Researchers from Institute of Chemistry of the Chinese Academy of Sciences (CAS), University of East Anglia and Lanzhou Institute of Chemical Physics of the CAS have synthesized 2-[1-(2,6-dibenzhydryl-4-methylphenylimino)ethyl]-6-[1-(arylimino) ethyl]pyridyl cobalt complexes which upon treatment with MAAO exhibits the highest activities reported to date toward ethylene polymerization, with an observed activity of up to 9.87 ×10⁶ g PE mol^-1(Co) h^-1, producing high-Mw (100–330 kg mol^-1) and narrow-M_w/M_n (1.9–4.0) polyethylene.

The molecular weights and the polydispersity indexes of the resultant polyethylenes could be readily controlled by finely tuning the nature of ligands through varying their substituents and modifying the reaction parameters, such as the molar ratio of Al/Co and reaction temperature.

The work has been supported by the National High-tech R&D Program of China (863 Program). The findings have been published in Dalton Trans. (Dalton Trans., 2011, 40, 10209–10214).

Dalton Trans.Paper

The synthetic procedure for 2-[1-(2,6-dibenzhydryl-4-methylphenylimino) ethyl]-6-[1-(arylimino)ethyl]pyridylcobalt(II) dichlorides.