Tuning the Luminescence of Metal–Organic Frameworks for Detection of Energetic Heterocyclic Compounds
摘要:
Herein we report three metal-organic frameworks (MOFs), TABD-MOF-1, -2, and -3, constructed from Mg2+, Ni2+, and Co2+, respectively, and deprotonated 4,4'-((Z,Z)-1,4-diphenylbuta-1,3-diene-1,4-diyl)dibenzoic acid (TABD-COOH). The fluorescence of these three MOFs is tuned from highly emissive to completely nonemissive via ligand-to-metal charge transfer by rational alteration of the metal ion. Through competitive coordination substitution, the organic linkers in the TABD-MOFs are released and subsequently reassemble to form emissive aggregates due to aggregation-induced emission. This enables highly sensitive and selective detection of explosives such as five-membered-ring energetic heterocyclic compounds in a few seconds with low detection limits through emission shift and/or turn-on. Remarkably, the cobalt-based MOF can selectively sense the powerful explosive 5-nitro-2,4-dihydro-3H-1,2,4-triazole-3-one with high sensitivity discernible by the naked eye (detection limit = 6.5 ng on a 1 cm(2) testing strip) and parts per billion-scale sensitivity by spectroscopy via pronounced fluorescence emission.
Rigidifying Effect of Metal–Organic Frameworks: Protect the Conformation, Packing Mode, and Blue Fluorescence of a Soft Piezofluorochromic Compound under Pressures up to 8 MPa
作者:Zhang-Wen Wei、Cheng-Xia Chen、Shao-Ping Zheng、Hai-Ping Wang、Ya-Nan Fan、Ye-Ye Ai、Mei Pan、Cheng-Yong Su
DOI:10.1021/acs.inorgchem.6b00429
日期:2016.8.1
We demonstrate that the conformation, packing mode, and blue fluorescence of a soft piezo-fluorochromic compound can be preserved by structurally fixing it into a solid calcium metal-organic framework (Ca-MOF, LIFM-40), which can survive pressures up to 8 MPa. DFT calculations have been combined with experimental results to inditate that the ligands adopting a specific conformation and packing without pi...pi interactions are the reasons for its rigidified blue emission.