Mononuclear metal (II) schiff base complexes derived from thiazole and O-vanillin moieties: Synthesis, characterization, thermal behaviour and biological evaluation

Abstract

The novel Schiff base ligand 2-(2-hydroxy-3-methoxybenzylidene)-N-(4-phenylthiazol-2-yl)hydrazinecarboxamide (L) obtained by the condensation of N-(4-phenylthiazol-2-yl)hydrazinecarboxamide with o-vanillin and its Cu(II), Co(II), Ni(II) and Zn(II) complexes were synthesized and characterized by elemental analysis and various physico-chemical techniques like, FT-IR, 1H NMR, ESI mass, UVVisible, ESR, TGA/DTA, magnetic measurements and molar conductance. The spectral results confirmed tridentate ONO donor binding of the ligand involving oxygen atom of amide carbonyl, azomethine nitrogen and oxygen of hydroxyl via deprotonation. Spectral analysis indicates octahedral geometry for all the complexes. Co(II) complex has 1:1 stoichiometry ratio of the type [M(L)(H2O)2Cl], whereas Cu(II), Ni(II) and Zn(II) complexes have 1:2 stoichiometric ratio of the type [M(L)2]. In order to evaluate the effect of antimicrobial activity of metal ions upon chelation, all the newly synthesized compounds were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleavage activities were also studied using plasmid DNA pBR322 as a target molecule. © 2015 Global Research Online. All rights reserved.