Synthesis, Spectroscopic Characterization, and Computational Exploration of Tetradentate Schiff Base Metal Complexes With Antimicrobial Evaluation

Abstract Mononuclear metal complexes of the first row transition metals Co(II), Ni(II), Cu(II), and Zn(II) were developed from the previously unknown tetradentate Schiff base ligand 2,2'‐(1E,1'E)‐(4‐methyl‐1,2‐phenylene) bis (azaneylylidene) bis (methaneylylidene) bis (4‐bromophenol). The structures were elucidated employing a multitude of spectral and physiochemical approaches, encompassing elemental analysis, NMR studies, ESI‐MS studies, electronic spectrum studies, and infrared investigations. Moreover, thermogravimetric analysis was performed in order to assess the complex's thermal stability. Furthermore, electron spin resonance studies were conducted for the copper complexes and thermo‐kinetic parameters were computed employing the Coats–Redfern method. DFT studies were executed via the B3LYP/LanL2DZ level of theory. Molecular docking on the 2CDU receptor protein provided computational insights into the potential antioxidant activity of the synthesized compounds, whereas the 1HNY receptor protein was used for screening the antidiabetic effect. The results demonstrate that the copper nitrate complex was found to be more efficient against the 1HNY receptor, whereas against the 2CDU receptor, the cobalt acetate complex possessed highest effectiveness. Antimicrobial studies using the in vitro method against E. coli , P. aeruginosa , B. subtilis , B. cereus , A. niger , and C. albicans were executed and the results showed the effectualness of the copper complexes when compared to the standard drugs. The ADME studies disclose the drug‐likeness of the metal chloride and metal acetate complexes.