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Kärkäs, M. D., Li, Y.-Y., Siegbahn, P. E. M., Liao, R.-Z. & Åkermark, B. (2018). Metal-Ligand Cooperation in Single-Site Ruthenium Water Oxidation Catalysts: A Combined Experimental and Quantum Chemical Approach. Inorganic Chemistry, 57(17), 10881-10895
Öppna denna publikation i ny flik eller fönster >>Metal-Ligand Cooperation in Single-Site Ruthenium Water Oxidation Catalysts: A Combined Experimental and Quantum Chemical Approach
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2018 (Engelska)Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 57, nr 17, s. 10881-10895Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Catalysts for oxidation of water to molecular oxygen are essential in solar-driven water splitting. In order to develop more efficient catalysts for this oxidatively demanding reaction, it is vital to have mechanistic insight in order to understand how the catalysts operate. Herein, we report the mechanistic details associated with the two Ru catalysts 1 and 2. Insight into the mechanistic landscape of water oxidation catalyzed by the two single-site Ru catalysts was revealed by the use of a combination of experimental techniques and quantum chemical calculations. On the basis of the obtained results, detailed mechanisms for oxidation of water by complexes 1 and 2 are proposed. Although the two complexes are structurally related, two deviating mechanistic scenarios are proposed with metal-ligand cooperation being an important feature in both processes. The proposed mechanistic platforms provide insight for the activation of water or related small molecules through nontraditional and previously unexplored routes.

Nationell ämneskategori
Kemi
Identifikatorer
urn:nbn:se:su:diva-161104 (URN)10.1021/acs.inorgchem.8b01527 (DOI)000443923700046 ()30133266 (PubMedID)
Tillgänglig från: 2018-10-30 Skapad: 2018-10-30 Senast uppdaterad: 2022-02-26Bibliografiskt granskad
Iqbal, M. N., Abdel-Magied, A. F., Abdelhamid, H. N., Olsén, P., Shatskiy, A., Zou, X., . . . Johnston, E. V. (2017). Mesoporous Ruthenium Oxide: A Heterogeneous Catalyst for Water Oxidation. ACS Sustainable Chemistry and Engineering, 5(11), 9651-9656
Öppna denna publikation i ny flik eller fönster >>Mesoporous Ruthenium Oxide: A Heterogeneous Catalyst for Water Oxidation
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2017 (Engelska)Ingår i: ACS Sustainable Chemistry and Engineering, E-ISSN 2168-0485, Vol. 5, nr 11, s. 9651-9656Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Herein we report the synthesis of mesoporous ruthenium oxide (MP-RuO2) using a template-based approach. The catalytic efficiency of the prepared MP-RuO2 was compared to commercially available ruthenium oxide nanoparticles (C-RuO2) as heterogeneous catalysts for water oxidation. The results demonstrated superior performance of MP-RuO2 for oxygen evolution compared to the C-RuO2 with respect to recyclability, amount of generated oxygen, and stability over several catalytic runs.

Nyckelord
Artificial photosynthesis, Electron microscopy, Heterogeneous catalysis, Oxygen evolution, Ruthenium, Water oxidation
Nationell ämneskategori
Kemi
Identifikatorer
urn:nbn:se:su:diva-150012 (URN)10.1021/acssuschemeng.7b02845 (DOI)000414825900016 ()
Tillgänglig från: 2017-12-19 Skapad: 2017-12-19 Senast uppdaterad: 2022-05-11Bibliografiskt granskad
Kärkäs, M. D. (2017). Photochemical Generation of Nitrogen-Centered Amidyl, Hydrazonyl, and Imidyl Radicals: Methodology Developments and Catalytic Applications. ACS Catalysis, 7(8), 4999-5022
Öppna denna publikation i ny flik eller fönster >>Photochemical Generation of Nitrogen-Centered Amidyl, Hydrazonyl, and Imidyl Radicals: Methodology Developments and Catalytic Applications
2017 (Engelska)Ingår i: ACS Catalysis, E-ISSN 2155-5435, Vol. 7, nr 8, s. 4999-5022Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

During the past decade, visible light photo catalysis has become a powerful synthetic platform for promoting challenging bond constructions under mild reaction conditions. These photocatalytic systems rely on harnessing visible light energy for synthetic purposes through the generation of reactive but controllable free radical species. Recent progress in the area of visible light photocatalysis has established it as an enabling catalytic strategy for the mild and selective generation of nitrogen-centered radicals. The application of visible light for photocatalytic activation of amides, hydrazones, and imides represents a valuable approach for facilitating the formation of nitrogen-centered radicals. Within the span of only a couple of years, significant progress has been made for expediting the generation of amidyl, hydrazonyl, and imidyl radicals from a variety of precursors. This Perspective highlights the recent advances in visible light-mediated generation of these radicals. A particular emphasis is placed on the unique ability of visible light photocatalysis in accessing elusive reaction manifolds for the construction of diversely functionalized nitrogen-containing motifs and as a platform for nontraditional bond disconnections in contemporary synthetic chemistry.

Nyckelord
amidyl radicals, C-H amidation, C-N bond formation, nitrogen-centered radicals, photochemistry, visible light
Nationell ämneskategori
Organisk kemi
Identifikatorer
urn:nbn:se:su:diva-147117 (URN)10.1021/acscatal.7b01385 (DOI)000407309100010 ()
Tillgänglig från: 2017-10-04 Skapad: 2017-10-04 Senast uppdaterad: 2024-07-04Bibliografiskt granskad
Abdel-Magied, A. F., Arafa, W. A. A., Laine, T. M., Shatskiy, A., Kärkäs, M. D., Åkermark, B. & Johnston, E. V. (2017). Substituent Effects in Molecular Ruthenium Water Oxidation Catalysts Based on Amide Ligands. ChemCatChem, 9(9), 1583-1587
Öppna denna publikation i ny flik eller fönster >>Substituent Effects in Molecular Ruthenium Water Oxidation Catalysts Based on Amide Ligands
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2017 (Engelska)Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 9, nr 9, s. 1583-1587Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

The production of clean and sustainable energy is considered as one of the most urgent issues for our society. Mastering the oxidation of water to dioxygen is essential for the production of solar fuels. A study of the influence of the substituents on the catalytic activity of a series of mononuclear Ru complexes (2a-e) based on a tetradentate ligand framework is presented. At neutral pH, using [Ru(bpy)(3)](PF6)(3) (bpy=2,2'-bipyridine) as the terminal oxidant, a good correlation between the turnover frequency (TOF) and the Hammett sigma(meta) parameters was obtained. Additionally, a general pathway for the deactivation of Ru-based catalysts 2a-e during the catalytic oxidation of water through poisoning by carbon monoxide was demonstrated. These results highlight the importance of ligand design for fine-tuning the catalytic activity of water oxidation catalysts.

Nyckelord
homogeneous catalysis, O-O bond formation, oxidation, ruthenium, water splitting
Nationell ämneskategori
Organisk kemi
Identifikatorer
urn:nbn:se:su:diva-144650 (URN)10.1002/cctc.201601382 (DOI)000400982900008 ()
Tillgänglig från: 2017-06-27 Skapad: 2017-06-27 Senast uppdaterad: 2022-02-28Bibliografiskt granskad
Gustafson, K. P. J., Shatskiy, A., Verho, O., Kärkäs, M. D., Schluschass, B., Tai, C.-W., . . . Johnston, E. V. (2017). Water oxidation mediated by ruthenium oxide nanoparticles supported on siliceous mesocellular foam. Catalysis Science & Technology, 7(1), 293-299
Öppna denna publikation i ny flik eller fönster >>Water oxidation mediated by ruthenium oxide nanoparticles supported on siliceous mesocellular foam
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2017 (Engelska)Ingår i: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 7, nr 1, s. 293-299Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Artificial photosynthesis is an attractive strategy for converting solar energy into fuel. In this context, development of catalysts for oxidation of water to molecular oxygen remains a critical bottleneck. Herein, we describe the preparation of a well-defined nanostructured RuO2 catalyst, which is able to carry out the oxidation of water both chemically and photochemically. The developed heterogeneous RuO2 nanocatalyst was found to be highly active, exceeding the performance of most known heterogeneous water oxidation catalysts when driven by chemical or photogenerated oxidants.

Ort, förlag, år, upplaga, sidor
Royal Society of Chemistry, 2017
Nationell ämneskategori
Organisk kemi
Forskningsämne
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-140390 (URN)10.1039/c6cy02121b (DOI)000392399900027 ()
Forskningsfinansiär
VetenskapsrådetBerzelii Centre EXSELENTEU, Europeiska forskningsrådetKnut och Alice Wallenbergs Stiftelse
Tillgänglig från: 2017-03-20 Skapad: 2017-03-20 Senast uppdaterad: 2022-02-28Bibliografiskt granskad
Rabten, W., Åkermark, T., Kärkäs, M. D., Chen, H., Sun, J., Andersson, P. G. & Åkermark, B. (2016). A ruthenium water oxidation catalyst based on a carboxamide ligand. Dalton Transactions, 45(8), 3272-3276
Öppna denna publikation i ny flik eller fönster >>A ruthenium water oxidation catalyst based on a carboxamide ligand
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2016 (Engelska)Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 8, s. 3272-3276Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Herein is presented a single-site Ru complex bearing a carboxamide-based ligand that efficiently manages to carry out the fourelectron oxidation of H2O. The incorporation of the negatively charged ligand framework significantly lowered the redox potentials of the Ru complex, allowing H2O oxidation to be driven by the mild oxidant [Ru(bpy)(3)](3+). This work highlights that the inclusion of amide moieties into metal complexes thus offers access to highly active H2O oxidation catalysts.

Nationell ämneskategori
Organisk kemi
Forskningsämne
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-128576 (URN)10.1039/c6dt00327c (DOI)000371028600011 ()26843437 (PubMedID)
Forskningsfinansiär
VetenskapsrådetKnut och Alice Wallenbergs StiftelseCarl Tryggers stiftelse för vetenskaplig forskning
Tillgänglig från: 2016-06-10 Skapad: 2016-03-30 Senast uppdaterad: 2022-03-23Bibliografiskt granskad
Shatskiy, A., Lomoth, R., Abdel-Magied, A. F., Rabten, W., Laine, T. M., Chen, H., . . . Åkermark, B. (2016). Catalyst-solvent interactions in a dinuclear Ru-based water oxidation catalyst. Dalton Transactions, 45(47), 19024-19033
Öppna denna publikation i ny flik eller fönster >>Catalyst-solvent interactions in a dinuclear Ru-based water oxidation catalyst
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2016 (Engelska)Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 47, s. 19024-19033Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Photocatalytic water oxidation represents a key process in conversion of solar energy into fuels and can be facilitated by the use of molecular transition metal-based catalysts. A novel straightforward approach for covalent linking of the catalytic units to other moieties is demonstrated by preparation of a dinuclear complex containing two [Ru(pdc)(pic)(3)]-derived units (pdc = 2,6-pyridinedicarboxylate, pic = 4-picoline). The activity of this complex towards chemical and photochemical oxidation of water was evaluated and a detailed insight is given into the interactions between the catalyst and acetonitrile, a common co-solvent employed to increase solubility of water oxidation catalysts. The solvent-induced transformations were studied by electrochemical and spectroscopic techniques and the relevant quantitative parameters were extracted.

Nationell ämneskategori
Organisk kemi
Forskningsämne
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-139388 (URN)10.1039/c6dt03789e (DOI)000390082900029 ()27853776 (PubMedID)
Forskningsfinansiär
VetenskapsrådetKnut och Alice Wallenbergs StiftelseCarl Tryggers stiftelse för vetenskaplig forskning
Tillgänglig från: 2017-02-07 Skapad: 2017-02-06 Senast uppdaterad: 2022-03-23Bibliografiskt granskad
Kärkäs, M. D. & Åkermark, B. (2016). Catalytic Water Oxidation by Ruthenium Complexes Containing Negatively Charged Ligand Frameworks. The chemical record, 16(2), 940-963
Öppna denna publikation i ny flik eller fönster >>Catalytic Water Oxidation by Ruthenium Complexes Containing Negatively Charged Ligand Frameworks
2016 (Engelska)Ingår i: The chemical record, ISSN 1527-8999, E-ISSN 1528-0691, Vol. 16, nr 2, s. 940-963Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Artificial photosynthesis represents an attractive way of converting solar energy into storable chemical energy. The H2O oxidation half-reaction, which is essential for producing the necessary reduction equivalents, is an energy-demanding transformation associated with a high kinetic barrier. Herein we present a couple of efficient Ru-based catalysts capable of mediating this four-proton-four-electron oxidation. We have focused on the incorporation of negatively charged ligands, such as carboxylate, phenol, and imidazole, into the catalysts to decrease the redox potentials. This account describes our work in designing Ru catalysts based on this idea. The presence of the negatively charged ligands is crucial for stabilizing the metal centers, allowing for light-driven H2O oxidation. Mechanistic details associated with the designed catalysts are also presented.

Ort, förlag, år, upplaga, sidor
Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim, 2016
Nyckelord
electrochemistry, photochemistry, ruthenium, sustainable chemistry, water splitting
Nationell ämneskategori
Organisk kemi
Identifikatorer
urn:nbn:se:su:diva-130880 (URN)10.1002/tcr.201500254 (DOI)000374765700024 ()26991306 (PubMedID)
Forskningsfinansiär
VetenskapsrådetKnut och Alice Wallenbergs StiftelseCarl Tryggers stiftelse för vetenskaplig forskning
Tillgänglig från: 2016-06-07 Skapad: 2016-06-07 Senast uppdaterad: 2022-02-23Bibliografiskt granskad
Abdel-Magied, A. F., Shatskiy, A., Liao, R.-Z., Laine, T. M., Arafa, W. A. A., Siegbahn, P. E. M., . . . Johnston, E. V. (2016). Chemical and Photochemical Water Oxidation Mediated by an Efficient Single-Site Ruthenium Catalyst. ChemSusChem, 9(24), 3448-3456
Öppna denna publikation i ny flik eller fönster >>Chemical and Photochemical Water Oxidation Mediated by an Efficient Single-Site Ruthenium Catalyst
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2016 (Engelska)Ingår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 24, s. 3448-3456Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Water oxidation is a fundamental step in artificial photosynthesis for solar fuels production. In this study, we report a single-site Ru-based water oxidation catalyst, housing a dicarboxylate-benzimidazole ligand, that mediates both chemical and light-driven oxidation of water efficiently under neutral conditions. The importance of the incorporation of the negatively charged ligand framework is manifested in the low redox potentials of the developed complex, which allows water oxidation to be driven by the mild one-electron oxidant [Ru(bpy)(3)](3+) (bpy = 2,2'-bipyridine). Furthermore, combined experimental and DFT studies provide insight into the mechanistic details of the catalytic cycle.

Nyckelord
electrochemistry, homogeneous catalysis, photochemistry, ruthenium, water oxidation
Nationell ämneskategori
Organisk kemi
Forskningsämne
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-141313 (URN)10.1002/cssc.201601171 (DOI)000394571500013 ()27966290 (PubMedID)
Forskningsfinansiär
VetenskapsrådetKnut och Alice Wallenbergs StiftelseCarl Tryggers stiftelse för vetenskaplig forskning
Tillgänglig från: 2017-04-03 Skapad: 2017-04-03 Senast uppdaterad: 2022-03-23Bibliografiskt granskad
Kärkäs, M. D., Liao, R.-Z., Laine, T. M., Åkermark, T., Ghanem, S., Siegbahn, P. E. M. & Åkermark, B. (2016). Molecular ruthenium water oxidation catalysts carrying non-innocent ligands: mechanistic insight through structure-activity relationships and quantum chemical calculations. Catalysis Science & Technology, 6(5), 1306-1319
Öppna denna publikation i ny flik eller fönster >>Molecular ruthenium water oxidation catalysts carrying non-innocent ligands: mechanistic insight through structure-activity relationships and quantum chemical calculations
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2016 (Engelska)Ingår i: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 6, nr 5, s. 1306-1319Artikel i tidskrift (Refereegranskat) Published
Abstract [en]

Robust catalysts that mediate H2O oxidation are of fundamental importance for the development of novel carbon-neutral energy technologies. Herein we report the synthesis of a group of single-site Ru complexes. Structure-activity studies revealed that the individual steps in the oxidation of H2O depended differently on the electronic properties of the introduced ligand substituents. The mechanistic details associated with these complexes were investigated experimentally along with quantum chemical calculations. It was found that O-O bond formation for the developed Ru complexes proceeds via high-valent Ru-VI species, where the capability of accessing this species is derived from the non-innocent ligand architecture. This cooperative catalytic involvement and the ability of accessing Ru-VI are intriguing and distinguish these Ru catalysts from a majority of previously reported complexes, and might generate unexplored reaction pathways for activation of small molecules such as H2O.

Nationell ämneskategori
Organisk kemi
Forskningsämne
organisk kemi
Identifikatorer
urn:nbn:se:su:diva-129099 (URN)10.1039/c5cy01704a (DOI)000371607600006 ()
Forskningsfinansiär
VetenskapsrådetKnut och Alice Wallenbergs StiftelseCarl Tryggers stiftelse för vetenskaplig forskning
Tillgänglig från: 2016-04-19 Skapad: 2016-04-14 Senast uppdaterad: 2022-05-09Bibliografiskt granskad
Organisationer
Identifikatorer
ORCID-id: ORCID iD iconorcid.org/0000-0002-6089-5454

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