Novel nickel (II) complexes chelating β‐diketiminate ligands: synthesis and simultaneous polymerization and oligomerization of ethylene

Two novel nickel (II) complexes, CH{C(CF3)NAr}2NiBr (1, Ar = 2,6-iPr2C6H3 and 2, 2,6-Me2C6H3), were synthesized by the reaction of the lithium salt of fluorinated β-diketiminate backbone ligands with (1,2-dimethoxyethane) nickel (II) bromide [(DME)NiBr2]. The solid-state structure of nickel (II) complex 2 as a dimer reveals four-coordination and a tetrahedral geometry with bromide bridged by single crystal X-ray measurement. Both complexes catalyze simultaneous polymerization and oligomerization of ethylene when activated by methylaluminoxane (MAO). It was found that the reaction temperature has a pronounced effect on the activity of ethylene polymerization and the molecular weight of obtained polyethylene. In addition, the nickel catalytic systems predominantly produce linear polyethylene with unsaturated end groups. Copyright © 2006 John Wiley & Sons, Ltd.

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