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

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) 2 Ga. Under similar conditions, the complex In + [C 2 O 2 ] •- 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 13 C substitution and by comparison with the vibrational properties of known carbonyl derivatives or with those forecast for novel species by DFT calculations.