Polymerization of Propene with Modified Constrained Geometry Complexes. Double-Bond Isomerization in Pendant Alkenyl Groups Attached to Cyclopentadienyl Ligands

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Title:Polymerization of Propene with Modified Constrained Geometry Complexes. Double-Bond Isomerization in Pendant Alkenyl Groups Attached to Cyclopentadienyl Ligands
Creators:
Staal, Oetze K. B.
Beetstra, Dirk J.
Jekel, Andries P.
Hessen, Bart
Teuben, Jan H.
Štěpnička, Petr
Gyepes, Róbert
Horáček, Michal
Pinkas, Jiří
Mach, Karel
Journal or Publication Title:
Collection of Czechoslovak Chemical Communications, 68, 6, pp. 1119-1130
Uncontrolled Keywords:Titanium, Half-sandwich complexes, X-Ray diffraction, CGC catalysts, Propene polymerization, NMR spectroscopy, Double-bond isomerization, Substituent effects

Abstract

Polymerization of propene with dimethylsilylene-bridged (amidocyclopentadienyl)dichlorotitanium(IV) complexes [TiCl<sub>2</sub>{η<sup>5</sup>-1-(<i>t</i>-BuSiMe<sub>2</sub>N-κ<i>N</i>)-2,3,4-Me<sub>3</sub>-5-R-C<sub>5</sub>}], where R = Me (<strong>1</strong>), H (<strong>2</strong>), Ph (<strong>3</strong>), 4-fluorophenyl (<strong>4</strong>), but-2-en-2-yl (<strong>5</strong>), and butyl (<strong>6</strong>), combined with excess methylaluminoxane revealed a moderate effect of the substituent R on the catalyst activity and the molecular weight of polypropene. The asymmetric substitution in the position adjacent to the bridging carbon atom resulted in polymer yields decreasing in the order <strong>1</strong> &gt; <strong>6</strong> &gt; <strong>3</strong> ≈ <strong>5</strong> &gt; <strong>4</strong> &gt; <strong>2</strong> while polymers with the molecular weights (<i>M</i><sub>w</sub>) close to 2.5 × 10<sup>5</sup> for <strong>1</strong>, <strong>3</strong>, and <strong>4</strong>, 1.5 × 10<sup>5</sup> for <strong>5</strong> and <strong>6</strong>, and 7.5 × 10<sup>4</sup> for <strong>2</strong> were obtained. The <sup>13</sup>C NMR analysis of the polymers has shown that atactic polypropene is slightly enriched with syndiotactic triads for all the catalysts. Investigation of the crystal structure of <strong>5</strong> by X-ray crystallography revealed that the double bond in but-3-en-2-yl had shifted to an internal position to give the isomeric, but-2-en-2-yl-substituted complex. Likewise, the spectroscopic data for complex <strong>7</strong> prepared from the ligand containing but-3-en-1-yl substituent, indicate the absence of terminal double bond. <p>

Title:Polymerization of Propene with Modified Constrained Geometry Complexes. Double-Bond Isomerization in Pendant Alkenyl Groups Attached to Cyclopentadienyl Ligands
Creators:
Staal, Oetze K. B.
Beetstra, Dirk J.
Jekel, Andries P.
Hessen, Bart
Teuben, Jan H.
Štěpnička, Petr
Gyepes, Róbert
Horáček, Michal
Pinkas, Jiří
Mach, Karel
Uncontrolled Keywords:Titanium, Half-sandwich complexes, X-Ray diffraction, CGC catalysts, Propene polymerization, NMR spectroscopy, Double-bond isomerization, Substituent effects
Divisions:Life and Chemical Sciences > Institute of Organic Chemistry and Biochemistry > Collection of Czechoslovak Chemical Communications
Journal or Publication Title:Collection of Czechoslovak Chemical Communications
Volume:68
Number:6
Page Range:pp. 1119-1130
ISSN:0010-0765
E-ISSN:1212-6950
Publisher:Institute of Organic Chemistry and Biochemistry
Related URLs:
URLURL Type
http://dx.doi.org/10.1135/cccc20031119UNSPECIFIED
ID Code:2108
Item Type:Article
Deposited On:06 Feb 2009 17:15
Last Modified:06 Feb 2009 16:15

Citation

Staal, Oetze K. B.; Beetstra, Dirk J.; Jekel, Andries P.; Hessen, Bart; Teuben, Jan H.; Štěpnička, Petr; Gyepes, Róbert; Horáček, Michal; Pinkas, Jiří; Mach, Karel (2003) Polymerization of Propene with Modified Constrained Geometry Complexes. Double-Bond Isomerization in Pendant Alkenyl Groups Attached to Cyclopentadienyl Ligands. Collection of Czechoslovak Chemical Communications, 68 (6). pp. 1119-1130. ISSN 0010-0765

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