کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
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1328237 | 977549 | 2007 | 8 صفحه PDF | دانلود رایگان |
Polypropene and poly(1-butene) have been synthesized under very similar experimental conditions with a series of MAO-activated C2-symmetric and C1-symmetric ansa-zirconocenes. The C1-symmetric zirconocenes bearing the bilaterally symmetric fluorenyl or bis(2-methylthieno)cyclopentadienyl ligand connected through a dimethylsilyl bridge to substituted indenyl ligands produce isotactic polybutene of similar or higher molecular mass and with noticeably higher isotacticity, compared to isotactic polypropene prepared with the same catalysts under comparable conditions. Structural and mechanistic reasons for such behavior are discussed on the basis of QM/MM calculations.
The propene and 1-butene polymerization behavior of a series of C2- and C1-symmetric zirconocenes has been reexamined. An attempt at rationalizing the observed influence of the olefin size on stereoselectivity on the basis of QM/MM calculations is reported.Figure optionsDownload as PowerPoint slide
Journal: Journal of Organometallic Chemistry - Volume 692, Issue 21, 1 October 2007, Pages 4784–4791