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 [H2NCy2][Ru5(CO)15(μ4,-PO)]

A new family of phosphorus functionalized, pentanuclear ruthenium clusters Ru-5(CO)(15)(mu(4)-PR) [R = (NPr2)-Pr-i, NCy2, F, OMe, OEt. (OPr)-Pr-i. O-] has been synthesized and representative compounds structurally characterized. The reaction of Ru-4(CO)(13)(mu(3)-PNR2) (1) (R = Cy, Pr-t) with Ru-3(CO)(12) in refluxing heptane yields H2Ru3(CO)(9)(mu(3)-PNR2) (2) and Ru-5(CO)(15)(mu(4)-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 Ru-5(CO)(15)(mu(4)-PF) (4) in high yield. In contrast, refluxing 3 with HBF4. H2O in CH2Cl2 yields 4 and [R2NH2][Ru-5(CO)(15)(mu(4)-PO)] (5), a cluster containing a mu(4)-phosphorus monoxide (PO) ligand. The reaction of 4 with alcohols affords the series of alkoxy phosphinidene cluster complexes Ru-5(CO)(15)(mu(4)-POR') (6) (R' = Me, Et, Pr-i). The structures of 2a (R = NCy2), 3a (R = NCy2), 4 (R = F), and the phosphorus monoxide cluster [H2NCy2][Ru-5(CO)(15)(mu(4)-PO)] (5a and 6a) (R' = Me) have been determined by X-ray diffraction studies. (C) 2000 Elsevier Science S.A. All rights reserved.