The theoretical study of the complexes produced from the interactions between hypohalous acids (HOX; X= F, Cl, Br, and I) and acetonitrile (AN) was carried out at the MP2/aug-cc-pVTZ level of theory. Three different conformations were produced, namely A, B, and C, in which conformations B and C were stabilized by only the N∙∙∙H HB and the N∙∙∙X XB interactions, respectively. In contrast, conformation A was stabilized by two O∙∙∙C TB and H∙∙∙X HB interactions through a cyclic structure. The characteristics of product complexes were analyzed by various methods such as molecular electrostatic potential (MEP), spectroscopy, binding energy (ΔE0), quantum theory of atoms in molecules (QTAIM), natural bond orbital (NBO), energy decomposition analysis (EDA), electron density differences (EDD) and non-covalent interaction (NCI) index.
