Reaction of ruthenium carbonyl chloride with iridium tetracarbonyl anion. Synthesis, crystal structure and characterisation of [Ru2Ir2H(CO)(12)Cl]: aheterometallic tetranuclear butterfly cluster with chloride bridge

Reaction between [Ru-2(CO)(6)Cl-4] and Na[Ir(CO)(4)] in tetrahydrofuran (TH F) yielded [Ru2Ir2H(CO)(12)Cl], a new iridium-ruthenium mixed-metal cluster of possible catalytic interest. The cluster was characterised by H-1-NMR a nd infrared spectroscopy and by single-crystal X-ray structure analysis. [R u2Ir2H(CO)(12)Cl] exhibits a butterfly arrangement of metal atoms, with thr ee terminal carbonyls on each metal atom, chloride ligand in the bridging p osition, and hydride ligand at the Ir-Ir edge. The trinuclear ruthenium clu ster [Ru-3(mu-Cl)(2)(CO)(8)(PPhMe2)(2)] was synthesised by reaction of [Ru- 2(CO)(6)Cl-4] with K[Ir(CO)(4)] in THF, followed by ligand substitution wit h [PPhMe2] in CH2Cl2 at ambient temperature. Determination of the structure by X-ray diffraction showed it to consist of an open trinuclear unit invol ving two metal-metal bonds. The open edge of the metal framework is support ed by two symmetric bridging chloride ligands. Both phosphorus ligands are cis to the chlorine atoms and trans to the unique ruthenium atom. (C) 1999 Elsevier Science S.A. All rights reserved.