Reactions of Laser-Ablated Iridium Atoms with O2. Infrared Spectra and DFT Calculations for Iridium Dioxide and Peroxo Iridium(VI) Dioxide in Solid Argon

Laser-ablated iridium atoms react with O 2 to give the linear dioxide OIrO and the side-bound dioxygen adduct (O 2 )IrO 2 as primary reaction products, with ν 3 absorptions at 930.0 and 875.0 cm -1, respectively. The (ν 1 + ν 3 ) combination bands for these species were observed, confirming the assignments of the ν 1 and ν 3 modes for (O 2 )IrO 2 and providing an estimate for the ν 1 mode in OIrO. The symmetric and antisymmetric stretching modes of the Ir(O 2 ) ring in (O 2 )IrO 2 were also observed. Density functional calculations support these assignments and show that the (O 2 )IrO 2 species is best formulated as a peroxide with iridium in the +6 oxidation state, providing the first example of an iridium(VI) oxo complex.