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设计、合成了一个带有横挂三联苯侧基的手性乙烯基单体——(+)-甲基丙烯酸-2,5-二[4′-((S)-2-甲基丁氧基)苯基]苄酯,进行了普通自由基和原子转移自由基聚合反应.所得聚合物具有比单体低30°左右的比旋光度,且在侧基的紫外吸收处呈现明显不同于单体的Cotton效应,说明其主链可能形成了具有相反旋光方向的螺旋构象.在所研究范围内,聚合条件对聚合物的旋光度没有明显的影响.在分子量较小时,聚合物的比旋光度随着分子量的增加而降低,说明主链螺旋构象的贡献在增大,而当分子量达到一定值后,聚合物的比旋光度不再随分子量的增加而显著变化.
A chiral vinyl monomer with (-) - (+) - methylacrylate-2,5-bis [4 ’- ) Phenyl] benzyl was synthesized by the free radical and atom transfer radical polymerization.The resulting polymer had a specific rotation of about 30 ° lower than that of the monomer and showed a significantly different UV absorbance at the side groups compared with the single Cotton effect of the body shows that the main chain may form a helical conformation with the opposite direction of rotation.In the studied range, the polymerization conditions have no significant effect on the optical rotation of the polymer.When the molecular weight is small, the specific rotation of the polymer Decrease with the increase of molecular weight, indicating that the contribution of the helical conformation of the main chain is increasing. When the molecular weight reaches a certain value, the specific optical rotation of the polymer no longer changes significantly with the increase of the molecular weight.