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首页> 外文期刊>Journal of the American Chemical Society >Mechanism of Helix Induction on a Stereoregular Poly((4-carboxyphenyl)acetylene) with Chiral Amines and Memory of the Macromolecular Helicity Assisted by Interaction with Achiral Amines
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Mechanism of Helix Induction on a Stereoregular Poly((4-carboxyphenyl)acetylene) with Chiral Amines and Memory of the Macromolecular Helicity Assisted by Interaction with Achiral Amines

机译：螺旋诱导手性胺类立体异构聚（（4-羧基苯基）乙炔）的机理和与手性胺相互作用辅助的大分子螺旋度的记忆

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摘要

Cis-transoidal poly((4-carboxyphenyl)acetylene) (poly-1) is an optically inactive polymer but forms an induced one-handed helical structure upon complexation with optically active amines such as (R)-(1-(1-naphthyl)ethyl)amine ((R)-2) in DMSO. The complexes show a characteristic induced circular dichroism (ICD) in the UV-visible region of the polymer backbone. Moreover, the macromolecular helicity of poly-1 induced by (R)-2 can be "memorized" even after complete replacement of (R)-2 by various achiral amines. We now report fully detailed studies on the mechanism of the helicity induction and memory of the helical chirality of poly-1 by means of UV-visible, CD, and infrared spectroscopies. We have found that a one-handed helix is cooperatively induced on poly-1 upon the ion pair formation of the carboxy groups of poly-1 with optically active amines and that the bulkiness of the chiral amines plays a crucial role for inducing an excess of a single-handed helix. On the other hand, the free ion formation was found to be essential for the macromolecular helicity memory of poly-1 after the replacement of the chiral amine by achiral amines, since the intramolecular electrostatic repulsion between the neighboring carboxylate ions of poly-1 significantly contributes to reduce the atropisomerization process of poly-1. On the basis of the mechanism of helicity induction and the memory of the helical chirality drawn from the present studies, we succeeded in creating an almost perfect memory of the induced macromolecular helicity of poly-1 with (R)-2 by using 2-aminoethanol as an achiral chaperoning molecule to assist in maintaining the memory of helical chirality.
机译：顺-反式聚（（4-羧基苯基）乙炔）（poly-1）是一种光学惰性聚合物，但与（R）-（1-（1-萘基）等光学活性胺络合后会形成诱导的单手螺旋结构）乙）胺（（R）-2）在DMSO中。该络合物在聚合物主链的UV-可见光区显示出特征性的诱导二色性（ICD）。此外，即使在（R）-2被各种非手性胺完全取代后，也可以“记忆”由（R）-2诱导的poly-1的大分子螺旋。现在，我们通过UV可见光，CD和红外光谱学报告了关于poly-1的螺旋手性的螺旋诱导和记忆机理的详细研究。我们发现，在poly-1与光学活性胺的离子对形成之后，在poly-1上协同诱导了单手螺旋，并且手性胺的庞大性对于诱导过量的手性起关键作用。单手螺旋。另一方面，发现手性胺被非手性胺替代后，自由离子的形成对于poly-1的大分子螺旋性记忆是必不可少的，因为poly-1的相邻羧酸根离子之间的分子内静电排斥作用显着减少poly-1的阻转异构化过程。根据本研究的螺旋诱导机理和对螺旋手性的记忆，我们通过使用2-氨基乙醇成功地创建了由（R）-2诱导的poly-1大分子螺旋的几乎完美的记忆。作为非手性伴侣分子，有助于维持对螺旋手性的记忆。

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  • 来源
    《Journal of the American Chemical Society》 |2004年第13期|p. 4329-4342|共14页
  • 作者

    Katsuhiro Maeda; Kazuhide Morino; Yoshio Okamoto; Takahiro Sato; Eiji Yashima;

  • 作者单位

    Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan;

    Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan;

    Department of Applied Chemistry, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan;

    Department of Macromolecular Science, Osaka University, Machikaneyama-cho 1-1, Toyonaka, Osaka 560-0043, Japan;

    Department of Molecular Design and Engineering, Graduate School of Engineering, Nagoya University, Chikusa-ku, Nagoya 464-8603, Japan;

  • 收录信息 美国《科学引文索引》(SCI);美国《工程索引》(EI);美国《生物学医学文摘》(MEDLINE);美国《化学文摘》(CA);
  • 原文格式 PDF
  • 正文语种 eng
  • 中图分类 化学;
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