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Discovery and Characterization of Acridine Radical Photoreductants
Photoinduced electron transfer (PET) is a phenomenon wherein the absorption of light by a chemical species provides an energetic driving force for an electron transfer reaction.(1–4) This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis,...
Autores principales: | , , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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2020
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138348/ https://www.ncbi.nlm.nih.gov/pubmed/32238940 http://dx.doi.org/10.1038/s41586-020-2131-1 |
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author | MacKenzie, Ian A. Wang, Leifeng Onuska, Nicholas P. R. Williams, Olivia F. Begam, Khadiza Moran, Andrew M. Dunietz, Barry D. Nicewicz, David A. |
author_facet | MacKenzie, Ian A. Wang, Leifeng Onuska, Nicholas P. R. Williams, Olivia F. Begam, Khadiza Moran, Andrew M. Dunietz, Barry D. Nicewicz, David A. |
author_sort | MacKenzie, Ian A. |
collection | PubMed |
description | Photoinduced electron transfer (PET) is a phenomenon wherein the absorption of light by a chemical species provides an energetic driving force for an electron transfer reaction.(1–4) This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics, and photosensitive materials. In recent years, research in the area of photoredox catalysis has leveraged PET for the catalytic generation of both neutral and charged organic free radical species. These technologies have enabled a wide range of previously inaccessible chemical transformations and have seen widespread utilization in both academic and industrial settings. These reactions are often catalyzed by visible-light absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium, or copper.(5,6) While a wide variety of closed shell organic molecules have been shown to behave as competent electron transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as an excited state donor or acceptor. This is perhaps somewhat unsurprising in light of previously reported doublet excited state lifetimes for neutral organic radicals, which are typically several orders of magnitude shorter than singlet lifetimes for known transition metal photoredox catalysts.(7–11) Herein we document the discovery, characterization, and reactivity of a neutral acridine radical with a maximum excited state oxidation potential of −3.36 V vs. SCE: significantly more reducing than elemental lithium and marking it as one of the most potent chemical reductants reported.(12) Spectroscopic, computational, and chemical studies indicate that the formation of a twisted intramolecular charge transfer species enables the population of higher energy doublet excited states, leading to the observed potent photoreductant behavior. We demonstrate that this catalytically-generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and bodes well for the adoption of this system in additional organic transformations requiring dissolving metal reductants. |
format | Online Article Text |
id | pubmed-7138348 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
record_format | MEDLINE/PubMed |
spelling | pubmed-71383482020-10-01 Discovery and Characterization of Acridine Radical Photoreductants MacKenzie, Ian A. Wang, Leifeng Onuska, Nicholas P. R. Williams, Olivia F. Begam, Khadiza Moran, Andrew M. Dunietz, Barry D. Nicewicz, David A. Nature Article Photoinduced electron transfer (PET) is a phenomenon wherein the absorption of light by a chemical species provides an energetic driving force for an electron transfer reaction.(1–4) This mechanism is relevant in many areas of chemistry, including the study of natural and artificial photosynthesis, photovoltaics, and photosensitive materials. In recent years, research in the area of photoredox catalysis has leveraged PET for the catalytic generation of both neutral and charged organic free radical species. These technologies have enabled a wide range of previously inaccessible chemical transformations and have seen widespread utilization in both academic and industrial settings. These reactions are often catalyzed by visible-light absorbing organic molecules or transition-metal complexes of ruthenium, iridium, chromium, or copper.(5,6) While a wide variety of closed shell organic molecules have been shown to behave as competent electron transfer catalysts in photoredox reactions, there are only limited reports of PET reactions involving neutral organic radicals as an excited state donor or acceptor. This is perhaps somewhat unsurprising in light of previously reported doublet excited state lifetimes for neutral organic radicals, which are typically several orders of magnitude shorter than singlet lifetimes for known transition metal photoredox catalysts.(7–11) Herein we document the discovery, characterization, and reactivity of a neutral acridine radical with a maximum excited state oxidation potential of −3.36 V vs. SCE: significantly more reducing than elemental lithium and marking it as one of the most potent chemical reductants reported.(12) Spectroscopic, computational, and chemical studies indicate that the formation of a twisted intramolecular charge transfer species enables the population of higher energy doublet excited states, leading to the observed potent photoreductant behavior. We demonstrate that this catalytically-generated PET catalyst facilitates several chemical reactions that typically require alkali metal reductants and bodes well for the adoption of this system in additional organic transformations requiring dissolving metal reductants. 2020-04-01 2020-04 /pmc/articles/PMC7138348/ /pubmed/32238940 http://dx.doi.org/10.1038/s41586-020-2131-1 Text en Users may view, print, copy, and download text and data-mine the content in such documents, for the purposes of academic research, subject always to the full Conditions of use:http://www.nature.com/authors/editorial_policies/license.html#terms |
spellingShingle | Article MacKenzie, Ian A. Wang, Leifeng Onuska, Nicholas P. R. Williams, Olivia F. Begam, Khadiza Moran, Andrew M. Dunietz, Barry D. Nicewicz, David A. Discovery and Characterization of Acridine Radical Photoreductants |
title | Discovery and Characterization of Acridine Radical Photoreductants |
title_full | Discovery and Characterization of Acridine Radical Photoreductants |
title_fullStr | Discovery and Characterization of Acridine Radical Photoreductants |
title_full_unstemmed | Discovery and Characterization of Acridine Radical Photoreductants |
title_short | Discovery and Characterization of Acridine Radical Photoreductants |
title_sort | discovery and characterization of acridine radical photoreductants |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7138348/ https://www.ncbi.nlm.nih.gov/pubmed/32238940 http://dx.doi.org/10.1038/s41586-020-2131-1 |
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