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C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center

Herein we report the direct observation of C–H bond activation at an isolated mononuclear Pd(iii) center. The oxidation of the Pd(ii) complex ((Me)N4)Pd(II)(neophyl)Cl (neophyl = –CH(2)C(CH(3))(2)Ph; (Me)N4 = N,N′-dimethyl-2,11-diaza[3.3](2,6)pyridinophane) using the mild oxidant ferrocenium hexaflu...

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Autores principales: Bouley, Bailey S., Tang, Fengzhi, Bae, Dae Young, Mirica, Liviu M.
Formato: Online Artículo Texto
Lenguaje:English
Publicado: The Royal Society of Chemistry 2023
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10074423/
https://www.ncbi.nlm.nih.gov/pubmed/37035706
http://dx.doi.org/10.1039/d3sc00034f
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author Bouley, Bailey S.
Tang, Fengzhi
Bae, Dae Young
Mirica, Liviu M.
author_facet Bouley, Bailey S.
Tang, Fengzhi
Bae, Dae Young
Mirica, Liviu M.
author_sort Bouley, Bailey S.
collection PubMed
description Herein we report the direct observation of C–H bond activation at an isolated mononuclear Pd(iii) center. The oxidation of the Pd(ii) complex ((Me)N4)Pd(II)(neophyl)Cl (neophyl = –CH(2)C(CH(3))(2)Ph; (Me)N4 = N,N′-dimethyl-2,11-diaza[3.3](2,6)pyridinophane) using the mild oxidant ferrocenium hexafluorophosphate (FcPF(6)) yields the stable Pd(iii) complex [((Me)N4)Pd(III)(neophyl)Cl]PF(6). Upon the addition of an acetate source, [((Me)N4)Pd(III)(neophyl)Cl]PF(6) undergoes Csp(2)–H bond activation to yield the cyclometalated product [((Me)N4)Pd(III)(cycloneophyl)]PF(6). This metalacycle can be independently prepared, allowing for a complete characterization of both the starting and final Pd(iii) complexes. The C–H activation step can be monitored directly by EPR and UV-Vis spectroscopies, and kinetic isotope effect (KIE) studies suggest that either a pre-association step such as an agostic interaction may be rate limiting, or that the C–H activation is partially rate-limiting in conjunction with ligand rearrangement. Density functional theory calculations support that the reaction proceeds through a κ(3) ligand coordination and that the flexible ligand structure is important for this transformation. Overall, this study represents the first example of discrete C–H bond activation occurring at a Pd(iii) center through a concerted metalation–deprotonation mechanism, akin to that observed for Pd(ii) and Pd(iv) centers.
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spelling pubmed-100744232023-04-06 C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center Bouley, Bailey S. Tang, Fengzhi Bae, Dae Young Mirica, Liviu M. Chem Sci Chemistry Herein we report the direct observation of C–H bond activation at an isolated mononuclear Pd(iii) center. The oxidation of the Pd(ii) complex ((Me)N4)Pd(II)(neophyl)Cl (neophyl = –CH(2)C(CH(3))(2)Ph; (Me)N4 = N,N′-dimethyl-2,11-diaza[3.3](2,6)pyridinophane) using the mild oxidant ferrocenium hexafluorophosphate (FcPF(6)) yields the stable Pd(iii) complex [((Me)N4)Pd(III)(neophyl)Cl]PF(6). Upon the addition of an acetate source, [((Me)N4)Pd(III)(neophyl)Cl]PF(6) undergoes Csp(2)–H bond activation to yield the cyclometalated product [((Me)N4)Pd(III)(cycloneophyl)]PF(6). This metalacycle can be independently prepared, allowing for a complete characterization of both the starting and final Pd(iii) complexes. The C–H activation step can be monitored directly by EPR and UV-Vis spectroscopies, and kinetic isotope effect (KIE) studies suggest that either a pre-association step such as an agostic interaction may be rate limiting, or that the C–H activation is partially rate-limiting in conjunction with ligand rearrangement. Density functional theory calculations support that the reaction proceeds through a κ(3) ligand coordination and that the flexible ligand structure is important for this transformation. Overall, this study represents the first example of discrete C–H bond activation occurring at a Pd(iii) center through a concerted metalation–deprotonation mechanism, akin to that observed for Pd(ii) and Pd(iv) centers. The Royal Society of Chemistry 2023-03-13 /pmc/articles/PMC10074423/ /pubmed/37035706 http://dx.doi.org/10.1039/d3sc00034f Text en This journal is © The Royal Society of Chemistry https://creativecommons.org/licenses/by-nc/3.0/
spellingShingle Chemistry
Bouley, Bailey S.
Tang, Fengzhi
Bae, Dae Young
Mirica, Liviu M.
C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center
title C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center
title_full C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center
title_fullStr C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center
title_full_unstemmed C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center
title_short C–H bond activation via concerted metalation–deprotonation at a palladium(iii) center
title_sort c–h bond activation via concerted metalation–deprotonation at a palladium(iii) center
topic Chemistry
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC10074423/
https://www.ncbi.nlm.nih.gov/pubmed/37035706
http://dx.doi.org/10.1039/d3sc00034f
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