Electrochemical and spectroscopic studies of europium(II/III) species in a hydrophobic room-temperature ionic liquid

The electrochemical and spectroscopic properties of divalent and trivalent europium species have been investigated in a hydrophobic room-temperature ionic liquid, 1-butyl-l-methylpyrrolidinium bis(trifluoromethylsulfonyl)amide (BMPTFSA). The diffusion coefficients of Eu(II) and Eu(III) estimated by chronoamperometry were (3.9 ± 0.4) x 10^-8 and (4.2 ± 0.7) x 10^-8cm² s^-1, respectively. The diffusion of Eu(II) is affected by the coordination between Eu(II) and TFSA^-. The TFSA^- ligand seems to act as a weaker ligand than CH ₃OH according to the splitting of the 5d levels observed from the absorption spectrum for Eu(II). The emission spectra of Eu(II) and Eu(III) were also obtained in BMPTFSA.