Dual-emission MOF⊃dye sensor for ratiometric fluorescence recognition of RDX and detection of a broad class of nitro-compounds

Through an ion exchange method, the composite 1⊃HPTS was prepared via the introduction of HPTS (8-hydroxy-1,3,6-pyrenetrisulfonicacid trisodium salt) into the channels of the compound [Zn(TIPA)(NO3−)2(H2O)]·5H2O (1). 1⊃HPTS exhibits durable dual-emission performance of both blue and yellow-green emission, and could act as a two-signal platform in aqueous solution. 1⊃HPTS exhibits ultrahigh sensitive response to a wide range of nitro-compounds, including nitroaromatics, aliphatic nitro-explosives and nitro-containing antibiotics. Particularly, 1⊃HPTS displays ratiometric fluorescence response against RDX. To the best of our knowledge, this is the first MOF-based probe with such an effect for the identification of RDX among luminescent materials. Moreover, the film based on the 1⊃HPTS sample shows high sensitivity towards 4-TNP vapor with good reusability. We also demonstrated that the detection of nitro-compounds using 1⊃HPTS predominantly involved photo-induced electron transfer and fluorescence resonance energy transfer.