Interplay between ion-pi and Ar/pi Van der Waals interactions

Abstract

[eng] This article analyzes the interplay between cation-pi or anion-pi interactions and Ar/pi Van der Waals interactions. Interesting cooperativity effects are observed when cation-pi/anion-pi and Ar/pi Van der Waals interactions coexist in the same complex. These effects are studied theoretically in terms of energetic and geometric features of the complexes, which are computed by ab initio methods. The symmetryadapted perturbation theory (SAPT) partition scheme was utilized to analyze the different energy contributions to the binding energy and to investigate the physical nature of the interplay between the interactions. By taking advantage of all aforementioned computational methods, the present study examines how these interactions mutually influence each other. Finally, our computational results at the SCS-RI-MP2/aug-cc-pwCVTZ level of theory for the Benzene/Ar complex (D0 = 0.90 kcal/mol and Re = 3.595 Å) are in a very good quantitative agreement with the experimental dissociation energy (0.90 ± 0.02 kcal/mol) and equilibrium distance (3.586 Å).