Original Articles: 2011 Vol: 3 Issue: 2
Effect of chelation on therapeutic potential of drugs: Synthesis, structure, antimicrobial and insecticidal activity of 3d-metal complexes involving Schiff-bases
Abstract
VO(II), Fe(II), Co(II), Cu(II) and Zn(II) metal complexes of Schiff bases derived from 2-
thiophenecarboxaldehyde with 2,6-dichloro-4-nitroaniline (TDNA) and 4-anisidine (TCA) are reported
and characterized based on elemental, FT-IR, UV-visible, molar conductance, FAB-mass, ESR, magnetic
susceptibility, thermal and XRD analysis. IR spectra show that TDNA and TCA are coordinated to the
metal ions in a bidentate manner with S and N donor sites of azomethine -N and thiophene-S. FAB-mass
spectra of [VO(TCA)2].SO4.4H2O have been investigated. FAB-mass and thermal data show degradation
pattern of the complexes. The thermal behavior of metal complexes shows that the hydrated complexes
loses water molecules of hydration in the first step; followed by decomposition of ligand molecules in the
subsequent step. The metal complexes exhibited good microbial screening results against a number of
medically important bacterial strains namely Escherichia coli, Staphylococcus aureus, Proteus mirabilis
and fungi as Aspergillus niger and Candida albicans. The antimicrobial activity was evaluated using well
diffusion technique. The solvent used, was DMSO. Schiff bases and their metal complexes were also
evaluated for their insecticidal activity on cockroaches (Periplanata americana) as the test insect. Schiff
bases and their metal complexes have been found active as an insecticide. Thus, the aim of this study is to
observe the impact of chelation on the therapeutic value of the bioactive organic compounds. The
antimicrobial and insecticidal screening results also indicate that the metal complexes are better
antimicrobial and insecticidal agents as compared to the Schiff bases