Synthesis, structure, and dynamic behavior in solution of arylamino-1,3,5-triazines - 1. Unsymmetrically substituted arylamino-1,3,5-triazines

Ten unsymmetrically substituted arylamino-1,3,5-triazines were synthesized and studied by dynamic NMR spectroscopy. The free energies of the hindered rotation Delta G(not equal) are in 59-77 kJ mol(-1) range. Using difference-mode NOE NMR experiments, the structures of the major and minor rotation isomers were proved. The DFT B3LYP/6-31G* calculations were performed. The difference between the calculated rotation barriers and the experimental values obtained by line shape analysis is less than 7.6 kJ mol(-1). The height of the rotation barrier varies in a 18 kJ mol(-1) range depending on the substituents in the triazine ring.