Biphenylamine Adjusted Bis(arylimino)Acenaphthene‐Nickel Catalysts for Ultra‐High‐Molecular‐Weight and Highly Branched Polyethylenes

ABSTRACT Employing 3,3',5,5'‐tetraisopropyl‐[1,1'‐biphenyl]‐4,4'‐diamine and six para ‐R substituted 2,6‐bis(benzhydryl)phenylamines (R = Me, i Pr, OMe, OCF 3 , Cl, F), a series of bis(arylimino)acenaphthene‐nickel (II) bromides, [1‐[2,6‐{(C 6 H 5 ) 2 CH} 2 ‐4‐R‐C 6 H 2 N]‐2‐[4'‐NH 2 ‐3,3',5,5'‐{(CH 3 ) 2 CH} 4 ‐1,1'‐(C 6 H 2 ) 2 ‐C 2 C 10 H 6 ]NiBr 2 ( Ni1, Ni2, Ni4 − Ni7 ) along with our previous two relative nickel complexes Ni3 and Ni8 (R = t Bu, NO 2 ), has all been synthesized in good yields and well characterized by FT‐IR, EA and X‐ray diffraction measurements. The molecular structures of nickel complexes indicate that the large steric hindrances of N‐ aryl groups build nest for core nickel in axial position. In the presence of AlMe 3 or Me 2 AlCl, all nickel complexes exhibit high activities with a maximum activity up to 15.1 × 10 6 g (PE) mol −1 (Ni) h −1 , producing high‐molecular‐weight polyethylenes (M n :2.9−9.2 × 10 5 g mol −1 ) along with narrower dispersities (PDI: 1.9−2.4). All polyethylenes obtained are highly branched with the branching content strongly affected by the combination of the structural complexes and the co‐catalyst employed. Moreover, the resultant polyethylenes perform excellent elastic properties, being polyethylene elastomers (PEE) as newly promising thermoplastic elastomer (TPE).