A Benzothiadiazole-Based Eu3+ Metal–Organic Framework as the Turn-On Luminescent Sensor toward Al3+ and Ga3+ with Potential Bioimaging Application

The design and preparation of novel multifunctional lanthanide metal–organic frameworks (Ln-MOFs) have been arisen widespread attention. In particular, Ln-MOFs have shown great luminescence potential in chemical sensing. Herein, a new benzothiadiazole-based Eu-MOF {[(CH3)2NH2][Eu(BTDB)2]·2H2O}n (JXUST-11) was obtained based on 4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzoic acid (H2BTDB), which exhibits a chain-based three-dimensional framework. Moreover, JXUST-11 is considered as a photoluminescent sensor to identify Al3+ and Ga3+ ions by fluorescence enhancement with the detection limits of 2.9 and 10.2 ppm, severally. Importantly, Al3+ and Ga3+ can be discerned with the naked eye by color change under a natural lamp. In addition, a portable MOF film based on JXUST-11 was developed for Al3+ and Ga3+ detection. This is the first Ln-MOF that can be employed as a naked-eye fluorescent probe to identify Ga3+. Interestingly, JXUST-11 is also capable of detecting Al3+ and Ga3+ in living cells.