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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 Ligands2017Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 9, nr 9, s. 1583-1587Artikkel i tidsskrift (Fagfellevurdert)
    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.
    Abdel-Magied, Ahmed F.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shatskiy, Andrey
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Liao, Rong-Zhen
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Arafa, Wael A. A.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. University Fayoum, Egypt.
    Siegbahn, Per E. M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Bjorn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Chemical and Photochemical Water Oxidation Mediated by an Efficient Single-Site Ruthenium Catalyst2016Inngår i: ChemSusChem, ISSN 1864-5631, E-ISSN 1864-564X, Vol. 9, nr 24, s. 3448-3456Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 3. 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 framework2016Inngår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 34, s. 13289-13293Artikkel i tidsskrift (Fagfellevurdert)
    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+).

  • 4.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Palo-Nieto, Carlos
    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.
    Cordova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid Sweden University.
    Highly Enantioselective Cascade Transformations by Merging Heterogeneous Transition Metal Catalysis with Asymmetric Aminocatalysis2012Inngår i: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 2, s. 851-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The concept of combining heterogeneous transition metal and amine catalysis for enantioselective cascade reactions has not yet been realized. This is of great advantage since it would allow for the recycling of expensive and non-environmentally friendly transition metals. We disclose that the use of a heterogeneous Pd-catalyst in combination with a simple chiral amine co-catalyst allows for highly enantioselective cascade transformations. The preparative power of this process has been demonstrated in the context of asymmetric cascade Michael/carbocyclization transformations that delivers cyclopentenes bearing an all carbon quaternary stereocenters in high yields with up to 30: 1 dr and 99% ee. Moreover, a variety of highly enantioselective cascade hetero-Michael/carbocyclizations were developed for the one-pot synthesis of valuable dihydrofurans and pyrrolidines (up to 98% ee) by using bench-stable heterogeneous Pd and chiral amines as co-catalysts.

  • 5.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Ghisu, Lorenza
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Hedin, Niklas
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bacsik, Zoltan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid-Sweden University, Sweden.
    Enantioselective Heterogeneous Synergistic Catalysis for Asymmetric Cascade Transformations2014Inngår i: Advanced Synthesis and Catalysis, ISSN 1615-4150, E-ISSN 1615-4169, Vol. 356, nr 11-12, s. 2485-2492Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    A modular design for a novel heterogeneous synergistic catalytic system, which simultaneously activates the electrophile and nucleophile by the combined activation modes of a separate metal and non-metal catalyst, for asymmetric cascade transformations on a solid surface is disclosed. This modular catalysis strategy generates carbocycles (up to 97.5: 2.5 er) as well as spirocyclic oxindoles (97.5: 2.5 to > 99: 0.5 er), containing all-carbon quaternary centers, in a highly enantioselective fashion via a one-pot dynamic relay process.

  • 6.
    Deiana, Luca
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Jiang, Yan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Palo-Nieto, Carlos
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Afewerki, Samson
    Incerti-Pradillos, Celia A.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Córdova, Armando
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Mid Sweden University, Sweden.
    Combined Heterogeneous Metal/Chiral Amine: Multiple Relay Catalysis for Versatile Eco-Friendly Synthesis2014Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 53, nr 13, s. 3447-3451Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein is described a versatile and broad synergistic strategy for expansion of chemical space and the synthesis of valuable molecules (e.g. carbocycles and heterocycles), with up to three quaternary stereocenters, in a highly enantioselective fashion from simple alcohols (31examples, 95:5 to >99.5:0.5 e.r.) using integrated heterogeneous metal/chiral amine multiple relay catalysis and air/O-2 as the terminal oxidant. A novel highly 1,4-selective heterogeneous metal/amine co-catalyzed hydrogenation of enals was also added to the relay catalysis sequences.

  • 7.
    Engström, Karin
    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.
    Gustafson, Karl P. J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shakeri, Mozaffar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Co-immobilization of an Enzyme and a Metal into the Compartments of Mesoporous Silica for Cooperative Tandem Catalysis: An Artificial Metalloenzyme2013Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 52, nr 52, s. 14006-14010Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Surpassing nature: A hybrid catalyst in which Candida antarctica lipase B and a nanopalladium species are co-immobilized into the compartments of mesoporous silica is presented. The metal nanoparticles and the enzyme are in close proximity to one another in the cavities of the support. The catalyst mimics a metalloenzyme and was used for dynamic kinetic resolution of a primary amine in high yield and excellent enantioselectivity.

  • 8.
    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-E.
    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 foam2017Inngår i: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 7, nr 1, s. 293-299Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 9.
    Görbe, Tamás
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Gustafson, Karl P. J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kervefors, Gabriella
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zheng, Haoquan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Design of a Pd(0)-CalB CLEA Biohybrid Catalyst and Its Application in a One-Pot Cascade Reaction2017Inngår i: ACS Catalysis, ISSN 2155-5435, E-ISSN 2155-5435, Vol. 7, nr 3, s. 1601-1605Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, a design of a biohybrid catalyst is described, consisting of Pd nanoparticles and a cross-linked network of aggregated lipase B enzyme of Candida antarctica (CalB CLEA) functioning as an active support for the Pd nanoparticles. Both entities of the hybrid catalyst showed good catalytic activity. The applicability was demonstrated in a one-pot reaction, where the Pd-catalyzed cycloisomerization of 4-pentynoic acid afforded a lactone that serves as an acyl donor in a subsequent selective enzymatic kinetic resolution of a set of sec-alcohols. The catalyst proved to be robust and could be recycled five times without a significant loss of activity.

  • 10.
    Jiang, Liying
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Johnston, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åberg, K. Magnus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Nilsson, Ulrika
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Ilag, Leopold L.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för analytisk kemi.
    Strategy for quantifying trace levels of BMAA in cyanobacteria by LC/MS/MS2013Inngår i: Analytical and Bioanalytical Chemistry, ISSN 1618-2642, E-ISSN 1618-2650, Vol. 405, nr 4, s. 1283-1292Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The cyanobacterial neurotoxin β-N-methylamino--alanine (BMAA) is an amino acid that is putatively associated with the pathology of amyotrophic lateral sclerosis/Parkinsonism –dementia complex (ALS-PDC) disease. It raises serious health risk concerns since cyanobacteria are ubiquitous thus making human exposure almost inevitable. The identification and quantification of BMAA in cyanobacteria is challenging because it is present only in trace amounts and occurs alongside structurally similar compounds such as BMAA isomers. This work describes an enhanced liquid chromatography/tandem mass spectrometry platform that can distinguish BMAA from its isomers β-amino-N-methyl-alanine, N-(2-oethyl) glycine (AEG), and 2,4-diaminobutyric acid, thus ensuring confident identification of BMAA. The method's sensitivity was improved fourfold by a post-column addition of acetonitrile. The instrument and method limits of detection were shown to be 4.2 fmol/injection (or 0.5 g/one column) and 0.1 μg/g dry weight of cyanobacteria, respectively. The quantification method uses synthesized deuterated BMAA as an internal standard and exhibits good linearity, accuracy, and precision. Matrix effects were also investigated, revealing an ion enhancement of around 18 %. A lab-cultured cyanobacterial sample (Leptolyngbya PCC73110) was analyzed and shown to contain about 0.73 μg/g dry weight BMAA. The isomer AEG, whose chromatographic properties closely resemble those of BMAA, was also detected. These results highlight the importance of distinguishing BMAA from its isomers for reliable identification as well as providing a sensitive and accurate quantification method for measuring trace levels of BMAA in cyanobacterial samples.

  • 11.
    Johnston, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Biomimetic oxidation methods: Efficient reoxidation of palladium and ruthenium by the use of a hybrid electron transfer catalyst.2009Licentiatavhandling, med artikler (Annet vitenskapelig)
  • 12.
    Johnston, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    New Tools for Green Catalysis: Studies on a Biomimetic Hybrid Catalyst and a Novel Nanopalladium Catalyst2011Doktoravhandling, med artikler (Annet vitenskapelig)
    Abstract [en]

    The first part of this thesis describes an improved synthetic route to hybrid (hydroquinone-Schiff base)cobalt catalysts. Preparation of the 5-(2,5-hydroxyphenyl)salicylaldehyde building block was improved by altering the protective groups of the hydroquinone (HQ) starting material. Both protection and deprotection could be carried out under mild conditions, resulting in high yields. By optimizing the reaction conditions of the Suzuki cross-coupling, an efficient and inexpensive synthetic route with a good overall yield was developed.

    The second part describes the use of the hybrid catalyst as an electron transfer mediator (ETM) in the palladium-catalyzed aerobic carbocyclization of enallenes. By covalently linking the HQ to the cobalt Schiff-base complex the reaction proceeded at lower temperatures with a five-fold increase of the reaction rate compared to the previously reported system.

    The third part describes the application of the hybrid catalyst in the biomimetic aerobic oxidation of secondary alcohols. Due to the effi­ciency of the intramolecular electron transfer, the hybrid catalyst allowed for a lower catalytic loading and milder reaction conditions compared to the previous separate-component system. Benzylic alcohols as well as aliphatic alcohols were oxidized to the corresponding ketones in excellent yield and selectivity using this methodology.

    The fourth part describes the synthesis and characterization of highly dispersed palladium nanoparticles supported on aminopropyl-modified siliceous mesocellular foam. The Pd nanocatalyst showed excellent activity for the aerobic oxidation of a wide variety of alcohols under air atmosphere. Moreover, the catalyst can be recycled several times without any decrease in activity or leaching of the metal into solution.

    Finally, the fifth part describes the application of the Pd nanocatalyst in transfer hydrogenations and Suzuki coupling reactions. The catalyst was found to be highly efficient for both transformations, resulting in chemoselective reduction of various alkenes as well as coupling of a variety of aryl halides with various boronic acids in excellent yields. Performing the latter reaction under microwave irradiation significantly increased the reaction rate, compared to conventional heating. However, no significant increase in reaction rate was observed for the transfer hydrogenations, under microwave heating.

  • 13.
    Johnston, Eric V
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bogár, Krisztián
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Enantioselective synthesis of (R)-bufuralol via dynamic kinetic resolution in the key step2010Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 75, nr 13, s. 4596-4599Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    An enantioselective synthesis of (R)-bufuralol via a ruthenium- and enzyme-catalyzed dynamic kinetic resolution (DKR) has been achieved. The synthesis starts from readily available 2-ethylphenol and provides (R)-bufuralol in high ee and a good overall yield of 31%.

  • 14.
    Johnston, Eric V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Oxidation of carbonyl compounds2010Inngår i: Modern Oxidation Methods / [ed] Jan-Erling Bäckvall, Weinheim: Wiley-VCH Verlag GmbH & Co. KGaA , 2010, 2, s. 353-369Kapittel i bok, del av antologi (Annet vitenskapelig)
  • 15.
    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 oxidation2010Inngår i: Abstracts of Papers, 240th ACS National Meeting, Boston, MA, United States, August 22-26, 2010 (2010), American Chemical Society , 2010Konferansepaper (Annet vitenskapelig)
  • 16.
    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 enallenes2009Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 15, nr 28, s. 6799-6801Artikkel i tidsskrift (Fagfellevurdert)
  • 17.
    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 catalyst2010Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 10, s. 1971-1976Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 18.
    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 catalysts2009Inngår i: European Journal of Organic Chemistry, ISSN 1434-193X, E-ISSN 1099-0690, nr 23, s. 3973-3976Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 19.
    Johnston, Eric V.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Shakeri, Mozaffar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Palmgren, Pål
    Eriksson, Kristofer
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Oscarsson, Sven
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Highly dispersed palladium nanoparticles on mesocellular foam: an efficient and recyclable heterogeneous catalyst for alcohol oxidation2012Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 39, s. 12202-12206Artikkel i tidsskrift (Fagfellevurdert)
  • 20.
    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 catalyst2011Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 50, nr 49, s. 11715-11718Artikkel i tidsskrift (Fagfellevurdert)
  • 21.
    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 Ligand2011Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, nr 28, s. 7953-7959Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 22.
    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 Oxidation2014Inngår i: Accounts of Chemical Research, ISSN 0001-4842, E-ISSN 1520-4898, Vol. 47, nr 1, s. 100-111Artikkel, forskningsoversikt (Fagfellevurdert)
    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.

  • 23.
    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 Oxidation2014Inngår i: Chemical Reviews, ISSN 0009-2665, E-ISSN 1520-6890, Vol. 114, nr 24, s. 11863-12001Artikkel, forskningsoversikt (Fagfellevurdert)
  • 24.
    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 Mediators2012Inngår i: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 51, nr 46, s. 11589-11593Artikkel i tidsskrift (Fagfellevurdert)
  • 25.
    Lee, Bao-Lin
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik A.
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Das, Biswanath
    Nordlander, Ebbe
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Light-induced water oxidation by a dinuclear iron-based molecular catalystManuskript (preprint) (Annet vitenskapelig)
  • 26.
    Lee, Bao-Lin
    et al.
    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.
    Inge, Andrew K.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Tran, Lien-Hoa
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Xu, Yunhua
    Hansson, Örjan
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Synthesis and characterization of oligonuclear Ru, Co, and Cu oxidation catalysts2010Inngår i: European Journal of Inorganic Chemistry, ISSN 1434-1948, E-ISSN 1099-1948, nr 34, s. 5462-5470Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    In this work, we report the preparation and crystal structures of three new oligonuclear complexes, Ru-2(bbpmp)(mu-OAc)(3) (4), [Co-2(bbpmp)(mu-OAc)(mu-OMe)](PF6) (5), [Cu-4(Hbbpmp)(2)(mu-OAc)(H2O)(2)](OAc)(PF6)(2) (6) {H(3)bbpmp = 2,6-bis[(2-hydroxybenzyl)-(2-pyridylmethyl)aminomethyl]-4-methylphenol (3)}. The structures of the complexes were determined by single-crystal X-ray diffraction. The oxidation states of ruthenium, cobalt and copper in the complexes are +3, +3 and +2, respectively. In 4 and 5, Ru-III and Co-III are coordinated to four oxygen and two nitrogen atoms in an octahedral geometry, while in 6, Cu-II adopts both octahedral (CuN2O4) and square-pyramidal (CuN2O3) geometry. The potential of the three complexes as oxidation catalysts has been investigated.

  • 27.
    Nagendiran, Anuja
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Verho, Oscar
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Haller, Clemence
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Cycloisomerization of Acetylenic Acids to gamma-Alkylidene Lactones using a Palladium(II) Catalyst Supported on Amino-Functionalized Siliceous Mesocellular Foam2014Inngår i: Journal of Organic Chemistry, ISSN 0022-3263, E-ISSN 1520-6904, Vol. 79, nr 3, s. 1399-1405Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Cycloisomerization of various gamma-acetylenic acids to their corresponding gamma-alkylidene lactones by the use of a heterogeneous Pd(II) catalyst supported on amino-functionalized siliceous mesocellular foam is described. Substrates containing terminal as well as internal alkynes were cyclized in high to excellent yields within 2-24 h under mild reaction conditions. The protocol exhibited high regio- and stereoselectivity, favoring the exo-dig product with high Z selectivity. Moreover, the catalyst displayed excellent stability under the employed reaction conditions, as demonstrated by its good recyclability and low leaching.

  • 28.
    Olsén, Peter
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Oschmann, Michael
    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.
    Synthesis of highly functional carbamates through ring-opening of cyclic carbonates with unprotected alpha-amino acids in water2018Inngår i: Green Chemistry, ISSN 1463-9262, E-ISSN 1463-9270, Vol. 20, nr 2, s. 469-475Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The present work shows that it is possible to ring-open cyclic carbonates with unprotected amino acids in water. Fine tuning of the reaction parameters made it possible to suppress the degree of hydrolysis in relation to aminolysis. This enabled the synthesis of functionally dense carbamates containing alkenes, carboxylic acids, alcohols and thiols after short reaction times at room temperature. When Glycine was used as the nucleophile in the ring-opening with four different five membered cyclic carbonates, containing a plethora of functional groups, the corresponding carbamates could be obtained in excellent yields (> 90%) without the need for any further purification. Furthermore, the orthogonality of the transformation was explored through ring-opening of divinylenecarbonate with unprotected amino acids equipped with nucleophilic side chains, such as serine and cysteine. In these cases the reaction selectively produced the desired carbamate, in 70 and 50% yield respectively. The synthetic design provides an inexpensive and scalable protocol towards highly functionalized building blocks that are envisioned to find applications in both the small and macromolecular arena.

  • 29.
    Persson, Andreas K. Å.
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Copper-catalyzed N-allenylation of allylic sulfonamides2009Inngår i: Organic Letters, ISSN 1523-7060, E-ISSN 1523-7052, Vol. 11, nr 17, s. 3814-3817Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Allylic allenic amides have been synthesized via a copper-catalyzed cross-coupling between allylic sulfonamides and bromoallenes in moderate to good yields. Copper(I) thiophene-2-carboxylate (CuTC) was used a source of copper with DMEDA as the ligand. The allenylated products obtained are potential substrates for palladium-catalyzed carbocyclizations.

  • 30.
    Shatskiy, Andrey
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Lomoth, Reiner
    Abdel-Magied, Ahmed F.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi. Nuclear Materials Authority, Egypt.
    Rabten, Wangchuk
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Laine, Tanja M.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Chen, Hong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK). KTH Royal Institute of Technology, Sweden.
    Sun, Junliang
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Andersson, Pher G.
    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.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Catalyst-solvent interactions in a dinuclear Ru-based water oxidation catalyst2016Inngår i: Dalton Transactions, ISSN 1477-9226, E-ISSN 1477-9234, Vol. 45, nr 47, s. 19024-19033Artikkel i tidsskrift (Fagfellevurdert)
    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.

  • 31.
    Verho, Oscar
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Dilenstam, Marléne D. V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Application and mechanistic studies of a water-oxidation catalyst in alcohol oxidation by employing oxygen-transfer reagents2012Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 18, nr 52, s. 16947-16954Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    By using a dimeric ruthenium complex in combination with tert-butyl hydrogen peroxide (TBHP) as stoichiometric oxidant, a mild and efficient protocol for the oxidation of secondary benzylic alcohols was obtained, thereby giving the corresponding ketones in high yields within 4 h. However, in the oxidation of aliphatic alcohols, the TBHP protocol suffered from low conversions owing to a competing Ru-catalyzed disproportionation of the oxidant. Gratifyingly, by switching to Oxone (2 KHSO5KHSO4K2SO4 triple salt) as stoichiometric oxidant, a more efficient and robust system was obtained that allowed for the oxidation of a wide range of aliphatic and benzylic secondary alcohols, giving the corresponding ketones in excellent yields. The mechanism for these reactions is believed to involve a high-valent RuV–oxo species. We provide support for such an intermediate by means of mechanistic studies.

  • 32.
    Verho, Oscar
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Gao, Feifei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Wan, Wei
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Nagendiran, Anuja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zheng, Haoquan
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Zou, Xiaodong
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Mesoporous silica nanoparticles applied as a support for Pd and Au nanocatalysts in cycloisomerization reactions2014Inngår i: APL materials, ISSN 2166-532X, Vol. 2, nr 11, s. 113316-Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Ultra-small mesoporous silica nanoparticles (MSNs) have been synthesized at room temperature with particle sizes ranging from 28 to 45 nm. These MSNs have been employed as heterogeneous supports for palladium and gold nanocatalysts. The colloidal nature of the MSNs is highly useful for catalytic applications as it allows for better mass transfer properties and a more uniform distribution of the nanocatalysts in solution. The two nanocatalysts were evaluated in the cycloisomerization of alkynoic acids and demonstrated to produce the corresponding alkylidene lactones in good to excellent yields under mild conditions. In addition to their high activity, the catalysts exhibit low degree of metal leaching and straight-forward recycling, which highlight the practical utility of MSNs as supports for nanocatalysts. (C) 2014 Author(s). All article content, except where otherwise noted, is licensed under a Creative Commons Attribution 3.0 Unported License.

  • 33.
    Verho, Oscar
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Karlsson, Erik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tuning of the Electronic Properties of a Cyclopentadienylruthenium Catalyst to Match Racemization of Electron-Rich and Electron-Deficient Alcohols2011Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 17, nr 40, s. 11216-11222Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The synthesis of a new series of cyclopentadienylruthenium catalysts with varying electronic properties and their application in racemization of secondary alcohols are described. These racemizations involve two key steps: 1) β-hydride elimination (dehydrogenation) and 2) re-addition of the hydride to the intermediate ketone. The results obtained confirm our previous theory that the electronic properties of the substrate determine which of these two steps is rate determining. For an electron-deficient alcohol the rate-determining step is the β-hydride elimination (dehydrogenation), whereas for an electron-rich alcohol the re-addition of the hydride becomes the rate-determining step. By matching the electronic properties of the catalyst with the electronic properties of the alcohol, we have now shown that a dramatic increase in racemization rate can be obtained. For example, electron-deficient alcohol 15 racemized 30 times faster with electron-deficient catalyst 6 than with the unmodified standard catalyst 4. The application of these protocols will extend the scope of cyclopentadienylruthenium catalysts in racemization and dynamic kinetic resolution.

  • 34.
    Verho, Oscar
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Kärkäs, Markus
    Åkermark, Torbjörn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för materialkemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Gustafson, Karl
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Svengren, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK), Avdelningen för oorganisk kemi och strukturkemi.
    Bäckvall, Jan-Erling
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Well-Defined Palladium Nanoparticles Supported on Amino-Functionalized Siliceous Mesocellular Foam: An Efficient Heterogeneous Catalyst for Chemically-Induced H2O OxidationManuskript (preprint) (Annet vitenskapelig)
  • 35.
    Verho, Oscar
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nagendiran, Anuja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nanopalladium on Amino-Functionalized Mesocellular Foam: An Efficient Catalyst for Suzuki Reactions and Transfer Hydrogenations2013Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 5, nr 2, s. 612-618Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    The applications of a heterogeneous Pd0-AmP-MCF nanoparticle catalyst in Suzuki cross-coupling reactions and transfer hydrogenations of alkenes are described. The catalyst was highly efficient for both transformations, resulting in 1)coupling of a wide range of aryl halides with various boronic acids in high yields and 2)chemoselective reduction of a variety of alkenes with the use of 1-methyl-1,4-cyclohexadiene as hydrogen donor. Moreover, the catalyst can be recycled several times without any significant decrease in activity or leaching of metal into solution, making the protocol economical and environmentally friendly. In the case of the Suzuki cross-coupling, a 15-fold increase in reaction rate was observed if the reaction was performed under microwave irradiation compared to conventional heating in an oil bath.

  • 36.
    Verho, Oscar
    et al.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nagendiran, Anuja
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Johnston, Eric V.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Nanopalladium on Amino-Functionalized Mesocellular Foam as an Efficient and Recyclable Catalyst for the Selective Transfer Hydrogenation of Nitroarenes to Anilines2014Inngår i: ChemCatChem, ISSN 1867-3880, E-ISSN 1867-3899, Vol. 6, nr 1, s. 205-211Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, we report on the use of nanopalladium on amino-functionalized siliceous mesocellular foam as an efficient heterogeneous catalyst for the transfer hydrogenation of nitroarenes to anilines. In all cases, the protocol proved to be highly selective and favored the formation of the desired aniline as the single product in high yields with short reaction times if naturally occurring and renewable -terpinene was employed as the hydrogen donor. Furthermore, the catalyst displayed excellent recyclability over five cycles and negligible leaching of metal into solution, which makes it an eco-friendly and economic catalyst to perform this transformation. The scalability of the protocol was demonstrated with the reduction of 4-nitroanisole on a 2g scale, in which p-anisidine was isolated in 98% yield.

  • 37.
    Verho, Oscar
    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.
    Gustafson, Karl P. J.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Tai, Cheuk-Wai
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Svengren, Henrik
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för material- och miljökemi (MMK).
    Kärkäs, Markus D.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Bäckvall, Jan-E.
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Åkermark, Björn
    Stockholms universitet, Naturvetenskapliga fakulteten, Institutionen för organisk kemi.
    Well-Defined Palladium Nanoparticles Supported on Siliceous Mesocellular Foam as Heterogeneous Catalysts for the Oxidation of Water2015Inngår i: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 21, nr 15, s. 5909-5915Artikkel i tidsskrift (Fagfellevurdert)
    Abstract [en]

    Herein, we describe the use of Pd nanoparticles immobilized on an amino-functionalized siliceous mesocellular foam for the catalytic oxidation of H2O. The Pd nanocatalyst proved to be capable of mediating the four-electron oxidation of H2O to O-2, both chemically and photochemically. The Pd nanocatalyst is easy to prepare and shows high chemical stability, low leaching, and recyclability. Together with its promising catalytic activity, these features make the Pd nanocatalyst of potential interest for future sustainable solar-fuel production.

1 - 37 of 37
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