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dc.creatorAssaleh, Mohamed H.
dc.creatorBožić, Aleksandra R.
dc.creatorBjelogrlić, Snežana K.
dc.creatorMilošević, Milena D.
dc.creatorSimić, Milena R.
dc.creatorMarinković, Aleksandar
dc.creatorCvijetić, Ilija
dc.date.accessioned2020-02-18T12:05:27Z
dc.date.available2020-02-18T12:05:27Z
dc.date.issued2019
dc.identifier.issn1040-0400
dc.identifier.urihttp://cherry.chem.bg.ac.rs/handle/123456789/3846
dc.description.abstractThiocarbohydrazones (TCHs) and structurally related molecules are versatile organic compounds which exert antioxidant, anticancer, and other beneficial health effects. The combination of UV/Vis, NMR spectroscopy, and quantum chemical calculations was used to rationalize the experimentally observed increase in the radical scavenging activity upon the addition of water in DMSO solution of TCHs. Mono- and bis(salicylaldehyde) TCHs (compounds 1 and 2) undergo water-induced E-to-Z isomerization which is followed by disruption of intramolecular hydrogen bond, ground state destabilization, and 11 kcal/mol decrease in the bond dissociation enthalpy (BDE). Electron spin delocalization is more pronounced in Z-isomers of 1 and 2. On the other hand, 2-acetylpyridine TCHs (compounds 3 and 4) undergo thione-to-thiol tautomerism which also decreases the BDE and facilitates the hydrogen atom transfer to 2,2-diphenyl-1-picrylhydrazyl radical (DPPH∙). The appearance of thiolic –SH group as another reactive site toward free radicals improves the antioxidant activity of 3 and 4. The spin density of 3- and 4-thiol radicals is delocalized over the entire thiocarbohydrazide moiety compared to more localized spin of thione radicals. Additional stabilization of thiol radicals corroborates with the increased antioxidant activity. This study provides the new insights on the solution structure of TCHs, and also highlights the importance of solution structure determination when studying the structure-antioxidant relationships of isomerizable compounds.
dc.relationinfo:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/172013/RS//
dc.relationinfo:eu-repo/grantAgreement/MESTD/Basic Research (BR or ON)/172055/RS//
dc.relationThe part of the bilateral project between Serbia and Montenegro titled “Synthesis of Schiff bases and investigation of their antimicrobial and antioxidant activity.”
dc.rightsrestrictedAccess
dc.sourceStructural Chemistry
dc.subjectAntioxidant activity
dc.subjectBond dissociation enthalpy
dc.subjectE/Z isomerism
dc.subjectSpin density distribution
dc.subjectTautomerism
dc.subjectThiocarbohydrazones
dc.titleWater-induced isomerism of salicylaldehyde and 2-acetylpyridine mono- and bis-(thiocarbohydrazones) improves the antioxidant activity: spectroscopic and DFT study
dc.typearticle
dc.rights.licenseARR
dcterms.abstractСимић, Милена Р.; Aссалех, Мохамед Х.; Божић, Aлександра Р.; Милошевић, Милена Д.; Бјелогрлић, Снежана К.; Цвијетић, Илија; Маринковић, Aлександар;
dc.citation.volume30
dc.citation.issue6
dc.citation.spage2447
dc.citation.epage2457
dc.identifier.wos000494698700034
dc.identifier.doi10.1007/s11224-019-01371-4
dc.citation.rankM22~
dc.description.otherSupplementary material: [http://cherry.chem.bg.ac.rs/handle/123456789/3848]
dc.type.versionpublishedVersion
dc.identifier.scopus2-s2.0-85068185532


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