Theoretical insights into the π-hole interactions in the complexes containing triphosphorus hydride (P 3 H 3 ) and its derivatives.

The π-hole of triphosphorus hydride (P3 H3 ) and its derivatives Z3 X3 (Z = P, As; X = H, F, Cl, Br) was discovered and analyzed. MP2/aug-cc-pVDZ calculations were performed on the π-hole interactions in the HCN...Z3 X3 complexes and the mutual influence between π-hole interactions and the hydrogen bond in the HCN...HCN...Z3 X3 and HCN...Z3 X3 ...HCN complexes studied. The π-hole interaction belongs to the typical closed-shell noncovalent interaction. The linear relationship was found between the most positive electrostatic potential of the π-hole (VS,max ) and the interaction energy. Moreover, the VS,max of the π-hole was also found to be linearly correlated to the electrostatic energy term, indicating the important contribution of the electrostatic energy term to the π-hole interaction. There is positive cooperativity between the π-hole interaction and the hydrogen bond in the termolecular complexes. The π-hole interaction has a greater influence on the hydrogen bond than vice versa. The mutual enhancing effect between the π-hole interaction and the hydrogen bond in the HCN...HCN...Z3 X3 complexes is greater than that in the HCN...Z3 X3 ...HCN complexes.