( 2) and Ru 5(CO) 15(μ 4-PNR 2) ( 3). An alternative high-yield synthesis for 3 is the reaction of 1 with Ru(CO) 5 in refluxing hexane. Treatment of 3 with HBF 4·Et 2O produces Ru 5(CO) 15(μ 4-PF) ( 4) in high yield. In contrast, refluxing 3 with HBF 4·H 2O in CH 2Cl 2 yields 4 and [R 2NH 2][Ru 5(CO) 15(μ 4-PO)] ( 5), a cluster containing a μ 4-phosphorus monoxide (PO) ligand. The reaction of 4 with alcohols affords the series of alkoxy phosphinidene cluster complexes Ru 5(CO) 15(μ 4-POR′) ( 6) (R′ = Me, Et, i PR). The structures of 2a (R = NCy 2), 3a (R = NCy 2), 4 (R = F), and the phosphorus monoxide cluster [H 2NCy 2][Ru 5(CO) 15(μ 4-PO)] ( 5a and 6a) (R′ = Me) have been determined by X-ray diffraction studies.