Stilbene ligand-based metal-organic frameworks for efficient dye adsorption and nitrobenzene detection

The technological developments of metal-organic framework (MOF) for selective adsorption and sensing have been achieved in recent years. Herein, we report two stilbene-based MOFs, denoted as Zn-3(SDC)(3)(bpy) (1) and Zn(SDC)(bpy)center dot 2DMF (2). MOFs 1 and 2 were synthesized in pure form by controlling the organic linker ratio and were used for the adsorptive removal of dye molecules. Despite their low adsorption capacities, the MOFs were more selective toward cationic dye (methylene blue) than anionic dye (methyl orange). The unique fluorescent property of the MOFs was harnessed for the sensing of harmful organic molecules. Interestingly, the fluorescence of 1 ' was quenched by aromatic analytes containing amine and nitro functional groups. However, 2 ' only showed modest fluorescence quenching by nitrobenzene. The quenching efficiency of nitrobenzene had a low detection limit for 1 ' and 2 ' (14.28 and 25.42 mu M, respectively). These MOFs can be used as adsorbents and highly sensitive chemical sensors.