Abstract
The total energies of the planar melamine-trimer models and the twisted models by 60 degrees were calculated by the CNDO/2 and EHMO methods.
It was noted that the energy difference between the planar and twisted trimer models is relatively small and it is within 1 kcal/mol. The calculated results suggest that the weight of the twisted structure in the conformation of oligomer may increase as the number of triazine ring of the oligomer increases.
In the present paper the conformation of melamine oligomer with twelve or thirteen triazine rings was evaluated assuming that the mixing rate of the planar dimer model to the twisted dimer is 1. The present oligomer models showed that there is no any hydrogen bond in the models.
