DARWIN Digitale Dissertationen German Version Strich

FU Berlin
Digitale Dissertation

Johann Mößler :
Synthesis, Spectroscopic Characterization and Electron Transfer Properties of Covalently Linked Chlorin- and Bacteriochlorin-Quinones as Model Compounds for Photosynthesis
Synthese, spektroskopische Charakterisierung und Elektronentransfereigenschaften kovalent verknüpfter Chlorin- und Bacteriochlorin-Chinone als Photosynthese-Modellverbindungen

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Abstract

This dissertation describes the synthesis and electron transfer properties of covalently linked biomimetic diads, containing a chlorin or a bacteriochlorin as electron donor and p-benzoquinone as electron aceptor.
Two meso-substituted chlorin-quinones, linked via the chlorin-positions 5 and 10, and a bacteriochlorin-quinone were obtained by reduction of a porphyrin-hydroquinone with diimine, followed by selective oxidation of the hydroquinone moiety with p--benzoquinone.
Semiempirical calculations of the LCAO-pz-coefficients, based on the results from EPR/ENDOR experiments on cation and anion radicals of (bacterio)chlorins and diads, predict a high efficient charge separation in a chlorin-quinone linked via the chlorin-position 10.
Time-resolved fluorescence spectroscopy in dichloromethane and toluene on 1,4-trans-cyclohexylene-linked diads show a strong dependency of the singulet electron transfer rate on the free enthalpy of electron transfer, while the LCAO-pz-coefficients at the linking positions seem to have only little influence on kET. It is assumed that the electron transfer takes place mainly through the solvent. The electron transfer in the free bases of these chlorin- and bacteriochlorin-quinones ist about five times faster than in the corresponding porphyrin-quinone. The charge-separated state tends to be more long-lived in chlorin-quinones linked via chlorin-position 10, confirming the predictions from the semiempirical calculations in part.
Time-resolved triplet EPR spectra show spin polarization patterns similar to natural chlorophylls. The kinetics of the triplet electron transfer were studied on a cyclohexylene-linked Zn(II)-chlorin-quinone in ethanol glass matrix at 130 K.

Table of Contents

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Titel, Inhalt und Zusammenfassung (Cover, contents and summary)

Kapitel 1: Einleitung und Zielsetzung (Introduction and Objective) 980 kB
1.1 Aufbau eines Photosynthese-Reaktionszentrums
1.2 Elektronentransfer im Reaktionszentrum
1.3 Biomimetische Modellverbindungen
1.4 Zielsetzung dieser Arbeit
1.5 Literatur zu Einleitung und Zielsetzung

Kapitel 2: Allgemeiner Teil (General Part) 216 kB
2.1 Theorie des Elektronentransfers
2.2 Biomimetische Elektronentransfer-Verbindungen
2.3 Literatur zum Allgemeinen Teil

Kapitel 3: Synthetischer Teil (Synthetic Part) 593 kB
3.1 Literaturbeispiele für Chlorinsynthesen
3.2 Syntheseplanung für die Zielverbindungen
3.3 Synthese der Chinon-Brückenbausteine
3.4 Kondensation der Porphyrin-Hydrochinone
3.5 Synthese der Hydroporphyrin-Chinone
3.6 Literatur zum synthetischen Teil

Kapitel 4: Spektroskopischer Teil (Spectroscopic Part)
4.1: NMR-Spektroskopie (NMR Spectroscopy) 1165 kB
4.2: EPR/ENDOR-Spektroskopie (EPR/ENDOR Spectroscopy) 2064 kB
4.3: Bestimmung der Redoxpotentiale (Determination of the Redox Potentials) 349 kB
4.4: UV/Vis-Spektroskopie (UV/Vis Spectroscopy) 662 kB
4.5: Stationäre Fluoreszenzspektroskopie (Stationary Fluorescence Spectroscopy) 108 kB
4.6: Zeitaufgelöste Fluoreszenzspektroskopie (Time-resolved Fluorescence Spectroscopy) 68 kB
4.7: Transienten-Absorptionsspektroskopie (Transient Absorption Spectroscopy) 22 kB
4.8: Literatur zum Spektroskopischen Teil (References for the Spectroscopic Part) 9 kB

Kapitel 5: Experimenteller Teil (Experimental Part) 194 kB
5.1 Allgemeines
5.2 Alkylverbrückte Chinon-Ester
5.3 Porphyrine
5.4 Chlorine und Bacteriochlorine
5.5 Literatur zum Experimentellen Teil

Kapitel 6: Zusammenfassung und Ausblick (Summary and Outlook) 32 kB
6.1 Zusammenfassung
6.2 Summary
6.3 Ausblick

Kapitel 7: Substanzschlüssel (Substance Index) 20 kB
7.1 Abkürzung der Gruppen
7.2 Synthetisierte Zielverbindungen

Kapitel 8: Literaturverzeichnis (References) 32 kB

Kapitel 9: Anhang (Appendix) 18 kB
9.1 Nomenklatur
9.2 Abkürzungen

More Information:

Online available: http://www.diss.fu-berlin.de/1999/32/indexe.html
Language of PhDThesis: german
Keywords: Porphyrins; Bacteriochlorins; Quinones; Photosynthesis; Electron Transfer; Biomimetic
DNB-Sachgruppe: 30 Chemie
Date of disputation: 27-Apr-1999
PhDThesis from: Fachbereich Biologie, Chemie, Pharmazie, Freie Universität Berlin
First Referee: Prof. Dr. Harry Kurreck
Second Referee: Prof. Dr. Jürgen-Hinrich Fuhrhop
Third Referee: Prof. Dr. Hans-Heinrich Limbach, Prof. Dr. Klaus Christmann
Contact (Author): moessler@chemie.fu-berlin.de
Contact (Advisor): kurreck@chemie.fu-berlin.de
Notes: Publication list: see http://www.diss.fu-berlin.de/1999/32/moessler.pdf
Date created:01-Jun-1999
Date available:02-Jun-1999

 

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