In sequel to a previous recent study4, netgtkebeduanube (MDA) was calculated by higher level ab initio methods namely 6-31G* abd NO3//6-31G* levels. The influence of polarization functions on the calculated pyramidality of nitrogen and on the magnitude of the anomeric effect is discussed. At the same time, a structural-statistical study was performed on molecules containing the N-C-N moiety retrieved from the Cambridge Structural Database (CSD). Both methods complement and improve results from the previous study. Special attention was given to the tertiary amine case and the N-C-N bond angle for which new MM2 parameters are put forward. These are mainly based on ab initio calculations of N,N-dimethylmethylenediamine and tetramethylmethylenediamine and on a comparative study of CN bond lengths in primary, secondary and tertiary amines.