Novel fluorescence liquid crystals based on thiophene-vinylnitrile Schiff-base derivatives

This paper reported the first example of thiophene-containing AIE fluorescence liquid crystals. Thiophene-vinylnitrile Schiff-base derivatives 5 with one alkyl chain and 6 with two alkyl chains were prepared conveniently in yields of 86% and 88%, respectively. They exhibited the smectic phases from 91.5 to 130.6℃ for sample 5 and 71.3 to 120.2℃ for sample 6. They displayed excellent fluorescence in aggregated states of solid film and mesophase. The absolute fluorescence quantum yields in solid film were as high as 0.64 for samples 5 and 0.76 for sample 6, respectively. These results suggested thiophene-vinylnitrile Schiff-base derivatives 5 and 6 were excellent fluorescence liquid crystals and the multiple alkyl chains on thiophene-vinylnitrile Schiff-base derivatives were favourable for the low temperature of mesophase and high fluorescence.