茂金属催化剂催化苯乙烯间规聚合 Ⅱ.Cp Ti(CH_2SiMe_3)_3/B(C_6F_5)_3的结构与活性中心

SYNDIOSPECIFIC POLYMERIZATION OF STYRENECATALYZED BY METALLOCENE CATALYSTSⅡ. Structure and Active Species of Cp*Ti(CH2SiMe3)3/B(C6F5)3

茂金属催化剂催化苯乙烯间规聚合＊Ⅱ．Ｃｐ＊Ｔｉ（ＣＨ２ＳｉＭｅ３）３／Ｂ（Ｃ６Ｆ５）３的结构与活性中心许光学（中山大学高分子研究所，广州５１０２７５）关键词阳离子配合物，茂金属化合物，均相催化剂，苯乙烯，间规聚合分类号Ｏ６４３／ＴＱ３２有关茂钛催化体...

The reaction of Cp*Ti(CH2SiMe3)3 solution with equimolar amount of B(C6F5)3 in hexane/toluene (volumic ratio 5) at 243 K resulted in almost quantitative formation of a new complex [Cp*Ti(CH2SiMe3)2]+[B(CH2SiMe3)(C6F5)3]-, which is identified by elemental analysis, 1H NMR and 13C NMR. The complex was thermally unstable and turned deep yellow liquid at RT. The addition of toluene to CD2Cl2 solution of the complex led to only partial conversion of the complex to [Cp*Ti(CH2SiMe3)2(η6PhMe)]+[B(CH2SiMe3)(C6F5)3]-, identified by 1H NMR. The complex has been investigated by ESR. At RT the formation of Ti(Ⅲ) cation [Cp*Ti(CH2SiMe3)]+ has been observed. The spectroscopic data combined with the polymerization activity measurement suggest that the Ti(Ⅲ) cation is the active species for styrene syndiospecific polymerization.