| abstract |
A catalyst composition comprising: a) (i) a catalyst containing at least one cycloalkadienyl ligand substituted with at least one electron donor residue and coordinated with a metal selected from the group consisting of scandium, yttrium, and lanthanide metals; or (ii) a catalyst containing two cycloalkadienyl ligands coordinated with a metal selected from the group consisting of scandium, yttrium, and lanthanide metals, said cycloalkadienyl ligands connected by a bridging group comprising at least one Group IVA element and at least one electron donor residue; and b) an activating cocatalyst of the formula R x M', wherein R is alkyl, aryl, or hydride; M' is a Group I, II, or IIIA metal or a Group I, II, or IIIA metal complexed with oxygen, nitrogen, or a halide; and x is equal to the valence of M'. |