A multi-responsive luminescent sensor based on a stable Eu(III) metal–organic framework for sensing Fe3+, MnO4−, and Cr2O72− in aqueous solutions.

A new water-stable three-dimensional (3D) Eu(III) metal–organic framework with the formula of {[Eu₃(BTDC)₄(HCOO)(H₂O)₂]·solvents}_n (JXUST-9) was successfully obtained by the solvothermal reaction of 2,1,3-benzothiadiazole-4,7-dicarboxylic acid (H₂BTDC) and Eu(NO₃)₃·6H₂O. The PXRD patterns indicate that JXUST-9 exhibits good stability when soaked in boiling water for at least 24 h. The fluorescence experiments indicate that JXUST-9 could be considered as a good multi-responsive sensing material for detecting Fe³⁺, MnO₄⁻ and Cr₂O₇²⁻ in aqueous solutions via the turn-off effect, and the detection limits are 0.94 μM, 1.23 μM and 1.23 μM, respectively. JXUST-9 can also be regenerated at least five times for sensing Fe³⁺, MnO₄⁻ and Cr₂O₇²⁻. Moreover, a rapid detection test paper incorporated with JXUST-9 has been produced, which is helpful for carrying out visual detection of Fe³⁺, MnO₄⁻ and Cr₂O₇²⁻ in daily applications. [ABSTRACT FROM AUTHOR]