Dramatic Effect of Heteroatom Backbone Substituents on the Ethylene Polymerization Behavior of Bis(imino)pyridine Iron Catalysts

Bis(imino)pyridine iron complexes bearing ether and thioether backbone substituents have been synthesized and evaluated for the polymerization of ethylene. The methoxy derivative is inactive whereas bulky phenoxides or thioether derivatives afford activities as high as the most active systems reported to date.