Synthesis and DNA-Binding Studies of Two Europium(III) Complexes

Abstract

Two new europium(III) complexes EuL₃NO₃ and EuL₂Cl₂ (L = coumarin-3-carboxylic anion), have been synthesized and characterized by IR, ¹H NMR, ¹³C NMR, MS and elemental analysis. The DNA binding property of the two complexes has been investigated employing fluorescence spectroscopy. The DNA binding constants for the two complexes have been measured to be 1.64 × 10⁴ L mol^-1 and 1.87 × 10³ L mol^-1 through fluorescence quenching method, indicating that the complexes EuL₃NO₃ prefer to intercalative binding to DNA. Both of the binding numbers of EuL₃NO₃ and EuL₂Cl₂ with DNA have been found to be 1, suggesting that each unit of complex bind with a unit of ct-DNA.