The Prediction of Amino Proton Chemical Shifts Using Optimally Selected Wave Function

Gas phase amino proton chemical shifts in the 54 of amines have been predicted using Gauge-independent atomic orbital (GIAO) method and optimally selected wave function. The effects of electron correlation, triple-x valance shell, diffuse function, and polarization function on calculated amino proton chemical shifts have been investigated using factorial design as a multivariate technique. Different optimized wave functions for different groups of amines were recommended. A wave function as the best level of the theory is proposed for homologue amines covered. In this context, B3LYP/6-311+G and HF/6-311+G wave functions have been recommended as the best and the most efficient level of theory for calculating amino proton chemical shifts of alkylamines and arylamines respectively. (C) 2011 Wiley Periodicals, Inc. Concepts Magn Reson Part A 38A: 25-32, 2011.