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Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions
Operando EPR, XANES/EXAFS, UV‐Vis and ATR‐IR spectroscopic methods have been coupled for the first time in the same experimental setup for investigation of unclear mechanistic aspects of selective aerobic oxidation of benzyl alcohol by a Cu/TEMPO catalytic system (TEMPO=2,2,6,6‐tetramethylpiperidiny...
Autores principales: | , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
John Wiley and Sons Inc.
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317854/ https://www.ncbi.nlm.nih.gov/pubmed/32118340 http://dx.doi.org/10.1002/chem.202000436 |
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author | Rabeah, Jabor Briois, Valérie Adomeit, Sven La Fontaine, Camille Bentrup, Ursula Brückner, Angelika |
author_facet | Rabeah, Jabor Briois, Valérie Adomeit, Sven La Fontaine, Camille Bentrup, Ursula Brückner, Angelika |
author_sort | Rabeah, Jabor |
collection | PubMed |
description | Operando EPR, XANES/EXAFS, UV‐Vis and ATR‐IR spectroscopic methods have been coupled for the first time in the same experimental setup for investigation of unclear mechanistic aspects of selective aerobic oxidation of benzyl alcohol by a Cu/TEMPO catalytic system (TEMPO=2,2,6,6‐tetramethylpiperidinyloxyl). By multivariate curve resolution with alternating least‐squares fitting (MCR‐ALS) of simultaneously recorded XAS and UV‐Vis data sets, it was found that an initially formed (bpy)(NMI)Cu(I)‐ complex (bpy=2,2′‐bipyridine, NMI=N‐methylimidazole ) is converted to two different Cu(II) species, a mononuclear (bpy)(NMI)(CH(3)CN)Cu(II)‐OOH species detectable by EPR and ESI‐MS, and an EPR‐silent dinuclear (CH(3)CN)(bpy)(NMI)Cu(II)(μ‐OH)(2) ⋅Cu(II) (bpy)(NMI) complex. The latter is cleaved in the further course of reaction into (bpy)(NMI)(HOO)Cu(II)‐TEMPO monomers that are also EPR‐silent due to dipolar interaction with bound TEMPO. Both Cu monomers and the Cu dimer are catalytically active in the initial phase of the reaction, yet the dimer is definitely not a major active species nor a resting state since it is irreversibly cleaved in the course of the reaction while catalytic activity is maintained. Gradual formation of non‐reducible Cu(II) leads to slight deactivation at extended reaction times. |
format | Online Article Text |
id | pubmed-7317854 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-73178542020-06-29 Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions Rabeah, Jabor Briois, Valérie Adomeit, Sven La Fontaine, Camille Bentrup, Ursula Brückner, Angelika Chemistry Full Papers Operando EPR, XANES/EXAFS, UV‐Vis and ATR‐IR spectroscopic methods have been coupled for the first time in the same experimental setup for investigation of unclear mechanistic aspects of selective aerobic oxidation of benzyl alcohol by a Cu/TEMPO catalytic system (TEMPO=2,2,6,6‐tetramethylpiperidinyloxyl). By multivariate curve resolution with alternating least‐squares fitting (MCR‐ALS) of simultaneously recorded XAS and UV‐Vis data sets, it was found that an initially formed (bpy)(NMI)Cu(I)‐ complex (bpy=2,2′‐bipyridine, NMI=N‐methylimidazole ) is converted to two different Cu(II) species, a mononuclear (bpy)(NMI)(CH(3)CN)Cu(II)‐OOH species detectable by EPR and ESI‐MS, and an EPR‐silent dinuclear (CH(3)CN)(bpy)(NMI)Cu(II)(μ‐OH)(2) ⋅Cu(II) (bpy)(NMI) complex. The latter is cleaved in the further course of reaction into (bpy)(NMI)(HOO)Cu(II)‐TEMPO monomers that are also EPR‐silent due to dipolar interaction with bound TEMPO. Both Cu monomers and the Cu dimer are catalytically active in the initial phase of the reaction, yet the dimer is definitely not a major active species nor a resting state since it is irreversibly cleaved in the course of the reaction while catalytic activity is maintained. Gradual formation of non‐reducible Cu(II) leads to slight deactivation at extended reaction times. John Wiley and Sons Inc. 2020-05-14 2020-06-10 /pmc/articles/PMC7317854/ /pubmed/32118340 http://dx.doi.org/10.1002/chem.202000436 Text en © 2020 The Authors. Published by Wiley-VCH Verlag GmbH & Co. KGaA. This is an open access article under the terms of the http://creativecommons.org/licenses/by-nc-nd/4.0/ License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non‐commercial and no modifications or adaptations are made. |
spellingShingle | Full Papers Rabeah, Jabor Briois, Valérie Adomeit, Sven La Fontaine, Camille Bentrup, Ursula Brückner, Angelika Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions |
title | Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions |
title_full | Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions |
title_fullStr | Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions |
title_full_unstemmed | Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions |
title_short | Multivariate Analysis of Coupled Operando EPR/XANES/EXAFS/UV–Vis/ATR‐IR Spectroscopy: A New Dimension for Mechanistic Studies of Catalytic Gas‐Liquid Phase Reactions |
title_sort | multivariate analysis of coupled operando epr/xanes/exafs/uv–vis/atr‐ir spectroscopy: a new dimension for mechanistic studies of catalytic gas‐liquid phase reactions |
topic | Full Papers |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7317854/ https://www.ncbi.nlm.nih.gov/pubmed/32118340 http://dx.doi.org/10.1002/chem.202000436 |
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