Solvent Effect in the Electrochemical Reduction of p‐Quinones in Several Aprotic Solvents

Sasaki, Kazuo; Kashimura, Tomoyuki; Ohura, Masahiro; Ohsaki, Yasushi; Ohta, Nobuaki

doi:10.1149/1.2086957

Cited by 90 publications

(75 citation statements)

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“…For the present study we have chosen 18 mono-and polynitrocompounds (1-18) including 15 nitroaromatic compounds and three cyclic nitramines, 9 benzo-, naphtho-and antraquinones (19)(20)(21)(22)(23)(24)(25)(26)(27), 17 mono-and polycyclic azacompounds (28)(29)(30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44) with different number of nitrogen atoms for which experimental data of reduction potentials are available (see Fig. 1).…”

Section: Computational Detailsmentioning

confidence: 99%

“…Calculated at the MPWB1K/tzvp level solvation Gibbs free energies for neutral and anion radical species are collected in Table S2 as Supporting Information. It must be noted, that experimental data are available for nitrocompounds in aqueous solution 3,28 quinones in acetonitrile solution 29 and azacyclic compounds in dimethylformamide solution. [30][31][32] Direct comparison of calculated and experimental values of solvation energies is available only for nitrobenzene, for which literature data provides a solvation free energy of neutral molecule (-4.17 kcal/mol or 20.177 V).…”

Section: Gibbs Solvation Free Energymentioning

confidence: 99%

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Toward robust computational electrochemical predicting the environmental fate of organic pollutants

Sviatenko

Isayev

Gorb³

et al. 2011

J Comput Chem

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A number of density functionals was utilized for the calculation of electron attachment free energy for nitrocompounds, quinones and azacyclic compounds. Different solvation models have been tested on the calculation of difference in free energies of solvation of oxidized and reduced forms of nitrocompounds in aqueous solution, quinones in acetonitrile, and azacyclic compounds in dimethylformamide. Gas-phase free energies evaluated at the mPWB1K/tzvp level and solvation energies obtained using SMD model to compute solvation energies of neutral oxidized forms and PCM(Pauling) to compute solvation energies of anion-radical reduced forms provide reasonable accuracy of the prediction of electron attachment free energy, difference in free solvation energies of oxidized and reduced forms, and as consequence yield reduction potentials in good agreement with experimental data (mean absolute deviation is 0.15 V). It was also found that SMD/M05-2X/tzvp method provides reduction potentials with deviation of 0.12 V from the experimental values but in cases of nitrocompounds and quinones this accuracy is achieved due to the cancelation of errors. To predict reduction ability of naturally occurred iron containing species with respect to organic pollutants we exploited experimental data within the framework of Pourbaix (Eh - pH) diagrams. We conclude that surface-bound Fe(II) as well as certain forms of aqueous Fe(II)aq are capable of reducing a variety of nitroaromatic compounds, quinones and novel high energy materials under basic conditions (pH > 8). At the same time, zero-valent iron is expected to be active under neutral and acidic conditions.

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Section: Computational Detailsmentioning

confidence: 99%

Section: Gibbs Solvation Free Energymentioning

confidence: 99%

Toward robust computational electrochemical predicting the environmental fate of organic pollutants

Sviatenko

Isayev

Gorb³

et al. 2011

J Comput Chem

View full text Add to dashboard Cite

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“…This is another point to be emphasized in the redox chemistry of CoQs, which differs from what is given in the literature [2,9,[31][32][33]. Various authors claim that the protonation is a fast process in the quinone redox chemistry, and the kinetic constraints met in the voltammetric behavior of quinones are due to the slow heterogeneous electron transfer step [2,9,10,13]. Features of the voltammograms given in Fig.…”

Section: Voltammetry Of Coenzyme Qs In Buffered and Non-buffered Aquementioning

confidence: 91%

“…Therefore, in majority of the works found in the literature, the redox chemistry of Coenzyme Q 1 to Coenzyme Q 10 members has been studied in non-aqueous media. Many studies of coenzyme Q members performed in organic solvents in the absence of protons reveal that a stepwise twoelectron reduction of these compounds occurs [9][10][11][12]. In the first step, a semi-quinone radical anion of CoQs is formed (CoQ − ), while in the second step a dianion is obtained (CoQ 2− ).…”

Section: Redox Chemistry Of Coenzyme Qs In Non-aqueous Mediamentioning

confidence: 99%

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Redox chemistry of coenzyme Q—a short overview of the voltammetric features

Gulaboski

Markovski

Zhu

2016

J Solid State Electrochem

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Quinones constitute a big family of organic redox active compounds that are overwhelmingly involved in important physiological processes. The most important members in the class of quinones are, indeed, the plastoquinones and the coenzyme Q (CoQ) derivatives. Voltammetry of coenzyme Q family members attracts significant attention since 50 years ago. In this work, we refer to some of the most important voltammetric features of coenzyme Qs studied in aprotic and in aqueous media. While the redox chemistry of coenzyme Q members in non-aqueous aprotic organic solvents can be described by two consecutive one-electron transfer steps, more complex situation exists in the voltammetry of coenzyme Qs performed in aqueous media. Although it has been claimed for a while that the voltammetric processes of coenzyme Qs in aqueous solutions proceed via formation of semiquinone radical intermediate species, it has been recently proven that this can be not completely true. Intensive voltammetric and spectroscopic studies of coenzyme Q systems in buffered and non-buffered aqueous media revealed that hydrogen bonding between electrochemically created CoQ species and the water molecules plays an important role in stabilizing electrochemically generated species of these systems. We also pay attention to the amazing redox chemistry of coenzyme Qs in strong alkaline media, while we refer to the chemical features of novel coenzyme Q derivatives obtained under such conditions. Hints are presented about the antioxidant capacity of some of the novel hydroxylated coenzyme Q systems. Also, the possibility of these systems to bind and transfer earth-alkaline cations across biomimetic membranes is shortly elaborated. In the end, we refer to some relevant theoretical works that describe closely the voltammetric behavior of various coenzyme Q systems. We believe that this short review will contribute towards better understanding of the amazing chemistry of coenzyme Q derivatives.

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EPR and MO calculation studies on α-aminoanthraquinone anion radicals in aprotic solvents

1999

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The EPR spectra of electrolytically produced anion radicals of 1,4‐diamino‐9,10‐anthraquinone, 1,4‐bis‐(methylamino)‐9,10‐anthraquinone, 1‐amino‐4‐hydroxy‐9,10‐anthraquinone, 1,5‐diamino‐9,10‐anthraquinone and 1,8‐diamino‐4,5‐dihydroxy‐9,10‐anthraquinone were measured in N,N‐dimethylamine (DMF) and dimethylsulfoxide (DMSO). The isotropic hyperfine coupling constants (hcc) are assigned according to dihydroxy‐substituted anthraquinones and molecular orbital (MO) calculations made in this study. The results are compared with the radical anions of 1,4‐diamino‐ and 1,5‐diamino‐9,10‐anthraquinone made in protic solvents by chemical reduction. A tentative assignment of the hcc is made for 1‐amino‐4‐hydroxy‐9,10‐anthraquinone by MO calculations. The result show that the self‐consistent isodensity polarised continuum model (SCI‐PCM) gives hcc constants with good accuracy compared to the experimental hcc values. Copyright © 1999 John Wiley & Sons, Ltd.

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Solvent Effect in the Electrochemical Reduction of p‐Quinones in Several Aprotic Solvents

Cited by 90 publications

References 0 publications

Toward robust computational electrochemical predicting the environmental fate of organic pollutants

Toward robust computational electrochemical predicting the environmental fate of organic pollutants

Redox chemistry of coenzyme Q—a short overview of the voltammetric features

EPR and MO calculation studies on α-aminoanthraquinone anion radicals in aprotic solvents

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