Reactions of the cluster anion [HRu3(CO)(11))](-) with dicyclohexylphosphine: Synthesis and molecular structure of H2Ru3(CO)(8)(PCy2)(2) and H2Ru3(CO)(6)(PCy2)(2)(HPCy2)(2)

The cluster anion [HRu3(CO)(11)](-) (1) reacts with dicyclohexylphosphine i n THF solution to give the anionic derivative [HRu3(CO)(8)(PCy2)(2)](-) (2) , protonation of which yields the neutral cluster H2Ru3(CO)(8)(PCy2)(2) (3) and, in the presence of excess phosphine, HRu3(CO)(7)(PCy2)(3) (4). In pro tic methanol as reaction medium, the reaction of 1 with HPCy2 gives directl y the neutral complex H2Ru3(CO)(6)(PCy2)(2)(HPCy2)(2) (5). together with 4. The single-crystal structure X-ray analysis of 3 shows a closed triangular Ru, framework. Tho electron count is in accordance with the EAN rule, but the structure analysis of 5 reveals an open, almost linear Ru, skeleton, wh ich is electron-deficient with respect to the EAN rule.