Novel fluorescent columnar liquid crystal based on tetraphenylethylene- rufigallol-tetraphenylethylene triads

In this article, two new tetraphenylethylene- rufigallol-tetraphenylethylene triads 7a and 7b were synthesized in yield of 50%. These compounds were characterized by mass spectrometry, NMR spectroscopy, and elemental analysis. Their mesomorphic behaviors were studied by polarizing optical microscopy, differential scanning calorimetry, and X-ray diffractometry. Investigation of their liquid crystalline behaviors indicated that compounds 7a and 7b possessed the hexagonal columnar mesophase. Compound 7b with dodecyl chains exhibited the low phase transition temperatures and wide range of mesophase temperatures in comparison with compound 7a . Compounds 7a and 7b exhibited excellent aggregation-induced emission in H 2 O/THF solution. The fluorescence quantum yields of these compounds in the solid state were 22% and 16%, respectively. Results from this study suggest that symmetrical trimer was a good approach to construct novel fluorescence columnar liquid crystals.