A Novel Multifunctional Eu (III)‐MOF Luminescence Sensor for Detecting NB, Fe 3+ , and Cr 2 O 7 2− With Outstanding Sensitivities and Selectivities

The bowl‐shaped flexible carboxylic acid zwitterion 1,1′,1″‐(2,4,6‐trimethylbenzene‐1,3,5‐triyl)tris (methylene)‐tris(4‐carboxy‐pyridinium)tribromide (H 3 L Br 3 ) ligand‐based lanthanide metal–organic framework (Ln‐MOF) was synthesized for the first time under solvothermal conditions. Single crystal X‐ray diffraction analysis indicates that the molecular formula of Ln‐MOF is [Eu L 2 (H 2 O) 4 Br 3 ]·2H 2 O ( 1 ). Luminescence sensing experiments demonstrate that 1 shows obvious fluorescence quenching for nitrobenzene (NB), Fe 3+ , and Cr 2 O 7 2− with low detection limits of 0.118 μM, 9.098 nM, and 17.409 nM, respectively. 1 can be regarded as a luminescence sensor with multiple functions, displaying high selectivity, wonderful antiinterference ability, outstanding sensitivity, and recyclability to detect NB, Fe 3+ , and Cr 2 O 7 2− .