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Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes
The photochromic norbornadiene/quadricyclane (NBD/QC) couple has found interest as a molecular solar thermal energy (MOST) system for storage of solar energy. To increase the energy difference between the two isomers, we present here the synthesis of a selection of benzo-fused NBD derivatives that c...
Autores principales: | , , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
MDPI
2020
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Materias: | |
Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7024342/ https://www.ncbi.nlm.nih.gov/pubmed/31941131 http://dx.doi.org/10.3390/molecules25020322 |
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author | Mansø, Mads Fernandez, Lorette Wang, Zhihang Moth-Poulsen, Kasper Nielsen, Mogens Brøndsted |
author_facet | Mansø, Mads Fernandez, Lorette Wang, Zhihang Moth-Poulsen, Kasper Nielsen, Mogens Brøndsted |
author_sort | Mansø, Mads |
collection | PubMed |
description | The photochromic norbornadiene/quadricyclane (NBD/QC) couple has found interest as a molecular solar thermal energy (MOST) system for storage of solar energy. To increase the energy difference between the two isomers, we present here the synthesis of a selection of benzo-fused NBD derivatives that contain an aromatic unit, benzene, naphthalene or phenanthrene, fused to one of the NBD double bonds, while the carbon atoms of the other double bond are functionalized with donor and acceptor groups. The synthesis protocols involve functionalization of benzo-fused NBDs with bromo/chloro substituents followed by a subjection of these intermediates to a cyanation reaction (introducing a cyano acceptor group) followed by a Sonogashira coupling (introducing an arylethynyl donor group, -C≡CC(6)H(4)NMe(2) or -C≡CC(6)H(4)OMe). While the derivatives have good absorption properties in the visible region (redshifted relative to parent system) in the context of MOST applications, they lack the ability to undergo NBD-to-QC photoisomerization, even in the presence of a photosensitizer. It seems that loss of aromaticity of the fused aromatics is too significant to allow photoisomerization to occur. The concept of destroying aromaticity of a neighboring moiety as a way to enhance the energy density of the NBD/QC couple thus needs further structural modifications, in the quest for optimum MOST systems. |
format | Online Article Text |
id | pubmed-7024342 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2020 |
publisher | MDPI |
record_format | MEDLINE/PubMed |
spelling | pubmed-70243422020-03-11 Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes Mansø, Mads Fernandez, Lorette Wang, Zhihang Moth-Poulsen, Kasper Nielsen, Mogens Brøndsted Molecules Article The photochromic norbornadiene/quadricyclane (NBD/QC) couple has found interest as a molecular solar thermal energy (MOST) system for storage of solar energy. To increase the energy difference between the two isomers, we present here the synthesis of a selection of benzo-fused NBD derivatives that contain an aromatic unit, benzene, naphthalene or phenanthrene, fused to one of the NBD double bonds, while the carbon atoms of the other double bond are functionalized with donor and acceptor groups. The synthesis protocols involve functionalization of benzo-fused NBDs with bromo/chloro substituents followed by a subjection of these intermediates to a cyanation reaction (introducing a cyano acceptor group) followed by a Sonogashira coupling (introducing an arylethynyl donor group, -C≡CC(6)H(4)NMe(2) or -C≡CC(6)H(4)OMe). While the derivatives have good absorption properties in the visible region (redshifted relative to parent system) in the context of MOST applications, they lack the ability to undergo NBD-to-QC photoisomerization, even in the presence of a photosensitizer. It seems that loss of aromaticity of the fused aromatics is too significant to allow photoisomerization to occur. The concept of destroying aromaticity of a neighboring moiety as a way to enhance the energy density of the NBD/QC couple thus needs further structural modifications, in the quest for optimum MOST systems. MDPI 2020-01-13 /pmc/articles/PMC7024342/ /pubmed/31941131 http://dx.doi.org/10.3390/molecules25020322 Text en © 2020 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Article Mansø, Mads Fernandez, Lorette Wang, Zhihang Moth-Poulsen, Kasper Nielsen, Mogens Brøndsted Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes |
title | Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes |
title_full | Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes |
title_fullStr | Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes |
title_full_unstemmed | Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes |
title_short | Donor-Acceptor Substituted Benzo-, Naphtho- and Phenanthro-Fused Norbornadienes |
title_sort | donor-acceptor substituted benzo-, naphtho- and phenanthro-fused norbornadienes |
topic | Article |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7024342/ https://www.ncbi.nlm.nih.gov/pubmed/31941131 http://dx.doi.org/10.3390/molecules25020322 |
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