Hirshfeld surface, DFT vibrational (FT-IR) and electronic (UV–vis) studies on 4-amino-1H-1,2,4-triazolium nitrate

Mechanistic investigation of molecular geometry, intermolecular interactions and spectroscopic properties of pyridinium nitrate

The molecular structure, vibrational frequencies of the fundamental modes and electronic transitions of the ionic liquid pyridinium nitrate ([H-Pyr]⁺[NO₃]^-) have been determined by means of density functional theory (DFT) at B3LYP/6-311++G (2d,2p) level. The chemical bonds nature and the intermolecular interactions in the title compound were investigated using the Quantum theory of atoms in molecules and Hirshfeld surface analysis. Natural bond orbital analysis has been performed in order to elucidate the hybridization and delocalization of electron density within the ion pair [H-Pyr]⁺[NO₃]^-. A detailed vibrational spectral analysis was carried out and the assignments of the observed bands have been proposed on the basis of potential energy distribution. A good correlation between experimental and theoretical IR frequencies was observed. To study the charge transfers occurred in the title molecule, UV-vis analysis was conducted.