Comparing propene polymerization with 1-butene polymerization catalyzed by MAO-activated C2- and C1-symmetric zirconocenes: An experimental and computational study on the influence of olefin size on stereoselectivity |
| |
Authors: | Pierluigi Mercandelli Angelo Sironi Isabella Camurati |
| |
Institution: | a Dipartimento di Chimica Strutturale, Università di Milano, via Venezian 21, I-20133 Milano, Italy b Basell Polyolefins, Centro Ricerche G. Natta, I-44100 Ferrara, Italy |
| |
Abstract: | 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. |
| |
Keywords: | Isotactic polypropylene Isotactic polybutene QM/MM calculations 13C NMR Metallocene catalysts Stereoselective olefin polymerization |
本文献已被 ScienceDirect 等数据库收录! |