Spectral, thermal, electrochemical and biological studies of Co(II), Ni(II), Cu(II) and Zn(II) complexes derived from 4-(3-bromo-4-hydroxy-5-methoxybenzylideneamino)-3-mercapto-6-methyl-5-oxo-1,2,4-triazine.

Abstract

The Schiff base4-(3-bromo-4-hydroxy-5-methoxybenzylideneamino)-3-mercapto-6-methyl-5-oxo-1,2,4-triazine and its Co(II), Ni(II), Cu(II) and Zn(II) complexes have been synthesized and characterized by IR, NMR, electronic, ESR, fluorescence, thermal, magnetic moment and electrochemical studies. IR and thermal data support the presence of coordinated water in the metal complexes. The electronic spectral and magnetic moment measurements indicate octahedral geometry for Co(II), Ni(II) and Zn(II) complexes and square planar for Cu(II) complexes. Biological studies of the ligand and its metal complexes have been carried out in vitro against Gram-positive (Staphylococcus aureus, Bacillus subtilis), Gram-negative (Escherichia coli) bacteria and fungi (Aspergillus niger, Aspergillus flavus). The results show increased antibacterial and antifungal activity of the metal complexes as compared to the ligand.
Keywords: Synthesis, 1,2,4-triazine, Schiff base, antimicrobial activity, metal complexes