Neutral nickel complexes chelating monoamidinate ligands: Syntheses, characterizations and catalytic properties toward ethylene oligomerization and norbornene polymerization

Three new neutral monoamidinate nickel complexes [(2,6-iPr–C6H3)NC(Ar1)–N(Ar2)]Ni(Ph)(PPh3) (1, Ar1 = phenyl, Ar2 = 2,6-diispropyphenyl; 2, Ar1 = p-tolyl, Ar2 = 2,6-dimethylphenyl; 3, Ar1 = p-tolyl, Ar2 = pentafluorophenyl) have been synthesized and characterized. The molecular structure of 3 has been determined by X-ray diffraction analysis. The nickel complexes activated with MAO were found to exhibit very high activity, up to 1.94 × 107 g PNBE/(mol Ni h), for vinyl-addition polymerization of norbornene and oligomerize ethylene producing a mixture of dimers and trimers with a moderate turnover frequency.

Graphical abstractThree monoamidinate nickel complexes were synthesized, characterized and used as pre-catalyst for ethylene oligomerization and norbronene polymerization. The nickel complexes oligomerized ethylene producing a mixture of dimers and trimers with a moderate turnover frequency, while exhibited very high activity for the vinyl-addition polymerization of norbornene in the presence of MAO.Figure optionsDownload full-size imageDownload as PowerPoint slide