Calculations of gas phase 1H NMR chemical shifts of alcohols:: An approach to optimize basis functions using factorial design

The wave functions for calculating gas phase H-1 chemical shifts of primary and secondary alcohols have been optimized using factorial design as multivariate technique. Gas-phase experimental H-1 chemical shifts of H-1 alcohols were used to establish the best levels of theory for obtaining H-1 chemical shift, among them the new experimental values of H-1 chemical shifts of 10 alcohols were obtained in our laboratory. HF/6-31G(d,p) wave function is proposed as the best level of theory for calculating H-1 chemical shifts of primary alcohols. For secondary alcohols, ONIOM(B3LYP/6-31G(d,p): HF/6-31G(d,p)) are recommended. An additional series of primary and secondary alcohols were used as test sets and their results confirmed the validity of approaches. (C) 2008 Wiley Periodicals, Inc.