Finely tuned nickel complexes as highly active catalysts affording branched polyethylene of high molecular weight: 1-(2,6-Dibenzhydryl-4- methoxyphenylimino)-2-(arylimino)acenaphthylenenickel halides

A series of unsymmetrical 1,2-bis(imino)acenaphthenenickel(II) halides containing N-2,6-dibenzhydryl-4-methoxyphenyl – a single bulky group with adjusted electron donating properties – has been synthesized and characterized. These compounds adopt distorted tetrahedral geometry and their 1H NMR spectra show the paramagnetically shifted peaks. On activation with a low amount of Et2AlCl or ethylaluminum sesquichloride (EASC), these nickel complexes display high activity in ethylene polymerization, yielding the polyethylene of high molecular weight. They are also stable at elevated temperature; superb activity of 2.51 × 106 g of PE (mol of Ni)−1 h−1 can be attained at 90 °C. The resultant polyethylene exhibits remarkable tensile strength of 24.5 MPa and high elongation at break (602.2%) as well as substantial elastic recovery. A new family of 1-(2,6-dibenzhydryl-4-methoxyphenylimino)-2-(arylimino) acenaphthylenenickel halides utilized as highly active and thermostable catalysts of ethylene polymerization produce ultra-high-molecular-weight polymer of remarkable physical properties. [Display omitted] •Highly active and thermostable nickel precatalyst.•Hyperbranched and ultra-high molecular weight polyethylene.•Novel thermoplastic elastomers.•Good mechanical properties (tensile strength, elongation at break and elastic recovery).•Solely polymerizing ethylene by nickel precatalyst.