title: A threshold for charge transfer in aromatic interactions? A quantitative study of pi-stacking interactions.
abstract: [structure: see text] Attractive interactions between substituted arenes in the parallel displaced configuration have been quantitatively studied using triptycene-derived molecular conformational reporters. Charge-transfer bands are observed for models where the interactions are between strong donor and acceptors. Substituent effects on the strength of the aromatic interaction follow opposite trends for strongly electron-deficient arenes and mildly perturbed arenes. The free energy of interactions for models with strong electron donors and acceptors does not follow a linear correlation in the Hammett plot. Electrostatic models alone do not account for the nonlinearity of the free energy-substituents plot.
authors.affiliation: Department of Chemistry and Biochemistry, Miami University, Oxford, Ohio 45056, USA. gungbw@muohio.edu
authors.forename: Benjamin W
authors.initials: BW
authors.lastname: Gung
authors.forename: Mehul
authors.initials: M
authors.lastname: Patel
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Xue
mesh_terms: D004583:Electrons; D006841:Hydrocarbons, Aromatic / Q000737:chemistry*; D008958:Models, Molecular; D055672:Static Electricity
chemical_list: D006841:Hydrocarbons, Aromatic