Comparison of density functional theory models' ability to reproduce experimental13C-NMR shielding values

A theoretical investigation on the isomerism and the NMR properties of thiosemicarbazones

“…The mPW1PW91 method is a hybrid density functional theory method that employs a 25% Hartree-Fock exchange contribution, the modified Perdew-Wang (mPW) exchange functional [44], and the PW91 correlation functional [45]. This hybrid density functional theory method gives accurate molecular properties such as geometries, vibrational frequencies, and enthalpies of formation, and it was also shown to give accurate NMR chemical shifts [46,47]. The results obtained in our previous study [42] showed that the methodology employed here is appropriate for studying this class of compounds.…”

NMR study and quantum mechanical calculations on the 2-[(2-aminoethyl)amino]-ethanol–H2O–CO2 system

“…The chemical shift of one AEEA conformer relative to TMS was calculated at MPW1PW91 level of theory with incorporation of solvent effects (details given in Supporting information); all other chemical shifts were calculated relative to this conformer (B3LYP level calculations used to determine relative shifts between AEEA conformers and species). The MPW1PW91 level has been reported to perform well in 13 C NMR calculations [21].…”

Solvent-Dependent Mixed Complex Formation—NMR Studies and Asymmetric Addition Reactions of Lithioacetonitrile to Benzaldehyde Mediated by Chiral Lithium Amides

“…[25] DFT single-point calculations at the MPW1PW91/6 ± 31 G(d) level of theory were performed on both the PM3-and the B3LYP/6 ± 31G(d)-optimized structures. [26] From the results of the calculations we concluded that the six-membered ring dimer with a bridging CH 2 CN unit appears to be the most stable complex among A 1, A 2, and A 2'. The A 2 structure is surprisingly 5.9 kcal mol À1 lower in energy than A 2'.…”