Comparison between Theoretical and Experimental Electric Dipole Moments of Selected N,N-Dimethylaniline Derivatives

Abstract

Electric dipole moments of nine N, N-dimethylaniline derivatives were determined experimentally in benzene solution according to literature methods. The theoretical dipole moments of these compounds were calculated from molecular orbital approximations according to the Del Re σ-electron treatment, the Hückel π-electron method, the Pariser-Parr-Pople treatment, the complete neglect of differential overlap method, and selected combinations of these methods. Parameters not previously reported were determined for the nitro group by reproduction of experimental dipole moments for use in the Del Re calculations. Comparisons between the experimental and theoretical moments indicate that the combination of the Del Re σ-electron and Hückel π-electron methods gave the best reproduction of the experimental dipole moment values while being considerably less expensive in terms of computer size and time, as well as requiring less time in preparing the data than more sophisticated methods examined.