The noncovalent interactions involving heteronuclear ethylene analogues H2CEH2 (E = Si, Ge and Sn) have been studied by the Møller–Plesset perturbation theory to investigate the competition and cooperativity between the hydrogen/halogen bond and π‐hole bond. H2CEH2 has a dual role of being a Lewis base and acid with the region of π‐electron accumulation above the carbon atom and the region of π‐electron depletion (π‐hole) above the E atom to participate in the NCX···CE (X = H and Cl) hydrogen/halogen bond and CE···NCY (Y = H, Cl, Li and Na) π‐hole bond, respectively. When HCN/ClCN interacts with H2CEH2 by two sites, the strength of hydrogen bond/halogen bond is stronger than that of π‐hole bond. The π‐hole bond becomes obviously stronger when the metal substituent of YCN (Y = Li and Na) interacting with H2CEH2, showing the character of partial covalent, its strength is much greater than that of hydrogen/halogen bond. In the ternary complexes, both hydrogen/halogen bond and π‐hole bond are simultaneously strengthened compared to those in the binary complexes, especially in the systems containing alkali metal.

Ab initio calculations have been performed to investigate the competition and conversion between the pnicogen bonds and hydrogen bonds in the complexes containing prototype organophosphorus compounds RPO2 (R = CH3...