Recently, single-crystal-to-single-crystal conversion has been a hot topic in the field of metal-organic framework (MOF) materials, which could improve the stability and properties due to the structural change. A new...

Comprehensive Summary Luminescent metal–organic frameworks (LMOFs) have become a promising class of fluorescence sensing materials, however, the multi‐responsive LMOF sensors for organic compounds are rather rare. Herein, a water stable and highly efficient luminescent MOF with the formula of {[Zn(BBZB)(2,6‐NDC)]·solvents}n (JXUST‐10, BBZB = 4,7‐bis(1H‐benzimidazole‐1‐yl)‐2,1,3‐benzothiadiazole and 2,6‐NDC = 2,6‐naphthalenedicarboxylate) was constructed by the incorporation of Zn2+ and two organic ligands (BBZB and 2,6‐NDC) featuring the conjugate system. JXUST‐10 is a three‐dimensional two‐fold interpenetrated framework with good fluorescent property. Based on the luminescent characteristic, JXUST‐10 can be used as a multi‐responsive sensor for detection of three different analytes including tetracycline, benzaldehyde and uric acid via different luminescent change behaviours. Remarkably, fluorescence test paper and LED light devices are used to detect analytes through the visual change of luminescence colour of JXUST‐10 from blue greenish to yellow greenish under ultraviolet light (365 nm) irradiation. Furthermore, the probable sensing mechanisms for three target analytes were also discussed.

A dual-functional sensor based on a two-dimensional metal–organic framework (MOF), namely, {[Cd­(BBZB)­(2,6-NDC)]·CH3OH} n (JXUST-6, BBZB = 4,7-bis­(1H-benzimidazole-1-yl)-2,1,3-benzothiadiazole and 2,6-NDC = 2,6-naphthalenedicarboxylate), has been designed and synthesized under solvothermal conditions. JXUST-6 exhibits good stability in aqueous solution, boiling water, and N,N-dimethylformamide (DMF) solution. Luminesecence studies of JXUST-6 reveal the existence of fluorescence red shift toward Al3+ and Ga3+ accompanied by turn-on fluorescence response. After gradually adding Al3+ solution to JXUST-6 suspended solution, the emission peak moved from 505 to 529 nm and triggered the color conversion from yellow to yellow-green under 365 UV light irradiation. Similarly, the addition of Ga3+ to JXUST-6 suspended solution caused the enhancement of fluorescence intensity as well as the red-shift from 505 to 530 nm. The detection limits of JXUST-6 toward Al3+ and Ga3+ ions are 0.081 and 0.047 ppm, respectively. Actually, the test paper can be used to sense Al3+ and Ga3+ ions, thereby expanding the potential application scope of JXUST-6. Importantly, JXUST-6 represents the rare turn-on MOF toward Ga3+. The red-shift effect of JXUST-6 toward Al3+ and Ga3+ could account for the formation of a strong exciplex between JXUST-6 and Al3+ and Ga3+. The theoretical caculation suggests that the occurrence of strong intramolecular charge transfer leads to turn-on effect toward Al3+ and Ga3+ ions.

A stable metal–organic framework with the formula {[Co(BBZB)(IPA)]·H2O} n (JXUST-23, BBZB = 4,7-bis(1H-benzimidazole-1-yl)-2,1,3-benzothiadiazole and H2IPA = isophthalic acid) was constructed by incorporating Co2+ ions and two conjugated ligands under solvothermal conditions. JXUST-23 takes a dinuclear cluster-based layer structure with a porosity of 2.7%. In this work, JXUST-23 was used to activate peroxymonosulfate (PMS) to degrade rhodamine B (RhB), a difficult-to-degrade pollutant in water. Compared with pure PMS or JXUST-23, the JXUST-23/PMS system displays the best degradation ability of RhB in neutral solution. When the mass ratio of JXUST-23 to PMS was 2:3, 99.72% of RhB (50 ppm) was removed within 60 min, and the reaction rate was 0.1 min–1. Furthermore, free radical quenching experiments show that SO4 •– was the main free radical during the process of RhB degradation. In addition, JXUST-23 exhibits good reusability for the degradation of the organic dye RhB, making it a potential candidate for environmental remediation.