A Photophysical Study of Sensitization‐Initiated Electron Transfer: Insights into the Mechanism of Photoredox Activity

The development of photocatalytic reactions has provided many novel opportunities to expand the scope of synthetic organic chemistry. In parallel with progress towards uncovering new reactivity, there is consensus that efforts focused on providing detailed mechanistic insight in order to uncover und...

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Bibliographic Details
Published in:Angewandte Chemie International Edition 2020-06, Vol.59 (24), p.9522-9526
Main Authors: Coles, Max S., Quach, Gina, Beves, Jonathon E., Moore, Evan G.
Format: Article
Language:English
Subjects:
Absorption spectroscopy
Aromatic compounds
catalysis
Electron transfer
Halides
Organic chemistry
photoredox chemistry
Reaction mechanisms
sensitization-initiated electron transfer
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Summary:The development of photocatalytic reactions has provided many novel opportunities to expand the scope of synthetic organic chemistry. In parallel with progress towards uncovering new reactivity, there is consensus that efforts focused on providing detailed mechanistic insight in order to uncover underlying excited‐state reactions are essential to maximise formation of desired products. With this in mind, we have investigated the recently reported sensitization‐initiated electron transfer (SenI‐ET) reaction for the C−H arylation of activated aryl halides. Using a variety of techniques, and in particular nanosecond transient absorption spectroscopy, we are able to distinguish several characteristic signals from the excited‐state species involved in the reaction, and subsequent kinetic analysis under various conditions has facilitated a detailed insight into the likely reaction mechanism. Sensitization‐initiated electron transfer (SenI‐ET) for photocatalysis has been investigated under various reaction conditions by nanosecond transient absorption (ns‐TA) spectroscopy. By characterising the kinetic behaviour of the different excited‐state species involved, detailed insight into the reaction mechanism has been obtained.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.201916359