A survey of wave function effects on theoretical calculation of gas phase 19F NMR chemical shifts using factorial design

The wave functions for calculating gas phase F-19 chemical shifts were optimally selected using the factorial design as a multivariate technique. The effects of electron correlation, triple-xi valance shell, diffuse function, and polarization function on calculated F-19 chemical shifts were discussed. It is shown that of the four factors, electron correlation and the polarization functions affect the results significantly. B3LYP/6-31 + G(df,p) wave functions have been proposed as the best and the most efficient level of theory for calculating F-19 chemical shifts. An additional series of fluoro compounds were used as a test set and their predicted F-19 chemical shifts Values confirmed the validity of the approaches. (C) 2009 Elsevier B.V. All rights reserved.