Largely Entangled Diamondoid Framework with High-Density Urea and Divergent Metal Nodes for Selective Scavenging of CO₂ and Molecular Dimension-Mediated Size-Exclusive H-Bond Donor Catalysis

Abstract

Pore environment modulation with high-density polarizing groups in metal–organic frameworks (MOFs) can effectively accomplish selective and multicyclic carbon dioxide (CO2) adsorption, whereas the incorporation of task-specific organic sites inside these porous vessels promise to evade self-quenching, solubility, and recyclability issues in hydrogen-bond donating (HBD) catalysis. However, concurrent amalgamation of both these attributes over a single platform is rare but extremely demanding in view of sustainable applications. We designed a robust diamondoid framework CSMCRI-17 (CSMCRI = Central Salt and Marine Chemicals Research Institute) from the mixed-ligand assembly of azo group-containing dicarboxylate ligand, urea-functionalized pyridyl linker, and Zn­(II) nodes with specific divergent coordination. Seven-fold interpenetration to the microporous structure largely augments N-rich functionality that facilitates high CO2 uptake in the activated form (17a) with good CO2 selectivity over N2 and CH4 that outperform many reported materials. The framework displays very strong CO2 affinity and no reduction in adsorption capacity over multiple uptake–release cycles. Benefitting from the pore–wall decoration with urea functionality from the pillaring strut, 17a further demonstrates hydrogen-bond-mediated Friedel–Crafts alkylation of indole with β-nitrostyrene under mild conditions, with multicyclic usability and excellent reactivity toward wide ranges of substituted nucleophiles and electrophiles. Interestingly, interpenetration-generated optimum-sized pores induce poor conversion to sterically encumbered substrate via molecular dimension-mediated size selectivity that is alternatively ascribed from additional control experiments and support the occurrence of HBD reaction within the MOF cavity. The catalytic path is detailed in light of the change of emission intensity of the framework by the electrophile as well as the judicious choice of the substrate, which authenticates the prime role of urea moiety-governed two-point hydrogen bonding.

Redox-Active and Urea-Engineered-Entangled MOFs for High-Efficiency Water Oxidation and Elevated Temperature Advanced CO2 Separation Cum Organic-Site-Driven Mild-Condition Cycloaddition

“…In particular, preferential CO 2 capture over N 2 at elevated temperatures is the most-demanding requisite for flue gas separation. , However, this feat is tricky as uptake capacity and selectivity are drastically reduced with rising temperature. As an integral part of adsorption, chemical fixation of CO 2 with epoxide is one of the most promising and sustainable technologies. − Such a reaction is 100% atom economic, and cyclic carbonates find utility in manufacturing of cosmetics and pharmaceuticals, lithium-ion battery, polar aprotic solvents, and so on. , Though CO 2 is a plentiful C1 source, its kinetic inertness demands backing of a catalyst. However, conventional homogeneous catalysts show major shortcomings in product separation, whereas majority of the heterogeneous catalysts require drastic condition. , In this milieu, Lewis acidic and basic functionality tagged MOFs can provide a synergic platform to facilitate cycloaddition.…”

“…Building on the above, coupled with our continued effort to design functionalized porous materials for environmental remediation and sustainable catalysis, ,− we report a chemically robust MOF CSMCRI-25 (CSMCRI = Central Salt & Marine Chemicals Research Institute) from the assembly of [1,1′-biphenyl]-4,4′-dicarboxylic acid (H 2 BPDC ), 1,3-di­(pyridin-4-yl)­urea linker ( L ), and [Co 2 (COO) 4 N 4 ] metal nodes (Scheme ). The OER activity of the activated MOF ( 25a ) in 1.0 M KOH shows 371 mV overpotential, while the Tafel slope of 53.5 mV/decade overpowers commercial as well as some benchmark electrocatalysts.…”

“…25−27 Such a reaction is 100% atom economic, and cyclic carbonates find utility in manufacturing of cosmetics and pharmaceuticals, lithium-ion battery, polar aprotic solvents, and so on. 16,28 Though CO 2 is a plentiful C1 source, its kinetic inertness demands backing of a catalyst. However, conventional homogeneous catalysts show major shortcomings in product separation, whereas majority of the heterogeneous catalysts require drastic condition.…”

Four Zn(ii)-5-(2-carboxy-phenoxy)-1,3-benzenedicarboxylate coordination polymers induced by different N-ligands: synthesis, structure, and fluorescence detection for BPA and IMH

“…7,8 MCPs can attain multi-dimensional structures through Zn/Cd metal ions, which have a variety of coordination geometries. [9][10][11][12] MCPs without unpaired electrons, especially Zn/Cd metal ions, have attracted special attention because of linker-based high emission, and are used extensively in MCP syntheses with fluorescence characteristics. 13,14 Zn 2+ has a flexible coordination environment and readily forms Zn-MCPs with geometries such as tetrahedral, trigonal bipyramidal, square pyramidal, and octahedral upon ligand coordination.…”

Robust Six-Connected Self-Penetrating Net with Two-Fold Interpenetration for Trace SO2 Removal and UO22+ Detection

“…Metal–organic frameworks (MOFs), built on various metal nodes and organic ligands, are now receiving increasing attention because of not only their intriguing topology matrixes but also their broad applications in adsorption, separation, catalysis, energy, and so on. − For the former, a subclass in the topology matrix, the intertwisting net, represents the special aesthetics. Among them, interpenetration was often encountered; by contrast, self-penetration seems more complicated, and only a few examples were found to belong to this class. − Accordingly, there were fewer cases with the combination of self-penetration and interpenetration. Therefore, more efforts have been made for the application of MOFs in light of their porosities.…”