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Development and Mechanistic Studies of Molecularly Defined Water Oxidation Catalysts: Catalysts for a Green and Sustainable Future
Stockholm University, Faculty of Science, Department of Organic Chemistry.
2013 (English)Doctoral thesis, comprehensive summary (Other academic)
Abstract [en]

This thesis deals with the development of complexes that are active catalysts for H2O oxidation. Promoting proton-coupled electron transfer has been a highly important feature in the development of these catalysts.

The first part deals with the modification of ligand frameworks for the development of a ruthenium complex capable of withstanding the highly oxidizing conditions required for H2O oxidation. 

The second part of the thesis describes the development of two single-site ruthenium(III) complexes, housing two meridionally coordinating tridentate benzimidazole ligands. Studies on these complexes revealed that they can mediate H2O oxidation, both by the use of a chemical oxidant and photochemically, and that the ligand frameworks were important in promoting proton-coupled electron transfer events.

In the third part, systematic modifications are introduced into one of the catalysts developed in the second part of the thesis. All of the complexes were shown to be active water oxidation catalysts (WOCs), and kinetic studies confirmed that all catalysts displayed a first-order dependence on catalyst concentration, thereby validating that H2O oxidation occurs on a single metal site. By using linear free-energy relationships it was possible to elucidate the unusual behavior exerted by the ligand framework during the catalytic cycle.

The fourth part concerns the development of a ruthenium(III) WOC, containing a tetradentate bioinspired ligand architecture, and its deactivation pathway during H2O oxidation catalysis. This revealed an unexplored, and perhaps general, deactivation pathway for ruthenium-based WOCs. Evidence was also found that the ruthenium WOC reaches a high-valent ruthenium(VI) state which is the active species in H2O oxidation.

Finally, the fifth and last part deals with the development of a dinuclear manganese complex. Utilizing a bioinspired, highly functionalized ligand, enabled the formation of the first homogeneous manganese-based WOC capable of promoting catalytic H2O oxidation with one-electron oxidants.

Place, publisher, year, edition, pages
Stockholm: Department of Organic Chemistry, Stockholm University , 2013. , 80 p.
Keyword [en]
artificial photosynthesis, water oxidation, photochemistry, electrochemistry
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
URN: urn:nbn:se:su:diva-86323ISBN: 978-91-7447-626-2 (print)OAI: oai:DiVA.org:su-86323DiVA: diva2:589336
Public defence
2013-02-22, Magnélisalen, Kemiska övningslaboratoriet, Svante Arrhenius väg 16 B, Stockholm, 13:00 (English)
Opponent
Supervisors
Note

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

Available from: 2013-01-31 Created: 2013-01-12 Last updated: 2013-08-19Bibliographically approved
List of papers
1. Light-Induced Water Oxidation by a Ru-complex Containing a Bio-Inspired Ligand
Open this publication in new window or tab >>Light-Induced Water Oxidation by a Ru-complex Containing a Bio-Inspired Ligand
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2011 (English)In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, no 28, 7953-7959 p.Article in journal (Refereed) Published
Abstract [en]

The new Ru-complex 8 containing the bio-inspired ligand 7 was successfully synthesized and characterized. Complex 8 could efficiently catalyze water oxidation using CeIV and RuIII as chemical oxidants. More importantly, this complex has sufficiently low overpotential to utilize ruthenium polypyridyl-type complexes as photosensitizers.

Keyword
homogeneous catalysis, oxidation, photochemistry, ruthenium, water splitting
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-56884 (URN)10.1002/chem.201003702 (DOI)000293383300033 ()
Funder
Knut and Alice Wallenberg Foundation
Available from: 2011-04-28 Created: 2011-04-28 Last updated: 2017-12-11Bibliographically approved
2. Water Oxidation by Single-Site Ruthenium Complexes: Using Ligands as Redox and Proton Transfer Mediators
Open this publication in new window or tab >>Water Oxidation by Single-Site Ruthenium Complexes: Using Ligands as Redox and Proton Transfer Mediators
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2012 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, no 46, 11589-11593 p.Article in journal (Refereed) Published
Keyword
electrochemistry, homogeneous catalysis, photocatalysis, ruthenium, water oxidation
National Category
Chemical Sciences
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-85016 (URN)10.1002/anie.201205018 (DOI)000310875700033 ()
Funder
Knut and Alice Wallenberg Foundation
Note

AuthorCount:9;

Available from: 2013-01-04 Created: 2013-01-04 Last updated: 2017-12-06Bibliographically approved
3. Molecular Single-site Ruthenium Complexes Containing a Basic Site: The Use of Structure-activity Relationships
Open this publication in new window or tab >>Molecular Single-site Ruthenium Complexes Containing a Basic Site: The Use of Structure-activity Relationships
(English)Manuscript (preprint) (Other academic)
Abstract [en]

A series of single-site ruthenium(III) complexes (2a-d) were synthesized and characterized, and employed in the oxidation of H2O. A linear free-energy relationship study was conducted in order to establish a correlation between the electrochemical properties and the electronic parameters of the introduced substituents in complexes 2a-d.

Keyword
water oxidation, transition metal catalysis, ruthenium
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-86766 (URN)
Available from: 2013-01-17 Created: 2013-01-17 Last updated: 2013-01-21Bibliographically approved
4. A Tailor-Made Molecular Ruthenium Catalyst for the Oxidation of Water and Its Deactivation through Poisoning by Carbon Monoxide
Open this publication in new window or tab >>A Tailor-Made Molecular Ruthenium Catalyst for the Oxidation of Water and Its Deactivation through Poisoning by Carbon Monoxide
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2013 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, no 15, 4189-4193 p.Article in journal (Refereed) Published
Keyword
energy conversion, homogeneous catalysis, oxidation of water, oxygen evolution, ruthenium
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-90011 (URN)10.1002/anie.201210226 (DOI)000317064600021 ()
Funder
Knut and Alice Wallenberg FoundationSwedish Research CouncilVinnova
Note

AuthorCount:5;

Available from: 2013-05-20 Created: 2013-05-20 Last updated: 2017-12-06Bibliographically approved
5. Photosensitized water oxidation by use of a bioinspired manganese catalyst
Open this publication in new window or tab >>Photosensitized water oxidation by use of a bioinspired manganese catalyst
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2011 (English)In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 50, no 49, 11715-11718 p.Article in journal (Refereed) Published
Keyword
homogeneous catalysis, manganese, N, O ligands, photocatalysis, water oxidation
National Category
Organic Chemistry
Research subject
Organic Chemistry
Identifiers
urn:nbn:se:su:diva-65534 (URN)10.1002/anie.201104355 (DOI)000298084900028 ()
Funder
Knut and Alice Wallenberg FoundationEU, European Research Council
Available from: 2011-12-12 Created: 2011-12-12 Last updated: 2017-12-08Bibliographically approved

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