Felipe Quiñones - Academia.edu (original) (raw)
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Universidad Nacional de Trujillo - Trujillo - La Libertad - Peru
Universidad Autónoma Metropolitana-Iztapalapa
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Papers by Felipe Quiñones
Journal of Electroanalytical Chemistry, 2005
The electrochemical reduction of 1,4-naphthoquinone (NQ), 5-hydroxy-1.4-naphthoquinone ( H N Q ) ... more The electrochemical reduction of 1,4-naphthoquinone (NQ), 5-hydroxy-1.4-naphthoquinone ( H N Q ) and 5.8-dihydroxy-1.4naphthoquinone (H2NQ) has been studied in dimethylsulfoxide and acetonitrile, both in the absence and in the presence of proton donors such as methanol and acetic acid. It was established that the intervention of intramolecular hydrogen bonds in the r-plicnolic-naphthoquinones (P-hydroxy-naphthoquinones) contributes significantly t o the stabilization of the quinone reduced species. This efIect is particularly important as a factor determining the strength of intermolecular interactions between the quinone diaiiiuii ,and proton donors. The intramolecular hydrogen bond diminishes the association capacity of the quinones and of theii. i-ed~ictiuii products with molecules of methanol, and avoids the protonation of the semiquinone with acetic acid, favoring only association processes. The low reactivity of the reduced intermediates towards the protonation by acetic acid suggests that analogues structures of H N Q and HzNQ will not be protonated. O 3005 Elsevier B.V. All rights reserved.
Journal of Electroanalytical Chemistry, 2005
The electrochemical reduction of 1,4-naphthoquinone (NQ), 5-hydroxy-1.4-naphthoquinone ( H N Q ) ... more The electrochemical reduction of 1,4-naphthoquinone (NQ), 5-hydroxy-1.4-naphthoquinone ( H N Q ) and 5.8-dihydroxy-1.4naphthoquinone (H2NQ) has been studied in dimethylsulfoxide and acetonitrile, both in the absence and in the presence of proton donors such as methanol and acetic acid. It was established that the intervention of intramolecular hydrogen bonds in the r-plicnolic-naphthoquinones (P-hydroxy-naphthoquinones) contributes significantly t o the stabilization of the quinone reduced species. This efIect is particularly important as a factor determining the strength of intermolecular interactions between the quinone diaiiiuii ,and proton donors. The intramolecular hydrogen bond diminishes the association capacity of the quinones and of theii. i-ed~ictiuii products with molecules of methanol, and avoids the protonation of the semiquinone with acetic acid, favoring only association processes. The low reactivity of the reduced intermediates towards the protonation by acetic acid suggests that analogues structures of H N Q and HzNQ will not be protonated. O 3005 Elsevier B.V. All rights reserved.