A terbium(iii) lanthanide–organic framework as a selective and sensitive iodide/bromide sensor in aqueous medium

Abstract

A potent luminescent sensor for the detection of iodide ions was developed based on a terbium(III)-based lanthanide–organic framework [Tb(cpia)(H₂O)₂]_n·nH₂O (1), which was prepared under hydrothermal conditions using the 5-(4-carboxyphenoxy)isophthalic acid (H₃cpia) bridging ligand. Compound 1 exhibits superior luminescence quenching behavior towards I⁻ with high sensitivity and selectivity among various anions and shows real-time response. Moreover, the mechanism of the selective luminescence quenching response for I⁻ can be mainly explained by the absorption competition between 1 and I⁻. According to this quenching mechanism, we find that compound 1 can also detect Br⁻ by adjusting the excitation wavelength. Significantly, this work could serve as a general guidance for the design and synthesis of pollutant sensors.