Synthesis and Optical/Thermal Behavior of New Azo Photolsomenzable Discotic Liquid Crystals

In this study. discotic azo compounds were prepared by it reductive coupling of 5-nitroisophthalic acid followed by a convergent synthesis, resulting it) Five new examples of azo photoisomerizable discotic molecules. which differ from each other by the linking groups (ester, amide or 1,3,4-oxadiazole) and number of aliphatic chain (4 or 8). The thermal and liquid crystalline properties of the compounds were completely characterized by differential scanning calorimetry, polarized optical microscopy and X-ray diffraction analysis. Two products presented a stable columnar hexagonal mesophase with 9 and 134 degrees C or range. The results obtained show that the Choice of the linking group and number of aliphatic chains has a significative influence in the materials properties. The pholoisomerization capacity was evaluated in solution by spectroscopic methods and also by H-1 NMR. indicating that these molecules m-e promising candidates. for controlling file conductivity in electro-optical devices.