Ethylene homopolymerization and copolymerization with functionalized 5-norbornen-2-yl monomers by a novel nickel catalyst system

The homopolymerization and the copolymerization of ethylene with functionalized 5-norbornen-2-yl derivatives by the nickel catalyst system L(Pr-i(2))Ni(eta(1)-CH2Ph)(PMe3) (1) [L = N-(2,6-diisopropylphenyl)-2-(2,6-diisopropylphenylimino)propanamideI and Ni(COD)(2) (bis(1,5-cyclooctadiene)nickel) produces polymers with high molecular weights and narrow molecular weight distributions. A typical ethylene polymerization reaction proceeds under 100 psi of ethylene and at 20 degreesC, using 1 (0.34 mM) and Ni(COD)(2) (0.83 mM). Likewise, under similar conditions, the copolymerization of ethylene with 5-norbornen-2-yl acetate (3) (0.15 M) for 90 min by 1 (0.67 mM) and Ni(COD)(2) (1.67 mm) produced a high molecular weight functionalized polyethylene bearing ester functionalities. 5-Norbornen-2-ol (0.15 M) underwent a similar copolymerization with ethylene for 20 min to yield a hydroxy-functionalized polyethylene. Narrow molecular weight distributions, coupled with the increase of polymer molar mass with time, are consistent with a quasi-living polymerization process in the case of ethylene homopolymerization and ethylene copolymerization with 3.