Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives
Autor(a) principal: | |
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Data de Publicação: | 2017 |
Outros Autores: | , , |
Tipo de documento: | Artigo |
Idioma: | eng |
Título da fonte: | Repositório Institucional da UFRGS |
Texto Completo: | http://hdl.handle.net/10183/273628 |
Resumo: | In this work, semi-empirical AM1 and DFT B3LYP/6-31G** calculations were applied in the study of the interconversion among tautomers of several naphthazarin and 5-amino-8-hydroxy-1,4-naphthoquinone β-substituted derivatives bearing electron-donor or electron-withdrawing groups. Using a semi-empirical method, detailed potential energy landscapes for proton transfers were built, from which four tautomers and four transition states of interconversions were identified for each compound. These structures were recalculated without restraints and, using the Boltzmann distribution, the populations for each of the four tautomers and their respective molar fractions were calculated. The calculations showed that the tautomeric equilibrium is shifted to the tautomer where the ring with the substituent has a quinonic nature and is more pronounced when the β-substituent is an electron donor group. For derivatives of 5-amino-8-hydroxy-1,4-naphthoquinone, an equilibrium between an aromatic and a 1,5-naphthoquinonic non-aromatic enamine was observed, being the former the most stable. |
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Grasel, Fábio dos SantosCastanho, Gabriel de OliveiraFontoura, Luiz Antonio MazziniNetz, Paulo Augusto2024-03-15T05:02:38Z20170103-5053http://hdl.handle.net/10183/273628001078600In this work, semi-empirical AM1 and DFT B3LYP/6-31G** calculations were applied in the study of the interconversion among tautomers of several naphthazarin and 5-amino-8-hydroxy-1,4-naphthoquinone β-substituted derivatives bearing electron-donor or electron-withdrawing groups. Using a semi-empirical method, detailed potential energy landscapes for proton transfers were built, from which four tautomers and four transition states of interconversions were identified for each compound. These structures were recalculated without restraints and, using the Boltzmann distribution, the populations for each of the four tautomers and their respective molar fractions were calculated. The calculations showed that the tautomeric equilibrium is shifted to the tautomer where the ring with the substituent has a quinonic nature and is more pronounced when the β-substituent is an electron donor group. For derivatives of 5-amino-8-hydroxy-1,4-naphthoquinone, an equilibrium between an aromatic and a 1,5-naphthoquinonic non-aromatic enamine was observed, being the former the most stable.application/pdfengJournal of the Brazilian Chemical Society. Campinas. Vol. 28, no. 4 (2017), p. 567-573TautomeriaTautomerismMolecular modelingElectronic effectComputational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivativesinfo:eu-repo/semantics/articleinfo:eu-repo/semantics/otherinfo:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/openAccessreponame:Repositório Institucional da UFRGSinstname:Universidade Federal do Rio Grande do Sul (UFRGS)instacron:UFRGSTEXT001078600.pdf.txt001078600.pdf.txtExtracted Texttext/plain28990http://www.lume.ufrgs.br/bitstream/10183/273628/2/001078600.pdf.txt75b94d814e7bdf29e0236b8608a50fe8MD52ORIGINAL001078600.pdfTexto completo (inglês)application/pdf1314739http://www.lume.ufrgs.br/bitstream/10183/273628/1/001078600.pdf8f5c4d64848f44f35709c8ea3096f1e8MD5110183/2736282024-03-16 05:08:23.225861oai:www.lume.ufrgs.br:10183/273628Repositório de PublicaçõesPUBhttps://lume.ufrgs.br/oai/requestopendoar:2024-03-16T08:08:23Repositório Institucional da UFRGS - Universidade Federal do Rio Grande do Sul (UFRGS)false |
dc.title.pt_BR.fl_str_mv |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
title |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
spellingShingle |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives Grasel, Fábio dos Santos Tautomeria Tautomerism Molecular modeling Electronic effect |
title_short |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
title_full |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
title_fullStr |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
title_full_unstemmed |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
title_sort |
Computational study of electronic effects from β-substituents on the tautomerism of naphthazarin derivatives |
author |
Grasel, Fábio dos Santos |
author_facet |
Grasel, Fábio dos Santos Castanho, Gabriel de Oliveira Fontoura, Luiz Antonio Mazzini Netz, Paulo Augusto |
author_role |
author |
author2 |
Castanho, Gabriel de Oliveira Fontoura, Luiz Antonio Mazzini Netz, Paulo Augusto |
author2_role |
author author author |
dc.contributor.author.fl_str_mv |
Grasel, Fábio dos Santos Castanho, Gabriel de Oliveira Fontoura, Luiz Antonio Mazzini Netz, Paulo Augusto |
dc.subject.por.fl_str_mv |
Tautomeria |
topic |
Tautomeria Tautomerism Molecular modeling Electronic effect |
dc.subject.eng.fl_str_mv |
Tautomerism Molecular modeling Electronic effect |
description |
In this work, semi-empirical AM1 and DFT B3LYP/6-31G** calculations were applied in the study of the interconversion among tautomers of several naphthazarin and 5-amino-8-hydroxy-1,4-naphthoquinone β-substituted derivatives bearing electron-donor or electron-withdrawing groups. Using a semi-empirical method, detailed potential energy landscapes for proton transfers were built, from which four tautomers and four transition states of interconversions were identified for each compound. These structures were recalculated without restraints and, using the Boltzmann distribution, the populations for each of the four tautomers and their respective molar fractions were calculated. The calculations showed that the tautomeric equilibrium is shifted to the tautomer where the ring with the substituent has a quinonic nature and is more pronounced when the β-substituent is an electron donor group. For derivatives of 5-amino-8-hydroxy-1,4-naphthoquinone, an equilibrium between an aromatic and a 1,5-naphthoquinonic non-aromatic enamine was observed, being the former the most stable. |
publishDate |
2017 |
dc.date.issued.fl_str_mv |
2017 |
dc.date.accessioned.fl_str_mv |
2024-03-15T05:02:38Z |
dc.type.driver.fl_str_mv |
info:eu-repo/semantics/article info:eu-repo/semantics/other |
dc.type.status.fl_str_mv |
info:eu-repo/semantics/publishedVersion |
format |
article |
status_str |
publishedVersion |
dc.identifier.uri.fl_str_mv |
http://hdl.handle.net/10183/273628 |
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0103-5053 |
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001078600 |
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http://hdl.handle.net/10183/273628 |
dc.language.iso.fl_str_mv |
eng |
language |
eng |
dc.relation.ispartof.pt_BR.fl_str_mv |
Journal of the Brazilian Chemical Society. Campinas. Vol. 28, no. 4 (2017), p. 567-573 |
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info:eu-repo/semantics/openAccess |
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openAccess |
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