Synthesis, crystal structure, antioxidant activities and DNA-binding studies of the Ln(III) complexes with 7-methoxychromone-3-carbaldehyde-(4′-hydroxy) benzoyl hydrazone

A novel chromone Schiff base, 7-methoxychromone-3-carbaldehyde-(4′-hydroxy) benzoyl hydrazone (L) and its Ln(III) complexes (Ln = La, Eu) were synthesized and characterized. The crystal structure of the La(III) complex was determined by single-crystal X-ray diffraction: crystallized in the orthorhombic system, space group Pbcn, Z = 8, a = 14.595(2) Å, b = 20.055(3) Å, c = 30.078(5) Å, R1 = 0.0657. Fluorescence titration spectra, electronic absorption titration spectra, EB displacement and viscosity measurement indicated that both the ligand and the complexes can bind to DNA via the intercalation mode, and that the binding affinity of the La(III) complex is higher than that of the Eu(III) complex and of the ligand (L). The antioxidant activity experiments show that these compounds also exhibit good antioxidant activities against OH and O2−. Moreover, the Eu(III) complex exhibits characteristic fluorescence of europium ion in different organic solvents.

Graphical abstractA novel Schiff base ligand, 7-methoxychromone-3-carbaldehyde-(4′-hydroxy) benzoyl hydrazone, and its La(III) and Eu(III) complexes were synthesized and their DNA-binding abilities, antioxidant activities and fluorescence properties were investigated in detail.Figure optionsDownload full-size imageDownload as PowerPoint slide