Prediction of 19F NMR chemical shifts for organic compounds with ORCA

Yueyang Li; Ping Zeng; Qing Lou; Xiao Su; Wei Li; Xiaojian Wang

doi:10.1016/j.jmr.2023.107611

Prediction of ¹⁹F NMR chemical shifts for organic compounds with ORCA

J Magn Reson. 2024 Jan:358:107611. doi: 10.1016/j.jmr.2023.107611. Epub 2023 Dec 13.

Authors

Yueyang Li¹, Ping Zeng¹, Qing Lou¹, Xiao Su¹, Wei Li², Xiaojian Wang³

Affiliations

¹ Institute of Advanced Synthesis, Institute of Chemical Biology and Functional Molecules, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China.
² 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).
³ Institute of Advanced Synthesis, Institute of Chemical Biology and Functional Molecules, School of Chemistry and Molecular Engineering, Nanjing Tech University, Nanjing 211816, China. Electronic address: ias_xjwang@njtech.edu.cn.

PMID: 38104491
DOI: 10.1016/j.jmr.2023.107611

Abstract

Accurate assignment of ¹⁹F NMR has long been a challenge, and quantum chemical methods are possible solutions. Herein we reported a scaling method for the prediction of ¹⁹F 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.

Keywords: (19)F NMR; DFT; ORCA; Scaling factor.