Effect of N‐Aryl Para‐Benzhydryl Substituent on the Thermal Stability of α‐Diimine Nickel Catalyst

Abstract

The thermal stability of α‐diimine nickel catalysts has always been the focus of research. The introduction of large groups in the backbone or N‐aryl ortho‐position is a relatively mature solution. However, the question of whether the N‐aryl bond rotation is a factor affecting the thermal stability of nickel catalysts is still open. In this work, the effects of N‐aryl para‐benzhydryl substitutes on catalyst thermal stability are investigated, and the results of ethylene polymerization and the factors affecting thermal stability (steric effect, electronic effect, five‐membered coordination ring stability, N‐aryl bond rotation, etc.) are systematically analyzed. It is believed that the introduction of large steric hindrance groups at the N‐aryl para‐position hinders the rotation of the N‐aryl bond. This obstacle effect is beneficial to improving catalyst thermal stability, and the obstacle capacity is weakened with the increase of ortho‐substituent size.