A theoretical investigation on the nature of Cl⋯N and Br⋯N halogen bonds in FArX⋯NCY complexes (X = Cl, Br and Y = H, F, Cl, Br, OH, NH2, CH3 and CN)

A theoretical study was performed to examine intermolecular halogen bonds interactions in FArX⋯NCY complexes (X = Cl, Br and Y = H, F, Cl, Br, OH, NH2, CH3 and CN). Examination of the electrostatic potentials of the NCY monomers indicates that the addition of substituents has a large influence upon the most negative electrostatic potential on the surface of the interacting nitrogen and thus modulates these halogen-bonding interactions. The calculated CCSD(T)/aug-cc-pVTZ interaction energies for the complexes span from −0.88 to −3.20 kcal/mol. The nature of Cl⋯N and Br⋯N interactions has been identified in terms of the bond critical point analysis within the quantum theory of atoms in molecules (QTAIM). According to energy decomposition analysis, the stabilities of the FArX⋯NCY interactions are predicted to be attributable mainly to electrostatic and polarization effects, while dispersion forces play a smaller role in stabilizing these complexes.