Nickel complexes of the different quinolone antibacterial drugs: Synthesis, structure and interaction with DNA

Three new nickel (II) complexes of the second/third-generation quinolone antibacterial drugs have been synthesized and structurally characterized. Single-crystal X-ray diffraction analysis shows that complex 1 exhibits 1D chain structure, and 2 and 3 2D sheet structures. UV study of the interaction of the complexes with calf-thymus DNA (CT-DNA) shows that complexes 1–3 can bind to the CT-DNA and exhibit the higher binding constant to CT-DNA than their parent drugs. Additionally, their competitive study with ethidium bromide (EB) also indicates that complexes can bind to DNA for the intercalative binding sites except for 1. Note that, due to uncoil the helix structure of DNA, 1 presents a higher value for KSV and Kb than other complexes.

Graphical abstractThree complexes of the different quinolone drugs were obtained. Spectrum studies indicate that 1–3 can bind to the CT-DNA and possess the higher binding constant than free drugs. Note that complex 1 presents a higher value for KSV and Kb than other complexes due to uncoil the helix structure of DNA.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► Three novel complexes are the rare crystal structures of quinolone complexes. ► Complexes can bind to the CT-DNA and exhibit the higher binding constant. ► Competitive binding studies with EB also show all complexes can bind to DNA. ► Complex 1 presents a higher value for KSV and Kb than other complexes.