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Author: Kreyenschulte, Carsten × End date: 2018 × Start date: 2017 × Type: Text × WGL Institute: LIKAT ×

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Now showing 1 - 5 of 5
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    Synthesis of Single Atom Based Heterogeneous Platinum Catalysts: High Selectivity and Activity for Hydrosilylation Reactions
    (Washington, DC : ACS Publ., 2017) Cui, Xinjiang; Junge, Kathrin; Dai, Xingchao; Kreyenschulte, Carsten; Pohl, Marga-Martina; Wohlrab, Sebastian; Shi, Feng; Brückner, Angelika; Beller, Matthias
    Catalytic hydrosilylation represents a straightforward and atom-efficient methodology for the creation of C-Si bonds. In general, the application of homogeneous platinum complexes prevails in industry and academia. Herein, we describe the first heterogeneous single atom catalysts (SACs), which are conveniently prepared by decorating alumina nanorods with platinum atoms. The resulting stable material efficiently catalyzes hydrosilylation of industrially relevant olefins with high TON (≈105). A variety of substrates is selectively hydrosilylated including compounds with sensitive reducible and other functional groups (N, B, F, Cl). The single atom based catalyst shows significantly higher activity compared to related Pt nanoparticles.
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    Correction: A robust iron catalyst for the selective hydrogenation of substituted (iso)quinolones
    (Cambridge : RSC, 2018) Sahoo, Basudev; Kreyenschulte, Carsten; Agostini, Giovanni; Lund, Henrik; Bachmann, Stephan; Scalone, Michelangelo; Junge, Kathrin; Beller, Matthias
    The authors regret that the term “(iso)quinolones” was used throughout the article, including the title, when the correct term should be “(iso)quinolines”. The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.
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    A robust iron catalyst for the selective hydrogenation of substituted (iso)quinolones
    (Cambridge : RSC, 2018) Sahoo, Basudev; Kreyenschulte, Carsten; Agostini, Giovanni; Lund, Henrik; Bachmann, Stephan; Scalone, Michelangelo; Junge, Kathrin; Beller, Matthias
    By applying N-doped carbon modified iron-based catalysts, the controlled hydrogenation of N-heteroarenes, especially (iso)quinolones, is achieved. Crucial for activity is the catalyst preparation by pyrolysis of a carbon-impregnated composite, obtained from iron(ii) acetate and N-aryliminopyridines. As demonstrated by TEM, XRD, XPS and Raman spectroscopy, the synthesized material is composed of Fe(0), Fe3C and FeNx in a N-doped carbon matrix. The decent catalytic activity of this robust and easily recyclable Fe-material allowed for the selective hydrogenation of various (iso)quinoline derivatives, even in the presence of reducible functional groups, such as nitriles, halogens, esters and amides. For a proof-of-concept, this nanostructured catalyst was implemented in the multistep synthesis of natural products and pharmaceutical lead compounds as well as modification of photoluminescent materials. As such this methodology constitutes the first heterogeneous iron-catalyzed hydrogenation of substituted (iso)quinolones with synthetic importance.
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    Selective cobalt nanoparticles for catalytic transfer hydrogenation of N-heteroarenes
    (Cambridge : RSC, 2017) Chen, Feng; Sahoo, Basudev; Kreyenschulte, Carsten; Lund, Henrik; Zeng, Min; He, Lin; Junge, Kathrin; Beller, Matthias
    Nitrogen modified cobalt catalysts supported on carbon were prepared by pyrolysis of the mixture generated from cobalt(ii) acetate in aqueous solution of melamine or waste melamine resins, which are widely used as industrial polymers. The obtained nanostructured materials catalyze the transfer hydrogenation of N-heteroarenes with formic acid in the absence of base. The optimal Co/Melamine-2@C-700 catalyst exhibits high activity and selectivity for the dehydrogenation of formic acid into molecular hydrogen and carbon dioxide and allows for the reduction of diverse N-heteroarenes including substrates featuring sensitive functional groups.
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    Hydrogenation of terminal and internal olefins using a biowaste-derived heterogeneous cobalt catalyst
    (Washington, DC [u.a.] : Assoc., 2018) Scharnagl, Florian Korbinian; Hertrich, Maximilian Franz; Ferretti, Francesco; Kreyenschulte, Carsten; Lund, Henrik; Jackstell, Ralf; Beller, Matthias
    Hydrogenation of olefins is achieved using biowaste-derived cobalt chitosan catalysts. Characterization of the optimal Co@Chitosan-700 by STEM (scanning transmission electron microscopy), EELS (electron energy loss spectroscopy), PXRD (powder x-ray diffraction), and elemental analysis revealed the formation of a distinctive magnetic composite material with high metallic Co content. The general performance of this catalyst is demonstrated in the hydrogenation of 50 olefins including terminal, internal, and functionalized derivatives, as well as renew-ables. Using this nonnoble metal composite, hydrogenation of terminal C==C double bonds occurs under very mild and benign conditions (water or methanol, 40° to 60°C). The utility of Co@Chitosan-700 is showcased for efficient hydrogenation of the industrially relevant examples diisobutene, fatty acids, and their triglycerides. Because of the magnetic behavior of this material and water as solvent, product separation and recycling of the catalyst are straightforward.