Room temperature columnar liquid crystalline phases of luminescent non-symmetric star-shaped molecules containing two 1,3,4-oxadiazole units

Abstract

In the present work, we show the synthesis and full characterization of 12 new 1,3,4-oxadiazole non-symmetrical star-shaped molecules containing amide or imine connecting groups, variable number and positions of linear or branched alkoxy chains and different sizes of the aromatic core. Thermal and liquid crystalline properties were investigated by POM, DSC, TGA and XRD scattering, while photophysical studies (UV-vis absorption, emission and quantum yield) were realized in solution and in solid state (film). Most compounds form enantiotropic hexagonal columnar phases while all molecules show blue luminescence. The variations in thermal and photophysical properties were correlated with different structural parameters showed by each molecule.