Abstract:

Two series of shiff-base type liquid crystalline crown ether potassium complexes containing dibenzo-18-crown-6 were synthesized from ligand scis(trans)- 4,4′-bis[(4′-alkoxylbiphenyl-4-carboxy) benzylideneamino] dibenzo-18-crown-6 in yield of 85.5%~92.1% and 88.7%~90.7% respectively. Their structures and properties were characterized by elemental analysis, IR, UV-Vis, AAS, DSC, XRD and polarizing optical microscopy with a heating stage( POM). Results showed that the complexes change into liquid crystal phase when they were heated over their respective melting points, and the complexes melting points Tm and isotropization temperature Ti change regularly with the increase of the carbon numbers in the end alkoxygroups. There is a gradual increase in smectic phase length and a gradual decrease in nemetic phase length. The liquid crystalline phase temperature range became broader after complexation

Key words: potassium complexes,liquid crystalline crown ether,schiffbase type,thermotropic liquid crystal