Soft matter anion sensing based on lanthanide (Eu³⁺ and TB ³⁺) luminescent hydrogels

Abstract

A novel design strategy has been applied to fabricate thermo-sensitive silica based lanthanide luminescent hydrogels (poly(N-isopropylacrylamide)), which possesses intense luminescence and exhibits host-guest interactions with anions. In detail, 2-(2-furyl)-4,5-imidazoledicarboxylic acid (a) was used as sensitizing ligand, which could not only transfer its energy to europium ion but also to terbium ion effectively. We observed that only HSO4- can give rise to fluorescence quenching to these target materials compared with CH3COO-, F-, Cl-, Br-, and I-. We regarded that it was mainly due to the anion's acidity which resulted the turned-off process. More importantly, the emission intensities of the two hydrogels significantly enhanced at lower critical solution temperature (33°C). Copyright © Taylor & Francis Group, LLC.