Department of Physics, St. Petersburg State University, St. Petersburg, Russia.
Department of Chemistry, Ben-Gurion University of the Negev, Beer-Sheva, Israel.
J Chem Phys. 2019 Mar 21;150(11):114305. doi: 10.1063/1.5090180.
In this computational work, we propose to use the NMR chemical shift difference of NH protons for 1:1 complexes formed by aniline and nitrogen-containing proton acceptors for the estimation of the hydrogen bond energy and geometry (N⋯H and N⋯N distances). The proposed correlations could be applied to other aromatic amines as well, in a gas phase, a solution, or a solid state, for both inter- and intramolecular hydrogen bonds. We considered a set of 21 complexes with the NHN hydrogen bond without proton transfer, including hydrogen bonds from weak to medium strong ones (2-21 kcal/mol), with neutral or anionic bases and with sp and sp hybridized nitrogen proton acceptors. For each complex apart from direct hydrogen bond energy calculation, we have tested several other ways to estimate the energy: (a) using a correlation between NH stretching band intensity and hydrogen bond energy and (b) using correlations between electron density properties at (3, -1) bond critical point (quantum theory of atoms in molecules analysis) and hydrogen bond energy. Besides for the studied type of complexes, we obtained refined linear correlations linking the local electron kinetic (G) and potential (V) energy densities with the hydrogen bond energy.
在这项计算工作中，我们建议使用苯胺和含氮质子受体形成的 1:1 配合物中 NH 质子的 NMR 化学位移差来估算氢键的能量和几何形状（N⋯H 和 N⋯N 距离）。所提出的相关性也可以应用于其他芳香胺，无论是在气相、溶液还是固态中，无论是分子间氢键还是分子内氢键。我们考虑了一组 21 个没有质子转移的 NHN 氢键复合物，包括从弱到中等强度（2-21 kcal/mol）的氢键，涉及中性或阴离子碱和 sp 和 sp 杂化的氮质子受体。对于每个复合物，除了直接计算氢键能量外，我们还测试了其他几种估计能量的方法：（a）使用 NH 伸缩带强度与氢键能量之间的相关性，以及（b）使用（3，-1）键临界点处电子密度特性（分子中的原子量子理论分析）与氢键能量之间的相关性。除了研究的复合物类型外，我们还获得了将局部电子动能（G）和势能（V）密度与氢键能量联系起来的改进线性相关性。
