Synthesis of Benzobisoxazole-Linked Two-Dimensional Covalent Organic Frameworks and Their Carbon Dioxide Capture Properties

Abstract

Developing novel synthetic strategies to construct crystalline polymeric materials with excellent chemical stability and high carbon capture capacity has become a challenging process. Herein, we report the synthesis of two novel 2D benzobisoxazole-linked covalent organic frameworks (BBO−COFs) utilizing C 3 -symmetric formyl-and C 2symmetric o-aminophenol-substituted molecular building blocks. The BBO−COFs exhibit excellent water stability, high surface areas, and great CO 2 uptake capacities. This general synthetic method affords the opportunity to prepare ordered BBO-based polymeric materials for carbon capture, chemical sensing, and organic electronic applications.

Mechanistic investigations into the cyclization and crystallization of benzobisoxazole-linked two-dimensional covalent organic frameworks

“…It is worth noting that this is the highest surface area reported to date for a benzoxazole-linked porous material. 27 , 31 , 32 The total pore volume of BBO-COF 3 calculated at P / P 0 = 0.989 provided a value of 1.22 cm 3 g –1 . The pore size distribution was estimated using nonlocal density functional theory (NLDFT) to provide an average pore size of 2.7 nm, which is close to the predicted value of 3.3 nm.…”

Synthesis and evaluation of N, O‐doped hypercrosslinked polymers and their performance in CO2 capture

“…The reason lies in the abundant microporous structure in polymer networks. The Q st of the final HCPs exceed those reported MOPs, such as the porous cationic polymer (PCP‐Cl, 28.5 kJ/mol), microporous organic polymers (MOPs, 22–26 kJ/mol) and are comparable to the azo‐linked polymers (ALPs, 28.6–32.5 kJ/mol), benzoazole‐linked polymers (BOLPs, 33.6 kJ/mol), crystalline polymer (BBO‐COF‐1, 30.2 kJ/mol) . These results proved that the introduction of nitrogen atoms or other electron‐rich atoms, (e.g.…”

2D Rigid Benzoxazole-Linked Covalent Organic Framework Films with High-Strength, High-Modulus Mechanical Behavior

“…To understand the reaction mechanism of TFPPy-BBO-COF film formation, we investigated the chemical composition of both the intermediate film and the final annealed film. We hypothesize that the film formation of TFPPy-BBO-COF proceeds via a different reaction mechanism compared to previous reports of benzoxazolelinked COFs, 7,28 particularly given that the first step of our procedure is performed in air. Our proposed mechanism is illustrated in Figure 1b, where the DAHQ monomer is initially oxidized to the p-benzoquinone form (DABQ), which then undergoes a condensation reaction with the aldehyde groups on TFPPy to form a reversible imine-linked intermediate.…”