Symmetry and 1 H NMR chemical shifts of short hydrogen bonds: impact of electronic and nuclear quantum effects
Symmetry and 1 H NMR chemical shifts of short hydrogen bonds: impact of electronic and nuclear quantum effects
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短氢键的对称性和 1 H NMR 化学位移：电子和核量子效应的影响
DOI：
10.1039/c9cp06840f
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发表时间：
2020
影响因子：
3.3
通讯作者：
Wang, Lu
中科院分区：
文献类型：
--
作者：
Zhou, Shengmin;Wang, Lu
短氢键 (SHB) 的供体和受体间距低于 2.7 Å，广泛存在于小分子和蛋白质中。由于结构紧凑，SHB 表现出突出的共价特征，具有伸长的供体氢键和高度低场 (>14 ppm) 1H NMR 化学位移。在这项工作中，我们对一组模型分子进行了第一原理模拟，以评估量子效应如何决定其 SHB 的对称性和化学位移。通过结合电子和原子核的量子力学性质的模拟，我们揭示了化学位移和 SHB 中质子位置之间的普遍关系，并揭示了观察到的低场光谱特征的起源。我们进一步开发了一种度量方法，可以直接根据 1H 化学位移准确有效地确定质子位置，这将有助于小分子和生物大分子中 SHB 的实验检查。
Short hydrogen bonds (SHBs), which have donor and acceptor separations below 2.7 Å, occur extensively in small molecules and proteins. Due to their compact structures, SHBs exhibit prominent covalent characters with elongated Donor–H bonds and highly downfield (>14 ppm) 1H NMR chemical shifts. In this work, we carry out first principles simulations on a set of model molecules to assess how quantum effects determine the symmetry and chemical shift of their SHBs. From simulations that incorporate the quantum mechanical nature of both the electrons and nuclei, we reveal a universal relation between the chemical shift and the position of the proton in a SHB, and unravel the origin of the observed downfield spectral signatures. We further develop a metric that allows one to accurately and efficiently determine the proton position directly from its 1H chemical shift, which will facilitate the experimental examination of SHBs in both small molecules and biological macromolecules.