Zinc(II) catalyzed synthesis of 2-(4-methoxyphenyl)-5-(2-pyridyl)-1,3,4-thiadiazole: Characterizations, crystal structure, DFT calculation, Hirshfeld surface analysis, and molecular docking analysis

Abstract

A new compound 2-(4-methoxyphenyl)-5-(2-pyridyl)-1,3,4-thiadiazole (Mppth) has been synthesized and characterized with the aid of IR, NMR, and single-crystal X-ray diffraction techniques. During the reaction, the substituted thiohydrazide got cyclized into the corresponding thiadiazole (Mppth) in the presence of zinc(II) nitrate via loss of H2O. The Mppth crystallizes in an orthorhombic system with space group P 21 21 21. The solid-state structure of Mppth is stabilized via intermolecular hydrogen bonding and π-π interaction between phenyl rings. The intermolecular interactions present in the crystal structure of Mppth are also confirmed with Hirshfeld surface analysis. The geometry optimization has been performed using the DFT method and geometrical parameters thus obtained for the Mppth correlate with the single-crystal X-ray data. The FMO analysis shows a small HOMO and LUMO energy gap of 5.48 eV for Mppth suggesting its potential application as NLO material. The electronic transition from the ground state to the excited state due to a transfer of electrons from the HOMO to LUMO levels is mainly associated with the π→π* transition. Molecular docking studies are also performed against CYP-19 (PDB: 3EQM), JAK2 (PDB: 5AEP), BCL-2 (PDB: 2O2F), and caspase3 (PDB: 1RE1) receptor proteins to obtain insights on anticancer activities of Mppth. The results displayed strong interactions with the receptors with binding energies -10.27, -7.40, -6.28, and -7.27 kcal/mol, respectively. From the docking results, the key binding interactions between the ligand and active site residues of the receptor were identified, which may provide important information for further research on the compound Mppth as anticancer agent.