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 (K b ) of Ni(II), Co(II) and Cu(II) complexes are 2.713 × 10 6 M −1 , 5.529 × 10 6 M −1 and 2.950 × 10 6 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 H 2 O 2, 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.

Physicochemical Properties and Biological Activities of Novel Hydrazonate Copper Complexes

“…The degree of distortion f (=g // /A // ) appears to be an empirical index of deviation from idealized geometry. Values of 110 -120 cm −1 are typical for planar complexes, whereas the range 130 -150 cm −1 is characteristic of slight to moderate distortion and 180 -250 cm −1 indicate considerable distortion [25]. The present compounds found to be ranking from 142 -177 cm −1 suggestive of slight to moderate distortion in geometry.…”

Water soluble transition metal [Ni(ii), Cu(ii) and Zn(ii)] complexes of N-phthaloylglycinate bis(1,2-diaminocyclohexane). DNA binding, pBR322 cleavage and cytotoxicity

“…Typical d–d transitions of 1 and 2 were observed at 725 nm and 761 nm in the visible region of the spectra validating the square-planar and octahedral geometry of the Cu( ii ) and Ni( ii ) centres, respectively. 29 However, these signatures were found to be missing in the absorption spectra of the Zn( ii ) complex as it has d 10 configuration.…”

Synthesis, Spectroscopic Characterization and Thermal Studies of Polymer-Metal Complexes Derived from Modified Poly Styrene-Alt-(Maleic Anhydride) as a Prospects for Biomedical Applications

“…The absorption bands of the nickel(II) complexes ( 3) and (4) fall between (17.241-16.474), (22.026-21.929), and (31.250-28.985) cm −1 . These bands reveal the complexes have octahedral geometry that attributed to the three spin allowed transitions: 3 A 2g (F)→ 3 T 1g (P), 3 A 2g (F)→ 3 T 1g (F) and 3 A 2g (F)→ 3 T 2g (F), respectively [58]. The electronic spectra of cobalt(II) complex (5) show absorption in the ranges of 18.181 and 14.492 cm −1 , which can be attributed to the 4 T 1 g(F)→ 4 T 1 g(P) and 4 T 1 g(F)→ 4 A 2 g(F), respectively [59,60].…”