A Stable Zn <sup>II</sup> Metal–Organic Framework with a Benzothiadiazole Carboxylate Ligand as Fluorescent Sensor for Zr <sup> 4 <b>+</b> </sup> , H <sub>2</sub> PO <sub>4</sub> <sup>–</sup> , and VB1 in Living Cells
Yaping Li, Xuan Li, Jianhua Zhang, Yanyan Tang, Qinglin Chen, Zhi‐Yuan Li, Chen Cao, Yongquan Wu, Sui‐Jun Liu
Abstract
A new N/O polydentate ligand with benzothiadiazole units (4-(7-(1 H -pyrazol-4-yl)benzo[ c ][1,2,5]thiadiazol-4-yl)benzoic acid, H 2 PZBTB) has been used to synthesize a stable zinc(II) metal–organic framework (MOF) under solvothermal conditions with the formula {[Zn 2 (PZBTB) 2 (H 2 O) 2 ]·0.5DMF} n ( JXUST-60, where JXUST denotes Jiangxi University of Science and Technology; DMF = dimethylformamide). JXUST-60 possesses a two-dimensional (2D) planar architecture, while interlayer interactions via π–π stacking result in the formation of a three-dimensional (3D) packing structure. JXUST-60 maintains structural integrity after being immersed in water and aqueous solutions with pH = 3–13 for 24 h. Fluorescence sensing experiments demonstrate that JXUST-60 can function as a turn-on MOF sensor for Zr 4+, dihydrogen phosphate (H 2 PO 4 – ), and vitamin B1 (VB1) through naked-eye recognition, with low detection limits of 0.06, 0.13, and 0.09 μM, respectively. It is worth noting that JXUST-60 is a rare sensor that recognizes VB1 through the turn-on effect and is the only Zn II MOF fluorescence sensor capable of recognizing Zr 4+ to date. In addition, the cyclic test demonstrates that JXUST-60 is a reusable sensor material. More importantly, JXUST-60 has good biocompatibility and low cytotoxicity to sense VB1 in living cells.