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Spin Delocalization in the Radical Cations of Porphyrin Molecular Wires: A New Perspective on EPR Approaches
[Image: see text] The spin delocalization in the radical cations of a series of ethyne-linked oligoporphyrins was investigated using EPR spectroscopy. The room-temperature spectral envelope for these oligomers deviates significantly from the benchmark N(–0.5) trend in line width expected for a compl...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical
Society
2019
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778911/ https://www.ncbi.nlm.nih.gov/pubmed/31512868 http://dx.doi.org/10.1021/acs.jpclett.9b02262 |
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author | Moise, Gabriel Tejerina, Lara Rickhaus, Michel Anderson, Harry L. Timmel, Christiane R. |
author_facet | Moise, Gabriel Tejerina, Lara Rickhaus, Michel Anderson, Harry L. Timmel, Christiane R. |
author_sort | Moise, Gabriel |
collection | PubMed |
description | [Image: see text] The spin delocalization in the radical cations of a series of ethyne-linked oligoporphyrins was investigated using EPR spectroscopy. The room-temperature spectral envelope for these oligomers deviates significantly from the benchmark N(–0.5) trend in line width expected for a completely delocalized spin density, in contrast to the butadiyne-linked analogues measured previously. Here, we show, using DFT calculations and complementary low-temperature ENDOR measurements, that this deviation is primarily driven by a more pronounced inequivalence of the (14)N spins within individual subunits for the ethyne-linked oligoporphyrins. Once this (14)N inequivalence is taken into consideration, the room-temperature and ENDOR spectra for both butadiyne-linked and ethyne-linked oligomers, up to N = 5, can be simulated by similar static delocalization patterns. This work highlights the importance of EPR in exploring such spin delocalization phenomena while also demonstrating that the N(–0.5) trend should not be interpreted in isolation but only in combination with careful simulation and theoretical modeling. |
format | Online Article Text |
id | pubmed-6778911 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2019 |
publisher | American Chemical
Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-67789112019-10-08 Spin Delocalization in the Radical Cations of Porphyrin Molecular Wires: A New Perspective on EPR Approaches Moise, Gabriel Tejerina, Lara Rickhaus, Michel Anderson, Harry L. Timmel, Christiane R. J Phys Chem Lett [Image: see text] The spin delocalization in the radical cations of a series of ethyne-linked oligoporphyrins was investigated using EPR spectroscopy. The room-temperature spectral envelope for these oligomers deviates significantly from the benchmark N(–0.5) trend in line width expected for a completely delocalized spin density, in contrast to the butadiyne-linked analogues measured previously. Here, we show, using DFT calculations and complementary low-temperature ENDOR measurements, that this deviation is primarily driven by a more pronounced inequivalence of the (14)N spins within individual subunits for the ethyne-linked oligoporphyrins. Once this (14)N inequivalence is taken into consideration, the room-temperature and ENDOR spectra for both butadiyne-linked and ethyne-linked oligomers, up to N = 5, can be simulated by similar static delocalization patterns. This work highlights the importance of EPR in exploring such spin delocalization phenomena while also demonstrating that the N(–0.5) trend should not be interpreted in isolation but only in combination with careful simulation and theoretical modeling. American Chemical Society 2019-09-12 2019-10-03 /pmc/articles/PMC6778911/ /pubmed/31512868 http://dx.doi.org/10.1021/acs.jpclett.9b02262 Text en Copyright © 2019 American Chemical Society This is an open access article published under a Creative Commons Attribution (CC-BY) License (http://pubs.acs.org/page/policy/authorchoice_ccby_termsofuse.html) , which permits unrestricted use, distribution and reproduction in any medium, provided the author and source are cited. |
spellingShingle | Moise, Gabriel Tejerina, Lara Rickhaus, Michel Anderson, Harry L. Timmel, Christiane R. Spin Delocalization in the Radical Cations of Porphyrin Molecular Wires: A New Perspective on EPR Approaches |
title | Spin Delocalization in the Radical Cations of Porphyrin
Molecular Wires: A New Perspective on EPR Approaches |
title_full | Spin Delocalization in the Radical Cations of Porphyrin
Molecular Wires: A New Perspective on EPR Approaches |
title_fullStr | Spin Delocalization in the Radical Cations of Porphyrin
Molecular Wires: A New Perspective on EPR Approaches |
title_full_unstemmed | Spin Delocalization in the Radical Cations of Porphyrin
Molecular Wires: A New Perspective on EPR Approaches |
title_short | Spin Delocalization in the Radical Cations of Porphyrin
Molecular Wires: A New Perspective on EPR Approaches |
title_sort | spin delocalization in the radical cations of porphyrin
molecular wires: a new perspective on epr approaches |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6778911/ https://www.ncbi.nlm.nih.gov/pubmed/31512868 http://dx.doi.org/10.1021/acs.jpclett.9b02262 |
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