Synthesis, spectroscopic, crystallographic, quantum and molecular docking investigations of cis-4,5-diphenylimidazolidine-2-thione

Abstract

We present the synthesis and characterization of stereoselective thione. The synthetic procedure includes readily available starting materials and minimum side products. The reaction of meso‑stilbenediamine with carbon disulphide in the presence of strong base gave cis-4,5-diphenylimidazolidine-2-thione (DPIT) in an excellent yield. The thione compound was characterized via FT-IR and mass spectroscopy. In addition, the crystal structure of it was determined by single crystal X-rays diffraction analysis which inferred that the molecular configuration was stabilized by intramolecular π⋯π stacking interaction. The crystal packing was mainly stabilized by N-H⋯S bonding. Hirshfeld surface analysis was performed for the exploration of the intermolecular interactions. Void analysis was carried out to predict the mechanical stability. Interaction energy between the molecular pairs is calculated which showed that the dispersion energy played a dominant role in the stabilization of the crystal packing. Moreover, the quantum computational methods were used to study the molecular structure and electronic properties of entitled compound. The molecular geometries were optimized for possible thione and thiole tautomeric structures. A comparison of total energy of molecular tautomers indicates that thione tautomer possesses lower total energy which is about 20.18 Kcal/mol lower than thiole tautomer. The electronic properties of thione derivative were studied including 3-D wavefunction delocalization of highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) orbitals and their orbital energy gap. The HOMO-LUMO energy gap for DPIT was found to be 4.874 eV. The delocalization of wavefunction indicates the probable presence of HOMO and HOMO-1 are mainly localized over C-S bond owing to the presence of lone pair of electrons in the sulfur atom. Additionally, the molecular docking study was also carried out for main protease (Mpro) of SARS-CoV-2. The binding energy calculation and investigation of intermolecular interactions highlighted the probable inhibition tendency of DPIT for SARS-CoV-2. The present experimental and computational studies indicate a significant potential of entitled molecule for electronic and biological perspectives.