Europium(III)-triflate interactions in water and aqueous methanol studied by UV–vis and luminescence

The use of perchlorates as non-complexing rare-earth ligands has been common. However, the possibility of perchlorate explosions in the presence of organic materials led many workers to substitute lanthanide triflates (lanthanides bound to the anion of trifluoromethanesulfonic acid) as the source of rare-earths for studies with other ligands. Using UV–visible and fluorescence emission measurements in water and 50% aqueous methanol, we have shown that triflate does not form complexes with 0.200M Eu(III) in the absence and presence of perchlorate.