Synthesis characterzation of structure, evaluation of biological properties of new ligand and metal complexes containing azomethine group

In recent years, Schiff base ligands have gained interest from researchers due to their diverse structural features and broad physicochemical properties. The synthesis, spectral characterization, and structure-activity relationships of Schiff base transition metal complexes have been extensively studied in numerous investigations. Developing new compounds with potential pharmaceutical applications has become an increasing focus within the scientific community. Medicinal inorganic chemistry is a challenging research field that continues to contribute significantly to understanding and treating difficult diseases by enabling the design and development of innovative diagnostic and therapeutic agents. Schiff base ligands, as nitrogen donors, can easily coordinate with transition metals to form metal complexes that serve as valuable resources for drug development through coordination chemistry. Due to their pharmacological effects and ability to form complexes with nearly all transition metals, Schiff base ligands remain an important subject of ongoing research. In this study, Co(II), Fe(II), and Pd(II) complexes with Schiff base ligand were synthesized, and their structures were elucidated using various analytical and spectroscopic methods. The analyses demonstrated that the Schiff base, as a bidentate ligand, binds to metal centers via azomethine nitrogen and phenolic oxygen atoms. The antioxidant activities of all the compounds were then evaluated. To assess antioxidant activity, various methods were used, including the total antioxidant capacity determination based on the ferric thiocyanate method, the FRAP method measuring Fe³⁺ ion reduction capacity, the CUPRAC method based on Cu²⁺ ion reduction, the DPPH radical scavenging activity, and the ABTS radical scavenging method. The results indicated that the antioxidant activities of all compounds increased with concentration. However, when these activities were compared, they remained at a low level relative to standard antioxidant substances.