TY  - GEN
A1  - Benzing, Kathrin Julia
N2  - This thesis deals with the study of the properties of bispidine iron(IV)-oxo complexes.
These are biomimetic model compounds for non-heme iron enzymes.
The first part describes the thermal spin crossover behavior of the tetradentate bispidine
ligands? iron(II) complexes. These compounds were precisely characterized using
UV-vis-NIR and Mößbauer spectroscopy as well as Evans NMR spectroscopy and SQUID
measurements. The tetradentate bispidine ligands? iron(IV)-oxo complexes were
characterized using UV-vis-NIR and Mößbauer spectroscopy. They were also analyzed
computationally with DFT calculations. In addition, it was possible to characterize a high
spin iron(IV)-oxo species by Mößbauer spectroscopy. This species? electron transfer
properties were analyzed.
The second part of this study is about the photocatalytic generation of an iron(IV) oxo
species with water as oxygen source. [RuII(bpy)3] 2+ was used as a photosensitizer. After
irradiating it with visible light it was oxidized with [CoIII(NH3)5(MeCN)] 3+ to
[RuIII(bpy)3] 3+, which catalytically generates in situ an iron(IV)-oxo species with water as
source of oxygen. This reaction is also interesting with regard to environmental issues as it
seems promising to use solar energy to produce highly energetic species.
The third part of this study covers the redox properties of the pentadentate bispidine
ligands? ferryl complexes when the redox inactive metal ion Sc3+ is present. The presence
of Sc3+ shifts the redox potential of the ferryl complex to higher potentials. This effect can
be used to manipulate the electron transfer properties of the ferryl compound. This FeIV(O)-
Sc3+ complex can serve as a model compound for the Mn4CaO5 cluster in the
photosystem II.
The last part of this study is about the non heme iron-oxo-catalyzed methanogenesis. The
ferryl complexes of the tetra- and pentadentate bispidine ligands produce methane from
methionine and other thioethers. In the first step of the process, methionine is oxidized to
methionine sulfoxide. A bifurcation of the reaction pathway to a sulfone or methyl radical
production marks the second step of the process. The generation of methyl radicals was
confirmed by spin trapping experiments. By way of detailed DFT calculations it was
possible to shed light on the mechanism of methane formation in a highly oxidative
environment.
TI  - Experimentelle und theoretische Untersuchungen der Eigenschaften von hochvalenten Bispidin-Eisen(IV)-Oxo-Komplexen
AV  - public
Y1  - 2015///
ID  - heidok19687
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/19687/
ER  -