Synthesis, spectroscopic characterization studies of chelating complexes and their applications as antimicrobial agents, DNA binding, molecular docking, and electrochemical studies.

N,N′‐bis(2,4‐dihydroxy benzaldehyde‐1,2‐diaminobenzene) (H4L) formed from the reaction of 2,4‐dihydroxybenzaldehyde and 1,2‐diaminobenzene was complexed with Cu (II), Co (II), Ni (II), Mn (II), and UO2(II) ions. The formed complexes have been characterized by their physical data, spectral studies such as FT‐IR, Uv–Vis., 1H & 13C NMR, Mass, elemental microanalysis (C.H.N.), thermal analysis, X‐ray diffraction, and magnetic susceptibility measurements. The molecular docking between the protein receptors of the H4L ligand and its complexes was studied as theoretical method. The ligand and its metal complexes (1–5) were tested for their ability to inhibit the growth of various pathogenic microbial strains. The biological significance of the Schiff base compound and complexes as antifungal, antibacterial, and anticandidal agents as well as cytotoxicity was studied. The tested microorganisms respond better to the metal complexes than the Schiff base ligand. In comparison to the ligand, complexes, and penicillin, the UO2(II) complex (5) demonstrated the strongest antibacterial activity. In comparison to ligand, complexes, and miconazole, the UO2(II) complex (5) has antifungal activity against Aspergillus niger and Candida albicans. Complexes (1) and (5) have higher activity of antibacterial than other complexes against Pseudomonas sp. and the highest antifungal and anticandidal activity in comparison with miconazole. The ligand and its complexes showed a dose‐dependent antibacterial action according to the minimum inhibition concentration test. Using Tafel polarization and electrochemical impedance spectroscopy experiments, the protective impact of the bis‐Schiff base ligand (H4L) ligand versus Q235 Steel and its adsorption performance were investigated. The interaction between H4L Schiff base and complexes (1)–(5) and calf thymus DNA shows hypochromism effect coupled with obvious bathochromic shift. [ABSTRACT FROM AUTHOR]