A computational tool to accurately and quickly predict 19F NMR shifts of molecules with fluorine-carbon and fluorine-boron bonds.
DOI: 10.14469/hpc/8772 Metadata
Created: 2021-08-27 08:58
Last modified: 2022-08-09 11:42
License: Creative Commons: Public Domain Dedication 1.0
Funding: P81664: "catalytic dir amidation react".
Co-author: Henry Rzepa Co-author: Andrew Whiting Co-author: Carla Alamillo-Ferrer Co-author: Richard Procter Co-author: Tom Sheppard
Description
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 organofluorine molecules, as a tool for assisting characterisation of reaction intermediates, products and associated mechanistic pathways, using a balanced training set. This was checked against a larger validation set of molecules, resulting in the recommendation of the wB97XD/aug-cc-pvdz DFT method and basis set as having the best balanced combination of accuracy and computational time, with a RMS error ~3.5ppm. The method was applied to the prediction of chemical shifts for conformers of flexible molecules in which gauche stereoelectronic effects involving fluorine dominate. Cationic molecules calculated without counter-anion showed normal errors, whilst anionic molecules showed slightly larger errors possibly due to omission of the counter-cation. The method was also applied to determining coordination equilibria of fluorinated boranes as an aid to determining the mechanisms in catalytic amidation involving boron catalysts.
Members
| DOI | Description |
|---|---|
| 10.14469/hpc/10395 | 4.1 - Conformational analysis of 2,2,3,3,4,4,5,5-octafluoropentan-1-ol |
| 10.14469/hpc/10243 | 4.2 - Crystal Structures - Ionic study |
| 10.14469/hpc/10394 | 3.1 - References and output files |
| 10.14469/hpc/9915 | 3.2 - Regression Plots |
| 10.14469/hpc/9242 | 3.3 - PredictionSet-19FNMR |
| 10.14469/hpc/9649 | 3.3 - Supertesting set 19F NMR |
| 10.14469/hpc/10261 | 4.2. Dissociative equilibria between 3- and 4-coordinate boron probed using 19F NMR shifts |
Associated DOIs
| Current dataset ... | DOI | Description |
|---|---|---|
| References | 10.1039/D2CP02317B | Associated publication |