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Stereo‐ and Temporally Controlled Coordination Polymerization Triggered by Alternating Addition of a Lewis Acid and Base
Author(s) -
Liu Bo,
Cui Dongmei,
Tang Tao
Publication year - 2016
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201605038
Subject(s) - lewis acids and bases , polymerization , isoprene , selectivity , chemistry , polymer chemistry , copolymer , pyridine , polystyrene , reagent , photochemistry , combinatorial chemistry , polymer , catalysis , organic chemistry
Significant progress has been made with regard to temporally controlled radical and ring‐opening polymerizations, for example, by means of chemical reagents, light, and voltage, whereas quantitative switch coordination polymerization is still challenging. Herein, we report the temporally and stereocontrolled 3,4‐polymerization of isoprene through allosterically regulating the active metal center by alternating addition of Lewis basic pyridine to “poison” the Lewis acidic active metal species through acid–base interactions and Lewis acidic Al i Bu 3 to release the original active species through pyridine abstraction. This process is quick, quantitative, and can be repeated multiple times while maintaining high 3,4‐selectivity. Moreover, this strategy is also effective for the switch copolymerization of isoprene and styrene with dual 3,4‐ and syndiotactic selectivity. Tuning the switch cycles and intervals enables the isolation of various copolymers with different distributions of 3,4‐polyisoprene and syndiotactic polystyrene sequences.