Covalent organic frameworks as metal-free heterogeneous photocatalysts for organic transformations

Zhi, Yongfeng; Li, Ziping; Feng, Xiao; Xia, Hong; Zhang, Yumin; Shi, Zhan; Mu, Ying; Liu, Xiaoming

doi:10.1039/c7ta07691f

Cited by 186 publications

(137 citation statements)

References 59 publications

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“…[32] In particular, imine-based COFs have attracted a good deal of attention and became, during the last few years, one of the most popular backbones in this field. [20,[36][37][38][39][40][41][42][43][44][45][46] Therefore, we wondered if imine-based COFs can be used to perform photo-activated synthetic transformations. [33][34][35] Despite the fact that some luminescent behavior has been reported for a simple iminebased layered COF, [36] the use of metal-free simple imine-based COFs, has not been studied in these sulfoxidation reactions.…”

Section: Introductionmentioning

confidence: 99%

Imine‐Based Covalent Organic Frameworks as Photocatalysts for Metal Free Oxidation Processes under Visible Light Conditions

et al. 2019

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Photochemistry of extended polyimine COF structures with laminar, spherical and 3D architectures has been examined. We show that these materials, composed by undecorated phenyl rings and imine fragments, can act as photocatalyts in oxidative transformations, being the crystalline laminar material the most active photocatalyst. The sulfoxidation reaction proceeds with good yields for a large variety of different sulfides. This process was carried out under visible light conditions (20 W), ethanol/ H 2 O as solvent, and the heterogeneous porous material can be recycled up to 9 times. The crystallinity favours the behavior as photocatalyst of laminar and spherical COFs whereas any particular effect on the 3D material activity was observed. Sulfoxidation reaction mainly proceeds through an energy transfer mechanism using crystalline laminar material. In addition, these materials as photocatalysts were used for the oxidation of phenyl boronic acid into phenol. . a) Catalytic runs in the oxidation of sulfide 2 a to 3 a in nine consecutive 24 hours catalytic runs by addition of 0.3 mmol of sulfide 2 a after each cycle (see S.I. for further information). The output of the catalytic reaction is expressed as mmol of 3 a generated per cycle. Characterization after one catalytic cycle: b) SEM image of crystalline Laminar-COF 1 b c) FT-IR (black colour before catalysis and red colour after catalysis) d) PXRD (black colour before catalysis, red colour, after catalysis). Scheme 1. Mechanistic plausible scenarios for photocatalytic aerobic sulfoxidation reactions (PC = photocatalyst).

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Section: Introductionmentioning

confidence: 99%

Imine‐Based Covalent Organic Frameworks as Photocatalysts for Metal Free Oxidation Processes under Visible Light Conditions

et al. 2019

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“…COF‐JLU5 (Figure c) catalyzes the aerobic cross‐dehydrogenative coupling reaction between N ‐aryltetrahydroisoquinoline and a wide range of nucleophilic precursors, such as nitroalkanes, dialkyl malonates, acetone, and phosphonates upon irradiation with visible light. These reactions proceed with a yield of up to 92 % and opens up a new synthetic pathway to the formation of C−C and C−P bonds . The combination of the porosity, crystallinity, and ordered π‐arrays as well as stability has resulted in COF‐JLU5 being superior to hydrazone‐based COFs in terms of catalytic activity .…”

Section: Built‐in Functionsmentioning

confidence: 99%

Covalent Organic Frameworks: Chemical Approaches to Designer Structures and Built‐In Functions

et al. 2019

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A new approach has been developed to design organic polymers using topology diagrams. This strategy enables covalent integration of organic units into ordered topologies and creates a new polymer form, that is, covalent organic frameworks. This is a breakthrough in chemistry because it sets a molecular platform for synthesizing polymers with predesignable primary and high‐order structures, which has been a central aim for over a century but unattainable with traditional design principles. This new field has its own features that are distinct from conventional polymers. This Review summarizes the fundamentals as well as major progress by focusing on the chemistry used to design structures, including the principles, synthetic strategies, and control methods. We scrutinize built‐in functions that are specific to the structures by revealing various interplays and mechanisms involved in the expression of function. We propose major fundamental issues to be addressed in chemistry as well as future directions from physics, materials, and application perspectives.

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“…Liu and co-workers [67] reported a2 D-COF (COF-JLU5) with high surfacea rea, strong crystallinity and robusts tability (in Figure 4). Liu and co-workers [67] reported a2 D-COF (COF-JLU5) with high surfacea rea, strong crystallinity and robusts tability (in Figure 4).…”

Section: Photocatalytic Reactionsmentioning

confidence: 99%

“…[68,69] [67] In 2015, Mao and co-workers [70] converted ac obalt-porphyrin-based covalent organic framework (Co-COF) into efficient oxygen reduction reaction electrocatalyst. are being rapidlyd eveloped.…”

Section: Electrocatalytic Reactionsmentioning

confidence: 99%

Recent Advances in Covalent Organic Frameworks for Catalysis

Liu

Wang

2020

Chemistry An Asian Journal

114

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Covalent organic frameworks (COFs) as an emerging type of crystalline porousm aterials, have obtained considerable attention recently.T hey have exhibitedd iverse structure and attractive performance in variousc atalytic reactions. It is highly expected to have as ystematic and comprehensive review summing up COFs-derivedcatalysts in homogeneous and heterogeneous catalysis, which is favorable to the judicious design of an efficient catalystf or targeted reaction. Herein, we focus on summarizing recent and significant developments in COFs materials, with an emphasis on both the synthetic strategies andt argetedf unctionalization, and categorize it in accordance with the different types of catalytic reactions.T heir potential catalysis applications are reviewed thoroughly.M oreover,apersonal view aboutt he future developmento fC OFs catalysts with respect to the large-scale production is also discussed.[ + + ] These authors contributed equally to this work.The ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

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Covalent organic frameworks as metal-free heterogeneous photocatalysts for organic transformations

Abstract: A robust two-dimensional covalent organic framework (COF-JLU5), which exhibits excellent heterogeneous photocatalytic performances for oxidative C–H functionalizations under visible-light irradiation using O2as a green oxygen source, is reported.

Cited by 186 publications

References 59 publications

Imine‐Based Covalent Organic Frameworks as Photocatalysts for Metal Free Oxidation Processes under Visible Light Conditions

Imine‐Based Covalent Organic Frameworks as Photocatalysts for Metal Free Oxidation Processes under Visible Light Conditions

Covalent Organic Frameworks: Chemical Approaches to Designer Structures and Built‐In Functions

Recent Advances in Covalent Organic Frameworks for Catalysis

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