Theoretical Study of Weak Interaction Between Fluorinated Six-Membered Nitrogen-heterocyclic Compound and Water

Weak interactions between fluorinated six-membered nitro-heterocyclic compounds and water have been studied at M062X/aug-cc-PVTZ level. Our computational study shows that perfluorinated substitution on pyridine is necessary for the existence of lp···π complex. For three tetrafluorinated pyridine isomers, the hydrogen bond complexes are more stable than the corresponding lp···π ones. While for the fluorinated binary nitrogen-heterocycles, the lp···π complexes 3FPa-II-LP and 3FPm-II-LP with IE values of −19.3 kJ mol⁻¹ and −16.9 kJ mol⁻¹, respectively, are competitive with their corresponding hydrogen bond ones 3FPa-II-HB (−19.7 kJ mol⁻¹) and 3FPm-II-HB (−16.5 kJ mol⁻¹). This suggests that different from the case of tetrafluorinated pyridine, 3FPa-II-LP and 3FPm-II-LP has the possibility to be investigated by the spectroscopy experiment. Electrostatic potential and AIM analysis explained the microscopic nature of the weak interactions from molecular scope.