Dimolybdenum complexes with sulfide and thiolate ligands as precursors to mixed-metal clusters: crystal structure of [Mo2Ru2(µ3-S)2(µ-SPri)2(CO)4(η-C5H5)2]

Abstract

The reaction of [Mo₂(CO)₄(µ-C₂Me₂)(η-C₅H₅)₂]1 with thiols, RSH, in boiling toluene provides a useful new route to the known compounds [Mo₂(µ-S)₂(µ-SR)₂(η-C₅H₅)₂](R = Et 2a or Prⁱ2b) in 40–45% yield. Both compounds exist as two isomers which were separated by chromatography for R = Et. The sulfur ligands in these complexes are formed by dealkylation of the thiols at the dimolybdenum centre. Reaction of 2 with [Ru₃(CO)₁₂] in refluxing tetrahydrofuran produced high yields of the mixed-metal clusters [Mo₂Ru₂(µ₃-S)₂(µ-SR)₂(CO)₄(η-C₅H₅)₂]3; the crystal structure of the Prⁱ-substituted complex 3b has been determined. The cluster consists of a tetrahedral metal core with both Mo₂Ru faces capped by triply bridging sulfides. One of the thiolate ligands still bridges the molybdenum–molybdenum edge, but the other has migrated to the ruthenium–ruthenium edge.