Redox mechanism of lumazine at a glassy carbon electrode

Diculescu, Victor C.; Militaru, Andra; Shah, Afzal; Qureshi, Rumana; Ţugulea, Laura; Oliveira-Brett, Ana Maria

doi:10.1016/j.jelechem.2010.05.020

Cited by 33 publications

(30 citation statements)

References 27 publications

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“…According to Scheme 1A, hydroxyderivative is formed in one electron, quasi-reversible reaction. The formation of this product has been reported for some compounds with similar structure [18].…”

Section: Redox Mechanismsupporting

confidence: 54%

“…According to the postulated reduction mechanism of quinoxaline core present in the molecule of varenicline [10], it can be assumed that similar reversible reduction of BRIM happens at the pyrazine ring of quinoxaline moiety, forming a dihydro-derivative, as in the case of other compounds containing the pyrazine ring [17][18][19][20][21]. The proposed mechanism is presented in the Scheme 1A.…”

Section: Redox Mechanismmentioning

confidence: 99%

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An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode

Aleksic

Radulović

Agbaba

et al. 2013

Electrochimica Acta

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Section: Redox Mechanismsupporting

confidence: 54%

Section: Redox Mechanismmentioning

confidence: 99%

An extensive study of electrochemical behavior of brimonidine and its determination at glassy carbon electrode

Aleksic

Radulović

Agbaba

et al. 2013

Electrochimica Acta

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“…The signals in the reverse scan with current intensities less than cathodic peaks offered another evidence for the quasi-reversible nature of DHDN reduction. 27 The current intensities of both peaks varied linearly with the square root of ν as consistent with the diffusion-controlled reduction of solution species. The slope of the plot of log I pc1 vs. log ν with a value of 0.54 (close to the theoretical value of 0.50) also witnessed the reduction process to be diffusion-limited.…”

Section: Resultsmentioning

confidence: 58%

“…27 Similarly the oxidation of the corresponding reduction product showed strong medium dependency up to pH 8. 4.…”

Section: Resultsmentioning

confidence: 93%

pH Dependent Electrochemistry of Anthracenediones at a Glassy Carbon Electrode

Ullah

Rauf

Rana

et al. 2015

J. Electrochem. Soc.

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The voltammetric response of 1-hydroxy-2(hydroxymethyl)anthracene-9,10-dione (HAC) and 1,8-dihydroxy-4,5-dinitro anthracenedione (DHDN) was investigated at a glassy carbon electrode in acidic, neutral and basic media by cyclic, square wave and differential pulse voltammetry. The oxidation of DHDN was evidenced by the appearance of one irreversible and two reversible peaks in the square wave voltammograms. The shift of peak potentials with change in pH demonstrated proton coupled electron transfer reactions. DHDN exhibited two steps pH dependent reduction while HAC reduced in a single step involving two electrons and two protons. The square wave voltammetric response showed the quasi-reversible nature of the reduction process of HAC. However, its oxidation followed irreversible behavior. The results of sensitive voltammetric techniques helped in proposing the electrode reaction mechanism of HAC and DHDN. Moreover, physical parameters such as diffusion coefficient, pKa and electron transfer rate constant were determined from scan rate, pH and concentration effects. Aromatic compounds with reducible electrophores play significantly important role in electron transport chains and photosynthesis.1,2 The primary metabolites of such compounds have been reported to act as potent antioxidants 3,4 Some of their metabolites function in the Mitchellian redox loops of mitochondrial and chloroplast electron transport chains. Their secondary metabolites are structurally diverse compounds that play defensive roles in many organisms. Tricyclic electro-reducible compounds find extensive applications in pharmacology and industry.5 Most of the biological activities and inhibitory effects of such compounds are related to their redox behavior and hydrogen bonding characteristics.6-8 Moreover, their redox properties are greatly dependent on the nature, number and position of different substituents. The synthesis, selection and application of new bicyclic and tricyclic electroactive compounds with more selective biological activity require the understanding of factors that could tune their redox characteristics. 9 Keeping this in mind, we investigated the electrochemical fate of tricyclic compounds, 1,8-dihydroxy-4,5-dinitro anthracenedione (DHDN) and 1-hydroxy-2(hydroxymethyl)anthracene-9,10-dione (HAC) having both electron donating and withdrawing groups attached to the aromatic rings. The hydroxyl groups of DHDN are expected to result in intramolecular hydrogen bonding. The nitro and OH groups present on the basic framework of the molecule have electron withdrawing and donating mesomeric effects. The nitro groups being electron acceptor will facilitate the ionization of OH groups and thus cause to lower the pK a value of the molecule. In addition, the intramolecular hydrogen bonding of OH with keto group is expected to influence the electrochemical characteristics of the molecule. These possibilities prompted us to examine the electron transfer reactions of DHDN by electrochemical techniques.A plethora of anthracenediones have been ...

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“…Then, the number of proton taking part in the reaction was calculated according Nernstian Equation [29,30]: Fig. 4B, the linear regression equation of E p versus pH was obtained as E p = 1.360-0.115 pH (R = 0.999).…”

Section: The Reaction Mechanism Of 8-hq On Mwnt/nafion/gcementioning

confidence: 99%