Alternating Sequence Control for Carboxylic Acid and Hydroxy Pendant Groups by Controlled Radical Cyclopolymerization of a Divinyl Monomer Carrying a Cleavable Spacer
Alternating Sequence Control for Carboxylic Acid and Hydroxy Pendant Groups by Controlled Radical Cyclopolymerization of a Divinyl Monomer Carrying a Cleavable Spacer
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DOI：
10.1002/anie.201607169
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发表时间：
2016-11-14
影响因子：
16.6
通讯作者：
Sawamoto, Mitsuo
中科院分区：
文献类型：
--
作者：
Ouchi, Makoto;Nakano, Marina;Sawamoto, Mitsuo
利用半缩醛酯（HAE）键易于由乙烯醚和羧酸形成，易于裂解成不同的官能团（-COOH和-OH）的特点，我们实现了乙烯基共聚物两个官能团的交替序列控制。甲基丙烯酸酯和丙烯酸酯基乙烯基通过HAE键连接，制备了可切割的二乙烯基单体，并在钌催化活性自由基聚合的优化条件下进行了环聚合。通过碳-13核磁共振光谱分析，在合成的环垂体中，随后的HAE键裂解导致由甲基丙烯酸和丙烯酸2-羟乙酯单元交替组成的共聚物。-COOH和-OH悬垂的交替序列在醚溶剂中具有较低的临界溶解温度（LCST），而相同组成比的无规共聚物没有观察到这一点。
By utilizing features of the hemiacetal ester (HAE) bond: easy formation from vinyl ether and carboxylic acid and easy cleavage into different functional groups (-COOH and -OH), we achieved control of the alternating sequence of two functional pendant groups of a vinyl copolymer. Methacrylateand acrylate-based vinyl groups were connected through HAE bonds to prepare a cleavable divinyl monomer, which was cyclo-polymerized under optimized conditions in a ruthenium-catalyzed living radical polymerization. Subsequent cleavage of the HAE bonds in the resultant cyclo-pendant led to a copolymer consisting of alternating methacrylic acid and 2-hydroxyethyl acrylate units as analyzed by C-13 NMR spectroscopy. The alternating sequence of -COOH and -OH pendants specifically provided a lower critical solution temperature (LCST) in an ether solvent, which was not observed with the random copolymer of same composition ratio.