Tailoring Polyethylenes by Nickel Complexes Bearing Modified 1‑(2-Benzhydryl­naphthylimino)-2-phenylimino­acenaphthylene Derivatives

A series of 1-(2-benzhydryl­naphthylimino)-2-phenylimino­acenaphthylene derivatives (<b>L1</b>–<b>L5</b>) was synthesized, characterized, and then reacted with (DME)­NiBr₂ to form the corresponding [1-(2-benzhydryl­naphthylimino)-2-phenylimino­acenaphthyl]­nickel bromides (<b>C1</b>–<b>C5</b>). All nickel complexes were fully characterized by their FT-IR spectra and elemental analysis. The molecular structures of the representative complexes <b>C1</b> and <b>C4</b> 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

Enhancing the Activity and Thermal Stability of Nickel Complex Precatalysts Using 1‑[2,6-Bis(bis(4-fluorophenyl)methyl)-4-methyl phenylimino]-2-aryliminoacenaphthylene Derivatives

The series of acenaphthylene-1-[2,6-bis­(bis­(4-fluorophenyl)­methyl)-4-methylphenylimino]-2-arylimine derivatives and their dichloronickel complexes were synthesized and fully characterized as well as the single-crystal X-ray diffraction of representative nickel complexes, revealing a distorted tetrahedral geometry. Upon activation with either MAO or Et₂AlCl, all nickel complexes showed high activities in ethylene polymerization; moreover, their catalytic systems showed better thermal stabilities on being manipulated at 80 °C as the industrial operating temperature