Luminescence investigations on Eu(III) thenoyltrifluoroacetonate complexes with amide ligands

The influence of amide ligands on the photoluminescent behavior of tris(thenoyltrifluoroacetonate)europium(III) in the solid state is reported. Elemental analysis showed that these compounds have the following formulas [Eu(TTA)(3) .(ANL)(2)] and [Eu(TTA)(3).PZA), where ANL = acetanilide and PZA = pyrazinamide. The photoluminescence spectra of the complexes recorded in the range 420-720nm at 77K show narrow bands arising from the (5)D(0)-->(7)F(J) transitions (where J=0-4), under excitation at 394nm. Based on the emission spectra and luminescence decay curves the intensity parameters (Omega(lambda)), lifetime (tau) and emission quantum efficiency (eta) were determined. The Omega(2) values indicate that the Eu(3+) ion in these complexes is in a highly polarizable chemical environment. The higher value of eta (60%) obtained for the complex with the ANL ligand, in comparison with the complex with the PZA ligand (30%), indicates a more efficient deactivation of the Eu(3+) ion in the [Eu(TTA)(3).PZA] complex.