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Helicity Induction of Polymers in Water and Its Memory

水中聚合物的螺旋诱导及其记忆

基本信息

批准号：
15350065
负责人：
YASHIMA Eiji
金额：
$ 9.34万
依托单位：
Nagoya University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2003
资助国家：
日本
起止时间：
2003 至 2005
项目状态：
已结题

项目摘要

The design and synthesis of helical polymers with controlled helix-sense have aroused considerable interest in recent years because of their unique structures and their possible applications in materials science. Recently, we found that macromolecular helicity with a predominantly one-handed helix could be induced in optically inactive poly(phenylacetylenes) bearing various functional groups upon complexation with chiral amines in DMSO, thus exhibiting an induced circular dichroism (ICD) in the polymer main chain. Moreover, the induced helical structures could be further memorized after replacement of the chiral amines by achiral amines. In this study, we investigated the helicity induction and the memory of helical chirality in water or in organic solvents by means of IR, UV, and CD spectroscopies. We found that the macromolecular helicity of charged poly(phenylacetylene)s induced by small chiral guests in water could be retained by the alternative deposition of achiral polyelectrolyt … More es with opposite charges, resulting in optically active multilayer thin films with a macromolecular helicity memory. This may be a kind of memory of the helicity resulting from helical polymers induced in water.We also demonstrated a novel hierarchical amplification of chirality during the transfer of chiral information from nonracemic guests to the helical systems either at macromolecular and subsequent supramolecular mesoscopic levels. The main chain stiffness with a dynamic helical charged polyacetylene that allows a formation of the liquid crystal (LC) phase is essential for realizing this hierarchical amplification of the chirality system. On the basis of the X-ray analyses, the most plausible helical structure of the LC helical polyacetylene is proposed to be a 23 unit/10 turn (23/10) helix.We further found the dual memory of both the enantiomeric right- and left-handed helical conformations induced in a polyacetylene based on the temperature-and solvent-stimulated helicity inversion of the polymer. The polyacetylene folds into a one-handed helix induced by noncovalent bonding interactions with a single enantiomeric amine. The induced helix underwent a reversible inversion of the helicity by temperature and solvents. The diastereomeric right- and left-handed helices obtained at different temperatures could be further memorized when the optically active amine was replaced by an achiral diamine, generating right- and left-handed helices of the mirror images from each other. Less

具有可控螺旋感的螺旋聚合物由于其独特的结构和在材料科学中的应用前景，近年来引起了人们极大的兴趣。近年来，研究人员发现，含多种官能团的非旋光性聚苯乙炔在DMSO中与手性胺络合后，可诱导出以单手螺旋为主的大分子螺旋，从而在聚合物主链上表现出诱导的圆二色性（ICD）。此外，用非手性胺取代手性胺可以进一步记忆诱导的螺旋结构。本研究利用红外光谱、紫外光谱和CD光谱研究了该化合物在水和有机溶剂中的螺旋性诱导和螺旋手性记忆。我们发现，由小的手性客体在水中引起的带电聚苯乙炔的大分子螺旋度可以通过非手性聚电解质的交替沉积而保留，从而得到具有大分子螺旋度记忆的光学活性多层薄膜。这可能是一种对螺旋聚合物在水中产生的螺旋度的记忆。我们还证明了在大分子和随后的超分子介观水平上，手性信息从非消旋客体转移到螺旋体系时，手性的一种新的层次放大。具有动态螺旋荷电聚乙炔的主链刚度是实现手性体系分层放大的必要条件。在x射线分析的基础上，提出了LC螺旋聚乙炔最合理的螺旋结构为23单位/10转（23/10）螺旋。我们进一步发现，基于温度和溶剂刺激的聚合物螺旋反转，在聚乙炔中诱导了对映体的右旋和左旋螺旋构象的双重记忆。聚乙炔折叠成单手螺旋与单一对映体胺的非共价键相互作用诱导。诱导螺旋在温度和溶剂的作用下发生了可逆的螺旋反转。当光学活性胺被非手性二胺取代时，可以进一步记忆在不同温度下得到的非对映体右旋和左旋螺旋，从而相互产生镜像的右旋和左旋螺旋。少