Formation of [Cu(CO2)(CH3OH)]+ and [Cu(N2)(CH3OH)]+ by gas-phase dissociation and exchange reactions

Electrospray ionization and multiple-stage tandem mass spectrometry were used to study the collision-induced dissociation of methanol-coordinated copper-acetate cations, and the ion-molecule reactions of specific product ions. Our experiments led to the discovery of unusual gas-phase ions with compositions such as [Cu(CO2)(CH3OH)](+) and [Cu(N-2)(CH3OH)](+). The latter is generated by spontaneous exchange of CO2 for N-2 in an ion-molecule reaction. Isotopic labeling studies and high mass-resolution measurements provide data to support the product ion composition assignments. Density functional theory calculations corroborate the experimental observations, both with respect to the preferential decarboxylation over methanol ligand elimination, and the spontaneous nature of the ion-molecule reactions. (C) 2018 Elsevier B.V. All rights reserved.