文献类型：期刊文献

英文题名：Synthesis and polymerization behavior of various substituted half-sandwich titanium complexes Cp′TiCl₂(OR*) as catalysts for syndiotactic polystyrene

作者：Qian, YL; Zhang, H; Zhou, JX; Zhao, W; Sun, XQ; Huang, JL

机构：[1]E China Univ Sci & Technol, Organomet Chem Lab, Shanghai 200237, Peoples R China

年份：2004

卷号：208

期号：1-2

起止页码：45

外文期刊名：JOURNAL OF MOLECULAR CATALYSIS A-CHEMICAL

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000187726200006)】；

语种：英文

外文关键词：half-sandwich titanocene; syndiotactic polystyrene; chiral alkoxyl ligand

摘要：A new set of chiral alkoxy substituted half-sandwich titanium complexes of Cp'TiCl2(OR*) (Cp' = Cp, CH3CH(CH3)Cp, CH3OCH2CH2Cp, CH3OCH2CH(CH3)Cp; R* = menthyl, fenchyl) were synthesized, characterized and tested as catalyst precursors for the syndiospecific polymerization of styrene. The structure of complex 8 was confirmed by X-ray crystallography. When chiral alkoxy groups took the place of chlorine atom, it was found that the intramolecular coordination of the oxygen on Cp ring to the titanium disappeared in the solid state. Under the same conditions, complexes 1-4 showed higher activity, and complexes 5-8 showed lower activity than CpTiCl3. The catalytic activity increased in the order 8 < 7 < 6 < 5 < CpTiCl3 < 4 < 3 < 2 < 1. The highest activity was 7.37 x 10(7) g s-PS/(mol Ti mol S h) for complex 1/methylaluminoxane (MAO) at a molar ratio of Al/Ti = 2000. Kinetic measurements of the polymerization were carried out at different temperature for complex 1. The effects of variation on temperature, Al/Ti ratio for catalytic activity and syndiotactic polystyrene (s-PS)% were also studied. (C) 2003 Elsevier B.V. All rights reserved.