New Europium(III)-TTA Complex Containing 2-Pyrrolidone as Coligand to Application as Luminescent Sensor: PbII and Ethanol in Gasoline

Abstract

This work describes the synthesis and application of an europium(III) complex, [Eu(TTA)3(2-pyr)(H2O)], containing 2-thenoyltrifluoroacetonate (TTA) and 2-pyrrolidone (2-pyr) as ligands, obtained as white solid and soluble in ethanol. In solution, the complex showed red emission, characteristic of the EuIII emission in the solid state (λexc = 375 nm and λem = 612 nm). The complex was tested with PbII, CdII, and HgII ions in water. The effect of metal ions was monitored and evaluated by hypersensitive transition 5D0 → 7F2 (612 nm). The results show that PbII suppresses the complex luminescence and present high sensitivity, according to the values for the Stern-Volmer constant (KSV = 2300 L mol-1), showing good linearity, i.e., determination coefficient (R2) of 0.9913, and low limit of detection (LOD = 6.03 µM). Luminescence quenching increased with the increasing concentration of PbII. These results indicate that the synthesized complex is a potential luminescent sensor for detecting PbII in a simple and fast way, being applicable for routine environmental analysis. When applied as an ethanol sensor in gasoline, the complex hypersensitive transition intensity decreased with the increasing volume of ethanol in gasoline, reaching the values of R2 = 0.9815 and LOD = 4.94% v/v.