Electrophilic aromatic substitution and single‐electron transfer (SET) by the phenylium ion in the gas phase: characterization of a long‐lived SET intermediate

Abstract

Gas-phase mass spectrometric studies and calculations were performed for the reaction of naked phenylium ion with several benzene halides. From these reactions, the molecular ion for biphenyl as the predominant product was obtained only from the reaction of phenylium ions with iodobenzene and bromobenzene. Furthermore, through the collision-induced dissociation (CID) of the ion at m/z 281, the only dissociation observed is the loss of a phenyl radical, which indicates that a single-electron transfer (SET) mechanism might have occurred within the reaction. Additionally, according to the comparison between the CID experiments of those isomeric compounds of the sigma-complexes and the CID experiment of the ion at m/z 281 captured in the ion trap, we have also defined the captured ion at m/z 281 as an SET-intimate ion pair rather than those of sigma-complexes or the diphenyliodonium.