Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix
Autor(a) principal: | |
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Data de Publicação: | 2021 |
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/10316/105275 https://doi.org/10.3390/molecules26144299 |
Resumo: | The prototropic tautomerism in 3(5)-aminopyrazoles was investigated by matrix isolation infrared (IR) spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In consonance with the experimental data, the calculations predict tautomer 3-aminopyrazole (3AP) to be more stable than the 5-aminopyrazole (5AP) tautomer (calculated energy difference: 10.7 kJ mol-1; Gibbs free energy difference: 9.8 kJ mol-1). The obtained matrix isolation IR spectra (in both argon and xenon matrices) were interpreted, and the observed bands were assigned to the tautomeric forms with help of vibrational calculations carried out at both harmonic and anharmonic levels. The matrix-isolated compound (in argon matrix) was then subjected to in situ broadband UV irradiation (λ > 235 nm), and the UV-induced transformations were followed by IR spectroscopy. Phototautomerization of the 3AP tautomer into the 5AP form was observed as the strongly prevalent reaction. |
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Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix3(5)-aminopyrazolesUV-induced phototautomerismmatrix isolationinfrared spectroscopyDFT and TD-DFT calculationsanharmonic frequenciesThe prototropic tautomerism in 3(5)-aminopyrazoles was investigated by matrix isolation infrared (IR) spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In consonance with the experimental data, the calculations predict tautomer 3-aminopyrazole (3AP) to be more stable than the 5-aminopyrazole (5AP) tautomer (calculated energy difference: 10.7 kJ mol-1; Gibbs free energy difference: 9.8 kJ mol-1). The obtained matrix isolation IR spectra (in both argon and xenon matrices) were interpreted, and the observed bands were assigned to the tautomeric forms with help of vibrational calculations carried out at both harmonic and anharmonic levels. The matrix-isolated compound (in argon matrix) was then subjected to in situ broadband UV irradiation (λ > 235 nm), and the UV-induced transformations were followed by IR spectroscopy. Phototautomerization of the 3AP tautomer into the 5AP form was observed as the strongly prevalent reaction.MDPI2021-07-15info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/105275http://hdl.handle.net/10316/105275https://doi.org/10.3390/molecules26144299eng1420-3049Secrieru, AlinaLopes, SusyCristiano, Maria L. S.Fausto, Ruiinfo: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:RCAAP2023-02-14T10:53:42Zoai:estudogeral.uc.pt:10316/105275Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:21:52.358653Repositório 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 |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
title |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
spellingShingle |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix Secrieru, Alina 3(5)-aminopyrazoles UV-induced phototautomerism matrix isolation infrared spectroscopy DFT and TD-DFT calculations anharmonic frequencies |
title_short |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
title_full |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
title_fullStr |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
title_full_unstemmed |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
title_sort |
Structure and IR Spectra of 3(5)-Aminopyrazoles and UV-Induced Tautomerization in Argon Matrix |
author |
Secrieru, Alina |
author_facet |
Secrieru, Alina Lopes, Susy Cristiano, Maria L. S. Fausto, Rui |
author_role |
author |
author2 |
Lopes, Susy Cristiano, Maria L. S. Fausto, Rui |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Secrieru, Alina Lopes, Susy Cristiano, Maria L. S. Fausto, Rui |
dc.subject.por.fl_str_mv |
3(5)-aminopyrazoles UV-induced phototautomerism matrix isolation infrared spectroscopy DFT and TD-DFT calculations anharmonic frequencies |
topic |
3(5)-aminopyrazoles UV-induced phototautomerism matrix isolation infrared spectroscopy DFT and TD-DFT calculations anharmonic frequencies |
description |
The prototropic tautomerism in 3(5)-aminopyrazoles was investigated by matrix isolation infrared (IR) spectroscopy, supported by DFT(B3LYP)/6-311++G(d,p) calculations. In consonance with the experimental data, the calculations predict tautomer 3-aminopyrazole (3AP) to be more stable than the 5-aminopyrazole (5AP) tautomer (calculated energy difference: 10.7 kJ mol-1; Gibbs free energy difference: 9.8 kJ mol-1). The obtained matrix isolation IR spectra (in both argon and xenon matrices) were interpreted, and the observed bands were assigned to the tautomeric forms with help of vibrational calculations carried out at both harmonic and anharmonic levels. The matrix-isolated compound (in argon matrix) was then subjected to in situ broadband UV irradiation (λ > 235 nm), and the UV-induced transformations were followed by IR spectroscopy. Phototautomerization of the 3AP tautomer into the 5AP form was observed as the strongly prevalent reaction. |
publishDate |
2021 |
dc.date.none.fl_str_mv |
2021-07-15 |
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/10316/105275 http://hdl.handle.net/10316/105275 https://doi.org/10.3390/molecules26144299 |
url |
http://hdl.handle.net/10316/105275 https://doi.org/10.3390/molecules26144299 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.none.fl_str_mv |
1420-3049 |
dc.rights.driver.fl_str_mv |
info:eu-repo/semantics/openAccess |
eu_rights_str_mv |
openAccess |
dc.publisher.none.fl_str_mv |
MDPI |
publisher.none.fl_str_mv |
MDPI |
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 |
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 |
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1799134109427040256 |