Fluorescence response of metalo-hydrogen-bonded organic framework (MHOF) with room temperature phosphorescence to organic pollutants

For health, environmental and safety reasons, it is necessary to conduct highly sensitive detection of organic contaminant antibiotics (sulfathiazole) and nitro explosive drugs (o-nitroaniline) in water. In this work, metal-hydrogen bonded organic framework (MHOF), {[Co(Ad)2(H2O)4]·(H2L)·2.5H2O}n (1), was synthesized by a one-pot hydrothermal method with 2,6-bis(3,5-dicarboxyphenoxy) pyridine (H4L) and adenine (Ad). This MHOF shows a 4-fold interpenetrated three-dimensional (3D) network structure. Importantly, 1 has excellent fluorescence properties and can be used as fluorescent chemical sensor to detect sulfathiazole (STZ) and 2-nitroanilin (2-NA) with limit of detection (LOD) 203 ppb and 6.8 ppb, respectively. By UV-vis absorption/emission spectroscopic measurements and DFT calculations, it is found that photoinduced electron transfer (PET) and fluorescence resonance energy transfer (FRET) are two potential quenching processes. This is the first report of metal-hydrogen bond organic frameworks (MHOFs) as a promising new fluorescent chemical sensor for the detection of organic pollutants in water.