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.