Conclusion and Discussion
Density functional models can successfully aid in the assignment of 1H and 13C
chemical shifts for α-mangostin, γ-mangostin, and garcinone D. For 1H chemical shift, the WP04
model shows the accuracy in the prediction of the chemical shift the same as the B3LYP model.
For 13C chemical shift prediction, the B3LYP model shows the better results than the other.
However there are some differences in accuracy for these three models, the correlation
coefficients (R2) are in acceptable ranges. It is believed that these models can be used to predict
the 1H chemical shift of other prenylated xanthones.
Acknowledgements