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 420-720 nm at 77 K show narrow bands arising from the ⁵D₀ → ⁷F _J transitions (where J = 0-4), under excitation at 394 nm. Based on the emission spectra and luminescence decay curves the intensity parameters (Ω_λ), lifetime (τ) and emission quantum efficiency (η) were determined. The Ω₂ values indicate that the Eu³⁺ion in these complexes is in a highly polarizable chemical environment. The higher value of η (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 Eu³⁺ion in the Eu(TTA)₃·PZA] complex.