摘要:
Compositions comprising Group 4 metal complexes in the +2 or +3 formal oxidation state and containing an anionic pentadienyl ligand or a substituted derivative thereof and activating cocatalysts are used as catalysts for polymerizing olefins, diolefins and/or acetylenically unsaturated monomers. Monovinylidene aromatic monomers in particular are polymerized to form highly syndiotactic polymers.