Macrocyclic Trinuclear Nickel Phenoxyimine Catalysts for High-Temperature Polymerization of Ethylene and Isospecific Polymerization of Propylene

• DOI: 10.1021/acs.macromol.7b00996
• Publication Date: 2017-08-16T18:52:13Z
• Authors: Zhongtao Chen; Xiangxiang Zhao; Xinyi Gong; Di Xu; Yuguo Ma
• Keywords: Tacticity; Coordination polymerization; Chain transfer; Thermal Stability; Molar mass distribution

A series of macrocyclic multinucleating phenoxyimine ligands and the corresponding neutral binuclear (2-Ni2) trinuclear (3-Ni3) nickel catalysts have been efficiently synthesized. The complex 3-Ni3 showed high activity, thermal stability, slow chain transfer in ethylene polymerization, thus producing polyethylene with molecular weight low branch density. Highly regiospecific isospecific polymerization propylene was also achieved 3-Ni3, generating regioregular highly isotactic Tm crystallinity. This is first example regio- stereocontrolled promoted by catalysts. Statistical analysis suggested selective 1,2-insertion enantiomorphic site control mechanism propagation step, likely caused unique steric effect potential cooperative effect.