Methoxy group containing bidentate Schiff base ligands and their transition metal complexes: Synthesis, structural characterisation, photoluminescence, antioxidant capacity and superoxide dismutase activity studies

Co(II), Ni(II) and Cu(II) complexes of the two new Schiff base ligands (HL1 and HL2 derived from 2-hydroxy-3-methoxybenzaldehyde and 2-hydroxy-l-naphtaldehyde with 2,4-dimethoxyaniline) have been prepared. The structures of the synthesized compounds were characterized by elemental analyses and spectral methods (IR, 1H NMR, 13C NMR, thermogravimetric analysis (TGA), magnetic susceptibility. IR spectra show that HL1 and HL2 coordinated to the metal ions in a neutral bidentate manner with ON donor sites of the phenolic oxygen and imine nitrogen atoms. The molecular structures of HL1 and HL2 ligands and complex [Cu(L-1)(2)]-H2O were also determined by single crystal X-ray diffraction studies. To determine the antioxidant properties of Schiff base ligands and transition metal complexes, the CUPRAC and DPPH methods of antioxidant assays were used. Superoxide dismutase activities (SOD) of the Schiff base complexes were investigated and results were discussed. (C) 2016 Elsevier B.V. All rights reserved.