| abstract |
Novel titanium or zirconium complexes containing one and only one cyclic delocalized, anionic, .pi.-bonded, group, said complexes corresponding to formula (I), wherein: M is titanium or zirconium in the +2 formal oxidation state; L is a group containing a cyclic, delocalized, anionic, .pi.-system through which the group is bound to M, and which group is also bound to Z: Z is a moiety bound to M via a .sigma.-bond, comprising boron, or a ember of Group 14 of the Periodic Table of the Elements, and also comprising nitrogen phosphorus, sulfur or oxygen, said moiety having up to 60 non-hydrogen atoms; and X is a neutral, conjugated or nonconjugated diene, optionally substituted with one or snore hydrocarbyl groups, said X having up to 40 carbon atoms and forming a .pi.-complex with M; are catalytically activated for use as addition polymerization catalysts. Preferably, L is an optionally substituted cyclopentadienyl or fused ring cyclopentadienyl group. |