New 1,3-dioxan-type ionic liquid crystal compounds having a large dielectric constant

New pyridinium-type thermotropic ionic liquid crystal materials having a 1, 3-dioxan ring in its central core: N-substituted-4-(5-alkyl-1,3-dioxan-2-yl )pyridinium bromides (6) were synthesized The mesomorphic behaviour of thes e compounds and dielectric constant perpendicular to the molecular axis wer e measured. The principal features of these compounds are that they exhibit a smectic A phase over a wide temperature range including room temperature -for example 6f: g -9 SmA 181 I (degreesC)-and they have a large dielectric constant perpendicular to the molecular axis.