Abstract: Novel iron and cobalt complexes of certain novel tricyclic ligands containing a “pyridine” ring and substituted with two imino groups are polymerization and/or oligomerization catalysts for olefins, especially ethylene. Depending on the exact structure of the ligand, and polymerization process conditions, products ranging from ?-olefins to high polymers may be produced. The polymers, especially polyethylenes, are useful for films and as molding resins.

Abstract: Olefins are polymerized by novel transition metal complexes of selected iminocarboxylate and iminoamido ligands, sometimes in the presence of cocatalysts such as alkylaluminum compounds or neutral Lewis acids. Olefins which may be (co)polymerized include ethylene, ?-olefins, and olefins containing polar groups such as olefinic esters for example acrylate esters. Also described are certain “Zwitterionic” transition metal complexes as polymerization catalysts for making polar copolymers. The resulting polymers are useful as thermoplastics and elastomers.