Visible‐Light Photocatalysis of C(sp3)‐H Fluorination by the Uranyl Ion: Mechanistic Insights |
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| Authors: | Dr. Liangliang Wu Dr. Xiaoyan Cao Prof. Xuebo Chen Prof. Weihai Fang Prof. Michael Dolg |
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| Affiliation: | 1. Key Laboratory of Theoretical and Computational Photochemistry of Ministry of Education, Department of Chemistry, Beijing Normal University, Beijing, China;2. Theoretical Chemistry, University of Cologne, Cologne, Germany |
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| Abstract: | The uranyl dication shows photocatalytic activity towards C(sp3)?H bonds of aliphatic compounds, but not towards those of alkylbenzenes or cyclic ketones. Theoretical insights into the corresponding mechanisms are still limited. Multi‐configurational ab initio calculations including relativistic effects reveal the inherent electron‐transfer mechanism for the uranyl catalyzed C?H fluorination under blue light. Along the reaction path of the triplet state it was found that the hydrogen atom abstraction triggered by the electron‐rich oxygen of the uranyl moiety is the rate‐limiting step. The subsequent steps, that is, N?F and O?H bond breakage in a manner of concerted asynchronicity, generation of the targeted fluorinated product, and recovery of the photocatalyst are nearly barrierless. Moreover the single electron transfer between the reactive substrates plays a fundamental role during the whole photocatalytic cycle. |
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| Keywords: | ab initio calculations C− H activation photocatalysis single-electron transfer uranium |
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