The interplay between anion-π and H-bonding interactions in X−···s-Triazine···(HF)n(HCl)3-n (X = F−, Cl− and CN−) complexes: DFT and DFT-D study

Abstract

ABSTRACT Anion-π interactions play an important role in supramolecular chemistry. The aim of this work is to explore the effect of H-bonding between s-Triazine and separated molecules (HF)n(HCl)3-n on the strength of anion-π interaction in X−–s-Triazine–(HF)n(HCl)3-n (X− = F–, Cl– and CN–) complexes. The M06-2X/6-311++G(d,p) binding energies (BEs) were corrected by using B2PLYP, mPW2PLYP, M06-2X-GD3 and B2PLYP-GD3 functionals. The molecular electrostatic potential (MESP) analysis revealed that involving multiple binding sites in s-Triazine (TA) through N···H H-bonding can enhance the MESP value over the ring centre of TA so that for H-bonding complexes containing HF is greater than those of HCl. The BE results revealed that the stability of X−–TA–(HF)n(HCl)3-n anion-π complexes in each series increases as the number of HF involved in H-bonding increases. The results showed that the complexes owning F– anion with higher interaction energies display the strong cooperativity effects in the ternary systems. B2PLYP functional showed stronger intramolecular dispersion effects than M06-2X one. Besides, a correlation was found between BE, MESP, bond distances, natural bond orbitals (NBO) and atoms in molecules (AIM) data.