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

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.

GRAPHICAL ABSTRACT

KEYWORDS:

• Anion-π
• H-bonding
• MESP
• s-Triazine
• Substitution effect

Disclosure statement

No potential conflict of interest was reported by the author(s).