Hydrogen selenide in M–Se and C–Se bond formation. [Cp*3Ir3Se2]2+ clusters: New synthesis, molecular and electronic structure and related studies

Abstract

Reaction of [Cp*IrCl2]2 with in situ generated H2Se at 140 °C gives triangular cluster [Cp*3Ir3Se2]2+ which was isolated and characterized as new [Cp*3Ir3Se2](BF4)2 (1) salt by X-ray, ESI-MS, 77Se NMR techniques, and by theoretical calculations. The same reaction in the presence of CH2O gives two Se-containing products – [Cp*3Ir3(μ3-Se)2][ZnCl3(MeOH)]2·MeOH (2) and (SeMe3)[ZnCl4] (3). Both complexes were characterized by X-ray diffractometry and 77Se NMR. Cyclic voltammetry of [Cp*3M3Se2]2+ (M = Rh, Ir) is reported. Two consecutive two-electron reversible reductions have been identified for [Cp*3Rh3Se2]2+. [Cp*3Ir3Se2]2+ undergoes only a single-step two electron quasi reversible reduction. Quantum-chemical calculations show the presence of Ir–Ir bonds inside the trinuclear cluster core.