Synthesis of schiff base ligands and transition metal complexes containing the different functional groups; their structural characterization, antioxidant capacity, superoxide dismutase enzyme activity and investigation of photolumi̇nescence properti̇es

In the scope of this thesis, Schiff base ligands (HL1, HL2 and HL3) derived from 2-hydroxy-1-naphtaldehyde, 2-hydroxy-3-methoxybenzaldehyde and 2-hydroxybenzaldehyde with 2,4-dimethoxyaniline and their transition metal complexes (in a 1:2 molar ratio M:L) of Co(II), Ni(II) and Cu(II) were prepared. The structures of the synthesized compounds were fully characterized by elemental analyses and spectral methods (IR, 1H-NMR, 13C-NMR, thermogravimetric analysis (TG), magnetic susceptibility). The crystal structures of HL2 and HL3 ligands and complexes Co(L1)2H2O, Ni(L1)2H2O, Cu(L1)2H2O and Cu(L2)2H2O were also determined by single crystal X-ray diffraction studies. X-ray structures of the Schiff base ligands (HL2 and HL3) results showed that the metal ions coordinated to bidentate ligand behavior with ON donor sites from the hydroxyl of the phenolic group and nitrogen of the imine group. The thermogravimetry analysis (TGA) of compounds were carried out in the range of 50-900 oC. Antioxidant properties of Schiff base ligands and their transition metal complexes were studied using the slightly modified CUPRAC and DPPH methods. Superoxide dismutase activities (SOD) of the complexes were investigated and results were discussed. The photoluminescence analysis of Schiff bases and their metal complexes were carried out in solid state and DMF solvent (1x10-5 M).