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Title:Fotokatalitsko dehalogeniranje in devtero-dehalogeniranje α-bromoacetofenona : magistrsko delo
Authors:ID Pegan, Anže (Author)
ID Kovačič, Sebastijan (Mentor) More about this mentor... New window
Files:.pdf MAG_Pegan_Anze_2026.pdf (4,71 MB)
MD5: D75BB96016D125F97F98DEA70603AC6D
 
Language:Slovenian
Work type:Master's thesis/paper
Typology:2.09 - Master's Thesis
Organization:FKKT - Faculty of Chemistry and Chemical Engineering
Abstract:Iskanje alternativnih poti za sintezo devteriranih spojin, s katerimi bi se izognili uporabi dragih katalizatorjev, predstavlja enega ključnih izzivov sodobne organske kemije. V magistrskem delu sem raziskoval vlogo Hantzschevega estra (dietil-1,4-dihidro-2,6-dimetil-3,5-piridindikarboksilat) kot homogenega fotoreducenta ter donorja elektronov in vodikovih atomov v reakcijah fotokatalitskega dehalogeniranja in devtero–dehalogeniranja α–bromoacetofenona. Osrednji cilj raziskave je bil optimizirati reakcijske pogoje, pri čemer sem poskuse izvajal z uporabo modre svetlobe. Preučeval sem vpliv topila, baze in svetlobe ter spremljal kinetiko reakcije. Ugotovil sem, da je za učinkovito pretvorbo substrata ključna stabilizacija intermediatov. Pri reduktivnem dehalogeniranju sem tako najvišjo pretvorbo v produkt dosegel v tetrahidrofuranu. V kontrolnih eksperimentih sem prišel do spoznanja, da ima baza ključno vlogo pri aktivaciji Hantzschevega estra. Izrazit vpliv topila sem opazil tudi v fotokatalitskih reakcijah devteriranja. Najvišjo izotopsko obogatitev sem dosegel v 1,1,1,3,3,3–heksafluoroizopropanolu (HFIP), medtem ko sem z odstranjevanjem plinov iz reakcijske mešanice, najvišji izkoristek dosegel v acetonitrilu. Nastanek produktov sem potrdil z 1H NMR, 13C NMR, COSY in HSQC spektroskopijo. V zadnjem delu sem preučil še vpliv heterogenega fotokatalizatorja poli(arilen ciano–vinilen). Ugotovil sem, da njegova prisotnost zaradi neustreznih redoks potencialov bistveno ne prispeva k izboljšanju kinetike že optimiziranega homogenega sistema. Visok teoretični izkoristek hidrogeniranega produkta ter 94–odstotna inkorporacija devterija potrjujeta visoko reakcijsko učinkovitost in selektivnost razvite fotokatalitske poti.
Keywords:Fotokemija, homogena kataliza, Hantzschev ester, devteriranje, dehalogeniranje, α–bromoacetofenon, blue LED, HFIP.
Place of publishing:Maribor
Place of performance:Maribor
Publisher:[A. Pegan]
Year of publishing:2026
Number of pages:1 spletni vir (1 datoteka PDF (XI, 74 str.))
PID:20.500.12556/DKUM-98383 New window
UDC:544.526-5:66.094.48(043.2)
COBISS.SI-ID:285068547 New window
Publication date in DKUM:16.07.2026
Views:312
Downloads:27
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:09.06.2026

Secondary language

Language:English
Title:Photocatalytic dehalogenation and deutero-dehalogenation of α-bromoacetophenone
Abstract:The search for alternative pathways for the synthesis of deuterated compounds, aiming to avoid the use of expensive catalysts, represents one of the key challenges in modern organic chemistry. In this Master’s thesis, the role of Hantzsch ester (diethyl 1,4-dihydro-2,6-dimethyl-3,5-pyridinedicarboxylate) as a homogeneous photoreductant and an electron and hydrogen atom donor in the photocatalytic dehalogenation and deutero-dehalogenation of α–bromoacetophenone was investigated. The primary objective of the research was to optimize the reaction conditions, which were performed under blue light irradiation and an inert atmosphere. The effects of solvent, base, and light were examined, while also monitoring the reaction kinetics. It was determined that the stabilization of intermediates is crucial for efficient substrate conversion. In reductive dehalogenation, the highest product conversion was achieved in tetrahydrofuran. Control experiments revealed that the base plays a key role in the activation of the Hantzsch ester and also demonstrated its ability to act as a hydrogen atom donor. A significant solvent effect was also observed in the photocatalytic deuteration reactions. The highest isotopic enrichment was achieved in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP), whereas the highest isolated yield was obtained in acetonitrile by degassing the reaction mixture. Product formation was confirmed using 1H NMR, 13C NMR, COSY, and HSQC spectroscopy. In the final part of the study, the influence of the heterogeneous photocatalyst poly(arylene cyano-vinylene) was examined. It was found that due to unfavorable redox potentials, its presence does not significantly improve the kinetics of the already optimized homogeneous system. The 99-percent theoretical yield of the hydrogenated product and the 94% deuterium incorporation confirm the high reaction efficiency and selectivity of the developed photocatalytic pathway.
Keywords:Photochemistry, homogenous catalysis, Hantzsch ester, deuteration, dehalogenation, α–bromoacetophenone, blue LED, HFIP.


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