Hybrid density functional methods empirically optimized for the computation of 13C and 1H chemical shifts in chloroform solution

Two hybrid generalized-gradient approximation density functionals, WC04 and WP04, are optimized for the prediction of C-13 and H-1 chemical shifts, respectively, using a training set of 43 molecules in chloroform solution. Tests on molecules not included in the training set, namely six stereoisomeric methylcyclohexanols and a ss-lactam antibiotic, indicate the models to be robust and moreover to provide results more accurate than those from equivalent B3LYP, PBE1, or m PW1PW91 calculations, particularly for the prediction of downfield resonances in nuclear magnetic resonance spectra. However, linear regression of the B3LYP, PBE1, and m PW1PW91 predicted values on the experimental data improves the accuracy of those models so that they are comparable to WC04 and WP04.