Sülzner Niklas, Haberhauer Julia, Hättig Christof, Hellweg Arnim
Lehrstuhl für Theoretische Chemie, Ruhr-Universität Bochum, Bochum, 44780, Germany.
Dassault Systèmes Deutschland GmbH, Am Kabellager 11-15, Köln, 51063, Germany.
J Comput Chem. 2022 Jun 5;43(15):1011-1022. doi: 10.1002/jcc.26864. Epub 2022 Apr 22.
In this contribution we extent the use of the conductor-like screening model for realistic solvation (COSMO-RS) to the prediction of pK values in acetone, a commonly used dipolar aprotic solvent. For this, we calculated the Gibbs free energy of dissociation of 120 organic acids (nine acrylic acids, 87 benzoic acids, nine phenols, and 15 benzenesulfonamides) using COSMO-RS at the two levels BP-TZVP and BP-TZVPD-FINE and determined the parameters for a linear free energy relation for the prediction by performing linear fits to experimental values. Our results suggest that the data set dissects into two groups, with the phenols being different from the other three subsets. The acrylic and benzoic acids and the sulfonamides can be treated together and yield an excellent linear correlation ( ) with an RMSD of only ~0.3. The slope is found to be significantly smaller than the theoretical value ( ), only 45% of it, which is in accordance with findings in the literature. The phenols, however, while similarly well correlated in their own subset with an RMSD of 1.7-1.9, exhibit a slope larger than one. We discuss both a higher uncertainty in the reference values as well as physical origins as possible reasons.
在本论文中，我们将类导体屏蔽模型用于真实溶剂化（COSMO-RS）的应用范围扩展至预测丙酮（一种常用的偶极非质子溶剂）中的pK值。为此，我们使用COSMO-RS在BP-TZVP和BP-TZVPD-FINE两个水平上计算了120种有机酸（9种丙烯酸、87种苯甲酸、9种酚类和15种苯磺酰胺）的解离吉布斯自由能，并通过对实验值进行线性拟合来确定用于预测的线性自由能关系参数。我们的结果表明，数据集可分为两组，酚类与其他三个子集不同。丙烯酸、苯甲酸和磺酰胺可以一起处理，并且产生了极好的线性相关性（ ），均方根偏差仅约为0.3。发现斜率明显小于理论值（ ），仅为其45%，这与文献中的发现一致。然而，酚类虽然在其自身子集中相关性同样良好，均方根偏差为1.7 - 1.9，但显示出大于1的斜率。我们讨论了参考值中较高的不确定性以及物理根源作为可能的原因。
