Synthesis, spectral characterization and DNA cleavage study of heterocyclic Schiff base metal complexes

Four novel N2O2 type Schiff base metal complexes of Cu(II), Ni(II), Co(II) and Zn(II) have been synthesized from a new Schiff base ligand derived from 4-aminoantipyrine, salicylaldehyde and 2-amino-3-hydroxy- pyridine. The ligand and its complexes have been characterized on the basis of Elemental analyses, Magnetic susceptibility, FAB Mass, UV-Vis., IR, H-1-NMR, ESR and CV spectral studies, as well as conductivity data. On the basis of spectral studies, a square-planar geometry for the complexes has been proposed. The ESR spectrum of Cu(II) complex was recorded at LNT and its salient features are reported. The in vitro antimicrobial activity of the investigated compounds was tested against the bacteria such as Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and fungi Candida albicans and Rhizopus stolonifer. The data indicate that most of the metal complexes have higher antimicrobial activity than the free ligand. DNA cleavage experiments performed on calf thymus DNA plasmids using metal complexes in the presence of H2O2 showed that all the complexes afford a pronounced DNA cleavage.