A DFT investigation of anion-π interactions between halogen oxyanions (XO3 −, X = Cl, Br, I) and aromatic π-systems (benzene and coronene)

Abstract

Abstract Anion-π interactions have proved to play a key role in many chemical and biochemical phenomena. In order to investigate the nature and the applications of these interactions, the anion-π interactions of the chlorate (ClO3 −), bromate (BrO3 −), and iodate (IO3 −) oxyanions with benzene and coronene have been studied using density functional theory (DFT). The structures, adsorption energies, and electronic properties of XO3 −(X = Cl, Br, I) adsorbed on benzene and coronene have been explored using dispersion corrected DFT hybrid functional, M06-2X-D3, with the def2-TZVP basis set. Benzene and coronene have been respectively used as a building block and a simple flake of graphene. The interaction of these anions with benzene is found to be unexpectedly favorable. Their binding strength is further increased when the anions are adsorbed on coronene. Moreover, energy decomposition analysis based on symmetry adapted perturbation theory (SAPT) has been performed and the nature of interaction is characterized using noncovalent interaction analysis (NCI) based on reduced density gradient (RDG) method. Generally, the favorable binding of these anions with benzene or coronene is mainly ascribed to dispersion interactions. These anion-π interactions with graphene flakes or with benzene can be utilized in the design of anions receptors and detectors.