A new Eu(III)-based metal-organic framework: synthesis, characterization, fluorescence detection of nitrobenzene and catalytic conversion of CO2.

• A new europium metal-organic framework is synthesized and fully characterized. • The MOF has good chemical stability, water stability and high thermal stability. • The MOF is a smart luminescent sensor for NB detection. • The MOF can effectively catalyze CO 2 and epoxides into cyclic carbonates. The employment of metal-organic frameworks (MOFs) as fluorescence sensors for the detection of environmental pollutants and/or heterogeneous catalysts for CO 2 conversion is of great importance for protecting human health. For this purpose, we synthesized a new Eu-MOF [Eu 2 (btpdc) 2 ·(HCOO) 2 ] n (1) (H 2 btpdc = benzo[ b ]thiophene-2,5-dicarboxylic acid) with its three-dimensional structure characterized by single-crystal X-ray diffraction. The powder X-ray diffraction (PXRD) and thermal gravimetric analysis (TGA) results indicate that 1 has high chemical durability, good water stability and high thermal stability. Fluorescence sensing investigations demonstrate that 1 is a smart chemical sensor towards nitrobenzene (NB) detection with high sensitivity, high selectivity and good regeneration performance. A high quenching constant (K sv = 2.33 × 105 M−1) and a low detection limit (LOD = 0.038 μM) are obtained. Combined with experiments and density functional theory calculations, the mechanisms of fluorescence quenching of 1 by NB were also revealed. Furthermore, 1 can serve as a smart catalyst for the cycloaddition reaction of CO 2 with epoxides to synthesize cyclic carbonates, displaying high activity, high selectivity, and good generality. A new three-dimensional Eu-MOF [Eu 2 (btpdc) 2 ·(HCOO) 2 ] n (H 2 btpdc = benzo[b]thiophene-2,5-dicarboxylic acid) was synthesized and structurally characterized. Function explorations demonstrate that the MOF is a smart chemical sensor towards nitrobenzene (NB) detection and also a highly active catalyst for the cycloaddition reaction of CO 2 with epoxides to synthesize cyclic carbonates. [Display omitted] [ABSTRACT FROM AUTHOR]