Dimetilamin, piridin temelli schiff bazı ve Cu(II), Co(II) ve Fe(II) komplekslerının sentezi, yapı aydınlatılması: Biyolojik aktivitelerinin incelenmesi

Schiff bases represent a vital class of ligands in coordination chemistry, coordinating with metal ions via azomethine nitrogen. Due to their ease of synthesis, widespread availability, and electronic properties, Schiff base ligands have been extensively studied in coordination chemistry. Recently, Schiff base coordination chemistry has gained attention in various fields such as organic synthesis, analytical chemistry, metal refinement, metallurgy, electroplating, and photography. Some Schiff bases have been reported to possess remarkable antibacterial, antifungal, and anticancer properties. The C=N group in these compounds plays a crucial role in biological activity. Coordination chemistry has become an appealing discipline for chemists and researchers due to its success in pharmacotherapy and drug development. This study aims to synthesize the original Schiff base ligand and its Cu(II), Co(II), and Fe(II) metal complexes, analyze their structures, and investigate their antioxidant activities. Using the condensation reaction between 4-(dimethylamino) benzaldehyde and 6-acetyl-2-amino-4,5,6,7-tetrahydrothieno[2,3-c]pyridine-3-carboxamide, the Schiff base ligand was obtained, followed by the design and synthesis of novel Cu(II), Fe(II), and Co(II) metal complexes. Various physicochemical and spectroscopic methods (including elemental analysis, magnetic susceptibility, 1H-NMR, 13C-NMR, FT-IR, UV-Vis, LC-MS, and thermogravimetric analysis) were employed to characterize the synthesized Schiff bases and metal complexes. Based on analytical data and spectroscopic analyses, molecular structures of [LFe2(H2O)6Cl3]1.5H2O, [LCo2(H2O)2Cl3]1.5H2O and [LCu2(H2O)2Cl3]3H2O were proposed for Fe(II), Co(II) and Cu(II) complexes, respectively. It was found that the Schiff base binds to the metal ions via azomethine and amine group nitrogen atoms and carbonyl group oxygen atoms. Magnetic moment and electronic spectrum data suggested octahedral structures for the Fe(II) complexes and square-planar structures for the Cu(II) and Co(II) complexes. The binuclear nature of the synthesized metal complexes was confirmed through elemental analysis, magnetic susceptibility measurement, and mass spectrometry. TGA analysis revealed the metal complexes to be more thermally stable than the ligands. Furthermore, in order to determine the antioxidant activities of Schiff base ligand and Co(II), Cu(II) and Fe(II) complexes, DPPH∙ free radical scavenging activity, reducing power of cupric ions (Cu2+) to cuprous ions (Cu+) by CUPRAC method and total antioxidant properties by ABTS+ method were investigated and the antioxidant activity results obtained were compared with standard antioxidant compounds. The study concluded that these compounds exhibit significant antioxidant activity