Conformational Space and Photochemistry of α-Terpinene
Autor(a) principal: | |
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Data de Publicação: | 2010 |
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/10316/18071 https://doi.org/10.1021/jp100770v |
Resumo: | α-Terpinene is a natural product that is isolated from a variety of plant sources and is used in the pharmaceutical and perfume industries. In the atmosphere, under the influence of sunlight, α-terpinene undergoes a series of photochemical transformations and contributes to the formation of the secondary organic aerosols. In the present work, α-terpinene has been isolated in low-temperature xenon and argon matrices, and its structure and photochemistry were characterized with the aid of FTIR spectroscopy and DFT calculations. The theory predicts three conformers resulting from the rotation of the exocyclic CH(CH3)2 framework, that is, Trans (T) and Gauche (G+ and G−) forms. The two Gauche conformers were estimated to be higher in energy, by ca. 1.75 kJ mol−1, than the most stable Trans form. The signatures of all three conformers were found to be present in the experimental low-temperature matrix spectra with the T form dominating in diluted matrices. The conformational ratio was found to shift in favor of the G+/G− forms upon annealing of the matrices as well as in the neat α-terpinene liquid. UV−C (λ > 235 nm) irradiation of matrix-isolated α-terpinene led to its isomerization into an open-ring species, which is produced in the Z configuration and in the conformations that require the smallest structural rearrangements of both the reagent and matrix. |
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Conformational Space and Photochemistry of α-Terpineneα-Terpinene is a natural product that is isolated from a variety of plant sources and is used in the pharmaceutical and perfume industries. In the atmosphere, under the influence of sunlight, α-terpinene undergoes a series of photochemical transformations and contributes to the formation of the secondary organic aerosols. In the present work, α-terpinene has been isolated in low-temperature xenon and argon matrices, and its structure and photochemistry were characterized with the aid of FTIR spectroscopy and DFT calculations. The theory predicts three conformers resulting from the rotation of the exocyclic CH(CH3)2 framework, that is, Trans (T) and Gauche (G+ and G−) forms. The two Gauche conformers were estimated to be higher in energy, by ca. 1.75 kJ mol−1, than the most stable Trans form. The signatures of all three conformers were found to be present in the experimental low-temperature matrix spectra with the T form dominating in diluted matrices. The conformational ratio was found to shift in favor of the G+/G− forms upon annealing of the matrices as well as in the neat α-terpinene liquid. UV−C (λ > 235 nm) irradiation of matrix-isolated α-terpinene led to its isomerization into an open-ring species, which is produced in the Z configuration and in the conformations that require the smallest structural rearrangements of both the reagent and matrix.American Chemical Society2010-04info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/18071http://hdl.handle.net/10316/18071https://doi.org/10.1021/jp100770vengMarzec, K. M.Reva, I.Fausto, R.Malek, K.Proniewicz, L. M.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:RCAAP2022-05-25T01:35:56Zoai:estudogeral.uc.pt:10316/18071Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:01:46.837306Repositório 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 |
Conformational Space and Photochemistry of α-Terpinene |
title |
Conformational Space and Photochemistry of α-Terpinene |
spellingShingle |
Conformational Space and Photochemistry of α-Terpinene Marzec, K. M. |
title_short |
Conformational Space and Photochemistry of α-Terpinene |
title_full |
Conformational Space and Photochemistry of α-Terpinene |
title_fullStr |
Conformational Space and Photochemistry of α-Terpinene |
title_full_unstemmed |
Conformational Space and Photochemistry of α-Terpinene |
title_sort |
Conformational Space and Photochemistry of α-Terpinene |
author |
Marzec, K. M. |
author_facet |
Marzec, K. M. Reva, I. Fausto, R. Malek, K. Proniewicz, L. M. |
author_role |
author |
author2 |
Reva, I. Fausto, R. Malek, K. Proniewicz, L. M. |
author2_role |
author author author author |
dc.contributor.author.fl_str_mv |
Marzec, K. M. Reva, I. Fausto, R. Malek, K. Proniewicz, L. M. |
description |
α-Terpinene is a natural product that is isolated from a variety of plant sources and is used in the pharmaceutical and perfume industries. In the atmosphere, under the influence of sunlight, α-terpinene undergoes a series of photochemical transformations and contributes to the formation of the secondary organic aerosols. In the present work, α-terpinene has been isolated in low-temperature xenon and argon matrices, and its structure and photochemistry were characterized with the aid of FTIR spectroscopy and DFT calculations. The theory predicts three conformers resulting from the rotation of the exocyclic CH(CH3)2 framework, that is, Trans (T) and Gauche (G+ and G−) forms. The two Gauche conformers were estimated to be higher in energy, by ca. 1.75 kJ mol−1, than the most stable Trans form. The signatures of all three conformers were found to be present in the experimental low-temperature matrix spectra with the T form dominating in diluted matrices. The conformational ratio was found to shift in favor of the G+/G− forms upon annealing of the matrices as well as in the neat α-terpinene liquid. UV−C (λ > 235 nm) irradiation of matrix-isolated α-terpinene led to its isomerization into an open-ring species, which is produced in the Z configuration and in the conformations that require the smallest structural rearrangements of both the reagent and matrix. |
publishDate |
2010 |
dc.date.none.fl_str_mv |
2010-04 |
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/10316/18071 http://hdl.handle.net/10316/18071 https://doi.org/10.1021/jp100770v |
url |
http://hdl.handle.net/10316/18071 https://doi.org/10.1021/jp100770v |
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 |
American Chemical Society |
publisher.none.fl_str_mv |
American Chemical Society |
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 |
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Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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RCAAP |
institution |
RCAAP |
reponame_str |
Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) |
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Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informação |
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1799133907998736384 |