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Title:Vpliv pH in strukture flavonoidov na njihove interakcije s Fe(II) ioni : diplomsko delo univerzitetnega študijskega programa I. stopnje
Authors:ID Vodenik, Iza (Author)
ID Hostnik, Gregor (Mentor) More about this mentor... New window
ID Frešer, Franjo (Comentor)
Files:.pdf UN_Vodenik_Iza_2025.pdf (3,52 MB)
MD5: 9E77256358943C91AF1B6B491117D3BD
 
Language:Slovenian
Work type:Bachelor thesis/paper
Typology:2.11 - Undergraduate Thesis
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:V diplomskem delu smo raziskovali vpliv vrednosti pH in strukture flavonoidov na njihove interakcije s Fe(II) ioni. Osredotočili smo se na analizo koordinacijskih spojin, ki so nastale pri reakciji med Fe(II) ioni in izbranimi flavonoidi (FL; katehin (C), epigalokatehin (EGC) in epigalokatehin galat (EGCG)). Z uporabo spektroskopije UV-Vis smo spremljali tvorbo koordinacijskih spojin pri treh različnih vrednostih pH (3,5, 4,5 in 5,5) in tako izrisali Jobove diagrame, s pomočjo katerih smo določili stehiometrijo tvorjenih koordinacijskih spojin. Stehiometrija koordinacijskih spojin (flavonoid:Fe(II)) pri C in EGC je enaka 1:1, pri EGCG pa 1:2. Rezultati so pokazali, da pH ne vpliva na stehiometrijo tvorjenih koordinacijskih spojin, medtem ko vpliva na količino koordinacijskih spojin, ki se tvorijo pri rekaciji med FL in Fe(II) ioni, saj se pri višjih vrednostih pH tvori več koordinacijske spojine. Pokazali smo, da strukturne razlike med proučevanimi FL pomembno vplivajo na njihovo sposobnost kelacije Fe(II) ionov. Vsak aromatski obroč z dvema fenolnima skupinama v poziciji orto namreč omogoča kelacijo enega Fe(II) iona. Eksperimentalnim podatkom Jobovega diagrama smo prilegali modelne funkcije. Model za C in EGC smo izpeljali na podlagi predpostavke, da C in EGC kelirata en Fe(II) ion, medtem ko smo pri izpeljavi modela za EGCG predpostavili, da EGCG kelira dva Fe(II) iona. S prileganjem modela smo določili konstante formacije in molarne absorpcijske koeficiente za proučevane koordinacijske spojine. Izračunali smo tudi, kako se množinska koncetracija nevezanega železa spreminja s sestavo raztopin.
Keywords:flavonoidi, Fe(II) ioni, koordinacijska spojina, Jobov diagram, spektroskopija UV-Vis, modeliranje
Place of publishing:Maribor
Place of performance:Maribor
Publisher:[I. Vodenik]
Year of publishing:2025
Number of pages:1 spletni vir (1 datoteka PDF (59 str.))
PID:20.500.12556/DKUM-94575 New window
UDC:547.972:544.152.3(043.2)
COBISS.SI-ID:248314371 New window
Publication date in DKUM:08.09.2025
Views:185
Downloads:45
Metadata:XML DC-XML DC-RDF
Categories:KTFMB - FKKT
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Licences

License:CC BY-NC-ND 4.0, Creative Commons Attribution-NonCommercial-NoDerivatives 4.0 International
Link:http://creativecommons.org/licenses/by-nc-nd/4.0/
Description:The most restrictive Creative Commons license. This only allows people to download and share the work for no commercial gain and for no other purposes.
Licensing start date:21.08.2025

Secondary language

Language:English
Title:Effect of pH and structure of flavonoids on their interactions with Fe(ii) ions
Abstract:In this thesis, we investigated the influence of pH and flavonoid structure on their interactions with Fe(II) ions. The focus was placed on the analysis of coordination compounds formed in reactions between Fe(II) ions and selected flavonoids (FL; catechin (C), epigallocatechin (EGC), and epigallocatechin gallate (EGCG)). Using UV-Vis spectroscopy, we monitored the formation of coordination compounds at three different pH values (3.5, 4.5, and 5.5), and constructed Job plots to determine the stoichiometry of the formed complexes. The stoichiometry of the coordination compounds (flavonoid:Fe(II)) was found to be 1:1 for C and EGC, and 1:2 for EGCG. Results showed that pH does not influence the stoichiometry of the coordination compounds, but it does affect the amount of coordination compound formed: higher pH values led to increased formation of coordination compounds. We demonstrated that structural differences between the studied flavonoids significantly influence their Fe(II)-chelating abilities. Specifically, each aromatic ring containing two hydroxyl groups in ortho-position enables chelation of one Fe(II) ion. Model functions were fitted to the experimental Job plot data. For C and EGC, the model was based on the assumption that each molecule chelates one Fe(II) ion, whereas for EGCG, the model assumed chelation of two Fe(II) ions per molecule. Through model fitting, we determined the formation constants and molar absorptivity coefficients for the studied coordination compounds. We also showed and compared how the molar concentration of unbound iron varies with the composition of the prepared solutions.
Keywords:flavonoids, Fe(II) ions, coordination compound, Job’s plot, UV-Vis spectroscopy, modelling


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