Schiff Base Metal Complexes as Dual Antimicrobial and Anticancer Agents: Synthesis, Characterization, DFT, and Molecular Docking Investigations

ABSTRACT A series of four metal complexes, [CdC 16 H 14 N 6 S 2 Cl 2 ] (1) , [FeC 17 H 22 N 6 OS 2 Cl 3 ] (2) , [ZrC 16 H 20 N 6 O 2 S 2 Cl 2 ] (3), and [MoC 18 H 12 N 6 O 2 S 2 Cl 2 ] (4) were prepared by the Schiff base derived from thiosemicarbazide and p‐chlorobenzaldehyde reacting with their respective metal salts. The synthesized ligand and its metal complexes were characterized using FT‐IR, 1 H NMR, UV–vis, molar conductivity, elemental analyses, and magnetic moment measurements. The antimicrobial potential of these compounds were evaluated against two Gram‐positive bacteria ( Staphylococcus aureus and Enterococcus faecalis ), two Gram‐negative bacteria ( Escherichia coli and Pseudomonas aeruginosa ), and two fungal species ( Fusarium oxysporum and Candida albicans ). The biocompatibility of ligands and metal complexes was assessed using the RBC lysis test. Further, the in vitro anticancer activities of synthesized compounds were evaluated against a breast cancer cell line (MDMB‐231), which revealed complex 1 and 4 as most potent against the cancer cell line. In addition, density functional theory (DFT) simulations were used to optimize the complexes structures, offering further information about their electrical characteristics. To investigate the interaction processes, AutoDock4 was used to perform docking studies on both DNA and Human serum albumin (HSA). Among all, the molybdenum complex exhibited the highest binding affinities toward both DNA and HSA with docking scores of –7.66 and –6.72 kcal/mol, respectively. The novelty of this study lies in the first systematic comparison of Cd(II), Fe(III), Zr(IV), and Mo(VI) complexes of a para‐chlorobenzaldehyde–thiosemicarbazone ligand, establishing new structure–activity relationships supported by docking and biological data.