A homoleptic beryllium carbonyl complex with an end-on and side-on bridging carbonyl ligand

Homoleptic dinuclear beryllium carbonyl cation complexes have been produced and characterized in the gas phase. Infrared photodissociation spectroscopic and theoretical results confirm that Be${}_2$(CO)${}_5$${}^{+}$ is a coordination saturated complex that can be assigned to a mixture of two almost isoenergetic structural isomers. Besides a beryllium-beryllium single-bonded (OC)${}_2$Be-Be(CO)${}_3$${}^{+}$ isomer, another structure involving an unusual end-on and side-on bridging carbonyl ligand with very low carbonyl stretching frequency is identified. (© 2020 Wiley‐VCH GmbH)