Collision‐induced dissociation reactions of o‐, m‐ and p‐methoxyphenyl anions in the gas phase

Abstract

AbstractOn the basis of collision‐induced‐dissociation experiments, we show that o‐, m‐ and p‐methoxyphenyl anions, generated under negative‐chemical‐ionization (NCI) conditions from the corresponding ethyl methoxybenzoates, are distinct species.The main collision‐induced‐dissociation channel for the o‐methoxyphenyl anion is formaldehyde loss. This ion also loses a CH2 moiety, which indicates that it can rearrange to a stable C6H5OCH2− primary carbanion.Methyl‐radical loss is the major collision‐induced‐dissociation channel for both the m‐ and p‐methoxyphenyl anions. The kinetic energy release accompanying this dissociation is significantly larger for the former anion than for the latter. It is suggested that this is due to a greater stability of the product radical ion, if generated from the m‐methoxyphenyl anion rather than from the p‐methoxyphenyl anion.