CNXeCl and CNXeBr species as halogen bond donors: a quantum chemical study on the structure, properties, and nature of halogen···nitrogen interactions.

In the present study, strength and characteristic of halogen bond interactions between CNXeY and NCZ molecules are investigated, where Y = Cl, Br and Z = H, CN, F, OH, CH₃, OCH₃, NH₂. MP2/aug-cc-pVTZ calculations indicate that the interaction energies for CNXeY⋯NCZ complexes lie in the range between -1.0 and -3.1 kcal mol⁻¹. Not surprisingly, the calculated interaction energies show a strong correlation with the negative electrostatic potentials on nitrogen atoms. One of the most important results of this study is that, according to energy decomposition analyses, Cl⋯N halogen bonds are largely dependent on dispersion effects, while electrostatic interactions are the major source of the attraction in Br⋯N bonds. The quantum theory of atoms in molecules (QTAIM) and natural bond orbital (NBO) analysis are used in this study to deepen the nature of the interactions considered. This appears to be the first report on a halogen bond involving halogenated xenon isocyanides.