Evaluation of DNA binding and DNA cleavage of nickel(II) complexes with tridentate α-N-heterocyclic thiosemicarbazones ligands

• Published in: Inorganica Chimica Acta Vol. 471; pp. 194 - 202
• Main Authors: Deng, JunGang, Su, Gaoxing, Chen, Peng, Du, Yunpeng, Gou, Yi, Liu, Yani
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 24.02.2018
• Subjects: DFT calculations; DNA interactions; Nickel(II) complexes; Thiosemicarbazones; DNA interactions; Nickel(II) complexes; Thiosemicarbazones; DFT calculations
• ISSN: 0020-1693; 1873-3255
• DOI: 10.1016/j.ica.2017.11.013

[Display omitted] •The processes of tautomeric change of thiosemicarbazones ligands were calculated using DFT calculations.•Structural properties of both Ni(II) complexes were studied by experimentally and theoretical calculations.•The DNA binding activity and DNA cleavage ability of both Ni(II) complexes were evaluated. Two mononuclear thiosemicarbazones nickel(II) complexes of the type [Ni(L1)2] (1) and [Ni(HL2)(L2)] (2), where HL1 = (E)-N-methyl-2-(quinolin-2-ylmethylene)hydrazinecarbothioamide and HL2 = (E)-N,N-dimethyl-2-(quinolin-2-ylmethylene)hydrazinecarbothioamidehave been synthesized and characterized by X-ray crystallography, infrared spectroscopy, elemental analysis and DFT calculations. Single-crystal diffraction analysis revealed that the HL1 ligands in 1 are predominantly in the thiolato resonance forms, while the HL2 ligands in 2 coordinate in thiolato and thione forms simultaneously. The interactions of both nickel(II) complexes with calf thymus DNA (CT-DNA) and supercoiled pBR322 plasmid DNA were investigated by fluorescence and UV-visible spectra, viscosity measurement, as well as agarose gel electrophoresis. The results of binding experiments displayed that both nickel(II) complexes were able to interact with CT-DNA via intercalative mode with a moderate binding affinity in the order 2 > 1. Gel electrophoresis assay revealed that the complexes could cleave the pBR322 plasmid DNA in a dose-dependent manner.