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

Abstract

The reaction of [HRu 3(CO) 11] − ( 1) with an excess of PCy 3 in refluxing THF gives the electron-deficient anion [HRu 3(CO) 7(PCy 3) 2] − ( 2) which has the rare electron count of 44e. As evidenced by the 1H and 31P NMR spectra, 2 exists in solution in the form of two isomers 2a and 2b, one of which crystallises from acetone as the tetraethylammonium salt. The single-crystal X-ray analysis shows a closed Ru 3 framework with the hydride ligand bridging the metal–metal bond between a phosphine-substituted and a phosphine-free ruthenium atom (isomer 2b).