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Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation

Herein we report the photophysical and photochemical properties of palladacycle complexes derived from 8-aminoquinoline ligands, commonly used auxiliaries in C–H activation. Spectroscopic, electrochemical and computational studies reveal that visible light irradiation induces a mixed LLCT/MLCT charg...

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Autores principales: Czyz, Milena L., Weragoda, Geethika K., Horngren, Tyra H., Connell, Timothy U., Gomez, Daniel, O'Hair, Richard A. J., Polyzos, Anastasios
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2020
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8157331/
https://www.ncbi.nlm.nih.gov/pubmed/34084410
http://dx.doi.org/10.1039/c9sc05722f
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author Czyz, Milena L.
Weragoda, Geethika K.
Horngren, Tyra H.
Connell, Timothy U.
Gomez, Daniel
O'Hair, Richard A. J.
Polyzos, Anastasios
author_facet Czyz, Milena L.
Weragoda, Geethika K.
Horngren, Tyra H.
Connell, Timothy U.
Gomez, Daniel
O'Hair, Richard A. J.
Polyzos, Anastasios
author_sort Czyz, Milena L.
collection PubMed
description Herein we report the photophysical and photochemical properties of palladacycle complexes derived from 8-aminoquinoline ligands, commonly used auxiliaries in C–H activation. Spectroscopic, electrochemical and computational studies reveal that visible light irradiation induces a mixed LLCT/MLCT charge transfer providing access to synthetically relevant Pd(iii)/Pd(iv) redox couples. The Pd(ii) complex undergoes photoinduced electron transfer with alkyl halides generating C(sp(3))–H halogenation products rather than C–C bond adducts. Online photochemical ESI-MS analysis implicates participation of a mononuclear Pd(iii) species which promotes C–X bond formation via a distinct Pd(iii)/Pd(iv) pathway. To demonstrate the synthetic utility, we developed a general method for inert C(sp(3))–H bond bromination, chlorination and iodination with alkyl halides. This new strategy in auxiliary-directed C–H activation provides predictable and controllable access to distinct reactivity pathways proceeding via Pd(iii)/Pd(iv) redox couples induced by visible light irradiation.
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spelling pubmed-81573312021-06-02 Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation Czyz, Milena L. Weragoda, Geethika K. Horngren, Tyra H. Connell, Timothy U. Gomez, Daniel O'Hair, Richard A. J. Polyzos, Anastasios Chem Sci Chemistry Herein we report the photophysical and photochemical properties of palladacycle complexes derived from 8-aminoquinoline ligands, commonly used auxiliaries in C–H activation. Spectroscopic, electrochemical and computational studies reveal that visible light irradiation induces a mixed LLCT/MLCT charge transfer providing access to synthetically relevant Pd(iii)/Pd(iv) redox couples. The Pd(ii) complex undergoes photoinduced electron transfer with alkyl halides generating C(sp(3))–H halogenation products rather than C–C bond adducts. Online photochemical ESI-MS analysis implicates participation of a mononuclear Pd(iii) species which promotes C–X bond formation via a distinct Pd(iii)/Pd(iv) pathway. To demonstrate the synthetic utility, we developed a general method for inert C(sp(3))–H bond bromination, chlorination and iodination with alkyl halides. This new strategy in auxiliary-directed C–H activation provides predictable and controllable access to distinct reactivity pathways proceeding via Pd(iii)/Pd(iv) redox couples induced by visible light irradiation. The Royal Society of Chemistry 2020-01-23 /pmc/articles/PMC8157331/ /pubmed/34084410 http://dx.doi.org/10.1039/c9sc05722f Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by/3.0/
spellingShingle Chemistry
Czyz, Milena L.
Weragoda, Geethika K.
Horngren, Tyra H.
Connell, Timothy U.
Gomez, Daniel
O'Hair, Richard A. J.
Polyzos, Anastasios
Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation
title Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation
title_full Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation
title_fullStr Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation
title_full_unstemmed Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation
title_short Photoexcited Pd(ii) auxiliaries enable light-induced control in C(sp(3))–H bond functionalisation
title_sort photoexcited pd(ii) auxiliaries enable light-induced control in c(sp(3))–h bond functionalisation
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8157331/
https://www.ncbi.nlm.nih.gov/pubmed/34084410
http://dx.doi.org/10.1039/c9sc05722f
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