Infrared spectroscopy of Be(CO) in the gas phase: electron transfer and C-C coupling of CO.

Beryllium-carbon dioxide cation complexes Be(CO) are produced by a laser vaporization-supersonic expansion ion source in the gas phase. Mass-selected infrared photodissociation spectroscopy supplemented by theoretical calculations confirms that Be(CO) is a coordination saturated complex that can be assigned to a mixture of two isomers. The first structure involves a bent CO ligand that is bound in a monodentate η-O coordination mode. Another isomer has a metal oxalate-type CO moiety with a C-C hemibond.