Synthesis, Crystal Structure, DNA-binding Properties and Antioxidant Activity of a Copper(II) Complex with Naphthalimide Schiff Base

The Schiff N-allylamine-4-(ethylenediamine-5-methylsalicylidene)-1,8-naphthalimide (H2L) and its copper(II) complex, [Cu(HL)(2)]center dot 0.5DMF, were synthesized and characterized. The crystal structure of the Cu-II complex reveals a slightly distorted square-planar arrangement provided by two N and O donors from two deprotonated ligands. In addition, the DNA-binding properties of the ligand and Cu-II complex were investigated by fluorescence spectra, electronic absorption, and viscosity measurements. The experimental studies of the DNA-binding properties indicated that the ligand and Cu-II complex reacted with DNA via intercalation binding mode, and binding affinity for DNA takes the order: ligand > Cu-II complex. The antioxidant assay in vitro suggested that both exhibited potential intensely antioxidant properties, and the ligand is more effective than its Cu-II complex.