Li Yueyang, Zeng Ping, Lou Qing, Su Xiao, Li Wei, Wang Xiaojian
Institute of Advanced Synthesis, Institute of Chemical Biology and Functional Molecules, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
Institute of Advanced Synthesis, Institute of Chemical Biology and Functional Molecules, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China; State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, Nanjing 210023, China(1).
J Magn Reson. 2024 Jan;358:107611. doi: 10.1016/j.jmr.2023.107611. Epub 2023 Dec 13.
Accurate assignment of F NMR has long been a challenge, and quantum chemical methods are possible solutions. Herein we reported a scaling method for the prediction of F NMR chemical shift with freely available ORCA program package. Performance of 31 DFT functionals coupled with 11 basis sets were evaluated and influence of geometry optimization was also studied with five functionals coupled with three basis sets. The significance of geometry was further examined through the execution of relaxed surface scans of seven flexible compounds, and averaged shieldings of obtained conformers yielded notable improvement of the correlation between calculated isotropic shielidings and experimental chemical shifts. Utilization of the best scaling factor obtained successfully assigned of fluorine atoms in multifluorinated molecules with different conformations. The method reported here was computationally inexpensive, easily available with acceptable accuracy.
长期以来，准确指定氟的核磁共振（F NMR）一直是一项挑战，而量子化学方法可能是解决方案。在此，我们报道了一种使用免费的ORCA程序包预测F NMR化学位移的标度方法。评估了31种密度泛函理论（DFT）泛函与11种基组的性能，并使用5种泛函与3种基组研究了几何优化的影响。通过对7种柔性化合物进行松弛表面扫描，进一步检验了几何结构的重要性，所得构象异构体的平均屏蔽显著改善了计算的各向同性屏蔽与实验化学位移之间的相关性。利用获得的最佳标度因子成功地指定了不同构象的多氟分子中氟原子的位置。本文报道的方法计算成本低，易于获得且具有可接受的准确性。
