Quantum-chemical defining of molecular structure of 1.2.4-triazole and calculation of its vibrational spectrum

Heterocyclic compounds are the most common group of organic compounds. They are part of many substances of natural origin, such as nucleic acids, chlorophyll, blood gene, alkaloids, and many vitamins. In the past few years, 1,2,4-triazoles and their derivatives have received a lot of attention from scientists due to their medicinal value. Triazoles and their derivatives are well-known five-membered heterocyclic compounds, and various procedures for their synthesis have been extensively studied. Recently, quantum chemical calculations, as one of the physicochemical methods, have been used to obtain data necessary to establish the mechanisms of complex organic reactions. This method occupies a special place among many physical and physicochemical methods for studying the structure of reaction molecules. In this work, the molecular structure of 1.2.4-triazole has been estimated by means of electron density functional method and by using the Gaussian software package and the frequencies of normal vibrations and the intensities of absorption bands in the IR spectrum of the 1.2.4-triazole molecule have been calculated. The vibrational spectrum of 1.2.4-triazole molecule has been estimated using a software package for calculating the vibrational spectrum of polyatomic molecules. The coincidence of calculated frequencies of absorption band maxima with the experimental frequencies and the qualitative reproduction of experimental spectrum showed that the selected force field and electro-optical parameters can be used to calculate vibrational spectra and interpret the IR spectra of heterocyclic compounds. (author)