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ID 14676
file
creator
Nishii, Kei
Hagihara, Hideaki
Ikeda, Tomiki
Akita, Munetaka
subject
Atactic
Metallocene catalysts
Polypropylene
Syndiotactic
NDC
Chemistry
description
Group 4 [η1:η3-tert- butyl(dimethylfluorenylsilyl)amido]dimethyl complexes [t-BuNSiMe 2Flu]MMe2 (M = Ti, 1; Zr, 2; Hf, 3) were synthesized in a one-pot synthesis starting from the ligand, MeLi and MCl4 (M = Ti, Zr, Hf), respectively. The structures of these complexes were determined by X-ray crystallography and the results obtained revealed that the fluorenyl ligand coordinates to center metal in a η3-manner irrespective of center metal employed. Propylene polymerization was conducted at 0 or 20 °C in toluene by 1-3 combined with dried methylaluminoxane (MAO), which was prepared from the toluene solutions of MAO by removing free trialkylaluminiums, and HNMe2PhB(C6F5)4 in the presence of triisobutylaluminium. The 1-dried MAO system gave the polymer with syndiotactic triad (rr) of 63 0x1.e2fc8p-891t 0 °C, whereas 2 and 3 did not give any polymer in the same conditions. The 2-dried MAO system gave the polymer with the highest syndiotacticity (rr = 97%) at 20 °C, although the activity was low. The 3-dried MAO system did not give any polymer even at 20 °C. When HNMe2PhB(C6F5)4 was used in place of dried MAO at 20 °C, 1 gave almost atactic polymer, while 2 and 3 gave highly syndiotactic one (rr > 90%). These results indicate that the catalytic performance strongly depended on the center metal of the ansa- fluorenylamidodimethyl complexes as well as cocatalysts employed.
journal title
Journal of Organometallic Chemistry
volume
Volume 691
issue
Issue 1-2
start page
193
end page
201
date of issued
2006-01
publisher
Elsevier
issn
0022-328X
publisher doi
language
eng
nii type
Journal Article
HU type
Journal Articles
DCMI type
text
format
application/pdf
text version
author
rights
Copyright (c) 2005 Elsevier B.V
relation is version of URL
http://dx.doi.org/10.1016/j.jorganchem.2005.08.027
department
Graduate School of Engineering