Synthesis and Characterization of Highly Conjugated Liquid Crystal Compounds

This thesis consists of synthesis of five new highly conjugated dimeric and trimericazo compounds which were synthesized according to the schemes shown below.- The first compound A1 consist of π-conjugated compounds containing 1,3,4oxadiazole as the central units with terminal azo phenyl.
- The second compound A2 consist of π-conjugated compounds containing 1,2,4triazole (V) as the central units with terminal azo phenyl group and lateral pbromobenzylideneamino group,as shown below (scheme2).
- Compound V 4,4`-(p-bromobenzylideneamino)-5,5`-mercapto[bis-1,2,4-triazole3-yl]phenyl was prepared as shown in scheme (3).
- The third compound A3 consist of π-conjugated compounds containingpyromelittic diimide as the central units with terminal azo phenyl group, asshown below (scheme 4).    
- The fourth compound A4 consist of π-conjugated compounds derived from 3,5 dihydroxy benzoic acid, as shown below (scheme 5).    
- The fifth compound A5 consist of trimeric π-conjugated compounds derived from 1,3,5-trihydroxy benzene, as shown below (scheme 6).    
- All the synthesized compounds were characterized using FTIR and CHNS-O analysis and some of them by  1HNMR
- The liquid crystalline properties of synthesized compounds which were verified using differential scanning calorimeter (DSC) and hot- stage polarizing optical microscope (POM) were discussed.
- The compounds show photoluminescence properties in the organic solution at room temperature, with the fluorescence band centered around 400 nm.