Theoretical Investigation of 2‐(5‐Mercapto‐1,3,4‐oxadiazol‐2‐yl)phenol and Some Metal Complexes: Thermodynamics, Antimicrobial Potential, and Nonlinear Optical Properties

The design of novel metal complexes is a vibrant area of research in medicinal and materials chemistry. This study aims to computationally investigate the thermodynamic parameters, chemical reactivities, antimicrobial activities, physicochemical properties, drug‐likeness, and nonlinear optical (NLO) properties of 2-(5-mercapto-1,3,4-oxadiazol-2-yl)phenol ( L ) and its Cu(II) , Co(II) , Ni(II) , and Zn(II) complexes. Geometry optimizations were performed using the B97‐3c method, while single‐point calculations were carried out at the PBE0/def2‐TZVP level of theory. The results demonstrate that complex formation is thermodynamically favorable and spontaneous. QTAIM and NCI analyses confirm the covalent nature of the metal–ligand bonds. The Co(II) complex emerged as the most reactive and lipophilic, indicating high biological potential. All compounds comply with Lipinski’s Rule of Five and exhibit promising ADMET profiles. The metal complexes showed superior predicted antimicrobial activity compared to the parent ligand L . Notably, the first ( β tot ) and second (γ) hyperpolarizabilities of L and its complexes significantly exceed those of standard references urea and para‐nitroaniline, respectively, highlighting their exceptional potential for NLO applications. These findings posit these compounds as compelling dual‐purpose candidates for future development as metallodrugs and in optoelectronic device fabrication, warranting experimental confirmation.