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<sup>1</sup>H-, <sup>13</sup>C-NMR and ethylene polymerization studies of zirconocene/MAO catalysts : effect of the ligand structure on the formation of active intermediates and polymerization kinetics

1H-, 13C-NMR and ethylene polymerization studies of zirconocene/MAO catalysts : effect of the ligand structure on the formation of active intermediates and polymerization kinetics

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BRYLIAKOV, Konstantin P., Nina V. SEMIKOLENOVA, Dmitrii V. YUDAEV, Vladimir A. ZAKHAROV, Hans-Herbert BRINTZINGER, Martin YSTENES, Erling RYTTER, Evgenii P. TALSI, 2003. 1H-, 13C-NMR and ethylene polymerization studies of zirconocene/MAO catalysts : effect of the ligand structure on the formation of active intermediates and polymerization kinetics. In: Journal of Organometallic Chemistry. 683(1), pp. 92-102. ISSN 0022-328X. Available under: doi: 10.1016/S0022-328X(03)00443-1

@article{Bryliakov2003ethyl-23855, title={1H-, 13C-NMR and ethylene polymerization studies of zirconocene/MAO catalysts : effect of the ligand structure on the formation of active intermediates and polymerization kinetics}, year={2003}, doi={10.1016/S0022-328X(03)00443-1}, number={1}, volume={683}, issn={0022-328X}, journal={Journal of Organometallic Chemistry}, pages={92--102}, author={Bryliakov, Konstantin P. and Semikolenova, Nina V. and Yudaev, Dmitrii V. and Zakharov, Vladimir A. and Brintzinger, Hans-Herbert and Ystenes, Martin and Rytter, Erling and Talsi, Evgenii P.} }

deposit-license Journal of Organometallic Chemistry ; 683 (2003), 1. - S. 92-102 eng Semikolenova, Nina V. 2013-07-24T19:16:31Z Brintzinger, Hans-Herbert Rytter, Erling 2003 Brintzinger, Hans-Herbert Talsi, Evgenii P. Zakharov, Vladimir A. Rytter, Erling Yudaev, Dmitrii V. Ystenes, Martin Bryliakov, Konstantin P. Semikolenova, Nina V. Talsi, Evgenii P. 2013-07-24T19:16:31Z Ystenes, Martin <sup>1</sup>H-, <sup>13</sup>C-NMR and ethylene polymerization studies of zirconocene/MAO catalysts : effect of the ligand structure on the formation of active intermediates and polymerization kinetics Bryliakov, Konstantin P. Zakharov, Vladimir A. Yudaev, Dmitrii V. Using <sup>1</sup>H- and <sup>13</sup>C-NMR spectroscopies, cationic intermediates formed by activation of L<sub>2</sub>ZrCl<sub>2</sub> with methylaluminoxane (MAO) in toluene were monitored at Al/Zr ratios from 50 to 1000 (L<sub>2</sub> are various cyclopentadienyl (Cp), indenyl (Ind) and fluorenyl (Flu) ligands). The following catalysts were studied: (Cp-R)<sub>2</sub>ZrCl<sub>2</sub> (R=Me, 1,2-Me<sub>2</sub>, 1,2,3-Me<sub>3</sub>, 1,2,4-Me<sub>3</sub>, Me<sub>4</sub>, Me<sub>5</sub>, n-Bu, t-Bu), rac-ethanediyl(Ind)<sub>2</sub>ZrCl<sub>2</sub>, rac-Me<sub>2</sub>Si(Ind)<sub>2</sub>ZrCl<sub>2</sub>, rac-Me<sub>2</sub>Si(1-Ind-2-Me)<sub>2</sub>ZrCl<sub>2</sub>, rac-ethanediyl(1-Ind-4,5,6,7-H<sub>4</sub>)<sub>2</sub>ZrCl<sub>2</sub>, (Ind-2-Me)<sub>2</sub>ZrCl<sub>2</sub>, Me<sub>2</sub>C(Cp)(Flu)ZrCl<sub>2</sub>, Me<sub>2</sub>C(Cp-3-Me)(Flu)ZrCl<sub>2</sub> and Me<sub>2</sub>Si(Flu)<sub>2</sub>ZrCl<sub>2</sub>. Correlations between spectroscopic and ethene polymerization data for catalysts (Cp-R)<sub>2</sub>ZrCl<sub>2</sub>/MAO (R=H, Me, 1,2-Me<sub>2</sub>, 1,2,3-Me<sub>3</sub>, 1,2,4-Me<sub>3</sub>, Me<sub>4</sub>, Me<sub>5</sub>, n-Bu, t-Bu) and rac-Me<sub>2</sub>Si(Ind)<sub>2</sub>ZrCl<sub>2</sub> were established. The catalysts (Cp-R)<sub>2</sub>ZrCl<sub>2</sub>/AlMe<sub>3</sub>/CPh<sub>3</sub>+B(C<sub>6</sub>F<sub>5</sub>)<sub>4</sub><sup>−</sup> (R=Me, 1,2-Me<sub>2</sub>, 1,2,3-Me<sub>3</sub>, 1,2,4-Me<sub>3</sub>, Me<sub>4</sub>, n-Bu, t-Bu) were also studied for comparison of spectroscopic and polymerization data with MAO-based systems. Complexes of type (Cp-R)<sub>2</sub>ZrMe<sup>+</sup>←Me<sup>−</sup>-Al≡MAO (IV) with different [Me-MAO]<sup>−</sup> counteranions have been identified in the (Cp-R)<sub>2</sub>ZrCl<sub>2</sub>/MAO (R=n-Bu, t-Bu) systems at low Al/Zr ratios (50–200). At Al/Zr ratios of 500–1000, the complex [L<sub>2</sub>Zr(μ-Me)<sub>2</sub>AlMe<sub>2</sub>]<sup>+</sup>[Me-MAO]<sup>−</sup> (III) dominates in all MAO-based reaction systems studied. Ethene polymerization activity strongly depends on the Al/Zr ratio (Al/Zr=200–1000) for the systems (Cp-R)<sub>2</sub>ZrCl<sub>2</sub>/MAO (R=H, Me, n-Bu, t-Bu), while it is virtually constant in the same range of Al/Zr ratios for the catalytic systems (Cp-R)<sub>2</sub>ZrCl<sub>2</sub>/MAO (R=1,2-Me<sub>2</sub>, 1,2,3-Me<sub>3</sub>, 1,2,4-Me<sub>3</sub>, Me<sub>4</sub>) and rac-Me<sub>2</sub>Si(Ind)<sub>2</sub>ZrCl<sub>2</sub>/MAO. The data obtained are interpreted on assumption that complex III is the main precursor of the active centers of polymerization in MAO-based systems.

Dateiabrufe seit 01.10.2014 (Informationen über die Zugriffsstatistik)

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