The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability
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| Format: | Artículo científico |
| Language: | en |
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Sociedad Química de México
2005
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| author | Carlos Frontana |
| author_facet | Carlos Frontana |
| contents | The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability Carlos Frontana Ignacio González Multidisciplinaria (Ciencias Naturales y Exactas) ESR quinones semiquinone self protonation cyclic voltammetry 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. 2005 artículo científico 1870-249X https://www.redalyc.org/articulo.oa?id=47549202 en http://www.redalyc.org/revista.oa?id=475 Journal of the Mexican Chemical Society application/pdf Sociedad Química de México Journal of the Mexican Chemical Society (México) Num.2 Vol.49 |
| format | Artículo científico |
| id | redalyc_47549202 |
| institution | Redalyc |
| language | en |
| publishDate | 2005 |
| publisher | Sociedad Química de México |
| spellingShingle | The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability Carlos Frontana Multidisciplinaria (Ciencias Naturales y Exactas) ESR quinones semiquinone self protonation cyclic voltammetry The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability Carlos Frontana Ignacio González Multidisciplinaria (Ciencias Naturales y Exactas) ESR quinones semiquinone self protonation cyclic voltammetry 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. 2005 artículo científico 1870-249X https://www.redalyc.org/articulo.oa?id=47549202 en http://www.redalyc.org/revista.oa?id=475 Journal of the Mexican Chemical Society application/pdf Sociedad Química de México Journal of the Mexican Chemical Society (México) Num.2 Vol.49 |
| title | The Role of Intramolecular Hydrogen Bonding in the Electrochemical Behavior of Hydroxy-Quinones and in Semiquinone Stability |
| topic | Multidisciplinaria (Ciencias Naturales y Exactas) ESR quinones semiquinone self protonation cyclic voltammetry |
| url | https://www.redalyc.org/articulo.oa?id=47549202 |