具有光学活性的3,5-二(烷基羰基-胆固醇)苯乙烯螺旋聚合物的奇偶效应

根据胆固醇含多个手性中心,将其引入到聚苯乙烯的侧链中,合成了一系列侧基含有手性链胆固醇基团的螺旋聚合物。这些无定形聚合物都有良好的热稳定性,随着柔性链上碳原子个数的增加,玻璃化转变温度逐渐降低。表征发现所有聚合物都为手性的螺旋结构聚合物,且随着柔性链的增长,所有的CD图上的科顿效应转变为同时含有正负科顿效应,最后转变为几乎只含有负科顿效应的现象,证明了手性胆固醇上的柔性链对聚合物分子的螺旋排列有着较大的影响。

Odd-Even Effect in a Series of Helical Polymers of Optically Active 3,5-Bis (alkoxycarbonyl-cholesterol) Styrene

Owing to the multiple chiral centers,cholesterol can be incorporated into polystyrene side chain to polymerize as helical polymer.A series of helical polymers containing chiral groups were synthesized.All of the amorphous polymers have good thermal stability.The glass transition temperature reduces gradually with the increasing number of the flexible chain carbon atoms.The polymers have helical structures because that the positive and negative Cotton effect can be found.With the growth of flexible chains,Cotton effect on all CD charts gradually changes from the only positive Cotton effect into both positive and negative Cotton effect.Chiral cholesterol flexible chains have great effect on the spiral arrangement of polymer molecules.