Synthesis, antimicrobial screening, and DNA-binding/cleavage of new pyrazole-based binuclear CoII, NiII, CuII, and ZnII complexes

Pyrazolato endogenous bridged binuclear CoII, NiII, CuII, and ZnII complexes were prepared and characterized by spectro-analytical methods. The hexadentate N4S2 donor was synthesized by condensation of 3,5-dichloroformyl-1H-pyrazole with thiosemicarbazide in dry ethanol. All the complexes were binuclear and octahedral in nature. The ligand and complexes are screened for antimicrobial and DNA-binding/cleavage activities. The binding/cleavage activities with Escherichia coli DNA are monitored with absorption, hydrodynamic, thermal denaturation, and electrophoresis studies. The ligand possesses significant activity against microbes which is further enhanced upon complexation. The DNA-binding study reveals classical intercalation. The NiII and CuII complexes exhibit higher binding ability.