(R=alkyl or aryl) complexes as catalysts for ethylene polymerization

(R=alkyl or aryl) complexes in combination with methylaluminoxane were found to be highly efficient catalysts towards ethylene polymerization. The species with aromatic R groups display higher activity than those with aliphatic ones. This tendency could not be correlated with the electronic properties of the complexes that were evaluated by cyclic voltammetry. The polyethylenes obtained in the catalytic processes were characterized by 1H NMR and DSC.