Bispentiptycenyl–Diimine–Nickel Complexes for Ethene Polymerization and Copolymerization with Polar Monomers

2019-01-11T18:49:34Z (GMT) by Yuki Kanai Sabine Foro Herbert Plenio
Ni<sup>2+</sup> coordinated within a bowl-shaped diimine ligand with two pentiptycenyl-substituents [(diimine)­NiBr<sub>2</sub>] displays excellent activity for the polymerization of ethene (7 atm) with activities of up to 34 × 10<sup>3</sup> kg­(mol Ni)<sup>−1</sup> h<sup>–1</sup> following activation with Et<sub>2</sub>AlCl. The resulting polymer is characterized by high molecular weights (<i>M</i><sub>n</sub> = 150 × 10<sup>3</sup> g·mol<sup>–1</sup>), low branching (12/1000 C), and a high melting point (<i>T</i><sub>m</sub> = 133 °C). The polymerization of ethene with polar comonomers leads to the formation of the respective polar polymers with very efficient incorporation of comonomer. The activity of the catalyst critically depends on the molar ratio of Et<sub>2</sub>AlCl activator and the polar functional group.