Prediction of 13C NMR chemical shifts by artificial neural network. I. Partial charge model as atomic descriptor.

Mulliken population analysis (MPA), Hirshfeld population analysis (HPA), Charge Model 5 (CM5) and Hu Lu Yang charge fitting method (HLY) were considered in order to reveal influence of atomic partial charges on the 13 C NMR chemical shifts. The test set included seven classes of organic molecules. Partial charges of carbon atoms were obtained from quantum-chemical calculations at DFT/HISS level. Linear regressions were constructed as estimators of accuracy of each model. The best approach was shown by multivariate regression with MPA, HPA, and CM5 charges as predictors in a linear model with mean value of R 2 = 0.8917. [ABSTRACT FROM AUTHOR]