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

Studies of the luminescence of Eu(3+)/quinaldinic acid sodium Eu(QA)(3)] and Eu(3+)/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 (5)D(0) and (5)D(1) levels of Eu(3+). In the aquated Eu/(QA)(3) complex, the most intense spectral band belongs to the (5)D(0) --> (7)F(1) transition (592 nm) and not to (5)D(0) --> (7)F(2) (616 nm), which otherwise occurs usually. In the cases of the Eu/(DOQCA)(3) complex the hypersensitive transition (5)D(0) --> (7)F(2) is the most intense as so far was reported for various Eu(3+) chelates.