Study on Luminescence Recognition of Fe3+, I- and F- by Europium and Terbium Carboxylic Acid Complexes

Complex 1 and 2 exhibit excellent red and green fluorescence, respectively. • Complexes 1 and 2 exhibit excellent selectivity towards Fe 3+ . • Complex 1 and 2 have good recognition of I - and F - in anions, respectively. • Complex 2 can achieve naked eye recognition of F - . To further advance research on rare earth complexes as Luminescent probes, this work investigates the cation and anion recognition capabilities of europium and terbium carboxylate complexes, Eu(ocpia) ( 1 ) and Tb(ocpia) ( 2 ), in dispersed systems. Cation recognition experiments were performed using DMF as the dispersion medium, with the complex concentration fixed at 0.2 mg/mL. Results demonstrate that both complexes 1 and 2 exhibit excellent selectivity for Fe³⁺, with detection limits as low as 0.076 μM and 0.069 μM, respectively. These findings indicate that complexes 1 and 2 hold great potential as fluorescent probes for Fe³⁺ detection. Anion recognition experiments were conducted in acetonitrile dispersion (0.2 mg/mL complex concentration). Complex 1 shows high selectivity for I⁻, achieving a detection limit of 0.052 μM. In contrast, complex 2 displays strong affinity for F⁻, with a detection limit of 0.087 μM. Notably, F⁻ can coordinate with complex 2 to form a soluble adduct, enabling visual, naked-eye recognition of F⁻. Collectively, these results highlight the promising application of complexes 1 and 2 as selective fluorescent probes for I⁻ and F⁻, respectively. Eu and Tb complexes exhibit excellent red and green fluorescence, respectively, and both have excellent recognition for Fe 3+ . Tb complex can experimentally recognize F - with naked eyes Download: Download high-res image (228KB) Download: Download full-size image