Dokument: Synthesis of Chiral Bimetallic Bipyridine-Bisoxazoline Complexes for Asymmetric Photocatalysis
| Titel: | Synthesis of Chiral Bimetallic Bipyridine-Bisoxazoline Complexes for Asymmetric Photocatalysis | |||||||
| URL für Lesezeichen: | https://docserv.uni-duesseldorf.de/servlets/DocumentServlet?id=63721 | |||||||
| URN (NBN): | urn:nbn:de:hbz:061-20230925-110038-5 | |||||||
| Kollektion: | Dissertationen | |||||||
| Sprache: | Englisch | |||||||
| Dokumententyp: | Wissenschaftliche Abschlussarbeiten » Dissertation | |||||||
| Medientyp: | Text | |||||||
| Autor: | Thieltges, David [Autor] | |||||||
| Dateien: |
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| Beitragende: | Prof. Dr. Czekelius, Constantin [Gutachter] Prof. Dr. Müller, Thomas J.J. [Gutachter] | |||||||
| Beschreibung: | This thesis aimed at the development of chiral bifunctional photocatalysts, that both serve to initiate photoredox reactivity and control stereoselectivity. The main focus was the comparison of heteroleptic ruthenium complexes of the form [Ru(R-bpy)2(BOX-bpy)] with R = H, tBu, OMe regarding the influence of substituents on the stereochemical outcome. The chiral bisoxazoline-bipyridine (BOX-bpy) ligands were synthesized by side-chain functionalization from 4,4’ dimethylbipyridine in a linear sequence of only four steps. Incorporation of the BOX-bpy ligand into the heteroleptic complexes paved the way for a comparative analysis of photophysical and electrochemical parameters, indicating that electron-donating substituents raise both the corresponding ligand orbitals and the metal-centred HOMO, while a BOX-bpy-centred orbital remains the energetically unaltered LUMO that preferably accepts an electron upon MLCT excitation. In order to determine the influence of the substituents on the preference for enantioselective transformations of Lewis acid-bound substrates with respect to racemic background reactions, five photoredox transformations were investigated. In an aerobic oxidation of a β keto ester, the obtained enantiomeric excesses reflected the anticipated electronic influences. The results lay the foundation for further research on directed excitation in heteroleptic photocatalysts through rational modification of orbital energies for adjustment of reactivities on opposing catalyst sides towards spatially preferred photochemical activation of Lewis acid-bound substrates leading to enantioselective activation. | |||||||
| Lizenz: |  Dieses Werk ist lizenziert unter einer Creative Commons Namensnennung 4.0 International Lizenz | |||||||
| Bezug: | 12.2017 - 05.2023 | |||||||
| Fachbereich / Einrichtung: | Mathematisch- Naturwissenschaftliche Fakultät » WE Chemie » Organische Chemie und Makromolekulare Chemie | |||||||
| Dokument erstellt am: | 25.09.2023 | |||||||
| Dateien geändert am: | 25.09.2023 | |||||||
| Promotionsantrag am: | 25.05.2023 | |||||||
| Datum der Promotion: | 17.08.2023 |
