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  • 1.
    Abdel-Magied, Ahmed F.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Arafa, Wael A. A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Substituent Effects in Molecular Ruthenium Water Oxidation Catalysts Based on Amide Ligands2017Ingår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 9, nr 9, s. 1583-1587Artikel i tidskrift (Refereegranskat)
    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.

  • 2. Abrahamsson, Maria
    et al.
    Lundqvist, Maria J.
    Wolpher, Henriette
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johansson, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Bergquist, Jonas
    Rasmussen, Torben
    Becker, Hans-Christian
    Hammarström, Leif
    Norrby, Per-Ola
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Persson, Petter
    Steric influence on the excited-state lifetimes of ruthenium complexes with bipyridyl-alkanylene-pyridyl ligands2008Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 47, nr 9, s. 3540-3548Artikel i tidskrift (Refereegranskat)
  • 3. Abrahamsson, Maria
    et al.
    Wolpher, Henriette
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johansson, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Larsson, Jan
    Kritikos, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Norrby, Per-Ola
    Bergquist, Jonas
    Sun, Licheng
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hammarström, Leif
    A New Strategy for Improvement of Photophysical Properties in Ruthenium(II) Polypyridyl Complexes. Synthesis, Photophysical and Electrochemical characterisation of Six Mononuclear Ruthenium(II) Bisterpyridine Type Complexes2005Ingår i: Inorganic Chemistry, ISSN 0020-1669, E-ISSN 1520-510X, Vol. 44, nr 9, s. 3215-3225Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis and characterization of six ruthenium(II) bistridentate polypyridyl complexes is described. These were designed on the basis of a new approach to increase the excited-state lifetime of ruthenium(II) bisterpyridine-type complexes. By the use of a bipyridylpyridyl methane ligand in place of terpyridine, the coordination environment of the metal ion becomes nearly octahedral and the rate of deactivation via ligand-field (i.e., metal-centered) states was reduced as shown by temperature-dependent emission lifetime studies. Still, the possibility to make quasi-linear donor−ruthenium−acceptor triads is maintained in the complexes. The most promising complex shows an excited-state lifetime of τ = 15 ns in alcohol solutions at room temperature, which should be compared to a lifetime of τ = 0.25 ns for [Ru(tpy)2]2+. The X-ray structure of the new complex indeed shows a more octahedral geometry than that of [Ru(tpy)2]2+. Most importantly, the high excited-state energy was retained, and thus, so was the potential high reactivity of the excited complex, which has not been the case with previously published strategies based on bistridentate complexes.

  • 4.
    Anderlund, Magnus F.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Högblom, Joakim
    Shi, Wei
    Huang, Ping
    Eriksson, Lars
    Weihe, Högni
    Styring, Stenbjörn
    Åkermark, Björn
    Magnuson, Ann
    Synthesis, Structure and Redox Chemistry of a Dinuclear Manganese Complex with a Novel Unsymmetric N5O2 LigandManuskript (Övrigt vetenskapligt)
  • 5.
    Anderlund, Magnus F.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zheng, J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ghiladi, M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kritikos, Mikael
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Rivière, Erik
    Sun, Licheng
    Girerd, Jean-Jaques
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A New, Dinuclear High Spin Manganese(III) Complex with Bridging Phenoxy and Methoxy Groups. Structure and Magnetic Properties2006Ingår i: Inorganic Chemistry Communications, ISSN 1387-7003, E-ISSN 1879-0259, Vol. 9, nr 12, s. 1195-1198Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A new μ-phenoxy-μ-metoxy di-manganese(III) complex with the trisphenolic ligand, 2,6-bis[((2-hydroxybenzyl)(2-pyridylmethyl)amino)methyl]-4-methylphenol, was isolated as a perchlorate salt. The X-ray structure shows that the two manganese(III) ions are in a distorted octrahedral enviroment with approximately perpendicular Jahn–Teller axes. Investigation of the molar magnetic susceptibility reveals a ferromagnetic coupling between the two high-spin manganese(III) ions. Fitting of the data led to g = 2 and J = 12.5 cm−1

  • 6. Andersson, Samir
    et al.
    Zou, Dapeng
    Zhang, Rong
    Sun, Shiguo
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Selective positioning of CB[8] on two linked viologens and electrochemically driven movement of the host molecule2009Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 8, s. 1163-1172Artikel i tidskrift (Refereegranskat)
  • 7.
    Arafa, Wael A. A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Berends, Hans-Martin
    Messinger, Johannes
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dinuclear manganese complexes for water oxidation: evaluation of electronic effects and catalytic activity2014Ingår i: Physical Chemistry, Chemical Physics - PCCP, ISSN 1463-9076, E-ISSN 1463-9084, Vol. 16, nr 24, s. 11950-11964Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    During recent years significant progress has been made towards the realization of a sustainable and carbon-neutral energy economy. One promising approach is photochemical splitting of H2O into O-2 and solar fuels, such as H-2. However, the bottleneck in such artificial photosynthetic schemes is the H2O oxidation half reaction where more efficient catalysts are required that lower the kinetic barrier for this process. In particular catalysts based on earth-abundant metals are highly attractive compared to catalysts comprised of noble metals. We have now synthesized a library of dinuclear Mn-2 (II,III) catalysts for H2O oxidation and studied how the incorporation of different substituents affected the electronics and catalytic efficiency. It was found that the incorporation of a distal carboxyl group into the ligand scaffold resulted in a catalyst with increased catalytic activity, most likely because of the fact that the distal group is able to promote proton-coupled electron transfer (PCET) from the high-valent Mn species, thus facilitating O-O bond formation.

  • 8. Berggren, Gustav
    et al.
    Kaynak, Filiz Betul
    Anderlund, Magnus F.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Åkermark, Björn
    Institutionen för organisk kemi.
    Tetraethylammonium [12,12-diethyl-2,2,9,9-tetramethyl-1,4,7,10-tetraza-5,6-benzotridecane-3,8,11,13-tetra-one(4-)]oxidomanganate(V)2007Ingår i: Acta Crystallographica Section E, ISSN 1600-5368, Vol. E63, s. m2672-m2673Artikel i tidskrift (Refereegranskat)
  • 9. Borgström, Magnus
    et al.
    Johansson, Olof
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lomoth, Reiner
    Berglund-Baudin, Helena
    Wallin, Staffan
    Sun, Licheng
    Åkermark, Björn
    Hammarström, Leif
    Electron Donor-Acceptor Dyads and Triads Based on Tris(bipyridine)ruthenium(II) and Benzoquinone: Synthesis, Characterization, and Photoinduced Electron Transfer Reactions2003Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 42, nr 17, s. 5173-5184Artikel i tidskrift (Refereegranskat)
  • 10. Borgström, Magnus
    et al.
    Shaikh, Nizamuddin
    Johansson, Olof
    Anderlund, Magnus F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Styring, Stenbjörn
    Åkermark, Björn
    Magnuson, Ann
    Hammarström, Leif
    Light Induced Magnanese Oxidation and Long-lived Charge Separation in a Mn2II,II-RuII-acceptor triadManuskript (Övrigt vetenskapligt)
  • 11. Das, Biswanath
    et al.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Demeshko, Serhiy
    Liao, Rong-Zhen
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Haukka, Matti
    Zeglio, Erica
    Abdel-Magied, Ahmed F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Meyer, Franc
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nordlander, Ebbe
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Water oxidation catalyzed by molecular di- and nonanuclear Fe complexes: importance of a proper ligand framework2016Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 34, s. 13289-13293Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The synthesis of two molecular iron complexes, a dinuclear iron(III,III) complex and a nonanuclear iron complex, based on the di-nucleating ligand 2,2'-(2-hydroxy-5-methyl-1,3-phenylene)bis(1H-benzo[d]imidazole-4-carboxylic acid) is described. The two iron complexes were found to drive the oxidation of water by the one-electron oxidant [Ru(bpy)(3)](3+).

  • 12.
    Ekström, Jesper
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Abrahamsson, Maria
    Olson, Carol
    Bergquist, Jonas
    Kanyak, Feliz B.
    Eriksson, Lars
    Sun, Licheng
    Åkermark, Björn
    Becker, Hans-Christian
    Hammarström, Leif
    Ott, Sascha
    Bio Inspired Side-on Attachment of a Ruthenium Photo-sensitizer to an Iron Hydrogenase Active Site Model2006Ingår i: Dalton Transactions, ISSN 1477-9226, nr 38, s. 4599-4606Artikel i tidskrift (Refereegranskat)
  • 13.
    Fryxelius, Jacob
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Anderlund, Magnus
    Xu, Yunhua
    Huang, Ping
    Magnuson, Ann
    Sun, Licheng
    Åkermark, Björn
    A Tetranuclear Mn Dimer of DimersManuskript (Övrigt vetenskapligt)
  • 14.
    Fryxelius, Jacob
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Pica, Delphine
    Eriksson, Lars
    Åkermark, Björn
    Preparation of Copper(II) Complexes of a Mixed Amide-Phenolate LigandIngår i: Inorganic Chemistry CommunicationsArtikel i tidskrift (Refereegranskat)
  • 15. Gao, Weiming
    et al.
    Ekström, Jesper
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianhui
    Chen, Changneng
    Eriksson, Lars
    Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi.
    Weng, Linhong
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Binuclear iron-sulfur complexes with bidentate phosphine ligands as active site models of Fe-hydrogenase and their catalytic proton reduction2007Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 46, nr 6, s. 1981-1991Artikel i tidskrift (Refereegranskat)
  • 16. Gao, Weiming
    et al.
    Liu, Jianhui
    Jiang, Weina
    Wang, Mei
    Weng, Linhong
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    An azadithiolate bridged Fe2S2 complex as active site model of FeFe-hydrogenase covalently linked to a Re(CO)3(bpy)(py) photosensitizer aiming for light-driven hydrogen production2008Ingår i: Comptes Rendus Chimie, ISSN 1631-0748, Vol. 11, nr 8, s. 915-921Artikel i tidskrift (Refereegranskat)
  • 17. Gao, Weiming
    et al.
    Liu, Jianhui
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Bidentate phosphine ligand based Fe2S2-containing macromolecules: synthesis, characterization, and catalytic electrochemical hydrogen production2006Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 45, nr 23, s. 9169-9171Artikel i tidskrift (Refereegranskat)
  • 18. Gao, Weiming
    et al.
    Liu, Jianhui
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Facile and highly efficient light-induced PR3/CO ligand exchange: a novel approach to the synthesis of [(mu-SCH2NnPrCH2S)Fe2(CO)4(PR3)2]2007Ingår i: Journal of Organometallic Chemistry, ISSN 0022-328X, Vol. 692, s. 1579-1583Artikel i tidskrift (Refereegranskat)
  • 19.
    Gao, Weiming
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Li, Mingrun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Romare, Kristina
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Royal Institute of Technology (KTH), Department of Organic Chemistry.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis of a [3Fe2S] cluster with low redox potential from [2Fe2S] hydrogenase models: electrochemical and photochemical generation of hydrogen2011Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, Vol. 2011, nr 7, s. 1100-1105Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    In the attempted replacement of carbon monoxide by the bis(phosphane) dppv in a dinuclear [2Fe2S] complex, a trinuclear [3Fe2S] complex with two bis(phosphane) ligands was unexpectedly obtained. On protonation, this gave a bridged hydride complex with an unusually low potential for the reduction of protons to molecular hydrogen. The redox potential also appears sufficiently positive for direct electron transfer from an excited [Ru(bpy)(3)](2+) sensitizer.

  • 20.
    Gao, Weiming
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Åkermark, Torbjörn
    Li, Mingrun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Eriksson, Lars
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för fysikalisk kemi, oorganisk kemi och strukturkemi, Avdelningen för strukturkemi.
    Sun, Licheng
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Attachment of a hydrogen-bonding carboxylate side chain to an [FeFe]-hydrogenase model complex: Influence on the catalytic mechanism2010Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 16, nr 8, s. 2537-2546Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Azapropanedithiolate (adt)-bridged model complexes of [FeFe]-hydrogenase bearing a carboxylic acid functionality have been designed with the aim of decreasing the potential for reduction of protons to hydrogen. Protonation of the bisphosphine complexes 46 has been studied by in situ IR and NMR spectroscopy, which revealed that protonation with triflic acid most likely takes place first at the N-bridge for complex 4 but at the FeFe bond for complexes 5 and 6. Using an excess of acid, the diprotonated species could also be observed, but none of the protonated species was sufficiently stable to be isolated in a pure state. Electrochemical studies have provided an insight into the catalytic mechanisms under strongly acidic conditions, and have also shown that complexes 3 and 6 are electro-active in aqueous solution even in the absence of acid, presumably due to hydrogen bonding. Hydrogen evolution, driven by visible light, has been observed for three-component systems consisting of [Ru(bpy)3]2+, complex 1, 2, or 3, and ascorbic acid in CH3CN/D2O solution by on-line mass spectrometry.

  • 21.
    Gao, Yan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liu, Jianhui
    Jiang, Wenfeng
    Xia, Ming
    Zhang, Wei
    Li, Minna
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Synthesis and photophysical and electrochemical properties of a binuclear Ru(bpy)3-Cu(III) corrole complex2007Ingår i: Journal of Porphyrins and Phthalocyanines, ISSN 1088-4246, Vol. 11, nr 5-6, s. 463-469Artikel i tidskrift (Refereegranskat)
  • 22. Gao, Yan
    et al.
    Liu, Jianhui
    Na, Yong
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Synthesis and characterization of manganese and copper corrole xanthene complexes as catalysts for water oxidation2007Ingår i: Tetrahedron, ISSN 0040-4020, Vol. 63, nr 9, s. 1987-1994Artikel i tidskrift (Refereegranskat)
  • 23.
    Gao, Yan
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Liu, Jianhui
    Sun, Licheng
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nucleophilic attack of hydroxide on a MnV oxo complex: a model of the O-O bond formation in the oxygen evolving complex of photosystem II2009Ingår i: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 131, nr 25, s. 8726-8727Artikel i tidskrift (Refereegranskat)
  • 24.
    Gustafson, Karl P. J.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Schluschass, Bastian
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Water oxidation mediated by ruthenium oxide nanoparticles supported on siliceous mesocellular foam2017Ingår i: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 7, nr 1, s. 293-299Artikel i tidskrift (Refereegranskat)
    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.

  • 25. Huang, Yong
    et al.
    Gao, Weiming
    Åkermark, Torbjörn
    Li, Mingrun
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    An Air-Stable Fe3S4 Complex with Properties Similar to Those of the HOXair State of the Diiron Hydrogenases2012Ingår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 27, s. 4259-4263Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A Fe3S4 complex bridged by azapropanedithiolate (adt), complex 6, was prepared as a potential model of the HOXair state of [FeFe]-hydrogenases. Complex 6 was characterized by IR and 1H NMR spectroscopy, and its structure was determined by X-ray crystallography. The electrochemical studies show that complex 6 is redox-active under acidic conditions, which provides insight into the catalytic mechanism. Hydrogen evolution, driven by visible light, was observed in CH3CN/D2O solution by online mass spectroscopy.

  • 26.
    Iqbal, M. Naeem
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Abdel-Magied, Ahmed F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Abdelhamid, Hani Nasser
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Olsén, Peter
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Mesoporous Ruthenium Oxide: A Heterogeneous Catalyst for Water Oxidation2017Ingår i: ACS Sustainable Chemistry & Engineering, ISSN 2168-0485, Vol. 5, nr 11, s. 9651-9656Artikel i tidskrift (Refereegranskat)
    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.

  • 27. Jiang, Shi
    et al.
    Liu, Jianhui
    Shi, Yu
    Wang, Zhen
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Fe-S complexes containing five-membered heterocycles: novel models for the active site of hydrogenases with unusual low reduction potential2007Ingår i: Dalton Transactions, ISSN 1477-9226, nr 8, s. 896-902Artikel i tidskrift (Refereegranskat)
  • 28. Jiang, Shi
    et al.
    Liu, Jianhui
    Shi, Yu
    Wang, Zhen
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Licheng
    Preparation, characteristics and crystal structures of novel N-heterocyclic carbene substituted furan- and pyridine-containing azadithiolate Fe-S complexes2007Ingår i: Polyhedron, ISSN 0277-5387, Vol. 26, nr 7, s. 1499-1504Artikel i tidskrift (Refereegranskat)
  • 29.
    Johansson, Olof
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Borgström, Magnus
    Lomoth, Reiner
    Palmblad, Magnus
    Bergquist, Jonas
    Hammarström, Leif
    Sun, Licheng
    Åkermark, Björn
    Electron Donor-Acceptor Dyads Based on Ruthenium(II) Bipyridine and Terpyridine Complexes Bound to Naphthalenediimide2003Ingår i: Inorganic Chemistry, ISSN 0020-1669, Vol. 42, nr 9, s. 2908-2918Artikel i tidskrift (Refereegranskat)
  • 30.
    Johansson, Olof
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lomoth, Reiner
    Sun, Licheng
    Åkermark, Björn
    Linkage Isomerism in a Bistridentate Ruthenium(II) ComplexManuskript (Övrigt vetenskapligt)
  • 31. Johansson, Olof
    et al.
    Wolpher, Henriette
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Borgström, Magnus
    Hammarström, Leif
    Bergquist, Jonas
    Sun, Licheng
    Åkermark, Björn
    Intramolecular charge separation in a hydrogen bonded tyrosine-ruthenium(II)-naphtalene diimide triad2004Ingår i: Chemical Communications, ISSN 1359-7345, nr 2, s. 194-195Artikel i tidskrift (Refereegranskat)
  • 32.
    Johansson, Olof
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wolpher, Henriette
    Borgström, Magnus
    Hammarström, Leif
    Bergquist, Jonas
    Sun, Licheng
    Åkermark, Björn
    Intramolecular charge separation in a hydrogen bonded tyrosune-ruthenium(II) baphthalene diimide triad2004Ingår i: Chemical Communications, ISSN 1359-7345, E-ISSN 1364-548X, s. 194-195Artikel i tidskrift (Refereegranskat)
  • 33.
    Johnston, Eric V
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Novel dinuclear Ru-complex for water oxidation2010Ingår i: Abstracts of Papers, 240th ACS National Meeting, Boston, MA, United States, August 22-26, 2010 (2010), American Chemical Society , 2010Konferensbidrag (Övrigt vetenskapligt)
  • 34.
    Johnston, Eric V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lindberg, Staffan A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient reoxidation of palladium by a hybrid catalyst in aerobic palladium-catalyzed carbocyclization of enallenes2009Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, nr 28, s. 6799-6801Artikel i tidskrift (Refereegranskat)
  • 35.
    Johnston, Eric V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tran, Lien-Hoa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient aerobic ruthenium-catalyzed oxidation of secondary alcohols by the use of a hybrid electron transfer catalyst2010Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 10, s. 1971-1976Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Biomimetic aerobic oxidation of secondary alcohols has been performed using hybrid catalyst 1 and Shvo's catalyst 2. This combination allows mild reaction conditions and low catalytic loading, due to the efficiency of intramolecular electron transfer. By this method a wide range of different alcohols have been converted into their corresponding ketones. Oxidation of benzylic as well as aliphatic, electron-rich, electron-deficient and sterically hindered alcohols could be oxidized in excellent yield and selectivity. Oxidation of (S)-1-phenyl-ethanol showed that no racemization occurred during the course of the reaction, indicating that the hydride 2b adds to the quinone much faster than it re-adds to the ketone product. The kinetic deuterium isotope effect of the oxidation was determined by the use of 1-phenylethanol (3a) and 1-deuterio-1-phenylethanol (3a-d1) in parallel and competitive manner, which gave the same isotope effect within experimental error (k(H)/k(D) approximate to 2.8). This indicates that there is no strong coordination of the substrate to the catalyst.

  • 36.
    Johnston, Eric V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tran, Lien-Hoa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Efficient synthesis of hybrid (hydroquinone-Schiff base)cobalt oxidation catalysts2009Ingår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 23, s. 3973-3976Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Hybrid catalysts A and B have recently been found to efficiently transfer electrons from a metal catalyst to molecular oxygen in biomimetic oxidations. In the present work hybrid catalysts A and B were synthesized in high yield from inexpensive starting materials. The key step is an efficient Suzuki cross-coupling, which allows the use of unprotected aldehyde 5. The new synthesis of the title hybrid catalysts is easy to carry out and can be scaled up.

  • 37. Karlsson, Erik A.
    et al.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Becerril, Valeria Saavedra
    Abrahamsson, Maria
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis and electron transfer processes in a new family of coupled Mn2–Ru complexesManuskript (preprint) (Övrigt vetenskapligt)
  • 38.
    Karlsson, Erik A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Becerril, Valeria Saavedra
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Abrahamsson, Maria
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis and Electron-Transfer Processes in a New Family of Ligands for Coupled Ru-Mn2 Complexes2014Ingår i: ChemPlusChem, ISSN 2192-6506, Vol. 79, nr 7, s. 936-950Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    A series of [Ru(bpy)(3)](2+)-type (bpy= 2,2'-bipyridine) photosensitisers have been coupled to a ligand for Mn, which is expected to give a dinuclear complex that is active as a water oxidation catalyst. Unexpectedly, photophysical studies showed that the assemblies had very short lived excited states and that the decay patterns were complex and strongly dependent on pH. One dyad was prepared that was capable of catalysing chemical water oxidation by using [Ru(bpy)(3)](3+) as an oxidant. However, photochemical water oxidation in the presence of an external electron acceptor failed, presumably because the short excited-state lifetime precluded initial electron transfer to the added acceptor. The photophysical behaviour could be explained by the presence of an intricate excited-state manifold, as also suggested by time-dependent DFT calculations.

  • 39.
    Karlsson, Erik A.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Hansson, Örjan
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Photosensitized water oxidation by use of a bioinspired manganese catalyst2011Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 50, nr 49, s. 11715-11718Artikel i tidskrift (Refereegranskat)
  • 40. Kleimark, Jonatan
    et al.
    Johansson, Charlotte
    Olsson, Susanne
    Håkansson, Mikael
    Hansson, Sverker
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Norrby, Per-Ola
    Sterically goverend selectivity in palladium-assisted allylic alkylation2011Ingår i: Organometallics, ISSN 0276-7333, E-ISSN 1520-6041, Vol. 30, s. 230-238Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    The selectivity in the Pd-assisted allylic alkylation has been investigated in a system with a ligand tethered to the allylic moiety. Isolation of (η3-allyl)Pd complexes and stoichiometric reaction with malonate nucleophiles allowed separation of various factors influencing the regioselectivity in a system that cannot undergo apparent rotation. Unexpectedly, trans effects were found to have only a minor influence on the selectivity, whereas changing the tether length could shift the preference from favored internal to dominant terminal attack. DFT-assisted analysis revealed that the dominant selectivity-determiningfactors are the forced rotation of the allylic moiety and an important steric repulsion from a syn-alkyl substituent

  • 41.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Shariatgorji, Mohammadreza
    Ilag, Leopold
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Hansson, Örjan
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Light-Induced Water Oxidation by a Ru-complex Containing a Bio-Inspired Ligand2011Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, nr 28, s. 7953-7959Artikel i tidskrift (Refereegranskat)
    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.

  • 42.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Artificial Photosynthesis: Photosynthesis: From Nanosecond Electron Transfer to Catalytic Water Oxidation2014Ingår i: Accounts of Chemical Research, ISSN 0001-4842, E-ISSN 1520-4898, Vol. 47, nr 1, s. 100-111Artikel, forskningsöversikt (Refereegranskat)
    Abstract [en]

    Human society faces a fundamental challenge as energy consumption is projected to increase due to population and economic growth as fossil fuel resources decrease. Therefore the transition to alternative and sustainable energy sources is of the Utmost importance. The conversion of solar energy into chemical energy, by splitting H2O to generate molecular O-2 and H-2, could contribute to solving the global energy problem. Developing such a system will require the combination of several complicated processes, such as light-harvesting, charge separation, electron transfer, H2O oxidation, and reduction of the generated protons. The primary processes of charge separation and catalysis, which occur in the natural photosynthetic machinery, provide us with an excellent blueprint for the design of such systems. This Account describes our efforts to construct supramolecular assemblies capable of carrying out photoinduced electron transfer and to develop artificial water oxidation catalysts (WOCs). Early work in our group focused on linking a ruthenium chromophore to a manganese-based oxidation catalyst. When we incorporated a tyrosine unit into these supramolecular assemblies, we could observe fast intramolecular electron transfer from the manganese centers, via the tyrosine moiety, to the photooxidized ruthenium center, which clearly resembles the processes occurring in the natural system. Although we demonstrated multi-electron transfer in our artificial systems, the bottleneck proved to be the stability of the WOCs. Researchers have developed a number of WOCs, but the majority can only catalyze H2O oxidation in the presence of strong oxidants such as Ce-IV, which is difficult to generate photochemically. By contrast, illumination of ruthenium(II) photosensitizers in the presence of a sacrificial acceptor generates [Ru(bpy)(3)](3+)-type oxidants. Their oxidation potentials are significantly lower than that of Ce-IV, but our group recently showed that incorporating negatively charged groups into the ligand backbone could decrease the oxidation potential of the catalysts and, at the same time, decrease the potential for H2O oxidation. This permitted us to develop both ruthenium- and manganese-based WOCs that can operate under neutral conditions, driven by the mild oxidant [Ru(bpy)(3)](3+). Many hurdles to the development of viable systems for the production of solar fuels remain. However, the combination of important features from the natural photosynthetic machinery and novel artificial components adds insights into the complicated catalytic processes that are involved in splitting H2O.

  • 43.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Molecular Single-site Ruthenium Complexes Containing a Basic Site: The Use of Structure-activity RelationshipsManuskript (preprint) (Övrigt vetenskapligt)
    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.

  • 44.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ghanem, Shams
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Molecular ruthenium water oxidation catalysts carrying non-innocent ligands: mechanistic insight through structure-activity relationships and quantum chemical calculations2016Ingår i: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 6, nr 5, s. 1306-1319Artikel i tidskrift (Refereegranskat)
    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.

  • 45.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Artificial Photosynthesis: Molecular Systems for Catalytic Water Oxidation2014Ingår i: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 114, nr 24, s. 11863-12001Artikel, forskningsöversikt (Refereegranskat)
  • 46.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalytic Water Oxidation by Ruthenium Complexes Containing Negatively Charged Ligand Frameworks2016Ingår i: The chemical record, ISSN 1527-8999, E-ISSN 1528-0691, Vol. 16, nr 2, s. 940-963Artikel i tidskrift (Refereegranskat)
    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.

  • 47.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Water oxidation using earth-abundant transition metal catalysts: opportunities and challenges2016Ingår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 37, s. 14421-14461Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Catalysts for the oxidation of H2O are an integral component of solar energy to fuel conversion technologies. Although catalysts based on scarce and precious metals have been recognized as efficient catalysts for H2O oxidation, catalysts composed of inexpensive and earth-abundant element(s) are essential for realizing economically viable energy conversion technologies. This Perspective summarizes recent advances in the field of designing homogeneous water oxidation catalysts (WOCs) based on Mn, Fe, Co and Cu. It reviews the state of the art catalysts, provides insight into their catalytic mechanisms and discusses future challenges in designing bioinspired catalysts based on earth-abundant metals for the oxidation of H2O.

  • 48.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Chen, Hong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). China University of Geosciences .
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A Tailor-Made Molecular Ruthenium Catalyst for the Oxidation of Water and Its Deactivation through Poisoning by Carbon Monoxide2013Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, nr 15, s. 4189-4193Artikel i tidskrift (Refereegranskat)
  • 49.
    Kärkäs, Markus D.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karim, Shams R.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lee, Bao-Lin
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Tobias
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Privalov, Timofei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Water Oxidation by Single-Site Ruthenium Complexes: Using Ligands as Redox and Proton Transfer Mediators2012Ingår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, nr 46, s. 11589-11593Artikel i tidskrift (Refereegranskat)
  • 50.
    Laine, Tanja M.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Huazhong University of Science & Technology, People's Republic of China.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    A Dinuclear Ruthenium-Based Water Oxidation Catalyst: Use of Non-Innocent Ligand Frameworks for Promoting Multi-Electron Reactions2015Ingår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, nr 28, s. 10039-10048Artikel i tidskrift (Refereegranskat)
    Abstract [en]

    Insight into how H2O is oxidized to O-2 is envisioned to facilitate the rational design of artificial water oxidation catalysts, which is a vital component in solar-to-fuel conversion schemes. Herein, we report on the mechanistic features associated with a dinuclear Ru-based water oxidation catalyst. The catalytic action of the designed Ru complex was studied by the combined use of high-resolution mass spectrometry, electrochemistry, and quantum chemical calculations. Based on the obtained results, it is suggested that the designed ligand scaffold in Ru complex 1 has a non-innocent behavior, in which metal-ligand cooperation is an important part during the four-electron oxidation of H2O. This feature is vital for the observed catalytic efficiency and highlights that the preparation of catalysts housing non-innocent molecular frameworks could be a general strategy for accessing efficient catalysts for activation of H2O.

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