Synthesis, structure, and DNA-binding study of a novel Zn (II) complex with fleroxacin and 1,10-phenanthroline monohydrate

Abstract

A novel metal-based compound of zinc complexing with fleroxacin (flrx) was prepared in the presence of 1,10-phenanthroline (phen) monohydrate and characterized by various techniques. The crystal structure of the complex ([Zn(flrx)(phen)(H2O)](NO3)·2H2O) was successfully disclosed through single-crystal X-ray diffraction, and Zn(II) connected with pyridone oxygen and the carboxylic oxygen atom of flrx by coordination bonds. The complex showed a square pyramid, and its structure was stabilized by intermolecular hydrogen bonding and π–π stacking. The interaction between the complex and calf thymus DNA (ctDNA) was studied. Results indicated that [Zn(flrx)(phen)(H2O)](NO3)·2H2O bound to ctDNA through a static mechanism, and the hydrophobic force was the main driving force in the binding process. Circular dichroism spectra, iodide quenching studies, and DNA melting temperature experiments indicated that the complex bound to ctDNA in the groove. Molecular docking further verified the groove binding mode and provided a visualized view for the interactions between the complex and ctDNA.