Electron-deficient triruthenium and triosmium clusters from the reaction of the cluster anions [HM3(CO)11]- (M = Ru, Os) with tricyclohexylphosphine in methanol

The reaction of Na[HRu3(CO)(11)] with an excess of tricyclohexylphosphine in methanol gives the neutral complex H2Ru3(CO)(6)(PCy3)(3) which is the first 44 e(-) triruthenium cluster reported. This highly electron-deficient species reacts with carbon monoxide to give the saturated 48 e(-) cluster Ru-3(CO)(9)(PCy3)(3). The electronic structure of the novel 44 e- cluster was established by EHT and DFT molecular orbital calculations of isoelectronic model compounds. The analogous reaction of [N(PPh3)(2)][HOs3(CO)(11)] with PCy3 in methanol affords the 46 e(-) cluster H2Os3(CO)(7)(PCy3)(3), the first trisubstituted derivative of H2Os3(CO)(10). In all cases methanol acts as source of protons for the formation of the hydride clusters. (C) 1999 Elsevier Science S.A. All rights reserved.