Cyclopenta[I]phenanthrene titanium trichloride derivatives: syntheses, crystal structure and properties as catalysts for styrene polymerization

Cyclopentalljphenanthrene titanium trichloride and its 2-methyl and phenyl derivatives were synthesized; the crystal structure of the 2-mcthyl-substituted complex was determined by X-ray diffraction analysis. In the presence of methylalumoxane (MAO), these complexes give highly active catalysts for the syndiotactic polymerization of styrene; the 2-phenyl-substituted complex exceeds all previously described catalysts in its catalytic activity.