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

Abstract The title molecule, 4-amino-1 H -1,2,4-triazolium nitrate ([4-am-1 H -124-tr] + [NO 3 ] – ), was synthesized and characterized by means of Hirshfeld surface analysis, vibrational (FT-IR) and electronic (UV–vis) studies. A density functional theory (DFT) calculations were accomplished at B3LYP level using 6–311++G(2d, 2p) basis set. A detailed analysis of the intermolecular interactions via Hirshfeld surface analysis and fingerprint plots revealed that the [4-am-1 H -124-tr] + [NO 3 ] – structure is stabilized mainly by formation of O⋯H/H⋯O and N⋯H/H⋯N hydrogen bonds. However, contributions from H⋯H and N⋯O/O⋯N contacts were also observed. UV– vis analysis (conducted in water-phase) clearly showed that charge transfers occurred in the title molecule. The energies of HOMO and LUMO, which were active in the electronic absorption spectrum, were obtained as well. Hence, a value of 5.2605 eV was obtained as a HOMO–LUMO energy gap. A comparative analysis between the calculated and experimental vibrational frequencies was carried out and significant bands were assigned. The results indicated a good correlation between experimental and theoretical IR frequencies.