Extending the 2D conjugated microporous polymers linked by thiazolo[5,4-<i>d</i>]thiazole for green light-driven selective aerobic oxidation of amines

Li, Xia; Zhang, Fu-Lin; Wang, Yuexin; Xiong, Kanghui; Lang, Xianjun

doi:10.1039/d2ta02603a

Cited by 21 publications

(5 citation statements)

References 71 publications

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“…The well-defined nanoporous structures associated with the high crystallinity of the as-prepared COFs made it possible to rationally evaluate their nanoconfined photocatalytic behaviors with respect to the different substrates. Normally, in order to achieve a similar organic transformation, a higher-energy blue-light source was usually used for the triazine-based porous polymers or benzothiazole-containing conjugated as photocatalysts in the previous report, which always led to the mixture of multi-brominated products. , In contrast, low-energy light irradiation could alleviate or avoid the possible photodegradation of catalysts, substrates, intermediates, and even products and thus be favorable for the improvement of either conversion or selectivity of photocatalytic chemical transformations. − On the basis of these considerations, upon the stimulation of a low-energy green light, the as-prepared COFs were tested for photocatalyzing the bromination of the phenyl derivatives with different methoxyl substituents. g-TPYBP-COF delivered much higher total conversions, which could be attributed to the fact that its larger channel sizes are beneficial to the mass rapid transport and the accessibility of catalytic active sites.…”

Section: Resultsmentioning

confidence: 99%

Hexatopic Vertex-Directed Approach to Vinylene-Linked Covalent Organic Frameworks with Heteroporous Topologies

Meng

et al. 2023

J. Am. Chem. Soc.

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A D 3h -symmetric hexatopic monomer was first prepared by attaching the three-fold ditopic moiety 2,6dimethylpyridine to the meta-positions of a phenyl ring. It was further condensed at its six pyridylmethyl carbons with linear ditopic aromatic dialdehydes, resulting in two vinylene-linked COFs with heteroporous topologies, as revealed by powder X-ray diffraction (PXRD), nitrogen sorption, and pore-size distribution analyses, as well as transmission electron microscopy (TEM) image. The linear-and cross-conjugations, respectively, arising from the 2,6-linked pyridines and meta-linked phenylenes in the hexatopic nodes rendered the resultant COFs with well-patterned π-delocalization, allowing for efficiently catalyzing the bromination of aromatic derivatives with the pore-size-dependent conversion yields and regioselectivity under the irradiation of green light.

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Section: Resultsmentioning

confidence: 99%

Hexatopic Vertex-Directed Approach to Vinylene-Linked Covalent Organic Frameworks with Heteroporous Topologies

Meng

et al. 2023

J. Am. Chem. Soc.

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“…It endows TzTz‐TA with enough potential for organic transformations as a photocatalyst in genuinely ambient conditions. However, because of exciton binding energy between E g opt and bandgap [ 18 ] and π–π stacking of interlayer of materials, [ 19 ] E g opt of prepared materials are narrower than actual bandgaps.…”

Section: Resultsmentioning

confidence: 99%

Tuning the Photocatalytic Activity through Linkages of Porous Conjugated Polymers Based on Triazines for a Selective Oxidation Reaction

Wang

Dong

et al. 2022

Adv Energy and Sustain Res

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Conjugated polymers like conjugated microporous polymers (CMPs) and covalent organic frameworks (COFs) are burgeoning metal‐free photocatalysts for selective oxidation reactions. They possess outstanding features and salient advantages that are inextricably linked to structures at the molecular level. More effort should be devoted to seeking appropriate linkages which can define their crystallinity as well as photocatalytic activity. Herein, with thiazolo[5,4‐d]thiazole (TzTz) and imine as linkages, TzTz‐TA and TTI‐COF are prepared with triazine as the core, respectively. Conclusively, TTI‐COF shows high crystallinity, whereas TzTz‐TA is amorphous, belonging to CMP. However, TzTz‐TA exhibits better photocatalytic activities than TTI‐COF for the blue light‐driven selective aerobic oxidation of amines. The superior photoelectric properties and a more suitable reduction potential are imposed by the TzTz linkages to override the shortcoming of lack of crystallinity for TzTz‐TA. High selectivities for imines by photocatalytic oxidation of benzyl amines are achieved over TzTz‐TA. In addition, TzTz‐TA emerges with remarkable recoverability and recyclable stability. This study implies that tuning the linkages is essential for boosting the photocatalytic activity of porous materials.

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“…By comparison, the CN peak at 1670 cm −1 in this small molecule can be also found in CMP-Tz and CMP-Tdz, which proved the successful synthesis of microporous catalysts. [18] The solid-state 13 C NMR spectrum showed typical chemical shifts between 120 and 140 ppm, which can be attributed to the aromatic rings in the molecular backbone. The signals from 80 to 100 ppm can be assigned to the carbon of the triple bond.…”

Section: Synthesis and Characterizationmentioning

confidence: 97%

Heterocyclic Modulated Electronic States of Alkynyl‐Containing Conjugated Microporous Polymers for Efficient Oxygen Reduction

Zhao

Wang

Zhang

et al. 2023

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carbon materials are catalytically inefficient, they can be promoted by heteroatom doping, especially nitrogen (N) atoms. For example, Dai and co-workers introduced the electron-donating N atoms into the sp 2 carbon nanotube through chemical doping, its electronegativity can induce charge redistribution of carbon (C) atoms in the skeleton of carbon nanotubes, and change the electronic structure of the surrounding C atoms, thus facilitating the improvement of catalytic performance and even higher than those of Pt-based catalysts in alkaline medium. [3] Huang et al. prepared pyridinic-N dominated graphene-like nanocarbon materials with high electrocatalytic activity by in situ alkaline activations of cellulose and ammonia injection methods. [4] Qu and co-workers synthesized N-atom doped graphene quantum dots by chemical vapor deposition methods, providing an efficient approach to designing efficient ORR electrocatalysts. [5] Such a heteroatom doping strategy has been regarded as a significant method to enhance ORR performance. In order to deeply modulate the definite skeleton, doping degree, and content of catalytic sites, [6] new metalfree catalytic systems with controllable electron environment of active centers at the molecular scale should be developed through organic heterocyclic strategy.Conjugated microporous polymers (CMPs) are a distinctive class of multifunctional porous materials that combine extended π-conjugated structures and permanent nanopores. With the advantages of adjustable molecular structure and high chemical stability, CMPs have emerged as new electrode materials for ORR catalysis. [7] Compared with conventional building blocks in CMP skeletons, electron-deficient units, especially, alkynyl groups with the advantage of convertible hybrid orbital, small steric hindrance, increased overlapping electron clouds, and high-density activity can modulate the electronic state of organic molecules and promote the adsorption of oxygen intermediates, [8] thus optimizing electrocatalytic activity and improving ORR performance. However, due to the rigid molecular skeleton of alkynyl-containing CMPs, they always exhibit low conductivity and crystallinity, as well as intrinsic trap-site density, leading to poor ORR catalytic activity. [9] Therefore, it is important to develop CMP-based heterostructureThe oxygen reduction reaction (ORR) is a key process in green energy conversion technology. Heteroatom doping has been proven to be a prospective strategy to prepare metal-free carbon-based electrocatalysts, but such methods often suffer from uncontrollable catalyst frameworks and imprecise active sites. Herein, an organic heterocyclic strategy is adopted to modulate the charge redistribution of alkynyl-containing conjugated microporous polymers (CMPs) by introducing varied five-membered heterocyclic structures. Among these CMPs, the S, 2N-containing thiadiazole heterocyclic molecule (CMP-Tdz) with carbonized alginate materials (C CA ) displays a remarkable quasi-four-electron-transfer ORR pathway, exhibiting...

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Extending the 2D conjugated microporous polymers linked by thiazolo[5,4-d]thiazole for green light-driven selective aerobic oxidation of amines

Abstract: Conjugated microporous polymers (CMPs) are emerging as multifaceted photocatalysts whose properties can be precisely tuned at the molecular level. Herein, a donor–π–acceptor (D–π–A) type CMP linked by the electron-deficient thiazolo[5,4...

Cited by 21 publications

References 71 publications

Hexatopic Vertex-Directed Approach to Vinylene-Linked Covalent Organic Frameworks with Heteroporous Topologies

Hexatopic Vertex-Directed Approach to Vinylene-Linked Covalent Organic Frameworks with Heteroporous Topologies

Tuning the Photocatalytic Activity through Linkages of Porous Conjugated Polymers Based on Triazines for a Selective Oxidation Reaction

Heterocyclic Modulated Electronic States of Alkynyl‐Containing Conjugated Microporous Polymers for Efficient Oxygen Reduction

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