Ethylene Polymerizations Catalyzed by Fluorinated "Sandwich" Diimine-Nickel and Palladium Complexes.

Nickel and palladium complexes bearing "sandwich" diimine ligands with perfluorinated aryl caps have been synthesized, characterized, and explored in ethylene polymerization reactions. The X-ray crystallographic analysis of the precatalysts and shows differences from their nonfluorinated analogues and , with the perfluorinated aryl caps centered precisely over the nickel and palladium centers, which results in higher buried volumes of the metal centers relative to the nonfluorinated analogues. The sandwich diimine-palladium complexes and containing perfluorinated aryl caps polymerize ethylene in a controlled fashion with activities that are substantially increased compared with their nonfluorinated analogues.