title: Intramolecular cation-π interactions in protonated phenylalanine derivatives.
abstract: The structures and properties of a series of phenylalanine (Phe) derivatives have been investigated in a joint computational and experimental infrared multiple photon dissociation (IRMPD) study. IRMPD spectra in the 1000-2000 cm-1region 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.
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Weiqiang
authors.initials: W
authors.lastname: Fu
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Patrick J J
authors.initials: PJ
authors.lastname: Carr
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Lecours
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Michael
authors.initials: M
authors.lastname: Burt
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Rick A
authors.initials: RA
authors.lastname: Marta
authors.affiliation: Laboratoire Chimie Physique - CLIO, Bâtiment 201, Porte 2, Campus Universitaire d'Orsay, Orsay, 91405, France.
authors.forename: Vincent
authors.initials: V
authors.lastname: Steinmetz
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Eric
authors.initials: E
authors.lastname: Fillion
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: Terrance B
authors.initials: TB
authors.lastname: McMahon
authors.affiliation: Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada. shopkins@uwaterloo.ca.
authors.forename: W Scott
authors.identifier: http://orcid.org/0000-0003-1617-9220
authors.initials: WS
authors.lastname: Hopkins