3D water-stable europium metal organic frameworks as a multi-responsive luminescent sensor for high-efficiency detection of Cr ₂O ₇ ²⁻, MnO ₄ ⁻, Cr ³⁺ ions and SDBS in aqueous solution

Abstract

A 3D water-stable europium metal organic framework has been synthesized. Fluorescence measurements show that the MOF can selectively and sensitively detect Cr ₂O ₇ ²⁻, MnO ₄ ⁻, Cr ³⁺ ions and SDBS in aqueous solutions.

Abstract

A microporous europium metal–organic framework (Eu-MOF), namely, {[Eu ₃(bpydb) ₃(HCOO)(OH) ₂(DMF)]·3DMF·2H ₂O} _n ( 1) with asymmetric trinuclear metal clusters extended by 4,4′-(4,4′-bipyridine-2,6-diyl) dibenzoic acid has been synthesized via the solvothermal method. PXRD of 1 confirms that it possesses excellent water stability and pH stability. The photo-luminescence properties of 1 exhibit effective recognition of Cr ₂O ₇ ²⁻, MnO ₄ ⁻, and Cr ³⁺ ions and SDBS. Furthermore, a wide linear range, high quenching constant and a low detection limit reveal that 1 can potentially act as a luminescence-based sensor for quantitative and highly sensitive detection of Cr ₂O ₇ ²⁻, MnO ₄ ⁻, and Cr ³⁺ ions as well as SDBS in aqueous solutions. To the best of our knowledge, the detection limit of 1 is the lowest value reported for Ln-MOF-based luminescent sensors to detect Cr ₂O ₇ ²⁻ ions (0.5 μM) in aqueous solutions. The use of a rare earth fluorescent probe for detecting MnO ₄ ⁻ ions is not common. It is the first time that Ln-MOF as a fluorescence probe is used for detecting SDBS. Moreover, fluorescent-based test papers of 1 have also been prepared, which can be helpful to develop visual detection for Cr ₂O ₇ ²⁻, MnO ₄ ⁻, and Cr ³⁺ ions as well as SDBS in daily applications.