Synthesis, Luminescence and DNA-Binding Properties of Eu(III) and Tb(III) Complexes with Amide-Based 2,3-Dihydroxynaphthalene Derivative

Abstract

The new ligand 2,2'-[2,3-naphthylenebis(oxy)]-bis(N,N-dibenzyl(acetamide) (L) and its Eu(III) and Tb(III) picrate complexes were synthesized. The complexes were characterized by elemental analysis, IR, TG-DSC and conductivity measurements. The luminescence properties of the two complexes were investigated. The result indicates that the triplet state energy level of the ligand matches better to the resonance level of Eu(III) than Tb(III) ion. Fluorescence intensity of the Eu(III) complex was reduced with the raising coordination ability of solvent. In addition, the DNA-binding properties of the two complexes have been investigated by electronic absorption, fluorescence and cyclic voltammetry. The results suggest that both complexes can bind to DNA via an intercalative binding mode and their binding affinity for DNA follows the order: Eu(III) complex > Tb(III) complex.