Electrochemical and Spectrofluorometric Behaviors of Eu(￥2) Complexes in Aqueous Solution

摘要

Eu(Ⅲ) exhibits one electron-transfer reduction at E1/2 =-0.617 V vs. Ag/AgCl and the hypersensitive peak at 618 nm corresponding to 5D0→7F2 transition in 0.10 M LiClO4 aqueous solutions. Upon the addition of carboxylate or sulfonate anions to the Eu(Ⅲ) aqueous solutions, the reduction potential shifts negatively and the reduction current decreases because of the complex formation between Eu(Ⅲ) ions and the anions. However, for the case of carboxylate anion (acetate or propionate) the shift of reduction peak potential and the emission intensity at 618 nm are greater. The results are interpreted in terms of the differences in the formation constants and the hypersensitivity.