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- Title
Stereo- and Temporally Controlled Coordination Polymerization Triggered by Alternating Addition of a Lewis Acid and Base.
- Authors
Liu, Bo; Cui, Dongmei; Tang, Tao
- Abstract
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 iBu3 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.
- Subjects
POLYMERIZATION -- Methodology; LEWIS acidity; PYRIDINE synthesis; ISOPRENE; STYRENE
- Publication
Angewandte Chemie, 2016, Vol 128, Issue 39, p12154
- ISSN
0044-8249
- Publication type
Article
- DOI
10.1002/ange.201605038