The mixed-metal carbonyl cluster anion [Ru3Ir(CO)13]–: synthesis, molecular structure, fluxionality, reactivity†
Abstract
The new cluster anion [Ru3Ir(CO)13]–1 was synthesized in high yield from [Ru3(CO)12] and [Ir(CO)4–. The single-crystal X-ray structure analysis of the bis(triphenylphosphoranylidene)ammonium salt revealed the presence of two isomers, [Ru3Ir(CO)11(µ-CO)2]–1a and Ru3Ir(CO)9(µ-CO)4]–1b in the same crystal. Both 1a and 1b present a tetrahedral Ru3Ir framework, differing only by the number of bridging carbonyl ligands. Variable-temperature 13C NMR spectroscopic studies of 1 revealed the fluxionality of the carbonyl ligands and the interconversion of both isomers in solution. Protonation of 1 gave the neutral cluster [HRu3Ir(CO)13] 2, whereas reaction of 1 with molecular hydrogen yielded the anion [H2Ru3Ir(CO)12]–3. Either hydrogenation of 2 or protonation of 3 gave [H3Ru3Ir(CO)12] 4. The tetrahedral structure of the hydrido derivatives was confirmed by a single-crystal X-ray structure analysis of the bis(triphenylphosphoranylidene)ammonium salt of 3.