Synthesis and structural characterization of ONO type tridentate ligands and their Co(II) and Ni(II) complexes: Investigation of electrical conductivity and antioxidant properties

Schiff base ligands were prepared from 5-bromo-2-hydroxybenzaldehyde and 2,4-dihydroxybenzaldehyde with 2,4-dimethoxyaniline and their Cobalt(II) and nickel(II) complexes were synthesized in a 1:2 M ratio M:L. The synthesized compounds were fully characterized by elemental analysis and different spectral methods (FT-IR, 1H-,13C NMR, thermogravimetric analysis (TGA), ICP-OES, magnetic susceptibility). X-ray analysis and FT-IR spectra suggest that Schiff base ligands are coordinated to the metal ions in a monoanionic tridentate manner with ONO-donor sites of the phenolate oxygen atom, nitrogen atom of the imine group and oxygen atom of the methoxy group. The electrical conductivity properties of all the compounds was also investigated. To determine the antioxidant properties of Schiff base ligands and their transition metal complexes, DPPH method was performed. © 2019 Elsevier B.V