...
  • 主题
高级搜索  >
历史搜索 清空历史
首页> 外文期刊>Chemistry: A European journal >Computational and experimental evidence of through-space NMR spectroscopic J coupling of hydrogen atoms
【24h】

Computational and experimental evidence of through-space NMR spectroscopic J coupling of hydrogen atoms

机译：氢原子的空域NMR光谱J耦合的计算和实验证据

获取原文
获取原文并翻译 | 示例
           
页面导航
  • 摘要
  • 著录项
  • 相似文献
  • 相关主题

摘要

J coupling in NMR spectroscopy is conventionally associated with covalent bonds. A noncovalent contribution often called through-space coupling (TSC) has been observed for heavy atoms. In this study, the TSC was detected and analyzed for the more common ~1H- ~1H coupling as well. In synthesized model molecules the hydrogen positions could be well controlled. For several coupling constants the through-space mechanism was even found to be the predominant factor. The nature and magnitude of the phenomenon were also analyzed by density functional computations. Calculated carbon- and hydrogen-coupling maps and perturbed electronic densities suggest that the aromatic system strongly participates in the noncovalent contribution. Unlike covalent coupling, which is usually governed by the Fermi contact, TSC is dominated by the diamagnetic term comprising interactions of nuclei with the electron orbital angular momentum. The computations further revealed a strong distance and conformational dependence of TSC. This suggests that the through-space coupling can be explored in molecular structural studies in the same way as the covalent one. Odd coupling: For the first time, J coupling was observed between ~1H, ~1H atoms in several synthetic molecules (see figure). DFT computations revealed an unexpected geometry dependence of the coupling, which can be potentially used in structural studies of van der Waals complexes.
机译：NMR光谱中的J偶联通常与共价键相关。对于重原子，已经观察到非共价贡献，通常被称为空间穿越耦合（TSC）。在这项研究中，还检测并分析了TSC中更常见的〜1H-〜1H耦合。在合成的模型分子中，氢的位置可以很好地控制。对于几个耦合常数，甚至发现通空机制是主要因素。现象的性质和严重程度还通过密度泛函计算进行了分析。计算的碳和氢耦合图和扰动的电子密度表明，芳族体系强烈参与非共价贡献。与通常由费米接触控制的共价耦合不同，TSC的抗磁性术语占主导地位，该抗磁性术语包括原子核与电子轨道角动量的相互作用。该计算进一步揭示了TSC的强距离和构象依赖性。这表明可以通过与共价键相同的方式在分子结构研究中探索空间耦合。奇偶耦合：首次在几个合成分子的〜1H，〜1H原子之间观察到J耦合（见图）。 DFT计算揭示了偶合的意外的几何依赖性，可潜在地用于范德华配合物的结构研究中。

著录项

相似文献

  • 外文文献
  • 中文文献
  • 专利
获取原文

客服邮箱：kefu@zhangqiaokeyan.com

京公网安备：11010802029741号 ICP备案号：京ICP备15016152号-6 六维联合信息科技 (北京) 有限公司©版权所有

  • 客服微信

  • 服务号