Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study
Autor(a) principal: | |
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Data de Publicação: | 2003 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
Texto Completo: | http://hdl.handle.net/10316/17830 https://doi.org/10.1039/B308116H |
Resumo: | Photoisomerization reactions were studied for 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones isolated in low-temperature Ar matrices. Two types of photoproducts: Dewar valence isomer and conjugated aldehyde–ketene were photogenerated upon UV irradiation of the matrix-isolated compounds. After prolonged irradiation practically all the initial material was converted to the corresponding Dewar isomers, whereas the population of aldehyde–ketene photoproducts was marginal. The structure of the main photoproducts was positively identified by comparison of their experimental IR spectra with the spectra theoretically predicted for the Dewar isomers. Good agreement between the experimental observations and the theoretical calculations allowed for reliable assignment of the infrared bands in the spectra of the initial forms of the studied compounds as well as in the spectra of the Dewar isomers. For the 4-hydroxy-6-methyl-α-pyrone the presence of its minor tautomeric form in a low-temperature matrix was detected |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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7160 |
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Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory studyPhotoisomerization reactions were studied for 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones isolated in low-temperature Ar matrices. Two types of photoproducts: Dewar valence isomer and conjugated aldehyde–ketene were photogenerated upon UV irradiation of the matrix-isolated compounds. After prolonged irradiation practically all the initial material was converted to the corresponding Dewar isomers, whereas the population of aldehyde–ketene photoproducts was marginal. The structure of the main photoproducts was positively identified by comparison of their experimental IR spectra with the spectra theoretically predicted for the Dewar isomers. Good agreement between the experimental observations and the theoretical calculations allowed for reliable assignment of the infrared bands in the spectra of the initial forms of the studied compounds as well as in the spectra of the Dewar isomers. For the 4-hydroxy-6-methyl-α-pyrone the presence of its minor tautomeric form in a low-temperature matrix was detectedRoyal Society of Chemistry2003-09-19info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/17830http://hdl.handle.net/10316/17830https://doi.org/10.1039/B308116HengBreda, SusanaLapinski, LeszekFausto, RuiNowak, Maciej J.info:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2020-05-29T10:04:40Zoai:estudogeral.uc.pt:10316/17830Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:01:44.288418Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse |
dc.title.none.fl_str_mv |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
title |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
spellingShingle |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study Breda, Susana |
title_short |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
title_full |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
title_fullStr |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
title_full_unstemmed |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
title_sort |
Photoisomerization reactions of 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones: An experimental matrix isolation and theoretical density functional theory study |
author |
Breda, Susana |
author_facet |
Breda, Susana Lapinski, Leszek Fausto, Rui Nowak, Maciej J. |
author_role |
author |
author2 |
Lapinski, Leszek Fausto, Rui Nowak, Maciej J. |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Breda, Susana Lapinski, Leszek Fausto, Rui Nowak, Maciej J. |
description |
Photoisomerization reactions were studied for 4-methoxy- and 4-hydroxy-6-methyl-α-pyrones isolated in low-temperature Ar matrices. Two types of photoproducts: Dewar valence isomer and conjugated aldehyde–ketene were photogenerated upon UV irradiation of the matrix-isolated compounds. After prolonged irradiation practically all the initial material was converted to the corresponding Dewar isomers, whereas the population of aldehyde–ketene photoproducts was marginal. The structure of the main photoproducts was positively identified by comparison of their experimental IR spectra with the spectra theoretically predicted for the Dewar isomers. Good agreement between the experimental observations and the theoretical calculations allowed for reliable assignment of the infrared bands in the spectra of the initial forms of the studied compounds as well as in the spectra of the Dewar isomers. For the 4-hydroxy-6-methyl-α-pyrone the presence of its minor tautomeric form in a low-temperature matrix was detected |
publishDate |
2003 |
dc.date.none.fl_str_mv |
2003-09-19 |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10316/17830 http://hdl.handle.net/10316/17830 https://doi.org/10.1039/B308116H |
url |
http://hdl.handle.net/10316/17830 https://doi.org/10.1039/B308116H |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
Royal Society of Chemistry |
publisher.none.fl_str_mv |
Royal Society of Chemistry |
dc.source.none.fl_str_mv |
reponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação instacron:RCAAP |
instname_str |
Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
instacron_str |
RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
collection |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
repository.name.fl_str_mv |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
repository.mail.fl_str_mv |
|
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1799133907906461696 |