| 1. |
- Li, Zhuwei, et al.
(författare)
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Engineering single-atom active sites anchored covalent organic frameworks for efficient metallaphotoredox C-N cross-coupling reactions
- 2022
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Ingår i: Science Bulletin. - : Elsevier BV. - 2095-9273. ; 67:19, s. 1971-1981
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Tidskriftsartikel (refereegranskat)abstract
- Photoredox catalysis has become an indispensable solution for the synthesis of small organic molecules. However, the precise construction of single-atomic active sites not only determines the catalytic performance, but also avails the understanding of structure-activity relationship. Herein, we develop a facile approach to immobilize single-atom Ni sites anchored porous covalent organic framework (COF) by use of 4,40,400-(1,3,5-triazine-2,4,6-triyl)trianiline and 2,6-diformylpyridine (Ni SAS/TD-COF). Ni SAS/TDCOF catalyst achieves excellent catalytic performance in visible-light-driven catalytic carbon-nitrogen cross-coupling reaction between aryl bromides and amines under mild conditions. The reaction provides amine products in excellent yields (71%-97%) with a wide range of substrates, including aryl and heteroaryl bromides with electron-deficient, electron-rich and neutral groups. Notably, Ni SAS/TD-COF could be recovered from the reaction mixture, corresponding to the negligible loss of photoredox performance after several cycles. This work provides a promising opportunity upon rational design of single-atomic active sites on COFs and the fundamental insight of photoredox mechanism for sustainable organic transformation.
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| 2. |
- Li, Zhuwei, et al.
(författare)
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Integrated nickel/polymer dual catalytic system for visible-light-driven sulfonamidation between aryl halides and aryl sulfonamides
- 2022
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Ingår i: CHEM CATALYSIS. - : Elsevier BV. - 2667-1093. ; 2:12, s. 3546-3558
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Tidskriftsartikel (refereegranskat)abstract
- By merging transition metal and heterogeneous photocatalyst, a metal-photoredox system has attracted more attention for cross -coupling of various dual photoredox catalysis. However, there is a grand challenge for the attenuated nucleophilicity of sulfonamides relative to alkyl amines. Herein, an integrated dual catalytic system of porous carbon nitride nanosheet with nitrogen vacancies (NV-P-C3N4)as a conjugated polymer semiconductor host in combination with transition-metal nickel (Ni) was constructed by a defect and morphology regulation strategy toward visible-light-driven sulfona-midation between aryl halides and aryl sulfonamides. The excellent nickel/photoredox-catalyzed C-N coupling reaction performance is ascribed to the large specific surface area, abundant active sites, long carrier lifetime, and efficient transfer and separation of photo -excited electrons and holes. This work highlights the opportunity to cooperate with heterogeneous catalysts and active metal sites for challenging cross-coupling reactions.
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