Computational simulation of the molecular ordering of 3,6-bis(4-butylphenyl)[1,2,4,5]tetrazine at the phase transition temperatures

Prediction of the phase type based on computer simulation of molecular ordering in nitrogen-containing heterocyclic compounds

“…On the other hand, equal rigidity of the St and Pl dimer configurations suggested the possibility of the nematic phase existence [14]. Therefore, for compound II was expected to exhibit nematic properties over a wider temperature range, conforming with the experimental data ΔТ N = 16 K (see table).…”

“…This is suggestive that compound I exists within the limits of rather weak ordering characteristic of liquid phase. The 1/µ 2 (St) value was larger than 1/µ 2 (Pl), typical of nematic compounds [13]. Indeed, compound I demonstrated nematic properties over a narrow range of mesomorphism ΔТ N = 2 K (see table).…”

“…The 1/µ 2 values for compound III were larger than those for compound II. Hence, molecular ordering in dimers of compound III was enhanced [15], allowing for appearance of smectic properties. The conclusion was confirmed experimentally: compound III was a smectic liquid crystal exhibiting a wide temperature range of mesomorphism ΔТ S = 68 K (see table).…”

“…In view of the above, we performed quantum-chemical simulation of the interaction energy and molecular ordering of butylsubstituted dimers: 3,6-bis(4-butylphenyl)-1,2,4,5-tetrazine (I), 2,5-bis(4-butylphenyl)pyrazine (II), 2,5-bis(4-butylphenyl)pyrimidine (III) and 3,6-bis(4-butylphenyl)pyridazine (IV) taking advantage of the approach based on dynamics of dimers molecular movement at a range of temperaure [13][14][15][16]. The reasons for the different liquid-crystalline properties of compounds I-IV could be then rationalized by comparison of the translational rigidity coefficients, reflecting the ability of free movement of the molecules in dimers.…”