Theoretical investigations of the C-X/π interactions between benzene and some model halocarbons

In this work, ab initio calculations have been carried out to investigate the interactions between the π face of benzene and several halocarbon molecules. The results derived from these calculations reveal the predominant noncovalent C-X/π interactions in all cases. The calculated interaction energies for the halocarbon-benzene complexes span over a reasonably narrow range, from -1.29 to -3.16 kcal/mol, indicating that the C-X/π interactions are comparable in strength to the well-documented C-H/π interactions. The significant gain of the attraction by electron correlation illustrates that the systems considered should be primarily stabilized by the dispersion interaction. As a charge density analysis has suggested, the charge-transfer force plays a minor role in the C-X/π interactions. The halogen-bonding nature of the C-X/π interactions has been identified in terms of the bond critical point analysis within the theory of atoms in molecules (AIM).