Hochschulschrift

CO releasing manganese complexes, reaction pathways and synthesis of multinuclear Mn-compounds

Abstract: Three different aspects of manganese complex chemistry are investigated in this work. The main part of this work is the investigation of the reaction pathways and products of manganese photoCORMs (CO releasing molecules for which the CO release can be triggered by UV or Vis irradiation). Secondly, investigations of arginase model systems including the development of a HPLC method to determine and quantify arginase activity were carried out. Furthermore, attempts to synthesize and characterize multinuclear manganese complexes with large ring shaped Schiff-base ligands, which might be used as model systems for the oxygen evolving complex (OEC) in photosystem II are made. The characterization of the multinuclear manganese complexes was problematic and therefore, the focus of this work was the investigation of manganese photoCORMs and the possibility of their use as an alternative route to multinuclear manganese complexes. Very detailed information on the CO release pathways of [MnI(CO)3(κ3-tpm)]+ and [MnI(CO)3(κ3-bpza)] could be obtained by IR-and UV/Vis-monitoring of the CO release. For the first time the remaining products of the CO release could be characterized as [MnIItpm2]2+ or [Mn2IIbpza4] and manganese oxides respectively. By showing in IR/LSV spectroelectrochemical experiments that the CO release can also be triggered by oxidation, an additional route of the CO release was investigated. The gathered information might be useful for further investigations of photoCORMs as drugs and also led to the right choice of tpa as ligand to obtain dinuclear manganese complexes ([Mn2III,IV(μ O)2(κ4 tpa)2]3+ and [Mn2II,II(μ-OAc)2(κ4-tpa)2]2+) in a very simple way by the light or oxidation triggered CO release of [MnI(CO)3(κ3 tpa)]+. For [Mn2II,II(μ-OAc)2(κ4-tpa)2]2+ arginase activity could be proven by a newly developed HPLC method using a pre column derivatisation with OPA (ortho-phthalaldehyde) to determine small amounts of ornithine in arginine rich solutions with a C18 column. Mass spectrometric investigations revealed the replacement of bridging acetates by hydroxides and therefore the possibility of this catalysis to be the same as the catalytic cycle of arginase. Overall, this work shows that well defined multinuclear manganese complexes, which can be used as model systems for metalloenzymes, can be obtained by the use of manganese photoCORMs as precursors

Standort
Deutsche Nationalbibliothek Frankfurt am Main
Umfang
Online-Ressource
Sprache
Englisch
Anmerkungen
cc_by http://creativecommons.org/licenses/by/4.0/deed.de cc
Albert-Ludwigs-Universität Freiburg, Dissertation, 2017

Klassifikation
Chemie
Schlagwort
Mangan
Kohlenmonoxid

Ereignis
Veröffentlichung
(wo)
Freiburg
(wer)
Universität
(wann)
2017
Urheber

DOI
10.6094/UNIFR/12860
URN
urn:nbn:de:bsz:25-freidok-128609
Rechteinformation
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Letzte Aktualisierung
25.03.2025, 13:48 MEZ

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Objekttyp

  • Hochschulschrift

Entstanden

  • 2017

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