Selective signaling of fluoride anion based on imidazole moieties

Abstract

The imidazole ring unit in both 2-(2'-hydroxyphenyl)-benzimidazole (ligand a) and a europium(III) complex exhibited specific luminescent responses in the presence of fluoride anions. UV-visible and (1) H-nuclear magnetic resonance spectra showed that the NH bond of the imidazole ring can form a hydrogen bond with added fluoride anions. The detection limits are 5 × 10(-6) m for organic ligand and 1.0 × 10(-6) m for the europium complex respectively. The response times are less than 3 s. The europium complex exhibits a linear response in a concentration range lower than 1.0 × 10(-6) m (Y = -666.86X + 730.1).