Porous organic polymers as a platform for sensing applications

Chemical Society Reviews, Journal Year: 2022, Volume and Issue: 51(6), P. 2031 - 2080

Published: Jan. 1, 2022

Sensing analysis is significantly important for human health and environmental safety. In this review, POPs used as platforms various sensing applications have been summarized discussed.

Language: Английский

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Covalent‐Organic Frameworks (COFs) as Proton Conductors

Advanced Energy Materials, Journal Year: 2021, Volume and Issue: 11(39)

Published: Sept. 1, 2021

Abstract Proton conductivity is the paramount property of proton‐conducting materials that are playing significant roles in diverse electrochemical devices with applications proton exchange membranes (PEMs) for fuel cells (PEMFCs). Considering scarcity fossil fuels, development clean and green renewable energy resources in‐demand across globe. Toward this direction, solid‐state conductors interest. The higher structural tunability, lower density, good crystallinity, accessible well‐defined pores, excellent thermal chemical stability covalent‐organic frameworks (COFs) make them versatile platforms as both under hydrous anhydrous conditions. Taking advantage such superior properties, reports on COFs have been increasing swiftly since 2014, which demands a summarization comprehensive discussion “at glance” visualization further development. In review, showcased newer class material. A presented by organizing strategies taken to develop COFs. Establishment structure–function relationships implementation discussed well. Moreover, challenges future prospects elaborately critically analyzed.

Language: Английский

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Facile construction of fully sp2-carbon conjugated two-dimensional covalent organic frameworks containing benzobisthiazole units

Nature Communications, Journal Year: 2022, Volume and Issue: 13(1)

Published: Jan. 10, 2022

Abstract Developing a facile strategy for the construction of vinylene-linked fully π -conjugated covalent organic frameworks (COFs) remains huge challenge. Here, versatile condition Knoevenagel polycondensation constructing 2D COFs was explored. Three new examples ( BTH-1 , 2 3 ) containing benzobisthiazoles units as functional groups were successfully prepared under this and mild condition. The electron-deficient benzobisthiazole cyano-vinylene linkages both integrated into conjugated skeleton acted acceptor moieties. Interestingly, we found highly ordered D-A system is favorable photocatalytic activity. BTH-3 with benzotrithiophene donor strong effect exhibited an attractive HER 15.1 mmol h −1 g visible light irradiation.

Language: Английский

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Constructing Synergistic Triazine and Acetylene Cores in Fully Conjugated Covalent Organic Frameworks for Cascade Photocatalytic H₂O₂ Production

Chemistry of Materials, Journal Year: 2022, Volume and Issue: 34(11), P. 5232 - 5240

Published: May 16, 2022

Covalent organic frameworks (COFs) are an ideal template for photocatalytic H2O2 synthesis because of the tunable chemical structures and semiconductor properties. However, photoactivity COFs is still under-improved due to inefficient intrinsic charge generation, fast recombination photogenerated charges, limited electron transport along frameworks. Herein, spatially separated synergistic triazine acetylene units first integrated into (EBA-COF BTEA-COF) production. The spatial separation cores leads efficient suppressed recombination, C═C linkage facilitates electrons over skeletons. Both experimental computational results suggested that synergistically promote in a two-electron pathway. EBA-COF showed attractive activity with production rate 1830 μmol h–1 gcat–1, superior most other COF-based catalysts. This study provides method designing photocatalysts active sites based on vinylene-linked COFs.

Language: Английский

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Stimuli-Responsive Crystalline Smart Materials: From Rational Design and Fabrication to Applications

Accounts of Chemical Research, Journal Year: 2022, Volume and Issue: 55(7), P. 1047 - 1058

Published: March 16, 2022

Stimuli-responsive smart materials that can undergo reversible chemical/physical changes under external stimuli such as mechanical stress, heat, light, gas, electricity, and pH, are currently attracting increasing attention in the fields of sensors, actuators, optoelectronic devices, information storage, medical applications, so forth. The current mostly concentrate on polymers, carbon materials, crystalline liquids, hydrogels, which have no or low structural order (i.e., responsive groups/moieties disorderly structures), inevitably introducing deficiencies a relatively response speeds, energy transformation inefficiencies, unclear structure-property relationships. Consequently, with well-defined regular molecular arrays offer new opportunity to create novel improved stimuli-responsive performance. Crystalline include framework (e.g., metal-organic frameworks, MOFs; covalent organic COFs) crystals molecules cages), obvious advantages compared amorphous materials. For example, be uniformly installed skeleton crystal form ordered arrays, making transfer between external-stimulus signals sites much faster more efficiently. Besides that, structures facilitate situ characterization their at level by means various techniques high-tech equipment spectra single-crystal/powder X-ray diffraction, thus benefiting investigation understanding mechanism behind behaviors Nevertheless, some unsolved challenges remain for (CSMs), hampering fabrication material systems practical applications. instance, materials' crystallinity increases, processability properties usually decrease, unavoidably hindering application. Moreover, exist micro/nanosized powders, difficult make macroscale. Thus, developing strategies balance establishing macroscale great significance applications.In this Account, we mainly summarize recent research progress achieved our groups, including (i) rational design an in-depth relationship (ii) creating modification improve Overall, Account summarizes state-of-the-art points out existing future development directions field.

Language: Английский

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Direct Construction of Isomeric Benzobisoxazole–Vinylene-Linked Covalent Organic Frameworks with Distinct Photocatalytic Properties

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(30), P. 13953 - 13960

Published: July 25, 2022

Vinylene/olefin-linked two-dimensional covalent organic frameworks (v-2D-COFs) have emerged as advanced semiconducting materials with excellent in-plane conjugation, high chemical stabilities, and precisely tunable electronic structures. Exploring new linkage chemistry for the reticular construction of v-2D-COFs remains in infancy challenging. Herein, we present a solid-state benzobisoxazole-mediated aldol polycondensation reaction two novel isomeric benzobisoxazole-bridged (v-2D-COF-NO1 v-2D-COF-NO2) trans cis configurations benzobisoxazole. Interestingly, benzobisoxazole linkers endow distinct optoelectronic electrochemical properties, ranging from light absorption emission to charge-transfer properties. When employed photocathode, v-2D-COF-NO1 exhibits photocurrent up ∼18 μA/cm2 under AM 1.5G irradiation at -0.3 V vs reversible hydrogen electrode (RHE), which is twice value v-2D-COF-NO2 (∼9.1 μA/cm2). With Pt cocatalyst, demonstrates photocatalytic evolution rate ∼1.97 mmol h-1 g-1, also clear contrast that (∼0.86 g-1) identical conditions. This work synthesis via structures

Language: Английский

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A Stable and Conductive Covalent Organic Framework with Isolated Active Sites for Highly Selective Electroreduction of Carbon Dioxide to Acetate

Angewandte Chemie International Edition, Journal Year: 2022, Volume and Issue: 61(36)

Published: June 13, 2022

Electroreduction of CO2 to acetate provides a promising strategy reduce emissions and store renewable energy, but is usually by-product. Here, we show stable conductive two-dimensional phthalocyanine-based covalent-organic framework (COF) as an electrocatalyst for reduction with single-product Faradaic efficiency (FE) 90.3(2)% at -0.8 V (vs. RHE) current density 12.5 mA cm-2 in 0.1 M KHCO3 solution. No obvious degradation was observed over 80 hours continuous operation. Combined the comparison properties other catalysts isolated metal active sites, theoretical calculations situ infrared spectroscopy revealed that copper-phthalocyanine site high electron conducive key step C-C coupling *CH3 produce acetate, can avoid *CO or *CHO ethylene ethanol.

Language: Английский

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Ionic Covalent Organic Frameworks for Energy Devices

Advanced Materials, Journal Year: 2021, Volume and Issue: 33(52)

Published: Oct. 8, 2021

Covalent organic frameworks (COFs) are a class of porous crystalline materials whose facile preparation, functionality, and modularity have led to their becoming powerful platforms for the development molecular devices in many fields (bio)engineering, such as energy storage, environmental remediation, drug delivery, catalysis. In particular, ionic COFs (iCOFs) highly useful constructing devices, functional groups can transport ions efficiently, nonlabile ordered all-covalent pore structures backbones provide ideal pathways long-term under harsh electrochemical conditions. Here, current research progress on use iCOFs specifically lithium-based batteries fuel cells, is reviewed terms iCOF backbone-design strategies, synthetic approaches, properties, engineering techniques, applications. categorized anionic or cationic COFs, how each these types lithium ions, protons, hydroxides illustrated. Finally, challenges future opportunities utilization described. This review will therefore serve reference state-of-the-art design application strategies focusing devices.

Language: Английский

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A Three-Dimensional sp² Carbon-Conjugated Covalent Organic Framework

Journal of the American Chemical Society, Journal Year: 2021, Volume and Issue: 143(38), P. 15562 - 15566

Published: Sept. 17, 2021

A first example of an sp2 carbon-conjugated three-dimensional (3D) covalent organic framework (COF) (BUCT-COF-4) is synthesized via the Knoevenagel condensation saddle-shaped aldehyde-substituted cyclooctatetrathiophene and 1,4-phenylenediacetonitrile. Ascribed to extended π-conjugation long-range ordered structures, BUCT-COF-4 displays high Hall electron mobility 1.97 cm2 V–1 s–1 at room temperature. After it doped with iodine, material not only exhibits enhanced up 2.62 in ambient air but also presents unexpected metal-free ferromagnetic phase transition arising from formation aligned spins unidirectional across whole 3D framework. This report a phenomenon COF materials, which would broaden promising applications open new frontier materials.

Language: Английский

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Synthesis of Vinylene-Linked Covalent Organic Frameworks by Monomer Self-Catalyzed Activation of Knoevenagel Condensation

Journal of the American Chemical Society, Journal Year: 2022, Volume and Issue: 144(8), P. 3653 - 3659

Published: Feb. 15, 2022

Reticular chemistry based on thermodynamically controlled linking modes and numerous organic building blocks has constituted versatile crystalline frameworks in molecular-level precision. However, vinylene-linked covalent (COFs) are still quite far from flexible tailoring either their structures or topologies, due to the lack of monomers with sufficient activities. Herein, we establish a strategy synthesize COFs via Knoevenagel condensation between tetratopic monomer 2,2',6,6'-tetramethyl-4,4'-bipyridine (TMBP) linear aromatic dialdehydes mixed solvent benzoic anhydride acid. Mechanistic investigation suggests that was promoted by pyridine self-catalyzed benzoylation upon cleavage molecules. The layered resultant highly crystallized into orthorhombic lattices vertically aligned AA stacking modes, delivering high surface areas up 1560 m2 g-1. π-extended conjugated skeletons comprising para-bipyridyl units vinylene linkages endow these substantial semiconducting properties, releasing visible-light-stimulated catalytic activity water-splitting hydrogen evolution rate as 3230 μmol g-1 h-1.

Language: Английский

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