Inhaltszusammenfassung

The synthesis of TOTs´, C3-symmetrical star-shaped mesogenes with a 1,3,5-triazine centre, 5-phenyl-1,3,4-oxadiazole arms and various peripheral alkoxy side chains is reported. Threefold Huisgen reaction on a central triazine tricarboxylic acid and suitable aryltetrazoles yields the title compounds. Selected analogues with a benzene centre are included in this study and allow an evaluation of the impact of the central unit on physical properties. Thermal (DSC, POM), optical (UV-Vis, fluoresce...The synthesis of TOTs´, C3-symmetrical star-shaped mesogenes with a 1,3,5-triazine centre, 5-phenyl-1,3,4-oxadiazole arms and various peripheral alkoxy side chains is reported. Threefold Huisgen reaction on a central triazine tricarboxylic acid and suitable aryltetrazoles yields the title compounds. Selected analogues with a benzene centre are included in this study and allow an evaluation of the impact of the central unit on physical properties. Thermal (DSC, POM), optical (UV-Vis, fluorescence), electric (TOF) and structural (single crystal, WAXS) properties of these compounds are investigated. The modification of alkoxy chain length and substitution pattern allows a tuning of physical properties. TOTs emit blue to yellow light, depending on conjugation length, donor-acceptor substitution and solvent polarity, whereas concentration quenches, aggregation enhances the emission. The width of the mesophases is typically around ΔT = 100 - 150 K but can even exceed 220 K. Polarization optical microscopy and X-ray diffraction on oriented filaments reveal that TOTs are highly ordered LCs with long range hexagonal columnar structure.» weiterlesen» einklappen

Autoren

Klassifikation

DDC Sachgruppe:
Chemie