Development of pi-conjugated helical polymers bearing both molecular recognition sites and dynamically axial chirality in the main chain

合成了以冠醚为主链分子识别位点的聚（联苯乙烯-邻苯乙烯）衍生物，并利用圆二色性（CD）光谱研究了聚合物与旋光性氨基酸和胺络合后的手性诱导和诱导的螺旋构象的稳定性，以构建新型螺旋共轭聚合物。所得聚合物与手性客体络合后，在氯仿-乙腈（1/9）中折叠成优选的手性螺旋构象。用非手性客体取代手性客体后，高分子的诱导螺旋度得以维持，聚合物的构象随溶剂的变化在优选手螺旋和随机螺旋之间发生可逆的变化。这是大分子螺旋记忆能够可逆构象变化的第一个例子。

Poly(biphenyleneethynylene-alt-phenyleneethynylene) derivatives bearing crown ether moieties as molecular recognition sites in the main chains were synthesized, and chirality induction in the obtained polymers upon complexation with optically active amino acids and amines and the stability of the induced helical conformation were investigated by using circular dichroism (CD) spectroscopy in order to construct novel helical pi-conjugated polymers. The obtained polymers folded into a preferred-handed helical conformation in chloroform-acetonitrile (1/9) upon complexation with chiral guests. After replacement of the chiral guests with achiral guests, the induced macromolecular helicity could be maintained and the polymer showed a reversible conformational change between preferred-handed helix and random coil in response to change in solvents. This is the first example of macromolecular helicity memory capable of reversible conformational change.