Spin delocalization in the radical cations of porphyrin molecular wires: A new perspective on EPR approaches
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 sp...
| Main Authors: | , , , , |
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| Format: | Journal article |
| Language: | English |
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American Chemical Society
2019
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| _version_ | 1826256445219274752 |
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| author | Moise, G Tejerina, L Rickhaus, M Anderson, H Timmel, C |
| author_facet | Moise, G Tejerina, L Rickhaus, M Anderson, H Timmel, C |
| author_sort | Moise, G |
| collection | OXFORD |
| description | 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 14N spins within individual subunits for the ethyne-linked oligoporphyrins. Once this 14N 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. |
| first_indexed | 2024-03-06T18:02:23Z |
| format | Journal article |
| id | oxford-uuid:003e5694-8755-4a40-9a6c-17399910716e |
| institution | University of Oxford |
| language | English |
| last_indexed | 2024-03-06T18:02:23Z |
| publishDate | 2019 |
| publisher | American Chemical Society |
| record_format | dspace |
| spelling | oxford-uuid:003e5694-8755-4a40-9a6c-17399910716e2022-03-26T08:28:28ZSpin delocalization in the radical cations of porphyrin molecular wires: A new perspective on EPR approachesJournal articlehttp://purl.org/coar/resource_type/c_dcae04bcuuid:003e5694-8755-4a40-9a6c-17399910716eEnglishSymplectic Elements at OxfordAmerican Chemical Society2019Moise, GTejerina, LRickhaus, MAnderson, HTimmel, CThe 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 14N spins within individual subunits for the ethyne-linked oligoporphyrins. Once this 14N 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. |
| spellingShingle | Moise, G Tejerina, L Rickhaus, M Anderson, H Timmel, C 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 |
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