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 i n methanol gives the neutral complex H2Ru3(CO)(6)(PCy3)(3) which is the fir st 44 e(-) triruthenium cluster reported. This highly electron-deficient sp ecies 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 fir st trisubstituted derivative of H2Os3(CO)(10). In all cases methanol acts a s source of protons for the formation of the hydride clusters. (C) 1999 Els evier Science S.A. All rights reserved.