The first principle study of chalcogen bonds, pnicogen bond and their mutual effects in a set of complexes between the triazine with SHF and PH2F ligands

Abstract

In the present study, the strength, nature and cooperativity effects of chalcogen and pnicogen bonds in a set of complexes between the triazine (TA) with SHF and PH2F are investigated at M06-2X/6–311++G (d, p) and CCSD/6–311++G (d, p) levels of theory. According to the results, the absolute values of complexation energies of chalcogen bonded systems are greater than the corresponding pnicogen bonded complexes. The simultaneous presence of two or three non-covalent interactions leads to negative cooperativity effects. Furthermore, the electron density values of chalcogen bonded complexes are more than their pnicogen ones, which emphasizes the stronger interactions in the former systems. Also, the LpN → σ*X-F interaction has been attenuated in the presence of two or three interactions, which is attributed to the presence of negative cooperativity effects. Finally, the aromaticity indices values show with an increase in the number of non-covalent interactions, the TA ring aromaticity character is decreased.