Isotactic-Specific Polymerization of Propene by a Cs-Symmetric Zirconium(IV) Complex Bearing a Dianionic Tridentate [−NNN−] Amidomethylpyrrol

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• 作者：Liana Annunziata ; Daniela Pappalardo ; Consiglia Tedesco ; Claudio Pellecchia
• 刊名：Macromolecules
• 出版年：2009
• 出版时间：August 11, 2009
• 年：2009
• 卷：42
• 期：15
• 页码：5572-5578
• 全文大小：815K
• 年卷期：v.42,no.15(August 11, 2009)
• ISSN：1520-5835

文摘

The synthesis and characterization of a new tridentate amidomethylpyrrolidepyridine ligand (LigH<sub>2sub>) and of the corresponding LigZr(NMe<sub>2sub>)<sub>2sub> complex (1) are described. Characterization of 1 by single-crystal X-ray diffraction analysis showed a slightly distorted square-pyramidal geometry. Variable-temperature NMR analysis suggested that 1 adopts a C<sub>ssub>-symmetric structure in solution. Complex 1 in combination with Al<sup>isup>Bu<sub>2sub>H and methylalumoxane afforded a highly active single-site catalyst for the polymerization of ethylene and propene, producing ultrahigh molecular weight linear polyethylene and isotactic polypropylene via an “enantiomorphic sites” mechanism of steric control.