UMP2 calculations with aug-cc-pVTZ basis set used to analyse intermolecular interactions in X3C···PH2Y···ClY (X = H, CH3; Y = CN, NC) complexes constructed via halogen bond and singleelectron pnicogen bond in two discovered minima in the potential energy surface. The first minima presents short P−C distances and, in all cases, high interaction energies compared to the second one that shows long P−C distances with a typical weak pnicogen bond interaction. The impacts of the halogen bonds on the single-electron pnicogen interaction in each complex are systematically investigated by the means of cooperative effects. In all cases studied, a favorable cooperativity is observed but these values are much higher for first minima, which ranges from −19.73 to −36.82 kJ mol−1, than second minima with cooperative energy values between −0.75 and −4.69 kJ mol1. In order to unveil the mechanism of the cooperativity, these effects are analysed in terms of geometric, energetic, electrostatic potential analysis, electron charge density analysis performed using (QTAIM), many-body interaction analysis and electron density analysis.
