Effects of molecular geometry on the fragmentation of ionized maleic and fumaric acids; an overdue reappraisal

Abstract

AbstractThe ionized geometric isomers maleic and fumaric acids ((Z)‐ and (E)‐ethenedicarboxylic acids) were studied by a variety of tandem mass spectrometric techniques. In agreement with much earlier work, the metastable ionized isomers do not reversibly interconvert. They do, however, have two dissociation channels, H2O and CO losses, for which common transition states are involved. Ionized maleic acid has one geometry‐specific dissociation, loss of CO2. Structures were assigned to all major fragment ions together with their heats of formation.