Sensitive and Anti-Interference Al3+ Sensing with a Luminescent Eu-MOF

A luminescent lanthanide metal–organic framework, [(TD)5Eu4(HCO2)2(DMF)4] (Eu-TD, TD/H2BTDB = 4,4′-(benzo[c][1,2,5] thiadiazole-4,7-diyl)dibenzoic acid), was synthesized via a solvothermal method by coordinating Eu3+ ions with the strongly emissive ligand H2BTDB. Single-crystal X-ray diffraction analysis reveals that the Eu-TD is in the hexagonal system with space group P6422. Eu-TD demonstrated exceptional selectivity toward Al3+ ions, exhibiting remarkable sensitivity with a low detection limit (limit of detection (LOD) = 0.04 μM) and excellent anti-interference properties. Eu-TD exhibits a pronounced Al3+-triggered luminescent turn-on response across varied aqueous environments, underscoring its viability for environmental monitoring applications. The selective Al3+ recognition in Eu-TD originates from Lewis basic N sites that strongly coordinate with Al3+ through acid–base interactions, concurrently enhancing the absorbance and amplifying the luminescence.