Abstract: | A family of unsymmetrical 1,2‐bis(imino)acenaphthene‐palladium methyl chloride complexes 1‐2,6‐{(C6H5)2CH}2‐ 4‐{C(CH3)3}‐C6H2N]‐2‐(ArN)C2C10H6]PdMeCl (Ar = 2,6‐Me2Ph Pd1 , 2,6‐Et2Ph Pd2 , 2,6‐iPr2Ph Pd3 , 2,4,6‐Me3Ph Pd4 , 2,6‐Et2‐4‐MePh Pd5 ) have been prepared and fully characterized by 1H/13C NMR, FTIR spectroscopies, and elemental analysis. X‐ray diffraction analysis of Pd2 complex revealed a square planar geometry. Upon activation with methylaluminoxane, all the palladium complexes displayed high activities for norbornene (NBE) homo‐polymerization producing insoluble polymer. For the copolymerization of NBE with ethylene, Pd4 complex exhibited good activities with high incorporation of ethylene (up to 59.2–77.4%) and the resultant copolymer showed high molecular weights as maximum as 150.5 kg mol?1. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 922–930 |