摘要
Two multi-nuclear titanium complexes [Ti（η^5-Cp^＊）Cl（μ-O）]3 （1） and [（η^5-Cp^＊TiCl）（μ-O）2（η^5-Cp^＊Ti）2（μ- O）（μ-O）2]2Ti （Cp^＊ = C5Me5） （2） have been investigated as the precatalysts for syndiospecific polymerization of styrene. In the presence of modified methylaluminoxane （MMAO） as a cocatalyst, complexes 1 and 2 display much higher catalytic activities towards styrene polymerization, and produce the higher molecular weight polystyrenes with higher syndiotacticities and melting temperatures （Tm） than the mother complex Cp^＊TiCl3 does when the polymerization temperature is above 70℃ and the Al/Ti molar ratio is in the low range especially.
Two multi-nuclear titanium complexes [Ti（η^5-Cp^＊）Cl（μ-O）]3 （1） and [（η^5-Cp^＊TiCl）（μ-O）2（η^5-Cp^＊Ti）2（μ- O）（μ-O）2]2Ti （Cp^＊ = C5Me5） （2） have been investigated as the precatalysts for syndiospecific polymerization of styrene. In the presence of modified methylaluminoxane （MMAO） as a cocatalyst, complexes 1 and 2 display much higher catalytic activities towards styrene polymerization, and produce the higher molecular weight polystyrenes with higher syndiotacticities and melting temperatures （Tm） than the mother complex Cp^＊TiCl3 does when the polymerization temperature is above 70℃ and the Al/Ti molar ratio is in the low range especially.
基金
This work was financially supported by the National Natural Science Foundation of China and SINOPEC (No. 20334030)
by the National Basic Research Program of China (No. 2005CB623801).
