Blue Glow Sticks: Cinnamic Acids and Arylacrylonitriles with Liquid-Crystalline Properties and Highly Fluorescent

Five new ?-conjugated chromophores derived from acrylic acid and acrylonitrile were synthesized their thermal photophysical behaviors analyzed. They designed through Knoevenagel condensations between arylacetylenebenzaldehydes a methylene group activated cyanoacetic malonic acids. The characterization of the target compounds was performed by Fourier transform infrared spectroscopy (FTIR), 1H nuclear magnetic resonance (NMR), 13C NMR, thermogravimetric analysis (TGA), absorption emission techniques. Arylcinnamic acids obtained as pure E-isomers. On other hand, arylacrylonitrile mixture E/Z-isomers E-isomer isolated in chromatographic columns. liquid crystal properties investigated differential scanning calorimetry polarized optical microscopy. All displayed smectic nematic mesophases. These materials intense fluorescence under UV-Vis light excitation. maximum peaks observed 342-356 nm while varied 428 to 460 chloroform solution. Higher values for quantum yield associated with compared arylacrylonitriles. solvatochromism studies showed significant increase red-shift spectra polarity solvent increased. In some cases, variation wavelength blue green region spectrum observed.