Helicity induction on a poly(phenylacetylene) derivative bearing a sulfonic acid pendant with chiral amines and memory of the macromolecular helicity in dimethyl sulfoxide
Helicity induction on a poly(phenylacetylene) derivative bearing a sulfonic acid pendant with chiral amines and memory of the macromolecular helicity in dimethyl sulfoxide
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DOI：
10.1295/polymj.pj2006028
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发表时间：
2006-01-01
期刊：
影响因子：
2.8
通讯作者：
Yashima, Eiji
中科院分区：
文献类型：
--
作者：
Hasegawa, Takashi;Maeda, Katsuhiro;Yashima, Eiji
以磺酸残基（poly-1）为侧基的有规立构聚苯乙炔衍生物在二甲基亚砜（DMSO）中通过非共价酸碱相互作用与各种手性胺络合后，形成主要为单手螺旋结构。在鲜明的对比，类似的聚（苯乙炔）的轴承相对较弱的羧基和膦酸残基作为侧基，聚-1-胺配合物表现出弱诱导圆二色性（ICD）在聚合物主链的UV-可见光区域。然而，在强酸，如对甲苯磺酸（TosOH）的存在下，ICD的强度显着增加，从聚-1和手性胺的磺酸残基之间形成有利的离子对，导致聚-1的螺旋感过量的增加。此外，在TosOH存在下由手性胺诱导的poly-1的大分子螺旋度在手性胺及其盐被完全去除并被非手性二胺取代后被“记忆”，即，乙二胺，在DMSO中，而没有观察到记忆效应的螺旋聚-1诱导相同的手性胺在TosOH的情况下。
A stereoregular poly(phenylacetylene) derivative bearing a sulfonic acid residue (poly-1) as the pendant was found to form a predominantly one-handed helix upon complexation with various chiral amines through noncovalent acid-base interactions in dimethyl sulfoxide (DMSO). In sharp contrast to analogous poly(phenylacetylene)s bearing relatively weak carboxy and phosphonic acid residues as the pendants, the poly-1-amine complexes exhibited a weak induced circular dichroism (ICD) in the UV-visible region of the polymer backbone. However, in the presence of a strong acid, such as p-toluenesulfonic acid (TosOH), the ICD intensity significantly increased, resulting from a favorable ion pair formation between the sulfonic acid residues of the poly-1 and chiral amines, leading to an increase in the helical sense excess of poly-1. Moreover, the macromolecular helicity of poly-1 induced by chiral amines in the presence of TosOH was "memorized" after the chiral amines and their salts were completely removed and replaced with an achiral diamine, i.e., ethylene diamine, in DMSO, while no memory effect was observed for a helical poly-1 induced by the same chiral amines in the absence of TosOH.