Evaluating electronic structure methods for accurate calculation of 19F chemical shifts in fluorinated amino acids

摘要

The ability of electronic structure methods (11 density functionals, HF, and MP2 calculations; two basis sets and two solvation models) to accurately calculate the ¹⁹F chemical shifts of 31 structures of fluorinated amino acids and analogues with known experimental ¹⁹F NMR spectra has been evaluated. For this task, BH and HLYP, ωB97X, and Hartree-Fock with scaling factors (provided within) are most accurate. Additionally, the accuracy of methods to calculate relative changes in fluorine shielding across 23 sets of structural variants, such as zwitterionic amino acids vs. side chains only, was also determined. This latter criterion may be a better indicator of reliable methods for the ultimate goal of assigning and interpreting chemical shifts of fluorinated amino acids in proteins. It was found that MP2 and M062X calculations most accurately assess changes in shielding among analogues. These results serve as a guide for computational developments to calculate ¹⁹F chemical shifts in biomolecular environments.