The synthesis and characterization of novel mono- and bi-nuclear pyridylimine-type palladium(II) complexes with long chain alkyl groups attached to the imino nitrogen are described. These complexes were evaluated as catalyst precursors for ethylene polymerization under relatively mild reaction conditions. Unlike N-aryl substituted pyridylimine-type analogues, these complexes when activated with methylaluminoxane (MAO) were capable of producing highly linear polyethylene with high molecular weights, the values of which can be tuned from 6 x 105 to I X 106 by varying polymerization temperature and the ratio of Al to Pd. (C) 2002 Elsevier Science B.V. All rights reserved.