Rozenberg M, Fausto R, Reva I
The Hebrew University of Jerusalem, Department of Inorganic and Analytical Chemistry, Jerusalem, Givat Ram 91904, Israel.
University of Coimbra, CQC, Department of Chemistry, 3004-535 Coimbra, Portugal.
Spectrochim Acta A Mol Biomol Spectrosc. 2021 Apr 15;251:119323. doi: 10.1016/j.saa.2020.119323. Epub 2020 Dec 15.
In the first part of this work, we report the FTIR spectra of pure NH and isotopically substituted ND (10-15% D and 80-90% D) polycrystalline hypoxanthine, xanthine, adenine and guanine recorded in the 400-4000 cm range, as a function of temperature (10-300 K). We provide assignments of the stretching and out-of-plane bending amine (NH) and imine (NH) bands to the distinct H-bonds present in the crystal, based on the temperature sensitivity and isotopic exchange behavior. Empirical correlations between spectral and thermodynamic or structural parameters enabled us to estimate the energies and lengths of H-bonds in the studied nucleobase crystals and to correlate them with literature data. The empirical H-bonding energies are compared with H-bonding and stacking energies computed for hypoxanthine. In the second part, strategies for using the empirical correlations together with information extracted from quantum mechanical data (in particular from the Bader's quantum theory of atoms in molecules, QTAIM) for the evaluation of hydrogen bonding properties are discussed, and their advantages and drawbacks pointed out. The justification for a cooperative use of quantum-mechanical calculations with empirical spectra-energy correlations is discussed.
在本研究的第一部分，我们报告了在400 - 4000厘米范围内记录的纯NH以及同位素取代的ND（10 - 15%D和80 - 90%D）多晶次黄嘌呤、黄嘌呤、腺嘌呤和鸟嘌呤的傅里叶变换红外光谱（FTIR），其作为温度（10 - 300K）的函数。基于温度敏感性和同位素交换行为，我们将伸缩振动和面外弯曲胺（NH）以及亚胺（NH）谱带归属于晶体中存在的不同氢键。光谱与热力学或结构参数之间的经验相关性使我们能够估计所研究核碱基晶体中氢键的能量和长度，并将它们与文献数据相关联。将经验氢键能与为次黄嘌呤计算的氢键和堆积能进行了比较。在第二部分中，讨论了将经验相关性与从量子力学数据（特别是从巴德分子中原子的量子理论，QTAIM）提取的信息一起用于评估氢键性质的策略，并指出了它们的优点和缺点。讨论了将量子力学计算与经验光谱 - 能量相关性协同使用的理由。
