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  • 1.
    Bruneau, Alexandre
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gustafson, Karl P. J.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yuan, Ning
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Persson, Ingmar
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Synthesis of Benzofurans and Indoles from Terminal Alkynes and Iodoaromatics Catalyzed by Recyclable Palladium Nanoparticles Immobilized on Siliceous Mesocellular Foam2017In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 23, no 52, p. 12886-12891Article in journal (Refereed)
    Abstract [en]

    Herein, we report on the utilization of a heterogeneous catalyst, consisting of Pd nanoparticles supported on a siliceous mesocellular foam (Pd-0-AmP-MCF), for the synthesis of heterocycles. Reaction of o-iodophenols and protected o-iodoanilines with acetylenes in the presence of a Pd nanocatalyst produced 2-substituted benzofurans and indoles, respectively. In general, the catalytic protocol afforded the desired products in good to excellent yields under mild reaction conditions without the addition of ligands. Moreover, the structure of the reported Pd nanocatalyst was further elucidated with extended X-ray absorption fine-structure spectroscopy, and it was proven that the catalyst could be recycled multiple times without significant loss of activity.

  • 2.
    Etman, Ahmed S.
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Alexandria University, Egypt.
    Asfaw, Habtom D.
    Yuan, Ning
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Li, Jian
    Zhou, Zhengyang
    Peng, Fei
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Persson, Ingmar
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Gustafsson, Torbjörn
    Edström, Kristina
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Peking University, China.
    A one-step water based strategy for synthesizing hydrated vanadium pentoxide nanosheets from VO2(B) as free-standing electrodes for lithium battery applications2016In: Journal of Materials Chemistry A, ISSN 2050-7488, Vol. 4, no 46, p. 17988-18001Article in journal (Refereed)
    Abstract [en]

    The synthesis of two dimensional (2D) materials from transition metal oxides, chalcogenides, and carbides mostly involve multiple exfoliation steps in which hazardous solvents and reagents are used. In this study, hydrated vanadium pentoxide (V2O5 center dot nH(2)O) nanosheets with a thickness of a few nanometers were prepared via a facile environmentally friendly water based exfoliation technique. The exfoliation process involved refluxing the precursor, vanadium dioxide (VO2(B)), in water for a few days at 60 degrees C. The proposed exfoliation mechanism is based on the intercalation/insertion of water molecules into the VO2(B) crystals and the subsequent cleavage of the covalent bonds holding the layers of VO2(B) together. The thermal and chemical analyses showed that the approximate chemical composition of the nanosheets is H0.4V2O5 center dot 0.55H(2)O, and the percentage of V-V content to that of V-IV in the nanosheets is about 80(3)% to 20(3)%. The exfoliated aqueous suspension of the V2O5 center dot 0.55H(2)O nanosheets was successfully deposited onto multi-walled carbon nanotube (MW-CNT) paper to form free-standing electrodes with a thickness of the V2O5 center dot 0.55H(2)O layer ranging between 45 and 4 mu m. A series of electrochemical tests were conducted on the electrodes to determine the cyclability and rate capability of lithium insertion into V2O5 center dot 0.55H(2)O nanosheets. The electrodes with the thinnest active material coating (similar to 4 mu m) delivered gravimetric capacities of up to 480 and 280 mA h g(-1) when cycled at current densities of 10 and 200 mA g(-1), respectively.

  • 3.
    Gustafson, Karl P. J.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Guðmundsson, Arnar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Bajnóczi, Éva
    Ning, Yuan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Persson, Ingmar
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    In-Situ Structure Determination of a Ruthenium Racemization Catalyst and its Activated Intermediates using X-ray Absorption SpectroscopyManuscript (preprint) (Other academic)
  • 4.
    Gustafson, Karl P. J.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Görbe, Tamás
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    de Gonzalo Calvo, Gonzalo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yuan, Ning
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Schreiber, Cynthia
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Shchukarev, Andrey
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Persson, Ingmar
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Application and further structure elucidation of Pd(0)-CalB CLEA biohybrid catalyst- Chemoenzymatic dynamic kinetic resolution of primary benzylic aminesManuscript (preprint) (Other academic)
  • 5.
    Gustafson, Karl P. J.
    et al.
    Stockholm University, Faculty of Science, Department of Organic Chemistry. Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Görbe, Tamás
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    de Gonzalo-Calvo, Gonzalo
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Yuan, Ning
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Schreiber, Cynthia L.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Shchukarev, Andrey
    Tai, Cheuk-Wai
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Persson, Ingmar
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bäckvall, Jan-E.
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Chemoenzymatic Dynamic Kinetic Resolution of Primary Benzylic Amines using Pd-0-CalB CLEA as a Biohybrid Catalyst2019In: Chemistry - A European Journal, ISSN 0947-6539, E-ISSN 1521-3765, Vol. 25, no 39, p. 9174-9179Article in journal (Refereed)
    Abstract [en]

    Herein, we report on the use a biohybrid catalyst consisting of palladium nanoparticles immobilized on cross-linked enzyme aggregates of lipase B of Candida antarctica (CalB CLEA) for the dynamic kinetic resolution (DKR) of benzylic amines. A set of amines were demonstrated to undergo an efficient DKR and the recyclability of the catalysts was studied. Extensive efforts to further elucidate the structure of the catalyst are presented.

  • 6.
    Lin, Junzhong
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Liu, Leifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Ning, Yuan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zheng, Haoquan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Titanium incorporated hierarchical porous silicate synthesized using D4R as building blocksManuscript (preprint) (Other academic)
    Abstract [en]

    Hierarchical porous materials as catalyst have provoked great attention recent years considering that it can offer enhanced molecular diffusion and mass transfer during the reaction. Titanium containing hierarchical porous silicate material has been successfully synthesized in present work. Double-four-ring units were used as the basic building blocks to construct the desired material. Both micropores and mesopores were found in the as synthesized material. The local structure of incorporated titanium species was carefully studied using various characterization techniques, such as XPS, UV-vis, XANES and EXAFS. Tetrahedral coordinated titanium can be mostly found in the as synthesized material in this work, the distorted the local structure was further revealed by using EXAFS.

  • 7.
    Lin, Junzhong
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Liu, Leifeng
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Yuan, Ning
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zheng, Haoquan
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Sun, Junliang
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Synthesis of hierarchical MCM-22 zeolite via a swelling and pillaring approachManuscript (preprint) (Other academic)
    Abstract [en]

    Zeolites are type of microporous crystalline material which have been widely used in various aspects of industry, such as separation, adsorption, and catalysis. However, great diffusion limitation can be provoked due to small pore size of mircoporus framework in catalytic reactions. Hierarchical zeolites have been proved to be a successful alternative to solve the diffusion problem. Particularly, the synthesis of hierarchical porous zeolite by swelling and pillaring lamellar MWW zeolitic precursor has been proved as an efficient approach to solve the diffusion limitations in the catalytic reactions. In this work, hierarchical MWW zeolite has been synthesized by swelling and pillaring of lamellar MWW zeolitic precursor (MCM-22) using D4R building units. The synthesis procedure has been carefully studied by various characterization methods, such as PXRD, TEM, N2 adsorption-desorption and etc.

  • 8.
    Yuan, Ning
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Church, Tamara L.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Brandt, Erik G.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Hedin, Niklas
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bernin, Diana
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Chalmers University, Sweden.
    Insights into Functionalization of Metal-Organic Frameworks Using In Situ NMR Spectroscopy2018In: Scientific Reports, ISSN 2045-2322, E-ISSN 2045-2322, Vol. 8, article id 17530Article in journal (Refereed)
    Abstract [en]

    Postsynthetic reactions of metal-organic frameworks (MOFs) are versatile tools for producing functional materials, but the methods of evaluating these reactions are cumbersome and destructive. Here we demonstrate and validate the use of in situ NMR spectroscopy of species in the liquid state to examine solvent-assisted ligand exchange (SALE) and postsynthetic modification (PSM) reactions of metal-organic frameworks. This technique allows functionalization to be monitored over time without decomposing the product for analysis, which simplifies reaction screening. In the case of SALE, both the added ligand and the ligand leaving the framework can be observed. We demonstrate this in situ method by examining SALE and PSM reactions of the robust zirconium MOF UiO-67 as well as SALE with the aluminum MOF DUT-5. In situ NMR spectroscopy provided insights into the reactions studied, and we expect that future studies using this method will permit the examination of a variety of MOF-solute reactions.

  • 9.
    Yuan, Ning
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Guðmundsson, Arnar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Gustafson, Karl
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Oschmann, Michael
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Verho, Oscar
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Bajnóczi, Éva
    Bäckvall, Jan-Erling
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    In Situ XAS Investigation of the Deactivation and Reactivation Mechanisms of a Heterogeneous Palladium(II) catalyst during the Cycloisomerization of Acetylenic Acids2019Manuscript (preprint) (Other academic)
    Abstract [en]

    The cause and mechanism of deactivation of a well-studied heterogeneous palladium(II) catalyst in the intramolecular lactonization of acetylenic acids to γ-alkylidene lactones have been investigated. It was shown that the deactivation was driven by the formation of reduced palladium species following the addition of the base triethylamine. In this work, X-ray absorption spectroscopy (XAS) was used to identify the palladium species and follow their evolution over the course of the reaction. It was also found that the choice of substrates has significant influences on the Pd species under the same reaction conditions. With these insights into the deactivation mechanism derived from XAS, different strategies were tested and illustrated to regain or maintain the active state of the catalyst. This information was further used to develop a new protocol, which can effectively prevent the deactivation of the catalyst and prolong its usage. 

  • 10.
    Yuan, Ning
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Majeed, Maitham H.
    Bajnóczi, Éva G.
    Persson, Axel R.
    Wallenberg, L. Reine
    Ken Inge, Andrew
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Heidenreich, Niclas
    Stock, Norbert
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Wendt, Ola F.
    Persson, Ingmar
    In Situ XAS Study of the Local Structure and Oxidation State Evolutions of Palladium in a Reduced Graphene Oxide Supported Pd(II) Carbene Complex during an Undirected C−H Acetoxylation Reaction2019In: Catalysis Science & Technology, ISSN 2044-4753, E-ISSN 2044-4761, Vol. 9, no 8, p. 2025-2031Article in journal (Refereed)
    Abstract [en]

    In situ X-ray absorption spectroscopy (XAS) investigations have been performed to provide insights into the reaction mechanism of a palladium(II) catalyzed undirected C–H acetoxylation reaction in the presence of an oxidant. A Pd(II) N-heterocyclic carbene complex p-stacked onto reduced graphene oxide (rGO) was used as catalyst. The Pd speciation during the catalytic process was examined by XAS, which revealed a possible mechanism over the course of the reaction. Pd(II) complexes in the as-synthesized catalyst first go through a gradual ligand substitution where chloride ions bound to Pd(II) are replaced by other ligands with a bond distance to Pd corresponding to carbon, nitrogen and/or oxygen (L). Parallel to this the mean oxidation state of Pd increases indicating the formation of Pd(IV) species. At a later stage, a fraction of the Pd complexes start to slowly transform into Pd nanoclusters. The mean average oxidation state of Pd decreases to the initial state at the end of the experiment which means that comparable amounts of Pd(0) and Pd(IV) are present. These observations from heterogeneous catalysis are in good agreement with its homogeneous analog and they support a Pd(II)-Pd(IV)-Pd(II) reaction mechanism.

  • 11.
    Yuan, Ning
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Huang, Zhehao
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Heidenreich, Niclas
    Leubner, Sebastian
    Inge, A. Ken
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Gaar, Jakob
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stock, Norbert
    Persson, Ingmar
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Probing the active catalytic species generated from Pd(II)@MIL-101-NH2 in Heck coupling reactions: An operando X-ray absorption spectroscopy studyArticle in journal (Refereed)
  • 12.
    Yuan, Ning
    et al.
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK). Swedish University of Agricultural Sciences, Sweden.
    Pascanu, Vlad
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Huang, Zhehao
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Valiente, Alejandro
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Heidenreich, Niclas
    Leubner, Sebastian
    Inge, Andrew Kentaro
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Gaar, Jakob
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Stock, Norbert
    Persson, Ingmar
    Martín-Matute, Belén
    Stockholm University, Faculty of Science, Department of Organic Chemistry.
    Zou, Xiaodong
    Stockholm University, Faculty of Science, Department of Materials and Environmental Chemistry (MMK).
    Probing the Evolution of Palladium Species in Pd@MOF Catalysts during the Heck Coupling Reaction: An Operando X-ray Absorption Spectroscopy Study2018In: Journal of the American Chemical Society, ISSN 0002-7863, E-ISSN 1520-5126, Vol. 140, no 26, p. 8206-8217Article in journal (Refereed)
    Abstract [en]

    The mechanism of the Heck C-C coupling reaction catalyzed by Pd@MOFs has been investigated using operando X-ray absorption spectroscopy (XAS) and powder X-ray diffraction (PXRD) combined with transmission electron microscopy (TEM) analysis and nuclear magnetic resonance (H-1 NMR) kinetic studies. A custom-made reaction cell was used, allowing operando PXRD and XAS data collection using high-energy synchrotron radiation. By analyzing the XAS data in combination with ex situ studies, the evolution of the palladium species is followed from the as-synthesized to its deactivated form. An adaptive reaction mechanism is proposed. Mononuclear Pd(II) complexes are found to be the dominant active species at the beginning of the reaction, which then gradually transform into Pd nanoclusters with 13-20 Pd atoms on average in later catalytic turnovers. Consumption of available reagent and substrate leads to coordination of Cl- ions to their surfaces, which causes the poisoning of the active sites. By understanding the deactivation process, it was possible to tune the reaction conditions and prolong the lifetime of the catalyst.

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