title: Fluorocarbon and hydrocarbon N-heterocyclic (C5-C7) imidazole-based liquid crystals.
abstract: By using three synthetic protocols, a series of fluorocarbon and hydrocarbon N-heterocyclic imidazole-based liquid crystals (LCs) and related imidazolium-based ionic liquid crystals (ILCs) have been prepared. The ring size of the N-heterocycle and the length of the N-terminal chain (on the imidazolium unit in the ILCs) were modified, and the influence of these structural parameters on liquid-crystal phases was investigated by means of polarizing optical microscopy (POM), differential scanning calorimetry (DSC), and X-ray diffraction (XRD). These new ILCs exhibit a disordered smectic phase (SmA), good thermal stabilities, a broad smectic phase range, a high dipole moment, relatively low melting points, but high clearing points and strong emission fluorescence relative to imidazole-based LCs. These encouraging results have led us to believe these fluorocarbon and hydrocarbon N-heterocyclic imidazole-based LCs and related imidazolium-based ILCs could be used as new liquid-crystalline materials.
authors.affiliation: College of Chemistry and Environment, South China Normal University, Guangzhou, 510006 (China), Fax: (+0086) 2039310287.
authors.forename: Hongren
authors.initials: H
authors.lastname: Chen
authors.forename: Fengying
authors.initials: F
authors.lastname: Hong
authors.forename: Guang
authors.initials: G
authors.lastname: Shao
authors.forename: Deyu
authors.initials: D
authors.lastname: Hang
authors.forename: Lei
authors.initials: L
authors.lastname: Zhao
authors.forename: Zhuo
authors.initials: Z
authors.lastname: Zeng
keywords: fluorine; heterocycles; ionic liquids; mesophases; phase transitions