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  1. Article ; Online: Elongation and branching of α-olefins by two ethylene molecules.

    Dietel, Thomas / Lukas, Fabian / Kretschmer, Winfried P / Kempe, Rhett

    Science (New York, N.Y.)

    2022  Volume 375, Issue 6584, Page(s) 1021–1024

    Abstract: α-Olefins are important starting materials for the production of plastics, pharmaceuticals, and fine and bulk chemicals. However, the selective synthesis of α-olefins from ethylene, a highly abundant and inexpensive feedstock, is restricted, and thus a ... ...

    Abstract α-Olefins are important starting materials for the production of plastics, pharmaceuticals, and fine and bulk chemicals. However, the selective synthesis of α-olefins from ethylene, a highly abundant and inexpensive feedstock, is restricted, and thus a broadly applicable selective α-olefin synthesis using ethylene is highly desirable. Here, we report the catalytic reaction of an α-olefin with two ethylene molecules. The first ethylene molecule forms a 4-ethyl branch and the second a new terminal carbon-carbon double bond (C2 elongation). The key to this reaction is the development of a highly active and stable molecular titanium catalyst that undergoes extremely fast β-hydride elimination and transfer.
    Language English
    Publishing date 2022-03-03
    Publishing country United States
    Document type Journal Article
    ZDB-ID 128410-1
    ISSN 1095-9203 ; 0036-8075
    ISSN (online) 1095-9203
    ISSN 0036-8075
    DOI 10.1126/science.abm5281
    Database MEDical Literature Analysis and Retrieval System OnLINE

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    In stock of ZB MED Cologne/Königswinter

    Zs.A 27: Show issues Location:
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    bis Jg. 1994: Bestellungen von Artikeln über das Online-Bestellformular
    Jg. 1995 - 2021: Lesesall (1.OG)
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  2. Article ; Online: Formation of a dimeric tungsten(i) complex via C-H activation.

    Noor, Awal / Qayyum, Sadaf / Schwarz, Stefan / Dietel, Thomas / Kempe, Rhett

    Dalton transactions (Cambridge, England : 2003)

    2020  Volume 49, Issue 6, Page(s) 1992–1996

    Abstract: An aminopyridinato ligand stabilized and coordinatively unsaturated dimeric tungsten(0) complex having an electronic structure with six metal centred HOMOs ( ... ...

    Abstract An aminopyridinato ligand stabilized and coordinatively unsaturated dimeric tungsten(0) complex having an electronic structure with six metal centred HOMOs (σ
    Language English
    Publishing date 2020-01-27
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472887-4
    ISSN 1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
    ISSN (online) 1477-9234 ; 1364-5447
    ISSN 0300-9246 ; 1477-9226
    DOI 10.1039/c9dt04847b
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  3. Book ; Online ; Thesis: Azimuthal correlations of high-pT photons and hadrons in Au+Au collisions at STAR

    Dietel, Thomas

    2006  

    Author's details von Thomas Dietel
    Language English
    Size Online-Ressource
    Document type Book ; Online ; Thesis
    Thesis / German Habilitation thesis Univ., Diss--Frankfurt (Main), 2006
    Database Former special subject collection: coastal and deep sea fishing

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  4. Article ; Online: Synthesis, structures and cytotoxic effects in vitro of cis- and trans-[Pt

    Rehm, Tobias / Rothemund, Matthias / Dietel, Thomas / Kempe, Rhett / Schobert, Rainer

    Dalton transactions (Cambridge, England : 2003)

    2019  Volume 48, Issue 43, Page(s) 16358–16365

    Abstract: Four new bis(N,N-dialkylbenzimidazol-2-ylidene)dichlorido platinum(ii) complexes 2 featuring N-alkyl substituents of increasing size (a: Me, b: Et, c: n-butyl, d: n-octyl) were synthesised and oxidised with ... ...

    Abstract Four new bis(N,N-dialkylbenzimidazol-2-ylidene)dichlorido platinum(ii) complexes 2 featuring N-alkyl substituents of increasing size (a: Me, b: Et, c: n-butyl, d: n-octyl) were synthesised and oxidised with PhICl
    Language English
    Publishing date 2019-10-18
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472887-4
    ISSN 1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
    ISSN (online) 1477-9234 ; 1364-5447
    ISSN 0300-9246 ; 1477-9226
    DOI 10.1039/c9dt02438g
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  5. Article ; Online: Manganese-Catalyzed Dehydrogenative Alkylation or α-Olefination of Alkyl-Substituted N-Heteroarenes with Alcohols.

    Zhang, Guoying / Irrgang, Torsten / Dietel, Thomas / Kallmeier, Fabian / Kempe, Rhett

    Angewandte Chemie (International ed. in English)

    2018  Volume 57, Issue 29, Page(s) 9131–9135

    Abstract: Catalysis with earth-abundant transition metals is an option to help save our rare noble-metal resources and is especially interesting when novel reactivity or selectivity patterns are observed. We report here on a novel reaction, namely the ... ...

    Abstract Catalysis with earth-abundant transition metals is an option to help save our rare noble-metal resources and is especially interesting when novel reactivity or selectivity patterns are observed. We report here on a novel reaction, namely the dehydrogenative alkylation or α-olefination of alkyl-substituted N-heteroarenes with alcohols. Manganese complexes developed in our laboratory catalyze the reaction with high efficiency whereas iron and cobalt complexes stabilized by the same ligands are essentially inactive. Hydrogen is liberated during the reaction, and bromine and iodine functional groups as well as olefins are tolerated. A variety of alkyl-substituted N-heteroarenes can be functionalized, and benzylic and aliphatic alcohols undergo the reaction.
    Language English
    Publishing date 2018-05-30
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.201801573
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  6. Article ; Online: Highly Active and Selective Manganese C=O Bond Hydrogenation Catalysts: The Importance of the Multidentate Ligand, the Ancillary Ligands, and the Oxidation State.

    Kallmeier, Fabian / Irrgang, Torsten / Dietel, Thomas / Kempe, Rhett

    Angewandte Chemie (International ed. in English)

    2016  Volume 55, Issue 39, Page(s) 11806–11809

    Abstract: The replacement of expensive noble metals by earth-abundant transition metals is a central topic in catalysis. Herein, we introduce a highly active and selective homogeneous manganese-based C=O bond hydrogenation catalyst. Our catalyst has a broad ... ...

    Abstract The replacement of expensive noble metals by earth-abundant transition metals is a central topic in catalysis. Herein, we introduce a highly active and selective homogeneous manganese-based C=O bond hydrogenation catalyst. Our catalyst has a broad substrate scope, it is able to hydrogenate aryl-alkyl, diaryl, dialkyl, and cycloalkyl ketones as well as aldehydes. A very good functional group tolerance including the quantitative and selective hydrogenation of a ketone in the presence of a non-shielded olefin is observed. In Mn hydrogenation catalysis, the combination of the multidentate ligand, the oxidation state of the metal, and the choice of the right ancillary ligand is crucial for high activity. This observation emphasizes an advantage and the importance of homogeneous catalysts in 3d-metal catalysis. For coordination compounds, fine-tuning of a complex coordination environment is easily accomplished in comparison to enzyme and/or heterogeneous catalysts.
    Language English
    Publishing date 2016--19
    Publishing country Germany
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ZDB-ID 2011836-3
    ISSN 1521-3773 ; 1433-7851
    ISSN (online) 1521-3773
    ISSN 1433-7851
    DOI 10.1002/anie.201606218
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  7. Article ; Online: A broadly tunable synthesis of linear α-olefins.

    Gollwitzer, Andreas / Dietel, Thomas / Kretschmer, Winfried P / Kempe, Rhett

    Nature communications

    2017  Volume 8, Issue 1, Page(s) 1226

    Abstract: The catalytic synthesis of linear α-olefins from ethylene is a technologically highly important reaction. A synthesis concept allowing the formation of selective products and various linear α-olefin product distributions with one catalyst system is ... ...

    Abstract The catalytic synthesis of linear α-olefins from ethylene is a technologically highly important reaction. A synthesis concept allowing the formation of selective products and various linear α-olefin product distributions with one catalyst system is highly desirable. Here, we describe a trimetallic catalyst system (Y-Al-Ni) consisting of a rare earth metal polymerization catalyst which can mediate coordinative chain transfer to triethylaluminum combined with a simultaneously operating nickel β-hydride elimination/transfer catalyst. This nickel catalyst displaces the grown alkyl chains forming linear α-olefins and recycles the aluminum-based chain transfer agent. With one catalyst system, we can synthesize product spectra ranging from selective 1-butene formation to α-olefin distributions centered at 850 gmol
    Language English
    Publishing date 2017-10-31
    Publishing country England
    Document type Journal Article ; Research Support, Non-U.S. Gov't
    ISSN 2041-1723
    ISSN (online) 2041-1723
    DOI 10.1038/s41467-017-01507-2
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  8. Article ; Online: N,N-Dialkylbenzimidazol-2-ylidene platinum complexes - effects of alkyl residues and ancillary cis-ligands on anticancer activity.

    Rehm, Tobias / Rothemund, Matthias / Bär, Alexander / Dietel, Thomas / Kempe, Rhett / Kostrhunova, Hana / Brabec, Viktor / Kasparkova, Jana / Schobert, Rainer

    Dalton transactions (Cambridge, England : 2003)

    2018  Volume 47, Issue 48, Page(s) 17367–17381

    Abstract: Eleven complexes of [(1,3-dialkylbenzimidazol-2-ylidene) ... ...

    Abstract Eleven complexes of [(1,3-dialkylbenzimidazol-2-ylidene)L
    MeSH term(s) Animals ; Antineoplastic Agents/chemical synthesis ; Antineoplastic Agents/chemistry ; Antineoplastic Agents/pharmacology ; Benzimidazoles/chemical synthesis ; Benzimidazoles/chemistry ; Benzimidazoles/pharmacology ; Cattle ; Cell Cycle/drug effects ; Cell Proliferation/drug effects ; Coordination Complexes/chemical synthesis ; Coordination Complexes/chemistry ; Coordination Complexes/pharmacology ; DNA/chemistry ; DNA/drug effects ; Dose-Response Relationship, Drug ; Drug Screening Assays, Antitumor ; HCT116 Cells ; Humans ; Kinetics ; Molecular Structure ; Plasmids ; Platinum/chemistry ; Platinum/pharmacology ; Structure-Activity Relationship ; Tumor Cells, Cultured
    Chemical Substances Antineoplastic Agents ; Benzimidazoles ; Coordination Complexes ; Platinum (49DFR088MY) ; DNA (9007-49-2) ; calf thymus DNA (91080-16-9)
    Language English
    Publishing date 2018-11-27
    Publishing country England
    Document type Journal Article
    ZDB-ID 1472887-4
    ISSN 1477-9234 ; 1364-5447 ; 0300-9246 ; 1477-9226
    ISSN (online) 1477-9234 ; 1364-5447
    ISSN 0300-9246 ; 1477-9226
    DOI 10.1039/c8dt03360a
    Database MEDical Literature Analysis and Retrieval System OnLINE

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  9. Article ; Online: Aminopyridinate-FI hybrids, their hafnium and titanium complexes, and their application in the living polymerization of 1-hexene.

    Haas, Isabelle / Dietel, Thomas / Press, Konstantin / Kol, Moshe / Kempe, Rhett

    Chemistry (Weinheim an der Bergstrasse, Germany)

    2013  Volume 19, Issue 42, Page(s) 14254–14262

    Abstract: Based on two well-established ligand systems, the aminopyridinato (Ap) and the phenoxyimine (FI) ligand systems, new Ap-FI hybrid ligands were developed. Four different Ap-FI hybrid ligands were synthesized through a simple condensation reaction and ... ...

    Abstract Based on two well-established ligand systems, the aminopyridinato (Ap) and the phenoxyimine (FI) ligand systems, new Ap-FI hybrid ligands were developed. Four different Ap-FI hybrid ligands were synthesized through a simple condensation reaction and fully characterized. The reaction of hafnium tetrabenzyl with all four Ap-FI hybrid ligands exclusively led to mono(Ap-FI) complexes of the type [(Ap-FI)HfBn2 ]. The ligands acted as tetradentate dianionic chelates. Upon activation with tris(pentafluorophenyl)borane, the hafnium-dibenzyl complexes led to highly active catalysts for the polymerization of 1-hexene. Ultrahigh molecular weights and extremely narrow polydispersities support the living nature of this polymerization process. A possible deactivation product of the hafnium catalysts was characterized by single-crystal X-ray analysis and is discussed. The coordination modes of these new ligands were studied with the help of model titanium complexes. The reaction of titanium(IV) isopropoxide with ligand 1 led to a mono(Ap-FI) complex, which showed the desired fac-mer coordination mode. Titanium (IV) isopropoxide reacted with ligand 4 to give a complex of the type [(ApH-FI)2 Ti(OiPr)2 ], which featured the ligand in its monoanionic form. The two titanium complexes were characterized by X-ray crystal-structure analysis.
    Language English
    Publishing date 2013-10-11
    Publishing country Germany
    Document type Journal Article
    ZDB-ID 1478547-x
    ISSN 1521-3765 ; 0947-6539
    ISSN (online) 1521-3765
    ISSN 0947-6539
    DOI 10.1002/chem.201301511
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