TRLFS and EXAFS investigations of lanthanide and actinide complexation by triflate and perchlorate in an ionic liquid

The solvation of the Eu-perchlorate (ClO4–) and triflate (CF3SO3–, OTf–) salts as well as of Cm(ClO4)3and Am(ClO4)3in the ionic liquid C4mimTf2N (1-butyl-3-methylimidazolium-bis(trifluoromethylsulfonyl)imide) has been comparatively investigated by application of laser fluorescence spectroscopy and X-ray absorption spectroscopy. Moreover, the ClO4–/OTf–ligand exchange reaction for the two actinide cations has been analyzed by the same spectroscopic techniques. A structural model for the different complexes was determined by the interpretation of the spectroscopic data. The lanthanide and the two actinide cations show the same coordination in C4mimTf2N. Moreover, a sequence for the strength of complexing ligands could be deduced from the spectroscopic data for the lanthanide and the two actinides: ClO4–>OTf–≥Tf2N–>H2O.