Stereo- and Temporally Controlled Coordination Polymerization Triggered by Alternating Addition of a Lewis Acid and Base
Stereo- and Temporally Controlled Coordination Polymerization Triggered by Alternating Addition of a Lewis Acid and Base
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交替添加路易斯酸和碱引发的立体和时间控制配位聚合
DOI：
10.1002/anie.201605038
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发表时间：
2016-09-19
影响因子：
16.6
通讯作者：
Tang, Tao
中科院分区：
文献类型：
--
作者：
Liu, Bo;Cui, Dongmei;Tang, Tao
在时间控制的自由基和开环聚合方面已经取得了重大进展，例如，通过化学试剂、光和电压，而定量开关配位聚合仍然具有挑战性。在此，我们报道了异构调控异戊二烯3，4-聚合的时间和立体控制，通过交替加入刘易斯碱性吡啶，通过酸碱相互作用“毒害”刘易斯酸性活性金属物种，和刘易斯酸性AliBu（3），通过吡啶提取释放原始活性物种。这个过程是快速的，定量的，可以重复多次，同时保持高的3，4-选择性。此外，该策略对具有3，4-和间同立构双重选择性的异戊二烯和苯乙烯的开关共聚合也是有效的。调节开关周期和间隔使得能够分离具有不同分布的3，4-聚异戊二烯和间同立构聚苯乙烯序列的各种共聚物。
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 AliBu(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.