Thermal and Photolytic Reactions of Gallium and Indium Atoms (M) and Their Dimers M₂ with Carbon Monoxide in Low-Temperature Matrices: Formation of Terminal, Bridged, and Ionic Carbonyl Derivatives

Abstract

Infrared spectroscopy has been used to chart the thermal reactions occurring following co-deposition of gallium or indium vapors with carbon monoxide-doped argon at ca. 12 K, as well as the reactions subsequently induced by irradiating the resulting matrix with UV light (λ = 200−400 nm). Following deposition, the molecules GaCO, InCO, Ga·GaCO, In·InCO, Ga(μ-CO)Ga, Ga(CO)2, In(CO)2, and In(CO)2·In were generated. Under the action of UV light, the Ga/CO system gives rise to the new gallium carbonyl Ga(μ-CO)2Ga. Under similar conditions, the complex In+[C2O2]•- is formed as a result of significant charge transfer between the metal and the CO ligands and with the concomitant linking together of two such ligands via a C−C bond. Assignments of the absorption bands are made and the products characterized on the basis of 13C substitution and by comparison with the vibrational properties of known carbonyl derivatives or with those forecast for novel species by DFT calculations.