Study of ellagic acid electro-oxidation mechanism
Само за регистроване кориснике
2013
Аутори
Simic, Aleksandra Z.Verbić, Tatjana
Sentić, Milica N.
Vojic, Mirjana P.
Juranić, Ivan O.
Manojlović, Dragan D.
Чланак у часопису (Објављена верзија)
Метаподаци
Приказ свих података о документуАпстракт
Ellagic acid is a biologically active polyphenol found in numerous fruits and vegetables. However, not many papers dealing with the electrochemical properties and protolytic equilibria of ellagic acid have been published so far. The electro-oxidation mechanism of ellagic acid was studied in methanol aqueous media (1:1, v/v) within the pH range of 1.5-9.0, t = 25 +/- A 1 A degrees C, using cyclic voltammetry on a glassy carbon electrode, and by semiempirical calculations. Results show that oxidation of ellagic acid is a pH-dependent, two-step quasireversible process. The slope of peak 1 indicates the exchange of the same number of electrons and protons within the whole studied pH range; the slope of peak 2 changes with the increase of pH, and three different regions are visible. As protolytic equilibria studies revealed that ellagic acid acts as a diprotic acid in the studied conditions (acidity constants were potentiometrically determined as pK (a1) = 5.42 +/- A 0.01 and pK (a2) = 6.76... +/- A 0.01), it is obvious that the electro-oxidation occurs at the hydroxyl group subjected to dissociation. The three different regions are therefore recognized as regions with different dominating species: unionized molecule (H(4)A), monoanion (H(3)A(-)), and dianion (H(2)A(2-)). UV/Vis spectral changes confirmed the proposed equilibria. Heat of formation and electron densities calculated at semiempirical level were used to propose the hydrogen and electron abstraction sites. According to the obtained results, a new mechanism of ellagic acid electro-oxidation is proposed.
Кључне речи:
Acidity constants / Cyclic voltammetry / Potentiometry / Semiempirical calculations / UV/Vis spectroscopyИзвор:
Monatshefte Fur Chemie, 2013, 144, 2, 121-128Издавач:
- Springer Wien, Wien
Финансирање / пројекти:
- Примена унапређених оксидационих процеса и наноструктурисаних оксидних материјала за уклањање загађивача из животне средине, развој и оптимизација инструменталних техника за праћење ефикасности (RS-MESTD-Basic Research (BR or ON)-172030)
- Рационални дизајн и синтеза биолошки активних и координационих једињења и функционалних материјала, релевантних у (био)нанотехнологији (RS-MESTD-Basic Research (BR or ON)-172035)
- High-Performance Computing Infrastructure for South East Europe's Research Communities (EU-FP7-261499)
DOI: 10.1007/s00706-012-0856-8
ISSN: 0026-9247
WoS: 000314333900003
Scopus: 2-s2.0-84878603814
Колекције
Институција/група
Hemijski fakultet / Faculty of ChemistryTY - JOUR AU - Simic, Aleksandra Z. AU - Verbić, Tatjana AU - Sentić, Milica N. AU - Vojic, Mirjana P. AU - Juranić, Ivan O. AU - Manojlović, Dragan D. PY - 2013 UR - https://cherry.chem.bg.ac.rs/handle/123456789/1593 AB - Ellagic acid is a biologically active polyphenol found in numerous fruits and vegetables. However, not many papers dealing with the electrochemical properties and protolytic equilibria of ellagic acid have been published so far. The electro-oxidation mechanism of ellagic acid was studied in methanol aqueous media (1:1, v/v) within the pH range of 1.5-9.0, t = 25 +/- A 1 A degrees C, using cyclic voltammetry on a glassy carbon electrode, and by semiempirical calculations. Results show that oxidation of ellagic acid is a pH-dependent, two-step quasireversible process. The slope of peak 1 indicates the exchange of the same number of electrons and protons within the whole studied pH range; the slope of peak 2 changes with the increase of pH, and three different regions are visible. As protolytic equilibria studies revealed that ellagic acid acts as a diprotic acid in the studied conditions (acidity constants were potentiometrically determined as pK (a1) = 5.42 +/- A 0.01 and pK (a2) = 6.76 +/- A 0.01), it is obvious that the electro-oxidation occurs at the hydroxyl group subjected to dissociation. The three different regions are therefore recognized as regions with different dominating species: unionized molecule (H(4)A), monoanion (H(3)A(-)), and dianion (H(2)A(2-)). UV/Vis spectral changes confirmed the proposed equilibria. Heat of formation and electron densities calculated at semiempirical level were used to propose the hydrogen and electron abstraction sites. According to the obtained results, a new mechanism of ellagic acid electro-oxidation is proposed. PB - Springer Wien, Wien T2 - Monatshefte Fur Chemie T1 - Study of ellagic acid electro-oxidation mechanism VL - 144 IS - 2 SP - 121 EP - 128 DO - 10.1007/s00706-012-0856-8 ER -
@article{ author = "Simic, Aleksandra Z. and Verbić, Tatjana and Sentić, Milica N. and Vojic, Mirjana P. and Juranić, Ivan O. and Manojlović, Dragan D.", year = "2013", abstract = "Ellagic acid is a biologically active polyphenol found in numerous fruits and vegetables. However, not many papers dealing with the electrochemical properties and protolytic equilibria of ellagic acid have been published so far. The electro-oxidation mechanism of ellagic acid was studied in methanol aqueous media (1:1, v/v) within the pH range of 1.5-9.0, t = 25 +/- A 1 A degrees C, using cyclic voltammetry on a glassy carbon electrode, and by semiempirical calculations. Results show that oxidation of ellagic acid is a pH-dependent, two-step quasireversible process. The slope of peak 1 indicates the exchange of the same number of electrons and protons within the whole studied pH range; the slope of peak 2 changes with the increase of pH, and three different regions are visible. As protolytic equilibria studies revealed that ellagic acid acts as a diprotic acid in the studied conditions (acidity constants were potentiometrically determined as pK (a1) = 5.42 +/- A 0.01 and pK (a2) = 6.76 +/- A 0.01), it is obvious that the electro-oxidation occurs at the hydroxyl group subjected to dissociation. The three different regions are therefore recognized as regions with different dominating species: unionized molecule (H(4)A), monoanion (H(3)A(-)), and dianion (H(2)A(2-)). UV/Vis spectral changes confirmed the proposed equilibria. Heat of formation and electron densities calculated at semiempirical level were used to propose the hydrogen and electron abstraction sites. According to the obtained results, a new mechanism of ellagic acid electro-oxidation is proposed.", publisher = "Springer Wien, Wien", journal = "Monatshefte Fur Chemie", title = "Study of ellagic acid electro-oxidation mechanism", volume = "144", number = "2", pages = "121-128", doi = "10.1007/s00706-012-0856-8" }
Simic, A. Z., Verbić, T., Sentić, M. N., Vojic, M. P., Juranić, I. O.,& Manojlović, D. D.. (2013). Study of ellagic acid electro-oxidation mechanism. in Monatshefte Fur Chemie Springer Wien, Wien., 144(2), 121-128. https://doi.org/10.1007/s00706-012-0856-8
Simic AZ, Verbić T, Sentić MN, Vojic MP, Juranić IO, Manojlović DD. Study of ellagic acid electro-oxidation mechanism. in Monatshefte Fur Chemie. 2013;144(2):121-128. doi:10.1007/s00706-012-0856-8 .
Simic, Aleksandra Z., Verbić, Tatjana, Sentić, Milica N., Vojic, Mirjana P., Juranić, Ivan O., Manojlović, Dragan D., "Study of ellagic acid electro-oxidation mechanism" in Monatshefte Fur Chemie, 144, no. 2 (2013):121-128, https://doi.org/10.1007/s00706-012-0856-8 . .