•Novel (μ-O){η3-(2,6-Et2-4-R-C6H2) N(Ph)CCHSiMe2NMe2ZrCl2}2, [R = Me (C1) and H (C2)].•The air-sensitive azaallylzirconium species were stabilized by the oxo-bridge.•Both azaallylzirconium complexes exhibited notable catalytic activities toward ethylene polymerization.•Obtained polyethylenes possess high molecular weights.The oxo-bridged azaallylzirconium chlorides (μ-O){η3-(2,6-Et2-4-R-C6H2) N(Ph)CCHSiMe2NMe2ZrCl2}2, [R = Me (C1) and H (C2)] have been prepared in reasonable yields from the reactions of zirconium tetrachloride and the correspondent ligands, Me2NMe2SiCH2(Ph)CN(2,6-Et2-4-R-C6H2). The representative complex C1 was crystallized and identified by the single-crystal X-ray diffraction, indicating oxo-bridged dinuclear azaallylzirconium structure. Both azaallylzirconium complexes exhibited notable catalytic activities toward ethylene polymerization in the presence of MAO, and obtained polyethylenes possess high molecular weights.Download high-res image (62KB)Download full-size image

A series of 1-(2-benzhydrylnaphthylimino)-2-phenyliminoacenaphthylene derivatives (L1–L5) was synthesized, characterized, and then reacted with (DME)NiBr2 to form the corresponding [1-(2-benzhydrylnaphthylimino)-2-phenyliminoacenaphthyl]nickel bromides (C1–C5). All nickel complexes were fully characterized by their FT-IR spectra and elemental analysis. The molecular structures of the representative complexes C1 and C4 were also determined by single-crystal X-ray diffraction. On activation with either methylaluminoxane (MAO) or diethylaluminum chloride (Et2AlCl), all title nickel complexes showed high activities toward ethylene polymerization; the resulting polyethylenes showed molecular weights higher than those obtained by using the nickel analogues bearing (2-benzhydrylnaphthylimino)pyridines and also had branches lower than those obtained by using other diiminoacenaphthylnickel analogues. Therefore, the modification of ligands could affect the catalytic behavior of their nickel complexes in order to tailor the molecular weights and branches of the resulting polyethylenes.