Synthesis and polymerization behavior of various substituted indenyl titanium complexes as catalysts for syndiotactic polystyrene

Abstract

Five substituted indenyltrichlorotitanium compounds have been synthesized and characterized by spectroscopic methods and their catalytic behavior for the polymerization of styrene was studied in the presence of methylaluminoxane (MAO) as a cocatalyst. Substituted indenyl ligands include 1,3-dimethyl, 1-methyl, 1-ethyl, 1-isopropyl and 1-(trimethylsilyl)indenyl groups. All five compounds gave extremely pure syndiotactic polystyrene, with conversion rates of at least 95%, and their catalytic properties were compared with the data obtained from the (eta(5)-indenyl)trichlorotitanium-MAO system. The catalytic activity is enhanced by less bulky and better electron-releasing substituents of the indenyl ligand.