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Title
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Probing the coordinative unsaturation and local environment of sites in an activated high-yield Ziegler-Natta catalyst
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Author
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Abstract
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| The typical activation of a fourth generation ZieglerNatta catalyst TiCl4/MgCl2/phthalate with triethyl aluminum generates Ti3+ centers that are investigated by multi-frequency continuous wave and pulse EPR methods. Two families of isolated, molecule-like Ti3+ species have been identified. A comparison of the experimentally derived g tensors and 35,37Cl hyperfine and nuclear-quadrupole tensors with DFT-computed values suggests that the dominant EPR-active Ti3+ species is located on MgCl2(110) surfaces (or equivalent MgCl2 terminations with tetra-coordinated Mg). O2 reactivity tests show that a fraction of these Ti sites is chemically accessible, an important result in view of the search for the true catalyst active site in olefin polymerization. |
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Language
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English
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Source (journal)
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Angewandte Chemie: international edition in English. - Weinheim
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Publication
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Weinheim
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2015
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ISSN
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1433-7851
0570-0833
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DOI
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10.1002/ANIE.201412052
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Volume/pages
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54
:16
(2015)
, p. 4857-4860
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ISI
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000352622400030
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Pubmed ID
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25706346
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Full text (Publisher's DOI)
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Full text (publisher's version - intranet only)
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