Octahedral Iridium Clusters:  Synthesis, Electrochemical Mechanisms of Formation, and Solid-State Structures of [Ir6(CO)14(μ-TePh)]- and [Ir6(CO)13(μ-TePh)2]

The diphenyl ditelluride PhTeTePh reacts with [Ir6(CO)15]2- (in refluxing tetrahydrofuran) or Ir6(CO)16 (in toluene) yielding [Ir6(CO)14(μ-TePh)]- or [Ir6(CO)13(μ-TePh)2], respectively. Analogous mono- and disubstituted iridium compounds were prepared with other diaryl disulfides or diselenides. Electrochemical experiments confirm the different reactivity of PhTeTePh and PhSSPh showing that the ditelluride adds to the electrogenerated transient radical [Ir6(CO)15]-• and the disulfide to [Ir6(CO)15]0. The two clusters consists of octahedra of iridium atoms with one or two edges bridged by phenyltellurolate ligands. The Ir−Ir bonds trans to the TePh unit are remarkably short.