Synthesis, Characterization, and Investigation of Mesogenic Properties of Bis(۲-oxo-۲H-Chromen-۶-yl)Terephthalate and Bis(۲-Oxo-۲H-Chromen-۷-yl)Terephthalate

The synthesis, characterization, and mesomorphic investigation of new liquid crystals are described. The goal was to synthesize esters starting with ۶- and ۷-hydroxycoumarin. The structures of the synthesized compounds were actually determined by FT-IR and ۱H-NMR. The mesophase behavior of the synthesized compounds was characterized and investigated by using (DSC) differential scanning calorimetry and (POM) polarizing the optical microscopy. The mesophase transitions are enantiotropic, the peaks being sharp and the mesomorphic range wide. The synthesized compounds exhibit a nematic phase.

Keywords:

Coumarin , Mesomorphic , Nematic , Schiff`s bases