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

Reaction of [Cp*IrCl2](2) with in situ generated H2Se at 140 degrees C gives triangular cluster [Cp*3Ir(3)Se(2)](2+) which was isolated and characterized as new [Cp*3Ir(3)Se(2)](BF4)(2) (1) salt by X-ray, ESI-MS, Se-77 NMR techniques, and by theoretical calculations. The same reaction in the presence of CH2O gives two Se-containing products - [Cp*3Ir(3)(mu(3)-Se)(2)][ZnCl3(MeOH)](2)center dot MeOH (2) and (SeMe3)[ZnCl4] (3). Both complexes were characterized by X-ray diffractometry and Se-77 NMR. Cyclic voltammetry of [Cp*3M(3)Se(2)](2+) (M = Rh, Ir) is reported. Two consecutive two-electron reversible reductions have been identified for [Cp*3Rh(3)Se(2)](2+). [Cp*3Ir(3)Se(2)](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. (C) 2014 Elsevier B. V. All rights reserved.