Charvati Evangelia, Sun Huai
School of Chemistry and Chemical Engineering, Materials Genome Initiative Center, and Key Laboratory of Scientific and Engineering Computing of Ministry of Education, Shanghai Jiao Tong University, Shanghai 200240, China.
J Phys Chem A. 2023 Mar 23;127(11):2646-2663. doi: 10.1021/acs.jpca.3c00095. Epub 2023 Mar 9.
The complex conformations of the cyclic moieties impact the physical and chemical properties of molecules. In this work, we chose 22 molecules of four-, five-, and six-membered rings and performed a thorough conformational sampling using Cremer-Pople coordinates. With consideration of symmetries, we obtained a total of 1504 conformational structures for four-membered, 5576 for five-membered, and 13509 for six-membered rings. All well-known and many less well-known conformers for each molecule were identified. We represented the potential energy surfaces (PESs) by fitting the data to common analytical force field (FF) functional forms. We found that the general features of PESs can be described by the essential FF functional forms; however, the accuracy of representation can be improved remarkably by including the torsion-bond and torsion-angle coupling terms. The best fit yields R-squared () values close to 1.0 and mean absolute errors in energy less than 0.3 kcal/mol.
环状部分的复杂构象影响分子的物理和化学性质。在这项工作中，我们选择了22个四元、五元及六元环分子，并使用克雷默-波普尔坐标进行了全面的构象采样。考虑到对称性，我们分别获得了1504个四元环、5576个五元环和13509个六元环的构象结构。确定了每个分子所有著名的以及许多不太著名的构象异构体。通过将数据拟合到常见的解析力场（FF）函数形式来表示势能面（PES）。我们发现，PES的一般特征可以用基本的FF函数形式来描述；然而，通过纳入扭转键和扭转角耦合项，可以显著提高表示的准确性。最佳拟合得到的决定系数（R²）值接近1.0，能量的平均绝对误差小于0.3 kcal/mol。
