Solvent‐Influenced Fragmentations in Free‐Standing Three‐Dimensional Covalent Organic Framework Membranes for Hydrophobicity Switching

Mohammed, Abdul Khayum; AlKhoori, Ayesha A.; Addicoat, Matthew A.; Varghese, Sabu; Othman, Israa; Jaoudé, Maguy Abi; Polychronopoulou, Kyriaki; Baias, Maria; Haija, Mohammad Abu; Shetty, Dinesh

doi:10.1002/anie.202200905

Cited by 31 publications

(18 citation statements)

References 43 publications

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“…Although the three-dimensional framework COF-300 was first reported in 2009, until now chemists had not succeeded in functionalizing COF-300 beyond the addition of −OH or −Br groups. − Herein, we have shown that linkage transformation is a versatile way to functionalize COF-300 with alkyl, acetyl, or trifluoroacetyl groups. The resulting library of COF-300 derivatives led to the discovery of an outstanding PFAS adsorbent, COF-300-dimethyl, with a saturation capacity for perfluorooctanoic acid exceeding 250 mg/g.…”

Section: Discussionmentioning

confidence: 89%

Linkage Transformations in a Three-Dimensional Covalent Organic Framework for High-Capacity Adsorption of Perfluoroalkyl Substances

Zeppuhar,

Rollins,

Huber

et al. 2023

ACS Appl. Mater. Interfaces

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Despite their many advantages, covalent organic frameworks (COFs) built from three-dimensional monomers are synthetically difficult to functionalize. Herein, we provide a new synthetic approach to the functionalization of a three-dimensional covalent organic framework (COF-300) by using a series of solidstate linkage transformations. By reducing the imine linkages of the framework to amine linkages, we produced a more hydrolytically stable material and liberated a nucleophilic amino group, poised for further functionalization. We then treated the amine-linked COF with diverse electrophiles to generate a library of functionalized materials, which we tested for their ability to adsorb perfluoroalkyl substances (PFAS) from water. The framework functionalized with dimethylammonium groups, COF-300-dimethyl, adsorbed more than 250 mg of perfluorooctanoic acid (PFOA) per 1 g of COF, which represents an approximately 14,500-fold improvement over that of COF-300 and underscores the importance of electrostatic interactions to PFAS adsorption performance. This work provides a conceptually new approach to the design and synthesis of functional three-dimensional COFs.

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Section: Discussionmentioning

confidence: 89%

Linkage Transformations in a Three-Dimensional Covalent Organic Framework for High-Capacity Adsorption of Perfluoroalkyl Substances

Zeppuhar,

Rollins,

Huber

et al. 2023

ACS Appl. Mater. Interfaces

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“…The Brunauer–Emmett–Teller (BET) specific surface areas of COF1, COF2, and COF3 obtained through nitrogen sorption isotherms at 77 K are 1790±80, 1180±50, and 1400±30 m 2 g −1 , respectively (standard deviation based on triplicate measurements of the COF films obtained from multiple batches of fabrication), which are higher than many COF, and amorphous porous organic polymer (POP)‐based free‐standing films (Figure 2f, S7, Table S3) [48, 49] . The unimodal pore size distribution calculated through the quenched sphere density functional theory (QSDFT) method, [50, 51] also suggested the highly ordered nature of the COF films consisting of one‐dimensional nanochannels (Figure S8).…”

Section: Resultsmentioning

confidence: 99%

Transformation of an Imine Cage to a Covalent Organic Framework Film at the Liquid–Liquid Interface

et al. 2023

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Dynamic covalent chemistry (DCC) opens up a fascinating route for the construction of well‐organized supramolecular architectures, starting from organic molecular cages to crystalline macromolecular covalent organic frameworks (COFs). Herein, for the first time, we have manifested a facile room‐temperature DCC‐directed transformation of discrete organic imine cage‐to‐COF film at the liquid–liquid interface. The unfolding of the cage leading to the generation of imine intermediates, followed by their interface‐assisted preorganization and subsequent growth of the COF film, are elucidated through detailed spectroscopic and microscopic investigations. The interfacial cage‐to‐COF transformation provides a facile route for the faster fabrication of free‐standing COF films with high porosity and crystallinity, demonstrating excellent performance towards molecular sieving and high solvent permeance. Thus, the current study opens up a new route for structural interconversion between two crystalline entities with diverse dimensionality employing DCC at the confined interface.

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“…reported the strategy of changing the interface of the two solvent to modulate the hydrophilicity/hydrophobicity of the resulting COFs membranes (Figure 8b). [ 90a ] The extent of the free functional groups in the imine‐ bonded (CN) covalent skeleton composed of tetrakis(4‐amino)phenylmethane (Tam) and 2, 5‐dibromoterephtahdehyde (Dbta) can be regulated by changing the interface of ethyl acetate/water or chloroform/water. Compared to the chloroform/water system (Tam Dbta‐2), the ethyl acetate/water system (Tam Dbta‐1) resulted in an increase in the amount of unreacted aldehyde functional groups (HCO) in the framework.…”

Section: Continuous Cofs Membranes Forms and Preparation Strategiesmentioning

confidence: 99%

Continuous Covalent Organic Frameworks Membranes: From Preparation Strategies to Applications

Sun

Liu

et al. 2023

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Covalent organic frameworks (COFs) are porous crystalline polymeric materials formed by the covalent bonding of organic units. The abundant organic units library gives the COFs species diversity, easily tuned pore channels, and pore sizes. In addition, the periodic arrangement of organic units endows COFs regular and highly connected pore channels, which has led to the rapid development of COFs in membrane separations. Continuous defect‐free and high crystallinity of COF membranes is the key to their application in separations, which is the most important issue to be addressed in the research. This review article describes the linkage types of covalent bonds, synthesis methods, and pore size regulation strategies of COFs materials. Further, the preparation strategies of continuous COFs membranes are highlighted, including layer‐by‐layer (LBL) stacking, in situ growth, interfacial polymerization (IP), and solvent casting. The applications in separation fields of continuous COFs membranes are also discussed, including gas separation, water treatment, organic solvent nanofiltration, ion conduction, and energy battery membranes. Finally, the research results are summarized and the future prospect for the development of COFs membranes are outlined. More attention may be paid to the large‐scale preparation of COFs membranes and the development of conductive COFs membranes in future research.

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Solvent‐Influenced Fragmentations in Free‐Standing Three‐Dimensional Covalent Organic Framework Membranes for Hydrophobicity Switching

Cited by 31 publications

References 43 publications

Linkage Transformations in a Three-Dimensional Covalent Organic Framework for High-Capacity Adsorption of Perfluoroalkyl Substances

Linkage Transformations in a Three-Dimensional Covalent Organic Framework for High-Capacity Adsorption of Perfluoroalkyl Substances

Transformation of an Imine Cage to a Covalent Organic Framework Film at the Liquid–Liquid Interface

Continuous Covalent Organic Frameworks Membranes: From Preparation Strategies to Applications

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