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ABSTRACT:
Metal complexes of Schiff base (L) ligand, prepared via condensation of 4- chlorobenzaldimine 4- aminoantipyrine, and 2- aminophenol are prepared. The ligand is characterized based on elemental analysis, Mass, IR, and NMR spectra.Metal complexes are reported and characterized based on elemental analyses, IR, electronic spectra, magnetic moment,molar conductance and cyclic voltammetry (cv). From the elemental analyses, 1:1[M]:[Ligand] complexes are prepared with the general formulae [M(L CL) (M=Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)). The IR results demonstrate that coordination sites are the two azomethine nitrogen and hydroxyl oxygen atoms. The electronic spectral and magnetic measurement data indicate that the complexes exhibit tetra geometry and Cu(II) exhibits distorted square planar around the metal centre. The in vitro biological screening effects of the synthesized compounds were tested against various microbial species and the results show that the metal complexes are more biological active than the ligand. The DNA cleavage activity of the ligand and its complexes were assayed on pUC18 DNA using gel electrophoresis. The result shows that the Co(II) and Cu(II) complexes have completely cleaved the DNA.
KEYWORDS: Electronic spectra, Antimicrobial, DNA, Ligand, Cyclic voltammetry.
INTRODUCTION:
Schiff bases of azomethine nitrogen donor heterocyclic ligand are well known due to their wide range of applications in pharmaceutical and industrial fields and have been found to act as antibacterial, antifungal, anticancer and herbicidal agents [1-7]. Schiff base can accommodate different metal centers involving various coordination modes thereby allowing successful synthesis of homo and hetro metallic complexes with varied stereochemistry [8,9]. This feature is employed for modeling active sites in biological systems. Results from these studies have also shown that complexation of metals to Schiff base ligands serves to improve the antimicrobial and anticancer activities of the ligands [10,11]. Metal complexes of nitrogen- oxygen chelating agents derived from 4- aminoantipyrine Schiff bases have been studied extensively due to their pronounced applications in biological, clinical, analytical and pharmacological areas [12-16].
Y.X. sun et al have studied the crystal structure of 4-(4chlorobenzylideneaminno)-1,5-dimethyl-2-phenyl1Hpyrazol3(2H)-one[17]. The present study deals with the synthesis, characterization and biological studies of the Schiff base derived from 4- chlorobenzaldimine 4aminoantipyrine and 2- aminophenol and its Co(II),Ni(II) and Cd(II) complexes.
EXPERIMENTAL SECTION:
4- Aminoantipyrine and 4- chlorobenzaldehyde were obtained from Sigma. Metal (II) chlorides were purchased from Merck....