Spectroscopic investigations and TD-DFT analysis of 5-Mercapto-1-phenyl-1H-tetrazole molecule: Experimental and theoretical insights

Abstract

In this study, in-depth insight molecular properties of 5-Mercapto-1-phenyl-1H-tetrazole based on the experimental as well as theoretical calculations is discussed. Room temperature FT-Raman and FT-IR spectroscopic experimental measurement is done to explore the vibrational characteristics. Detail theoretical calculations performed in several steps. The theoretical calculation of Raman and IR spectra of monomer and dimer, are compared to the experimental FT-Raman and FT-IR spectra exhibit –SH group is only participate in the intermolecular interactions through hydrogen bonding. The hydrogen bonding S-H⋯N induces a significant change in the energy of the –SH vibration due to the delocalization of the proton's orbital. This delocalization in the intermolecular interactions mechanism is discussed on the basis of electronegativity of atoms and molecular electrostatic potential surface of the fully optimized structure. The detail natural bond orbital analysis of 1-H tetrazole molecule with subsequent addition of mercapto functional and phenyl group addition is done to explore the hybridization and hyper-conjugation effect in each 1H-tetrazole derivative to discuss the stability. These studies explicitly reveal the chemical reactivity and active site of three subsequent of 1-H tetrazole molecule fallowed by the addition of mercapto functional and phenyl group. TD-DFT evaluation is done to interprtate electronic absorption properties in different solvents. The HOMO and LUMO energies and delocalization of charges in different solute-solvent interaction is discussed.