L-丙烯酸薄荷酯与2,5-二(4'-己氧基苯基)苯乙烯无规共聚物的合成和旋光性质  

SYNTHESIS AND CHIROPTICAL PROPERTIES OF RANDOM COPOLYMERS OF L-MENTHYL ACRYLATE AND 2,5-BIS(4′-HEXYLOXYPHENYL)STYRENE

作　　者：崔家喜[1] 宛新华[1] 

机构地区：[1]北京分子科学国家实验室高分子化学与物理教育部重点实验室北京大学化学学院高分子科学与工程系,北京100871

出　　处：《高分子学报》2011年第10期1202-1207,共6页Acta Polymerica Sinica

基　　金：国家自然科学基金(基金号21074001);中国博士后科学基金(基金号20080440249和200902012)资助项目

摘　　要：通过自由基共聚合制备了一系列L-丙烯酸薄荷酯(L-MtA)与2,5-二(4'-己氧基苯基)苯乙烯(BHPSt)的共聚物L-MtA(x)-co-BHPSt(1-x).利用UV-Vis和1H-NMR光谱表征了共聚物的组成,根据Kelen-Tüds(K-T)方法计算得到的L-MtA和BHPSt的竞聚率分别为0.36和2.46,说明两结构单元在聚合物链中倾向于无规排列.当BHPSt含量较少时,共聚物在三联苯侧基的紫外吸收区呈现明显的Cotton效应,说明某种手性结构的形成;而当BHPSt含量足够大时,共聚物具有和光学活性螺旋链聚{(+)-2,5-二[4'-((S)-2-甲基丁氧基)苯基]苯乙烯}(PMBPS)类似的圆二色光谱,说明BHPSt链段能够形成稳定的螺旋构象,且由于L-MtA单元的手性诱导,其旋向在某一方向占优.A series of copolymers based on L-menthyl acrylate（L-MtA） and 2,5-bis（4′-hexyloxyphenyl）styrene（BHPSt）,namely L-MtA（x）-co-BHPSt（1-x）,were prepared via conventional radical copolymerization.UV-Vis absorption and 1H-NMR spectra were used to determine the compositions of the resultant copolymers.Based on the copolymer composition from UV-Vis absorption spectra,the reactivity ratios of BHPSt（rBHPSt） and L-MtA（rL-MtA） were estimated as 2.46 and 0.36,respectively,with Kelen-Tüds linearization method,implying a random nature of the copolymer.All the copolymers displayed chiroptical properties distinguished from the corresponding monomer mixtures,an indicative of the formation of new chiral structure.When the content of PHPSt was large enough,the copolymer exhibited CD patterns similar with that of optically active helical poly{（＋）-2,5-bis[4′-（（S）-2-methylbutoxy）phenyl]styrene},suggesting BHPSt segment was long enough to form stable helical conformation and an excess of screw sense was induced by chiral L-MtA.This work provides an efficient and simple method to obtain optically active helical polymers from achiral vinyl monomer through radical polymerization.

关 键 词：比旋光度 旋光性共聚物 手性传递 自由基聚合 竞聚率 

分 类 号：O631.3[理学—高分子化学]