Synthesis and Conformational Study of Liquid Crystal Materials : Synthesis, Conformational Theoretical and Physical Study of Liquid Crystal compounds Containing 1,3,4-Oxadiazole Unit

A new two series of liquid crystal compounds containing 1,3,4-oxadiazole were synthesized and characterized by melting points, elemental analysis FTIR and 1HNMR spectroscopy. The liquid crystal properties of the synthesized compounds were verified by using hot-stage polarizing optical microscopy and differential scanning calorimeter. All of the compounds in both two series show mesomorphic properties. All members of those two series exhibit smectic A, smectic C and/ or nematic phases. Continually, to improve the physical study, Silver nanoparticles were prepared by reduction method and identified by mostly analysis XRD, SEM and AFM. From all of these techniques the particle size of nano seemed less than (50) nm. A theoretical investigating of core geometry by doing the conformational search over its affective torsion angles with PM3 and RM1 methods in order to include the effect of quantum mechanical factors that effect on the core geometry. Dielectric properties and other physical properties such as electrical conductivity (AC) and relaxation time or activation energy have been studied for two systems pure liquid crystals and their doped with silver nano particles.