3 research outputs found

    A Stable Y(III)-Based Amide-Functionalized Metal–Organic Framework for Propane/Methane Separation and Knoevenagel Condensation

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    Here, a Y­(III)-based metal–organic framework, JLU-MOF112 {[Y3(μ3-O)2(μ3-OH)­(H2O)2(BTCTBA)2]·2­[(CH3)2NH2]·5DMF·C6H5Cl·4H2O}, has been successfully synthesized under solvothermal conditions. JLU-MOF112 was constructed with amide-functionalized tricarboxylate ligands and Y­(III)-based infinite chains, where the Y3 repeating units are arranged in a trans order. The overall framework could be viewed as a novel (3,5)-connected net with two types of channels along the [100] and [010] directions. JLU-MOF112 possesses a large BET surface area (1553 m2 g–1), a permanent pore volume (0.67 cm3 g–1), and outstanding thermal and chemical stability, which give JLU-MOF112 potential for the purification of natural gas, especially the equimolar separation of C3H8/CH4 with a high selectivity of 176. In addition, benefiting from the amide functional groups as Brønsted basic sites and the exposure of open metal sites as Lewis acid sites after activation, JLU-MOF112 can serve as a high-efficiency heterogeneous catalyst for Knoevenagel condensation by the reactions of malononitrile with benzaldehyde (yield of 98%, turnover number of 392, and turnover frequency of 3.27 min–1) and diverse aldehyde compounds. A rational mechanism was put forward that the Knoevenagel condensation was catalyzed by the synergistic effect of the Lewis acid sites and Brønsted basic sites, engendering the polarization of the carbonyl groups and the deprotonation of the methylene groups for nucleophilic attack

    Three Robust Isoreticular Metal–Organic Frameworks with High-Performance Selective CO<sub>2</sub> Capture and Separation

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    Based on the hard-soft acid base (HSAB) theory, three robust isoreticular metal–organic frameworks (MOFs) with nia topology were successfully synthesized by solvothermal reaction {[In3O(BHB)(H2O)3]NO3·3DMA (JLU-MOF110(In)), [Fe3O(BHB)(H2O)3]NO3 (JLU-MOF110(Fe)), and [Fe2NiO(BHB)(H2O)3] (JLU-MOF110(FeNi)) (DMA = N,N-dimethylacetamide, H6BHB = 4,4″-benzene-1,3,5-triyl-hexabenzoic acid)}. Both JLU-MOF110(In) and JLU-MOF110(Fe) are cationic frameworks, and their BET surface areas are 301 and 446 m2/g, respectively. By modification of the components of metal clusters, JLU-MOF110(FeNi) features a neutral framework, and the BET surface area is increased up to 808 m2/g. All three MOF materials exhibit high chemical and thermal stability. JLU-MOF110(In) remains stable for 24 h at pH values ranging from 1 to 11, while JLU-MOF110(Fe) and JLU-MOF110(FeNi) persist to be stable for 24 h at pH from 1 to 12. JLU-MOF110(In) exhibits thermal stability up to 350 °C, whereas JLU-MOF110(Fe) and JLU-MOF(FeNi) can be stable up to 300 °C. Thanks to the microporous cage-based structure and abundant open metal sites, JLU-MOF110(In), JLU-MOF110(Fe), and JLU-MOF110(FeNi) have excellent CO2 capture capacity (28.0, 51.5, and 99.6 cm3/g, respectively, under 298 K and 1 bar). Interestingly, the ideal adsorption solution theory results show that all three MOFs exhibit high separation selectivity toward CO2 over N2 (35.2, 43.2, and 43.2 for CO2/N2 = 0.15/0.85) and CO2 over CH4 (14.4, 11.5, and 10.1 for CO2/CH4 = 0.5/0.5) at 298 K and 1 bar. Thus, all three MOFs are potential candidates for CO2 capture and separation. Among them, JLU-MOF110(FeNi) displays the best separation potential, as revealed by dynamic column breakthrough experiments
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