Sensitized Luminescence of Trivalent Lanthanide Complexes Eu3+/Quinaldinic Acid and Eu3+/1,4-Dihydro-Oxo-Chinoline-3-Carboxilic Acid

Studies of the luminescence of Eu3+/quinaldinic acid sodium [Eu(QA)3] and Eu3+/1,4-dihydro-4-oxo-quinoline-carboxylic acid sodium [Eu/(DOQCA)3], both in solid form and in aqueous solution, are presented in room temperature. The energy transfer to the emitting levels of the lanthanide ions are discussed on the basis of the emission spectra and lifetime data of 5D0 and 5D1 levels of Eu3+. In the aquated Eu/(QA)3 complex, the most intense spectral band belongs to the 5D0 → 7F1 transition (592 nm) and not to 5D0 → 7F2 (616 nm), which otherwise occurs usually. In the cases of the Eu/(DOQCA)3 complex the hypersensitive transition 5D0 → 7F2 is the most intense as so far was reported for various Eu3+ chelates.