Modeling pH-Dependent NMR Chemical Shift Perturbations in Peptides

Impact of solvent interactions on 1H and 13C chemical shifts investigated using DFT and a reference dataset recorded in CDCl3 and CCl4

¹H and ¹³C chemical shifts of 35 small, rigid molecules were measured under standardized conditions in chloroform-d and in tetrachloromethane. The solvent change mainly affects carbon shifts of polar functional groups. This difference due to specific interactions with CDCl₃ cannot be adequately reproduced by DFT calculations in implicit solvent. The new dataset provides an accurate basis for the validation and calibration of shift calculations, especially with respect to improved solvent models.

¹H and ¹³C chemical shifts of 35 small, rigid molecules were measured under standardized conditions in CDCl₃ and in CCl₄. Specific solvent interactions lead to chemical shift differences that cannot be reproduced by DFT in implicit solvent.