Instituto Mexicano del Petróleo , Eje Central Lázaro Cárdenas Norte 152 , Mexico City 07730 , Mexico.
J Chem Inf Model. 2020 Feb 24;60(2):611-620. doi: 10.1021/acs.jcim.9b00909. Epub 2019 Nov 26.
In the present contribution, we have developed a database, called the FAR-database, where the acronym FAR stands for Fused Aromatic Rings, which presents the results of nuclear independent chemical shifts calculations, NICS(0), NICS(1), NICS(0), and NICS(1), of 660 neutral benzenoid-PAHs and cyclopenta-fused PAHs. The FAR-database provides NICS data of aromaticity of PAHs that could be used in data science and machine learning. To the best of our knowledge, no such database is available in the literature. The importance of this database lies in its potential to transform data into insight and knowledge. Additionally, a new visual representation of the NICS aromaticity pattern, based on the magnitude of the NICS value, is presented. Nowadays calculations of NICS(0) or NICS(1) have become popular methods to evaluate aromaticity of systems. By looking at all the 660 systems in the FAR-database, it becomes evident that NICS(0), NICS(1), and NICS(1) present similar NICS aromaticity patterns for most of the systems. But the NICS aromaticity patterns found with NICS(0) in many cases do not agree with the NICS aromaticity patterns found with NICS(0), NICS(1), and NICS(1). There are cases where the NICS(0) aromaticity pattern does not show an aromatic character at all. From XY NICS scan at planes from Z = 0 to Z = 1, it is found that as the Z-height is increased, the π-electron ring current effects are dominant, and the σ-bonding contributions are diminished. Therefore, it is recommended here to compute NICS(1) instead of NICS(0) when analyzing NICS of PAHs.
在本研究中，我们开发了一个名为 FAR 数据库的数据库，该数据库的缩写 FAR 代表融合芳香环，其中包含 660 种中性苯并环芳烃和并五苯环芳烃的核独立化学位移计算结果，NICS(0)、NICS(1)、NICS(0)和 NICS(1)。FAR 数据库提供了可用于数据科学和机器学习的 PAHs 芳香度的 NICS 数据。据我们所知，文献中尚无此类数据库。该数据库的重要性在于它将数据转化为洞察力和知识的潜力。此外，还提出了一种基于 NICS 值大小的 NICS 芳香性模式的新的可视化表示。如今，NICS(0)或 NICS(1)的计算已成为评估系统芳香性的流行方法。通过查看 FAR 数据库中的所有 660 个系统，可以明显看出，对于大多数系统，NICS(0)、NICS(1)和 NICS(1)呈现出相似的 NICS 芳香性模式。但是，用 NICS(0)找到的 NICS 芳香性模式在许多情况下与用 NICS(0)、NICS(1)和 NICS(1)找到的 NICS 芳香性模式不一致。在某些情况下，NICS(0)芳香性模式根本没有显示出芳香特征。通过对 Z = 0 到 Z = 1 平面上的 XY NICS 扫描发现，随着 Z 高度的增加，π 电子环电流效应占主导地位，σ 键合贡献减小。因此，建议在分析 PAHs 的 NICS 时，用 NICS(1)代替 NICS(0)进行计算。
