Electron-deficient triruthenium clusters: synthesis and molecular structure of the anion [HRu3(CO)(7)(PCy3)(2)](-), a second example of an Ru-3 cluster presenting an electron count of 44 electrons

The reaction of [HRu3(CO)(11)](-) (1) with an excess of PCy3 in refluxing T HF gives the electron-deficient anion [HRu3(CO)(7)(PCy3)(2)](-) (2) which h as the rare electron count of 44e. As evidenced by the H-1 and P-31 NMR spe ctra, 2 exists in solution in the form of two isomers 2a and 2b, one of whi ch crystallises from acetone as the tetraethylammonium salt. The single-cry stal X-ray analysis shows a closed Ru, framework with the hydride ligand br idging the metal-metal bond between a phosphine-substituted and a phosphine -free ruthenium atom (isomer 2b). (C) 1999 Elsevier Science S.A. All rights reserved.