The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability

The study of a selected group of α and β-hydroxyquinones ([α] 2-hydroxy-1,4-naphthoquinone2HNQ, [β] 5-hydroxy-1,4-naphthoquinone 5HNQ and [β, β]5,8-dihydroxy-1,4-naphthoquinoneDHNQ) showed that both type of functionalities differ considerably in...

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Detalhes bibliográficos
Autores: Carlos Frontana, Ignacio González
Formato: artículo
Estado:Versión publicada
Fecha de publicación:2005
País:México
Recursos:Universidad Autónoma Metropolitana
Repositorio:Redalyc-UAM
OAI Identifier:oai:redalyc.org:47549202
Acesso em linha:https://www.redalyc.org/articulo.oa?id=47549202
Access Level:acceso abierto
Palavra-chave:Química
ESR
quinones
semiquinone
self protonation
cyclic voltammetry
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spelling The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone StabilityCarlos FrontanaIgnacio GonzálezQuímicaESRquinonessemiquinoneself protonationcyclic voltammetryThe study of a selected group of α and β-hydroxyquinones ([α] 2-hydroxy-1,4-naphthoquinone2HNQ, [β] 5-hydroxy-1,4-naphthoquinone 5HNQ and [β, β]5,8-dihydroxy-1,4-naphthoquinoneDHNQ) showed that both type of functionalities differ considerably in terms of electrochemical andchemical reactivity, and these differences are also manifest even upon comparison between compoundsof the same group. The results proved that the energy needed to electrochemically reduce the studiedhydroxyquinones is related both to the stability of intramolecular hydrogen bonds (IHBs) andcoupled chemical reactions occurring during their electrochemical reduction such as self-protonationsequences in 2HNQ. The analysis of the electron transfer kinetics associated with the monoelectronicreductions occurring for 5HNQ and DHNQ showed that IHB effects do not affect the kinetics of thefirst reduction process, but induce great changes in the second electron transfer kinetics. Thissuggests that semiquinone species are chemically different for the studied compounds, as wascorroborated by the analysis of the electronic structure of semiquinone species by ESR spectroscopy.This analysis seems to be related to the loss of symmetry in the electrogenerated radical and inducesa lower rate ks value for the second reduction transfer of 5HNQ, compared with DHNQ.Sociedad Química de México2005info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articleapplication/pdf1870-249Xhttps://www.redalyc.org/articulo.oa?id=47549202Journal of the Mexican Chemical Society (México) Num.2 Vol.49reponame:Redalyc-UAMinstname:Universidad Autónoma Metropolitanainstacron:UAMenhttp://www.redalyc.org/revista.oa?id=475Journal of the Mexican Chemical Societyinfo:eu-repo/semantics/openAccessoai:redalyc.org:475492022025-03-05T19:09:05Z
dc.title.none.fl_str_mv The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
title The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
spellingShingle The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
Carlos Frontana
Química
ESR
quinones
semiquinone
self protonation
cyclic voltammetry
title_short The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
title_full The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
title_fullStr The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
title_full_unstemmed The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
title_sort The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
dc.creator.none.fl_str_mv Carlos Frontana
Ignacio González
author Carlos Frontana
author_facet Carlos Frontana
Ignacio González
author_role author
author2 Ignacio González
author2_role author
dc.subject.none.fl_str_mv Química
ESR
quinones
semiquinone
self protonation
cyclic voltammetry
topic Química
ESR
quinones
semiquinone
self protonation
cyclic voltammetry
description The study of a selected group of α and β-hydroxyquinones ([α] 2-hydroxy-1,4-naphthoquinone2HNQ, [β] 5-hydroxy-1,4-naphthoquinone 5HNQ and [β, β]5,8-dihydroxy-1,4-naphthoquinoneDHNQ) showed that both type of functionalities differ considerably in terms of electrochemical andchemical reactivity, and these differences are also manifest even upon comparison between compoundsof the same group. The results proved that the energy needed to electrochemically reduce the studiedhydroxyquinones is related both to the stability of intramolecular hydrogen bonds (IHBs) andcoupled chemical reactions occurring during their electrochemical reduction such as self-protonationsequences in 2HNQ. The analysis of the electron transfer kinetics associated with the monoelectronicreductions occurring for 5HNQ and DHNQ showed that IHB effects do not affect the kinetics of thefirst reduction process, but induce great changes in the second electron transfer kinetics. Thissuggests that semiquinone species are chemically different for the studied compounds, as wascorroborated by the analysis of the electronic structure of semiquinone species by ESR spectroscopy.This analysis seems to be related to the loss of symmetry in the electrogenerated radical and inducesa lower rate ks value for the second reduction transfer of 5HNQ, compared with DHNQ.
publishDate 2005
dc.date.none.fl_str_mv 2005
dc.type.none.fl_str_mv info:eu-repo/semantics/publishedVersion
info:eu-repo/semantics/article
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv 1870-249X
https://www.redalyc.org/articulo.oa?id=47549202
identifier_str_mv 1870-249X
url https://www.redalyc.org/articulo.oa?id=47549202
dc.language.none.fl_str_mv en
language_invalid_str_mv en
dc.relation.none.fl_str_mv http://www.redalyc.org/revista.oa?id=475
dc.rights.none.fl_str_mv Journal of the Mexican Chemical Society
info:eu-repo/semantics/openAccess
rights_invalid_str_mv Journal of the Mexican Chemical Society
eu_rights_str_mv openAccess
dc.format.none.fl_str_mv application/pdf
dc.publisher.none.fl_str_mv Sociedad Química de México
publisher.none.fl_str_mv Sociedad Química de México
dc.source.none.fl_str_mv Journal of the Mexican Chemical Society (México) Num.2 Vol.49
reponame:Redalyc-UAM
instname:Universidad Autónoma Metropolitana
instacron:UAM
instname_str Universidad Autónoma Metropolitana
instacron_str UAM
institution UAM
reponame_str Redalyc-UAM
collection Redalyc-UAM
repository.name.fl_str_mv
repository.mail.fl_str_mv
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score 14,964248

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