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dc.creatorSimić, Aleksandra Z.
dc.creatorVerbić, Tatjana
dc.creatorSentić, Milica
dc.creatorVojic, Mirjana P.
dc.creatorJuranić, Ivan
dc.creatorManojlović, Dragan
dc.date.accessioned2019-01-30T17:37:09Z
dc.date.available2019-01-30T17:37:09Z
dc.date.issued2013
dc.identifier.issn0026-9247
dc.identifier.urihttp://cer.ihtm.bg.ac.rs/handle/123456789/1319
dc.description.abstractEllagic 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.en
dc.publisherSpringer Wien, Wien
dc.relationinfo:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/172030/RS//
dc.relationinfo:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/172035/RS//
dc.relationinfo:eu-repo/grantAgreement/EC/FP7/261499/EU//
dc.rightsrestrictedAccess
dc.sourceMonatshefte Fur Chemie
dc.subjectAcidity constantsen
dc.subjectCyclic voltammetryen
dc.subjectPotentiometryen
dc.subjectSemiempirical calculationsen
dc.subjectUV/Vis spectroscopyen
dc.titleStudy of ellagic acid electro-oxidation mechanismen
dc.typearticle
dc.rights.licenseARR
dcterms.abstractСентић, Милица; Војиц, Мирјана П.; Симиц, Aлександра З.; Вербиц, Татјана З.; Манојловиц, Драган Д.; Јураниц, Иван О.;
dc.citation.volume144
dc.citation.issue2
dc.citation.spage121
dc.citation.epage128
dc.citation.other144(2): 121-128
dc.citation.rankM22
dc.identifier.doi10.1007/s00706-012-0856-8
dc.identifier.rcubConv_2918
dc.identifier.scopus2-s2.0-84878603814
dc.identifier.wos000314333900003
dc.type.versionpublishedVersion


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