The dual role of halogen, chalcogen, and pnictogen atoms as Lewis acid and base: Triangular XBr:SHX:PH2X complexes (X = F, Cl, Br, CN, NC, OH, NH2, and OCH3)

Abstract

Using ab initio calculations, we have investigated the possibility of formation of triangular XBr:SHX:PH2X complexes, where X5 F, Cl, Br, CN, NC, OH, NH2, and OCH3. These complexes are formed through the interaction of a positive electrostatic potential region (r-hole) on a molecule with the negative region in another one. The results show that the combined halogen, chalcogen, and pnictogen interactions can give rise to stable cyclic structures. The interaction energies of these complexes span over a wide range, from 23.55 to 224.93 kcal/mol. Nice quadratic correlations are found between the interaction energies and binding distances in the trimers. To understand the nature of the interactions in these complexes, molecular electrostatic potential and quantum theory of atoms in molecule analyses are performed. VC 2015 Wiley Periodicals, Inc.