The interplay between the triel bond and the pnicogen bond in BF3···NCXH2···Y (X = P, As, Sb; Y = H2O, NH3) complexes was studied theoretically. Both bonds exhibited cooperative effects, with shorter binding distances, larger interaction energies, and greater electron densities found for the ternary complexes than for the corresponding binary ones. The cooperative effects between the triel bond and the pnicogen bond were probed by analyzing molecular electrostatic potentials, charge transfer, and orbital interactions. The results showed that the enhancement of the triel bond can mainly be attributed to the electrostatic interaction, while the strengthening of the pnicogen bond can be ascribed chiefly to the electrostatic and orbital interactions. In addition, the origins of both the triel bond and the pnicogen bond were deduced via energy decomposition.
Keywords: Pnicogen bonds; Synergistic effects; Triel bonds.