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Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State
Synthesis of two dicyclopentaannelated hexa‐peri‐hexabenzocoronene (PHBC) regioisomers was carried out, using nonplanar oligoaryl precursors with fluorenyl groups: mPHBC 8 with two pentagons in the “meta”‐configuration was obtained as a stable molecule, while its structural isomer with the “para”‐co...
Autores principales: | , , , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
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John Wiley and Sons Inc.
2021
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251543/ https://www.ncbi.nlm.nih.gov/pubmed/33749985 http://dx.doi.org/10.1002/anie.202102932 |
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author | Chen, Qiang Baumgarten, Martin Wagner, Manfred Hu, Yunbin Hou, Ian Cheng‐Yi Narita, Akimitsu Müllen, Klaus |
author_facet | Chen, Qiang Baumgarten, Martin Wagner, Manfred Hu, Yunbin Hou, Ian Cheng‐Yi Narita, Akimitsu Müllen, Klaus |
author_sort | Chen, Qiang |
collection | PubMed |
description | Synthesis of two dicyclopentaannelated hexa‐peri‐hexabenzocoronene (PHBC) regioisomers was carried out, using nonplanar oligoaryl precursors with fluorenyl groups: mPHBC 8 with two pentagons in the “meta”‐configuration was obtained as a stable molecule, while its structural isomer with the “para”‐configuration, pPHBC 16, could be generated and characterized only in situ due to its high chemical reactivity. Both PHBCs exhibit low energy gaps, as reflected by UV‐vis‐NIR absorption and electrochemical measurements. They also show open‐shell singlet ground states according to electron paramagnetic resonance (EPR) measurements and density functional theory (DFT) calculations. The use of fully benzenoid HBC as a bridging moiety leads to significant singlet biradical characters (y (0)) of 0.72 and 0.96 for mPHBC 8 and pPHBC 16, respectively, due to the strong rearomatization tendency of the HBC π‐system; these values are among the highest for planar carbon‐centered biradical molecules. The incorporation of fully unsaturated pentagons strongly perturbs the aromaticity of the parent HBC and makes the constituted benzene rings less aromatic or antiaromatic. These results illustrate the high impact of cyclopentaannelation on the electronic structures of fully benzenoid polycyclic aromatic hydrocarbons (PAHs) and open up a new avenue towards open‐shell PAHs with prominent singlet biradical characters. |
format | Online Article Text |
id | pubmed-8251543 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2021 |
publisher | John Wiley and Sons Inc. |
record_format | MEDLINE/PubMed |
spelling | pubmed-82515432021-07-06 Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State Chen, Qiang Baumgarten, Martin Wagner, Manfred Hu, Yunbin Hou, Ian Cheng‐Yi Narita, Akimitsu Müllen, Klaus Angew Chem Int Ed Engl Communications Synthesis of two dicyclopentaannelated hexa‐peri‐hexabenzocoronene (PHBC) regioisomers was carried out, using nonplanar oligoaryl precursors with fluorenyl groups: mPHBC 8 with two pentagons in the “meta”‐configuration was obtained as a stable molecule, while its structural isomer with the “para”‐configuration, pPHBC 16, could be generated and characterized only in situ due to its high chemical reactivity. Both PHBCs exhibit low energy gaps, as reflected by UV‐vis‐NIR absorption and electrochemical measurements. They also show open‐shell singlet ground states according to electron paramagnetic resonance (EPR) measurements and density functional theory (DFT) calculations. The use of fully benzenoid HBC as a bridging moiety leads to significant singlet biradical characters (y (0)) of 0.72 and 0.96 for mPHBC 8 and pPHBC 16, respectively, due to the strong rearomatization tendency of the HBC π‐system; these values are among the highest for planar carbon‐centered biradical molecules. The incorporation of fully unsaturated pentagons strongly perturbs the aromaticity of the parent HBC and makes the constituted benzene rings less aromatic or antiaromatic. These results illustrate the high impact of cyclopentaannelation on the electronic structures of fully benzenoid polycyclic aromatic hydrocarbons (PAHs) and open up a new avenue towards open‐shell PAHs with prominent singlet biradical characters. John Wiley and Sons Inc. 2021-04-07 2021-05-10 /pmc/articles/PMC8251543/ /pubmed/33749985 http://dx.doi.org/10.1002/anie.202102932 Text en © 2021 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited. |
spellingShingle | Communications Chen, Qiang Baumgarten, Martin Wagner, Manfred Hu, Yunbin Hou, Ian Cheng‐Yi Narita, Akimitsu Müllen, Klaus Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State |
title | Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State |
title_full | Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State |
title_fullStr | Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State |
title_full_unstemmed | Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State |
title_short | Dicyclopentaannelated Hexa‐peri‐hexabenzocoronenes with a Singlet Biradical Ground State |
title_sort | dicyclopentaannelated hexa‐peri‐hexabenzocoronenes with a singlet biradical ground state |
topic | Communications |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8251543/ https://www.ncbi.nlm.nih.gov/pubmed/33749985 http://dx.doi.org/10.1002/anie.202102932 |
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