Novel Multifunctional Samarium–Organic Framework for Fluorescence Sensing of Ag+, MnO4–, and Cimetidine and Electrochemical Sensing of o‑Nitrophenol in Aqueous Solutions

A novel Sm-metal–organic framework (MOF) sensor with the molecular formula Sm8(HDBA)6·H2O has been prepared based on a penta-carboxyl organic ligand (H5DBA = 3,5-di­(2′,4′-dicarboxylphenyl)­benzoic acid) and samarium nitrate under solvothermal conditions. Sm-MOF is characterized by single-crystal X-ray diffraction analysis, elemental analysis, thermogravimetric analysis, and powder X-ray diffraction analysis. Structural analysis shows that the dimer metal units are alternately connected to form a one-dimensional chain, and this chain is connected by the bridging carboxyl oxygen of the ligand H5DBA to form a two-dimensional double-layer plane, which then expands into a three-dimensional microporous framework. Fluorescence detection studies show that Sm-MOF can detect Ag+ ions, MnO4– anions, and cimetidine tablets with high sensitivity and selectivity and can also be used to electrochemically detect o-nitrophenol in water. High-sensitivity detection capability of the Sm-MOF can enrich the application of samarium complexes in multifunctional sensors.