Mechanistic Insights into Visible-Light Photocatalysis for C(sp3)-H Fluorination by Uranyl.

Mechanistic Insights into Visible-Light Photocatalysis for C(sp3)-H Fluorination by Uranyl.
Angew Chem Int Ed Engl. 2018 Jul 09;:
Authors: Wu L, Cao X, Chen X, Fang W, Dolg MF
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, i.e., 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 wholephotocatalytic cycle.
PMID: 29984885 [PubMed - as supplied by publisher]

Source: Angewandte Chemie - July 9, 2018 Category: Chemistry Authors: Wu L, Cao X, Chen X, Fang W, Dolg MF Tags: Angew Chem Int Ed Engl Source Type: research