规整度是影响合成高分子材料性能的关键因素。
该文中,研究人员介绍了一种用于乙烯基醚阳离子聚合的手性有机Brnsted酸催化剂,1,1′-bi-2-萘酚衍生的N,N′-二(三氟基)磷酰胺咪酸盐(PADI),首次实现乙烯醚与三硫代碳酸酯链转移剂的有机催化、高度立体选择性、阳离子可逆加成-碎裂链转移(RAFT)聚合。该无金属RAFT工艺可以在低催化剂负载量(低至200 ppm)下提供具有高立体选择性、可控分子量和窄分散性的等规聚乙烯醚。
此外,通过从立体选择性阳离子RAFT聚合到可见光调节阳离子和自由基RAFT聚合的机械转换,三硫代碳酸酯链端允许链延伸以合成包含等规聚(乙烯基醚)嵌段的二嵌段共聚物。
附:英文原文
Title: Organocatalytic, Stereoselective, Cationic Reversible Addition–Fragmentation Chain-Transfer Polymerization of Vinyl Ethers
Author: Xun Zhang, Zan Yang, Yu Jiang, Saihu Liao
Issue&Volume: December 30, 2021
Abstract: Tacticity is a crucial factor affecting the properties of synthetic polymer materials. Here, we introduce a type of chiral organic Brnsted acid catalyst, 1,1′-bi-2-naphthol-derived N,N′-bis(triflyl)phosphoramidimidates (PADIs), for the cationic polymerization of vinyl ethers, which enables the development of the first organocatalytic, highly stereoselective, cationic reversible addition–fragmentation chain-transfer (RAFT) polymerization of vinyl ethers with a trithiocarbonate chain-transfer agent. This metal-free RAFT process could afford isotactic poly(vinyl ethers) with high stereoselectivity, controllable molecular mass, and narrow dispersity at low catalyst loadings (as low as 200 ppm). Moreover, the trithiocarbonate chain-end allows for chain extension to synthesize diblock copolymers comprising an isotactic poly(vinyl ether) block, by a mechanistic switching from stereoselective cationic RAFT polymerization to visible-light-regulated cationic and radical RAFT polymerization.
DOI: 10.1021/jacs.1c11501
Source: https://pubs.acs.org/doi/10.1021/jacs.1c11501
JACS:《美国化学会志》,创刊于1879年。隶属于美国化学会,最新IF:14.612
官方网址:https://pubs.acs.org/journal/jacsat
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