Molecular Insights into Carbon Dioxide Sorption in Hydrazone-Based Covalent Organic Frameworks with Tertiary Amine Moieties

Abstract

Tailorable sorption properties at the molecular level are key for efficient carbon capture and storage and a hallmark of covalent organic frameworks (COFs). Although amine functional groups are known to facilitate CO 2 uptake, atomistic insights into CO 2 sorption by COFs modified with amine-bearing functional groups are scarce. Herein, we present a detailed study of the interactions of carbon dioxide and water with two isostructural hydrazone-linked COFs with different polarities based on the 2,5-diethoxyterephthalohydrazide linker. Varying amounts of tertiary amines were introduced in the COF backbones by means of a copolymerization approach using 2,5-bis(2-(dimethylamino)ethoxy)terephthalohydrazide in different amounts ranging from 25 to 100% substitution of the original DETH linker. The interactions of the frameworks with CO 2 and H 2 O were comprehensively studied by means of sorption analysis, solid-state NMR spectroscopy, and quantum-chemical calculations. We show that the addition of the tertiary amine linker increases the overall CO 2 sorption capacity normalized by the surface area and of the heat of adsorption, whereas surface areas and pore size diameters decrease. The formation of ammonium bicarbonate species in the COF pores is shown to occur, revealing the contributing role of water for CO 2 uptake by amine-modified porous frameworks.

Rational Design of Covalent Cobaloxime–Covalent Organic Framework Hybrids for Enhanced Photocatalytic Hydrogen Evolution

“… 14 At the same time, this COF is a well-known and versatile platform that is chemically robust due to its hydrazone-linked structure. 28 , 29 In this study, we used COF-42 as a platform for covalent postsynthetic modification with cobaloxime complexes. The synthesis of COF-42 by solvothermal acid-catalyzed condensation of 1,3,5-triformylbenzene (TFB) and 2,5-diethoxyterephthalohydrazide (DETH) followed published protocols.…”

Inorganic nanocrystal-dynamic porous polymer assemblies with effective energy transfer for sensitive diagnosis of urine copper

“…Covalent organic frameworks (COFs), based on the autoassembly of aromatic units through the reversible character of polymerization reactions, are a type of dynamic porous polymer. [13][14][15][16] Due to their designable building blocks and tunable porous structures, COFs have been considered to be functional organic equivalents of inorganic microporous solids for utilization in gas separation, [17][18][19] ion enrichment, 20 optoelectronics, [21][22][23] catalysis, [24][25][26] drug transport, 27,28 and biosensing. [29][30][31][32] Based on the reversible formation of covalent bonds, they combine error-correction capability and molecular robustness.…”

Crystalline Covalent Organic Frameworks from Triazine Nodes as Porous Adsorbents for Dye Pollutants

“…These observations are in good agreement with the corresponding values for COF materials reported in the literature. 28−30 In summary, FTIR results indicate that a highly polymerized COF was successfully prepared via condensation.…”