A new theoretical approach was recently addressed to predict cyclodextrin host–guest binding constants with the GFN2-xTB semiempirical quantum method. Within such a strategy, a set of starting supramolecular arrangements is automatically obtained through the UD-APARM software, and many optimized host–guest systems are used to obtain each binding constant. In the present work, within the scope of the multi-equilibrium treatment, we carried out a theoretical study concerning the host–guest systems formed with paraoxon (PRX), methyl-parathion (MPTN), and parathion (PTN) into α-cyclodextrin (α-CD), for which experimental data were addressed. Those guests correspond to pesticides in use, and their inclusion plays a role in remediation technology. The procedure for estimating binding constants for the host–guest system is discussed in terms of the ranges for the supramolecular parameters employed in exploring the GFN2-xTB Potential Energy Surface (PES). As a result, by investigating an unprecedented number of starting systems (3,076), we identified that proper exploration of the GFN2-xTB PES gives a reliable prediction of the binding constant in solution. Furthermore, with the study of different starting associations, for PTN/α-CD, we found an excellent linear correlation (R² = 0.987) between GFN2-xTB data and experimental information, which, as in our previous study, supports the discussed methodology for application in predicting binding constants for CD-based host–guest systems.

Graphical abstract

中文翻译：

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将对氧磷、对硫磷和甲基对硫磷纳入 α-环糊精：GFN2-xTB 多平衡量子研究

最近提出了一种新的理论方法，利用 GFN2-xTB 半经验量子方法来预测环糊精主客体结合常数。在这样的策略中，通过UD-APARM软件自动获得一组起始超分子排列，并使用许多优化的主客体系统来获得每个结合常数。在本工作中，我们在多平衡处理的范围内，对对氧磷（PRX）、甲基对硫磷（MPTN）和对硫磷（PTN）形成α-环糊精的主客体系统进行了理论研究。 （α-CD），其实验数据已得到解决。这些客体对应于正在使用的农药，它们的加入在修复技术中发挥着作用。根据用于探索 GFN2-xTB 势能面 (PES) 的超分子参数范围讨论了估计主客体系统结合常数的程序。因此，通过研究数量空前的起始系统 (3,076)，我们发现对 GFN2-xTB PES 的正确探索可以可靠地预测溶液中的结合常数。此外，通过对不同起始关联的研究，对于 PTN/α-CD，我们发现了良好的线性相关性（R²  = 0.987) GFN2-xTB 数据和实验信息之间的差异，正如我们之前的研究一样，这支持了所讨论的用于预测基于 CD 的主客体系统的结合常数的方法。

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