New 1,3-dioxane type ionic liquid crystal compounds having a different counter anion

New pyridinium type thermotropic ionic liquid crystal materials having a 1, 3-dioxane ring in their central core: N-substituted-4-(5-alkyl-1,3-dioxan-2 -yl)pyridinium halides (6) were synthesized. These componds exhibited a sme ctic A phase over a very wide temperature range including room temperature [for example 6-5: G-24 SmA 152 I (degrees C)]. The size of the counter anio n affected the transition temperatures between the isotropic state and the smectic A phase.