Beneficial influence of nanocarbon on the aryliminopyridylnickel chloride catalyzed ethylene polymerization

• The influence of nanocarbons on nickel-catalyzed ethylene polymerization is studied.
• Task specific ligands and nickel complexes were synthesized.
• In all cases, a controlled increase of the polyethylene branching is observed.
• Few layer graphene allows increase of the catalytic activity and molecular weight.

A series of 1-aryliminoethylpyridine ligands (L1―L3) was synthesized by condensation of 2-acetylpyridine with 1-aminonaphthalene, 2-aminoanthracene or 1-aminopyrene, respectively. Reaction with nickel dichloride afforded the corresponding nickel (II) chloride complexes (Ni1–Ni3). All compounds were fully characterized and the molecular structures of Ni1 and Ni3 are reported. Upon activation with methylaluminoxane (MAO), all nickel complexes exhibit high activities for ethylene polymerization, producing waxes of low molecular weight and narrow polydispersity. The presence of multi-walled carbon nanotubes (MWCNTs) or few layer graphene (FLG) in the catalytic medium can lead to an increase of productivity associated to a modification of the polymer structure.