Experimental and theoretical investigation on the thermal isomerization reaction of tristriazolotriazines

Abstract

The isomerization of tristriazolotriazione with tangential substituents to radial isomers occurs in a cascade of three ring opening/rotation/ring closure steps of the central triazine. Donor substitution accelerates the isomerization which can be catalyzed by Brønsted acids. The velocity of the rearrangements drops with each step by a factor of 4, whereas the gain in heat of formation increases. Density functional theory (DFT) calculations led to transition states; their energies correspond to the experimental data. Threefold isomerization strongly affects the mesomorphic properties.