Highly Isoselective Coordination Polymerization of ortho- Methoxystyrene with b-Diketiminato Rare-Earth-Metal Precursors**
作者:Dongtao Liu, Changguang Yao, RongWang,MeiyanWang, ZichuanWang, Chunji Wu, Fei Lin, Shihui Li, Xinhua
关键字:stereoselective coordination, polar ortho-methoxystyrene,cationic b-diketiminato rareearth-metal species

Stereoselective coordination/insertion polymerization of the polar ortho-methoxystyrene has been achieved for the first time by using the cationic b-diketiminato rareearth-metal species. High activity and excellent isoselectivity (mmmm>99%) were acheived. The unmasked Lewis-basic methoxy group does not poison the Lewis-acidic metal center, but instead activates the polymerization through s-p chelation to the active species together with the vinyl group, thus lower the coordination and activation energies as compared with those of styrene derivatives lacking the methoxy group.