A Water-Stable Tb-MOF As a Rapid, Accurate, and Highly Sensitive Ratiometric Luminescent Sensor for the Discriminative Sensing of Antibiotics and D₂O in H₂O

Abstract

The design and development of self-calibrating ratiometric luminescent sensors for the fast, accurate, and sensitive discrimination and determination of pollutants in wastewater is highly desirable for public and environmental health. Herein, a 3D porous Tb(III)-based metal-organic framework (MOF), {[Tb(HL)(H₂O)₂]·<i>x</i>(solv)}_<i>n</i> (<b>1</b>), was facilely synthesized using a urea-functionalized tetracarboxylate ligand, 5,5'-(((1,4-phenylenebis(azanediyl))bis(carbonyl))bis(azanediyl))diisophthalic acid (H₄L). The activated framework showed a good water stability in both aqueous solutions at a wide pH range of 2-14 and simulated antibiotic wastewaters. Interestingly, this Tb-MOF exhibited dual luminescence owing to the partial energy transfer from the antenna H₄L to Tb³⁺. More importantly, activated <b>1</b> (<b>1a</b>) that was dispersed in water showed a fast, accurate, and highly sensitive discrimination ability toward antibiotics with a good recyclability, discriminating three different classes of antibiotics from each other via the quenching or enhancement of the luminescence and tuning the emission intensity ratio between the H₄L ligand and the Tb³⁺ center for the first time. Simultaneously, <b>1a</b> is a ratiometric luminescent sensor for the rapid, accurate, and quantitative discrimination of D₂O from H₂O. Furthermore, this complex was successfully used for the effective determination of antibiotics and D₂O in real water samples. This work indicates that <b>1a</b> represents the first ever MOF material for the discriminative sensing of antibiotics and D₂O in H₂O and promotes the practical application of Ln-MOF-based ratiometric luminescent sensors in monitoring water quality and avoiding any major leak situation.