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Published on: February 6, 2019
在基于螺旋酸的N-酸中,由内分子非共价C键驱动的构造偏好
Muhammad Imran Ali1, Javid Hussain2, Muhammad Usman Anwar2
1Department of Chemistry, Quaid-i-Azam University Islamabad 45320 Pakistan moazzam@qau.edu.pk.
非共价碳结合 (C-结合) 稳定了新型水子中的 cis 构造,甚至在极性溶剂中. 这种相互作用对于理解溶液中的分子结构和超分子化学至关重要.
科学领域:
- 超分子化学 超分子化学
- 有机化学 有机化学
- 化学物理 化学物理
背景情况:
- 非共价碳结合 (C-结合) 是一种主要通过X射线晶体学和计算研究的σ-孔相互作用.
- 由于溶解干扰,在溶液中,特别是DMSO等极性溶剂中存在C键的证据有限.
- 由于固体阻碍,NH-胺键通常有利于转变形状.
研究的目的:
- 调查C键在稳定新型螺旋酸基N-酸在溶液中的特定构造中的作用.
- 探索在极性溶剂中通过分子内C键稳定的cis形状的普遍性.
主要方法:
- 合成了三种新的基于螺旋酸的N-酸 (化合物1-3).
- 在DMSO-d6.6中使用1H和13C核磁共振 (NMR) 谱法进行溶液状态表征.
- 单晶X射线衍射分析.
- 密度函数理论 (DFT) 的计算.
主要成果:
- 核磁共振数据显示,DMSO中化合物1 (82%) 和2 (76%) 中的cis构造具有显著的偏好,这归因于分子内C结合.
- 化合物3也有利于DMSO的cis构成 (60%),但由于竞争的键,在较小程度上.
- X射线结晶学证实了化合物1和2的cis构造,而化合物3则以转化形式结晶.
- DFT计算支持实验结果,预测溶液中cis形状的稳定性更高.
结论:
- 内部分子C键可以有效地稳定N-酸在DMSO等极极性溶剂中的cis构造.
- 在C-结合,结合和固体效应之间的相互作用决定了溶液和固体状态的形状偏好.
- 这项研究强调了C键在超分子化学和分子识别中的重要性.
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