The chalcogen bond in FP(S)N⋅⋅⋅SX, FPNS⋅⋅⋅SX, FPSN⋅⋅⋅SX (X = F, Cl, Br, OH, CH, NH) complexes.

As a kind of intermolecular noncovalent interaction, chalcogen bonding plays a critical role in the fields of chemistry and biology. In this paper, S⋅⋅⋅S chalcogen bonds in three groups of complexes, FP(S)N⋅⋅⋅SX, FPNS⋅⋅⋅SX, and FPSN⋅⋅⋅SX (X = F, Cl, Br, OH, CH, NH), were investigated at the MP2/aug-cc-pVTZ level of theory. The calculated results show that the formation of S⋅⋅⋅S chalcogen bond is in the manner of attraction between the positive molecular electrostatic potential (V) of chalcogen bond donator and the negative V of chalcogen bond acceptor. It is found that a good correlation exists between the S⋅⋅⋅S bond length and the interaction energy. The energy decomposition indicates the electrostatic energy and polarization energy are closely correlated with the total interaction energy. NBO analysis reveals that the charge transfer is rather closely correlated with the polarization, and the charge transfer has a similar behavior as the polarization in the formation of complex. Our results provide a new example for interpreting the noncovalent interaction based on the σ-hole concept. Graphical abstract The chalcogen bonds in the studied binary complexes are Coulombic in nature, and the charge transfer has a similar behavior as the polarization in the formation of the complex.