Thermotropic liquid crystalline ionic stilbazoles and their miscible mixtures with non-ionic carbazolyl compounds

Abstract

Abstract New thermotropic ionic liquid crystals were prepared from trans-4-nitro-4′-stilbazole and alkyl halides. trans-N-Alkyl-4-nitro-4′-stilbazolium bromides containing alkyl chains with 7 to 10 carbons and the chloride homologues containing alkyl chains with 5 to 10 carbons exhibited smectic phases. For example, trans-N-decyl-4-nitro-4′-stilbazolium bromide and trans-N-hexyl-4-nitro-4′-stilbazolium chloride showed smectic phases from 175 to 186°C and from 129 to 190°C, respectively. The temperature range of mesophases increased with decreasing size of the counteranions. The miscibility of trans-N-alkyl-4-nitro-4′-stilbazolium bromide in Schiff's base compounds having various electronegative groups was examined by differential scanning calorimetry and polarizing microscopy. Miscible binary mixtures were prepared from trans-N-alkyl-4-nitro-4′-stilbazolium bromides and 4-alkoxy-N-(9-methyl-2-carbozolyl-methylene)anilines. The 1:1 (mole ratio) binary mixture of trans-N-hexyl-4-nitro-4′-stilbazolium bromid...