Synthesis, Characterization and Antioxidant Studies of Triazine Schiff Bases and Their Nickel(II) and Zinc(II) Complexes

Abstract

The synthesis, characterization, thermogravimetric and antioxidant activity studies of Schiff bases derived from 4-phenyl-1,3,5-triazine-2,6-diamine and 3-hydroxy salicylaldehyde (H₂L1), 4-hydroxy salicylaldehyde (H₂L2) together with their nickel(II) and zinc(II) complexes are reported. The ligands were characterized by IR, ¹H and ¹³C NMR, UV-Vis spectroscopy as well as elemental analysis. Spectral studies reveal that the ligands were acting as tetradentate chelating agents and coordinated to the metal center via deprotonated phenolate oxygen and azomethine nitrogen atoms in a 1:1 ligand to metal ratio. The antioxidant activities of the ligands and complexes were examined using the DPPH radical scavenging method. The results show that the ligands exhibit higher radical scavenging ability than the complexes.