A computational tool to accurately and quickly predict 19F NMR chemical shifts of molecules with fluorine-carbon and fluorine-boron bonds.
A computational tool to accurately and quickly predict 19F NMR chemical shifts of molecules with fluorine-carbon and fluorine-boron bonds.
复制标题
一种计算工具，可准确快速地预测具有氟-碳和氟-硼键的分子的 19F NMR 化学位移。
DOI：
10.1039/d2cp02317b
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发表时间：
2022
期刊：
影响因子：
--
通讯作者：
Dumon AS
中科院分区：
文献类型：
--
作者：
Dumon AS
我们报告的评估密度泛函理论（DFT）为基础的程序预测19 F NMR化学位移在适度的计算成本的范围内的分子与氟键，作为一种工具，用于协助表征反应中间体和产品，并作为一种援助，以确定机械途径。然后使用另外两个测试集检查分子的平衡学习集的结果，从而推荐ω B 97 XD/aug-cc-pvdz DFT方法和基组具有准确度和计算时间的最佳组合，RMS误差为3.57 ppm。没有反阴离子计算的阳离子分子显示正常的误差，而阴离子分子显示出更大的误差。该方法被施加到预测的构象平均19 F化学位移的2，2，3，3，4，4，5，5-八氟戊-1-醇，其中涉及氟的gauche立体电子效应占主导地位，并确定氟化硼烷的配位平衡的位置，作为一种援助，以验证中间物种的相对能量参与催化酰胺化反应，涉及硼催化剂。
We report the evaluation of density-functional-theory (DFT) based procedures for predicting 19F NMR chemical shifts at modest computational cost for a range of molecules with fluorine bonds, to be used as a tool for assisting the characterisation of reaction intermediates and products and as an aid to identifying mechanistic pathways. The results for a balanced learning set of molecules were then checked using two further testing sets, resulting in the recommendation of the ωB97XD/aug-cc-pvdz DFT method and basis set as having the best combination of accuracy and computational time, with a RMS error of 3.57 ppm. Cationic molecules calculated without counter-anion showed normal errors, whilst anionic molecules showed somewhat larger errors. The method was applied to the prediction of the conformationally averaged 19F chemical shifts of 2,2,3,3,4,4,5,5-octafluoropentan-1-ol, in which gauche stereoelectronic effects involving fluorine dominate and to determining the position of coordination equilibria of fluorinated boranes as an aid to verifying the relative energies of intermediate species involved in catalytic amidation reactions involving boron catalysts.