Synthesis of constrained geometry catalysts containing indenyl group as a cyclopentadienyl derivative and investigation of their ethylene homo-and copolymerization

Syntheses of two metallocene compounds having constrained geometry are demonstrated. One of them is (t-butylamido)dimethyl(indenyl)silanetitanium [(BDMI)TiCl₂] containing indenyl group as a Cp derivative and Me₂Si as a bridge between indenyl and heteroatom. The other one is (t-butylamido)methylphenyl(indenyl)silanetitanium dichloride[(BMPI)TiCl₂] having indenyl and (Me)(Ph)Si as a bridge. Ethylene homopolymerization and its copolymerization with 1-octene have been investigated with these two catalysts along with a typical Dow CGC, (t-butylamido)dimethyl(tetramethylcyclo-pentadienyl)silanetitanium dichloride to compare polymerization characteristics. The outcome shows that Dow CGC exhibits the highest catalytic activity, but copolymerization reactivity with 1-octene was lower than that of the prepared catalysts. These behaviors can be rationalized by the peculiar electronic effect among catalysts due to the different structures of complexes.