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Rapid Syndiospecific (Co)Polymerization of Fluorostyrene with High Monomer Conversion
Author(s) -
Wang Zichuan,
Wang Meiyan,
Liu Jingyao,
Liu Dongtao,
Cui Dongmei
Publication year - 2017
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201704584
Subject(s) - polymerization , chemistry , ligand (biochemistry) , steric effects , styrene , monomer , polymer chemistry , photochemistry , copolymer , catalysis , methylene , fluorine , chelation , medicinal chemistry , stereochemistry , organic chemistry , polymer , biochemistry , receptor
Fluoromonomers are difficult to polymerize through a coordination mechanism owing to the strong chelation between fluorine and catalysts and the electron‐deficient double‐bond. We report herein the unprecedented polymerization of para ‐fluorostyrene ( p FS) with excellent activity (1.12×10 7 g mol Ln −1 h −1 ), distinguished syndioselectivity ( rrrr >99 %) and high conversion (98.4 %) using rare‐earth‐metal catalysts bearing a pyridyl methylene fluorenyl ligand. DFT calculations reveal polar fluorine loses overwhelming coordination priority to the active central metal ion due to the sterically bulky and electron‐donating CGC‐ligand, thus its power of poisoning the active species is dramatically weakened. Based on this, copolymerization of p FS and styrene (St) has been successfully achieved with high activity and controllable p FS insertion. Conversely, the unlinked half‐sandwich rare‐earth‐metal system shows relatively lower activity, because both the transition‐states and intermediates incorporate a μ 1 ‐F chelated p FS.