Universität Rostock, Institut für Chemie, Abteilung für Physikalische Chemie, Dr.-Lorenz-Weg 2, 18059, Rostock, Germany.
Department LL&M, Competence Centre CALOR, University of Rostock, Albert-Einstein-Str. 25, 18059, Rostock, Germany.
Phys Chem Chem Phys. 2021 Nov 17;23(44):25226-25238. doi: 10.1039/d1cp03817f.
In molecules with two functional groups that form hydrogen bonds, the structure-property relationship can depend significantly on the strength of intra-molecular hydrogen bonding. This bonding can cause a substantial conformational change that is accompanied by a frequency shift in the infrared spectrum, which provides the basis for experimental studies. Despite its great importance in biological systems, the available literature data for the strength of this bonding are scarce and not in agreement. In this work, we present the results of four thermodynamic methods for the determination of the strength of intramolecular hydrogen bonds. Comprehensive thermochemical analysis of 1-amino-2-alcohols and 2-amino-1-alcohols was performed with Fourier-transform infrared spectroscopy, high-level G4 quantum-chemical calculations, the homomorph scheme with enthalpies of vaporization and a group contribution method. With the combination of these four thermodynamic methods, the strength of intramolecular hydrogen bonding in 1,2-aminoalcohols and 2,1-aminoalcohols was evaluated quantitatively. The results were correlated with NBO parameters to find an explanation for the different strengths of intramolecular hydrogen bonds in total charge transfer and second order stabilization energies.
在具有两个形成氢键的官能团的分子中，结构-性质关系可能显著取决于分子内氢键的强度。这种键合会导致构象发生实质性变化，伴随着红外光谱中频率的移动，这为实验研究提供了基础。尽管它在生物系统中非常重要，但关于这种键合强度的可用文献数据很少且不一致。在这项工作中，我们介绍了四种确定分子内氢键强度的热力学方法的结果。通过傅里叶变换红外光谱、高级 G4 量子化学计算、同态方案和基团贡献方法对 1-氨基-2-醇和 2-氨基-1-醇进行了综合热化学分析。通过这四种热力学方法的结合，定量评估了 1,2-氨基醇和 2,1-氨基醇中分子内氢键的强度。结果与 NBO 参数相关联，以找到总电荷转移和二阶稳定化能中分子内氢键强度不同的解释。
