AIM and ELF Analyses of Halogen Bonding in NCS:BrCl Complexes

The nature of halogen bonding in five complexes formed between the thiocyanate (NCS) radical and a BrCl molecule was analyzed by quantum theory of atoms in molecules (QTAIM) and electron-localization function (ELF) in this paper. The calculated results show that the geometry of the halogen atom bonded at the N-atom is stable than those bonded at S- or C-atom. The molecular electrostatic potentials determine the geometries and stabilities of the complexes. The valence basin of the S- or N-atom in the electron-donating NCS radical is compressed and its population decreases during the process of formation of the halogen-bonded complexes.