The catalytic performance of metal-organic framework (MOF)-based catalysts can be enhanced by increasing their catalytic sites, which prompts us to explore the multicore cluster-based skeletons by using designed functional ligands. Herein, the exquisite combination of [Tb4(μ2-OH)2(CO2)8] cluster and 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) ligand generated a highly robust nanoporous framework of {[Tb4(BDCP)2(μ2-OH)2]·3DMF·5H2O}n (NUC-58), in which each four {Tb4} clusters are woven together to generate an elliptical nanocage (aperature ca. 12.4 Å). As far as we know, NUC-58 is an excellent nanocage-cluster-based {Tb4}-organic framework with the outstanding confined pore environments of a large specific surface area, high porosity, and plentiful coexisting Lewis acid-base sites of Tb3+, μ2-OH and Npyridine atoms. Performed experiments exhibited that NUC-58 owns a better catalytic performance for the cycloaddition reactions under mild conditions with a high turnover number and turnover frequency. Furthermore, NUC-58, as an eminent heterogeneous catalyst, can enormously boost the Knoevenagel condensation reactions. Thus, this work opens a path for the precise design of polynuclear metal cluster-based MOFs with excellent catalysis, stability, and regenerative behavior. 

Nanocage-Based Tb<sup>3+</sup>-Organic Framework for Efficiently Catalyzing the Cycloaddition Reaction of CO<sub>2</sub> with Epoxides and Knoevenagel Condensation

Bifunctional {Pb10K2}–Organic Framework for High Catalytic Activity in Cycloaddition of CO2 with Epoxides and Knoevenagel Condensation

The catalytic performance of metal-organic framework (MOF)-based catalysts can be enhanced by increasing their catalytic sites, which prompts us to explore the multicore cluster-based skeletons by using designed functional ligands. Herein, the exquisite combination of [Tb4(μ2-OH)2(CO2)8] cluster and 2,6-bis(2,4-dicarboxylphenyl)-4-(4-carboxylphenyl)pyridine (H5BDCP) ligand generated a highly robust nanoporous framework of {[Tb4(BDCP)2(μ2-OH)2]·3DMF·5H2O}n (NUC-58), in which each four {Tb4} clusters are woven together to generate an elliptical nanocage (aperature ca. 12.4 Å). As far as we know, NUC-58 is an excellent nanocage-cluster-based {Tb4}-organic framework with the outstanding confined pore environments of a large specific surface area, high porosity, and plentiful coexisting Lewis acid-base sites of Tb3+, μ2-OH and Npyridine atoms. Performed experiments exhibited that NUC-58 owns a better catalytic performance for the cycloaddition reactions under mild conditions with a high turnover number and turnover frequency. Furthermore, NUC-58, as an eminent heterogeneous catalyst, can enormously boost the Knoevenagel condensation reactions. Thus, this work opens a path for the precise design of polynuclear metal cluster-based MOFs with excellent catalysis, stability, and regenerative behavior.

Nanocage-Based Tb3+-Organic Framework for Efficiently Catalyzing the Cycloaddition Reaction of CO2 with Epoxides and Knoevenagel Condensation.

Metal‒organic frameworks (MOFs) have shown great potential in catalytic fields, especially zeroing in on environmental issues by chemical fixations of hazardous gases towards value-added products. Despite that, difficulties in in-situ...

Practice of Function-Oriented Synthesis: High-Efficiency CO2 Conversion and Knoevenagel Condensation by Two Novel In3-based MOFs with High-Density Active Sites under Mild Conditions

Overuse of nitenpyram and nitrofurazone in agricultural products poses enormous risks to ecosystems, and effective detection and quantification of these residual pollutants are of great concern. Although several strategies have been established for detecting nitenpyram and nitrofurazone in water, searching for a new sensor material with great sensitivity, selectivity, and recyclability remains challenging. Here, we design and synthesize a stable metal-organic framework (MOF) (Zn-CPTA) by employing an organic linker based on the coordination features of benzene-1,4-dicarboxylate and picolinic acid. Zn-CPTA is a 3D framework built from Zn-O-Zn chains called rod secondary building units, which contains 1D open channels modified by uncoordinated carboxyl O atoms and exhibits impressive chemical stability in aqueous solutions within a pH range from 2 to 12. Especially, fluorescent Zn-CPTA can quickly and sensitively detect nitenpyram and nitrofurazone in aqueous solutions with a high quenching constant and low detection limit (LOD) (KSV values for nitenpyram and nitrofurazone are 1.67 × 104 and 1.02 × 105 M-1 with LOD of 0.625 and 0.126 μM, respectively), as well as outstanding selectivity and recyclability. Notably, the LOD value is the lowest among the reported MOFs used for nitrofurazone detection. Besides, experiments and density functional theory calculations are combined to explain the quenching mechanism. Finally, the practical application of Zn-CPTA was further explored in real environment samples with satisfactory recoveries.

Rational Synthesis of a Stable Rod MOF for Ultrasensitive Detection of Nitenpyram and Nitrofurazone in Natural Water Systems.

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.

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

Herein, a novel copper metal–organic framework (MOF), [Cu2(CPTPTA)(H2O)]·CH3NH3+·4H2O·7NMF (1) (H5CPTPTA = 5′-(4-carboxyphenyl)-[1,1′:3′,1′′-terphenyl]-3,3′′,5,5′′-tetracarboxylic acid, NMF = N-methylformamide), has been successfully synthesized via solvothermal reaction. By applying a linker desymmetrization strategy, compound 1 was constructed by a reduced-symmetry ligand CPTPTA5−, leading to three types of channels with various functional sites. Meanwhile, the functional sites promoted the adsorption of CO2, the uptakes being 123.2(2) and 66.8(2) cm3 g−1 at 273 and 298 K, respectively. Furthermore, the smaller channel exists as two kinds of active sites: Lewis acid sites (LASs) and Bronsted acid sites (BASs); whereas the larger one only exists as LASs. The synergistic catalysis of LASs and BASs makes compound 1 exhibit excellent CO2 cycloaddition efficiency towards propylene oxide, and the yield can reach 97%. Overall, such a linker desymmetrization strategy can afford an effective approach to synthesize novel functional MOF materials.

The multifunctional design of metal–organic framework by applying linker desymmetrization strategy: synergistic catalysis for high CO2-epoxide conversion

Borong Zhang

Papers

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

Practice of Function-Oriented Synthesis: High-Efficiency CO2 Conversion and Knoevenagel Condensation by Two Novel In3-based MOFs with High-Density Active Sites under Mild Conditions

The multifunctional design of metal–organic framework by applying linker desymmetrization strategy: synergistic catalysis for high CO2-epoxide conversion

A novel ternary inorganic organic hybrid flame retardant containing biomass and MOFs for high-performance rigid polyurethane foam