Bivalent Ni(II), Co(II) and Cu(II) complexes of [(E)-[(2-methyl-1,3-thiazol-5-yl)methylidene]amino]thiourea: synthesis, spectral characterization, DNA and in-vitro anti-bacterial studies

Abstract

The present work describes the preparation of bivalent Ni(II), Co(II) and Cu(II) complexes of [(E)-[(2-methyl-1,3-thiazol-5-yl)methylidene]amino]thiourea (MTHC) by mixing in 1:2 ratio of corresponding metal salt and Schiff base ligand in ethanolic medium. The prepared ligand and its complexes are confirmed using elemental analysis, magnetic moments, FT-IR, NMR, electronic and ESR spectroscopy techniques. The spectroscopic data reveals that metal complexes are in square planar in nature. In DNA binding studies, the higher intrinsic binding constants (Kb) of Ni(II), Co(II) and Cu(II) complexes are 2.713 × 106 M−1, 5.529 × 106 M−1 and 2.950 × 106 M−1 respectively, evident that complexes are avid binder with DNA base pairs. The moderate anti-bacterial activity (in-vitro) against staphylococcus epidermidis, Bacillus subtilis, Pseudomonas aeruginosa and Escherichia coli bacterial culture may be due to the high electron density of ligand which prevents the charge reduction of metal ion. In the presence and absence of H2O2, it is notified that there is no appreciable DNA cleavage activity of Ni(II) and Co(II) complexes except Cu(II) complex which is due to aprotonation in the medium.

Keywords

• [(E)-[(2-methyl-1,3-thiazol-5-yl)methylidene]amino]thiourea
• Transition metal complexes
• DNA interactions And antibacterial activity