Reversible Intramolecular Single-Electron Oxidative Addition Involving a Hemilabile Noninnocent Ligand

Using the noninnocent ligand Q[= 4,6-di-tert-butyl-(2-methylthiophenylimino)-o-berizoquinone] with a thioether group as potential coordination function, it has been possible to substantiate a single-electron transfer induced oxidative addition;within the complex [IrCp*Q](0/+) (Cp* = C5Me5) via structural characterization (catecholato -> semiquinonato transition coupled with reversible S -> Ir coordination), via cyclic voltammetry, EPR, and DFT (semiquinone formulation with about 8% Ir participation). The intramolecular rearrangement of the 16-electron precursor [IrCp*Q] triggered by electron removal illuminates the complementary activities of the substrate binding metal and the electron-buffering ligand as was recently employed by Ringenberg et al. in dihydrogen activation (Organometallics 2010, 29, 1956).