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Synthesis of π-Extended Thiele’s and Chichibabin’s Hydrocarbons and Effect of the π-Congestion on Conformations and Electronic States
[Image: see text] The biradicaloid of Chichibabin’s hydrocarbon exits in a unique thermal equilibrium between closed-shell singlet and open-shell triplet forms. Conceptually, the incorporation of nonplanar aromatic groups, such as anthraquinodimethane (AQD), in these species could bring about stabil...
Autores principales: | , , , |
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Formato: | Online Artículo Texto |
Lenguaje: | English |
Publicado: |
American Chemical Society
2022
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Acceso en línea: | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9136924/ https://www.ncbi.nlm.nih.gov/pubmed/35426674 http://dx.doi.org/10.1021/jacs.2c02318 |
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author | Nishiuchi, Tomohiko Aibara, Seito Sato, Hiroyasu Kubo, Takashi |
author_facet | Nishiuchi, Tomohiko Aibara, Seito Sato, Hiroyasu Kubo, Takashi |
author_sort | Nishiuchi, Tomohiko |
collection | PubMed |
description | [Image: see text] The biradicaloid of Chichibabin’s hydrocarbon exits in a unique thermal equilibrium between closed-shell singlet and open-shell triplet forms. Conceptually, the incorporation of nonplanar aromatic groups, such as anthraquinodimethane (AQD), in these species could bring about stabilization of the individual singlet and triplet spin biradicaloids by creating a high energy barrier for conformational interconversion between folded (singlet) and twisted (triplet) forms. Moreover, this alteration could introduce the possibility of controlling spin states through conformational changes induced by chemical and physical processes. Herein, we report the preparation of AQD-containing, π-extended Thiele’s (A-TH) and Chichibabin’s (A-CH) hydrocarbons, which have highly π-congested structures resulting from the presence of bulky 9-anthryl units. The π-congestion in these substances leads to steric frustration about carbon–carbon double bonds and creates flexible dynamic motion with a moderate activation barrier between folded singlet and twisted triplet states. These constraints make it possible to isolate the twisted triplet state of A-CH. In addition, simple mechanical grinding of the folded singlet of A-CH produces the twisted triplet. |
format | Online Article Text |
id | pubmed-9136924 |
institution | National Center for Biotechnology Information |
language | English |
publishDate | 2022 |
publisher | American Chemical Society |
record_format | MEDLINE/PubMed |
spelling | pubmed-91369242022-05-28 Synthesis of π-Extended Thiele’s and Chichibabin’s Hydrocarbons and Effect of the π-Congestion on Conformations and Electronic States Nishiuchi, Tomohiko Aibara, Seito Sato, Hiroyasu Kubo, Takashi J Am Chem Soc [Image: see text] The biradicaloid of Chichibabin’s hydrocarbon exits in a unique thermal equilibrium between closed-shell singlet and open-shell triplet forms. Conceptually, the incorporation of nonplanar aromatic groups, such as anthraquinodimethane (AQD), in these species could bring about stabilization of the individual singlet and triplet spin biradicaloids by creating a high energy barrier for conformational interconversion between folded (singlet) and twisted (triplet) forms. Moreover, this alteration could introduce the possibility of controlling spin states through conformational changes induced by chemical and physical processes. Herein, we report the preparation of AQD-containing, π-extended Thiele’s (A-TH) and Chichibabin’s (A-CH) hydrocarbons, which have highly π-congested structures resulting from the presence of bulky 9-anthryl units. The π-congestion in these substances leads to steric frustration about carbon–carbon double bonds and creates flexible dynamic motion with a moderate activation barrier between folded singlet and twisted triplet states. These constraints make it possible to isolate the twisted triplet state of A-CH. In addition, simple mechanical grinding of the folded singlet of A-CH produces the twisted triplet. American Chemical Society 2022-04-15 2022-04-27 /pmc/articles/PMC9136924/ /pubmed/35426674 http://dx.doi.org/10.1021/jacs.2c02318 Text en © 2022 American Chemical Society https://creativecommons.org/licenses/by/4.0/Permits the broadest form of re-use including for commercial purposes, provided that author attribution and integrity are maintained (https://creativecommons.org/licenses/by/4.0/). |
spellingShingle | Nishiuchi, Tomohiko Aibara, Seito Sato, Hiroyasu Kubo, Takashi Synthesis of π-Extended Thiele’s and Chichibabin’s Hydrocarbons and Effect of the π-Congestion on Conformations and Electronic States |
title | Synthesis
of π-Extended Thiele’s
and Chichibabin’s Hydrocarbons and Effect of the π-Congestion
on Conformations and Electronic States |
title_full | Synthesis
of π-Extended Thiele’s
and Chichibabin’s Hydrocarbons and Effect of the π-Congestion
on Conformations and Electronic States |
title_fullStr | Synthesis
of π-Extended Thiele’s
and Chichibabin’s Hydrocarbons and Effect of the π-Congestion
on Conformations and Electronic States |
title_full_unstemmed | Synthesis
of π-Extended Thiele’s
and Chichibabin’s Hydrocarbons and Effect of the π-Congestion
on Conformations and Electronic States |
title_short | Synthesis
of π-Extended Thiele’s
and Chichibabin’s Hydrocarbons and Effect of the π-Congestion
on Conformations and Electronic States |
title_sort | synthesis
of π-extended thiele’s
and chichibabin’s hydrocarbons and effect of the π-congestion
on conformations and electronic states |
url | https://www.ncbi.nlm.nih.gov/pmc/articles/PMC9136924/ https://www.ncbi.nlm.nih.gov/pubmed/35426674 http://dx.doi.org/10.1021/jacs.2c02318 |
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