Intramolecular cation–π interactions in protonated phenylalanine derivatives

This is the authors' abstract. We don't add key points for this paper.

region show that protonation is localized on the amine group in all cases. Intramolecular cation-π interactions between the ammonium group and the phenyl ring heavily influence molecular geometries and properties such as gas phase basicity and proton affinity. By varying substituents on the phenyl ring, one can sensitively tune the cation-π interaction and, therefore, the molecular structure and properties. Variations in molecular structures and properties as a function of phenyl ring substitution are shown to correlate with substituent Hammett parameters.