A luminescent metal-organic framework with tetragonal nanochannels as an efficient chemosensor for nitroaromatic explosives detection

• Published in: CrystEngComm 2021-06, Vol.23 (21), p.391-396
• Main Authors: Xie, Wei, Jiang, Wei, Xu, Guang-Juan, Zhang, Shu-Ran, Xu, Yan-Hong, Su, Zhong-Min
• Format: Article
• Language: English
• Subjects: Chemical sensors; Chemoreceptors; Crystal structure; Crystallography; Dimethyl acetamide; Electron transfer; Electrons; Energy transfer; Explosives; Explosives detection; Fluorescent indicators; Metal-organic frameworks; Nanochannels; Nitrogen dioxide; Quenching; Recyclability
• ISSN: 1466-8033; 1466-8033
• DOI: 10.1039/d1ce00331c

A novel 3D MOF [(Zn 4 O)(H 2 O) 2 (TPA) 2 ]·8DMA ( 1 ) (H 3 TPA = 4,4′,4′′-nitrilotrisbenzoic acid; DMA = N , N -dimethylacetamide) with tetragonal nanochannels has been rationally obtained under solvothermal conditions using the fluorescent ligand H 3 TPA. MOF 1 demonstrates a unique (3,6)-connected network with nanosized square channels, displaying strong blue emission. Interestingly, 1 can be used as a fluorescent probe, which can detect nitroaromatic explosives efficiently and selectively via fluorescence quenching phenomena. As the number of -NO 2 groups increase, fluorescence quenching becomes more obvious, which is maybe because the energy transfer from the electron-donating framework to electron-withdrawing nitroaromatic analytes becomes greater. Notably, the sensor is particularly sensitive to picric acid (PA), showing complete fluorescence quenching at a PA concentration as low as 30 ppm. MOF 1 can be recycled in the detection of nitroaromatic explosives with excellent recyclability. Additionally, the photo-induced electron transfer mechanism was validated through theoretical calculations for the fluorescence quenching. A 3D MOF with nanosized channels can act as an effective fluorescence probe, showing obvious fluorescence "turn-off" for nitroaromatic explosives.