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

Abstract

Seeking strategies to enhance the chemical stability of metal−organic framework (MOF) materials has become a focus for practical applications, which prompts us to carry out the exploratory self-assembly of microporous heterometallic MOFs by introducing alkali metal ions. Herein, the exquisite combination of scarcely reported S-shaped [Pb 10 K 2 (μ 2 -OH) 2 (COO) 24 ] clusters and 2,4,6tri(2,4-dicarboxyphenyl)pyridine (H 6 TDP) ligands under solvothermal conditions generated a highly robust microporous framework ofopen channels along the a-axis. Thanks to the excellent confined pore environments, such as large surface area, rich Lewis acid sites including Pb 2+ and K + , plentiful Lewis base sites including the μ 2 -OH group and N pyridine atom, and open channels, activated NUC-45a exhibits excellent catalytic performance in the cycloaddition of CO 2 with various epoxides under mild conditions. Moreover, NUC-45a, as a heterogeneous catalyst, shows a high catalytic activity for Knoevenagel condensation of aldehydes and malononitrile with high catalytic stability and recyclability. Meanwhile, both reactions have a high turnover number and turnover frequency. This work shows that the use of multifunctional organic ligands and the introduction of alkali metal ions are conducive to the construction of porous cluster-based metal−organic materials with excellent heterogeneous catalysis.

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

“…In recent years, porous metal–organic frameworks (MOFs), as a promising class of multirole solid materials with a periodic network structure, have received extensive attention and been developed rapidly because of their potential applications in the fields of gas adsorption, homogeneous catalysis, magnetism, and so on. − Undoubtedly, the performance of MOFs is closely related to their topology, which can be effectively realized by using different organic ligands and secondary building units (SBUs). , So far, for achieving the aim of Lewis acid–base bifunctional synergistic catalysis, structure-oriented polycarboxylic ligands with functional groups, such as N/O–heterocyclic donor groups, are becoming more widely recognized. In addition, metal-cluster-based MOFs provide a new platform for the systematic study of the relationship between structure and performance because they have the characteristics of diverse building elements, stable frame structures, predictable topology types, and adjustable material functions. − …”

Nanocage-based {In2Tm2}-organic framework for efficiently catalyzing the cycloaddition reaction of CO2 with epoxides and Knoevenagel condensation

“…Thus, converting CO 2 into valuable chemicals has strategic significance of environmental friendliness and sustainability. 20–23 Accordingly, it is significant for the sustainable development of society to implement strategies of CO 2 capture and storage/sequestration (CCS), which have prompted the innovative preparation of functional microporous MOF-based materials. 24–26 At present, the method for the preparation of cyclic carbonates by cycloaddition reaction using CO 2 and epoxides is consistent with the concept of “green preparation theory” and “atomic economy principle”.…”

Bifunctional Self-Penetrating Co(II)-Based 3D MOF for High-Performance Environmental and Energy Storage Applications

“…Metal−organic frameworks (MOFs) have been exploited in a wide range of research sectors due to their varied network topologies and potential applications such as magnetism, 1−3 gas adsorption, 4,5 separation, 6,7 luminescence, 8−11 drug delivery, 12 adsorption, 13−15 photocatalysis, 16,17 heterogeneous catalysis, 18,19 and so on. The key parameter used to identify the MOFs is the number of used organic linkers and inorganic secondary building units (metal nodes).…”

“…Metal–organic frameworks (MOFs) have been exploited in a wide range of research sectors due to their varied network topologies and potential applications such as magnetism, − gas adsorption, , separation, , luminescence, − drug delivery, adsorption, − photocatalysis, , heterogeneous catalysis, , and so on. The key parameter used to identify the MOFs is the number of used organic linkers and inorganic secondary building units (metal nodes). − The attractive properties, structural features, and intriguing topologies are coupled with high surface area, porosity, and thermal stability. , MOFs comprising the mixed ligands polycarboxylate and N-donor linkers are also employed among the functional organic ligands to enhance the dimensionality of the structure. − It is still a difficult task, however, because a variety of delicate factors, including metal nodes, organic linkers, temperatures, solvents, and pH values, may significantly influence the final architectures of the MOFs. − …”