Oxadiazoles及Triazoles等雜環有機液晶之設計與探討

• Main Author: 蘇人俊
• Other Authors: 李文仁
• Format: Others
• Language: zh-TW
• Published: 2001
• Online Access: http://ndltd.ncl.edu.tw/handle/87774141321098605164

碩士 === 國立中央大學 === 化學研究所 === 89 === ABSTRACT The synthesis, characterization and mesomophic properties of a new type of liquid crystalline compounds, 2,5-bis(3,4,5-trialkoxyphenyl)-1,3,4-oxadiazoles and 4-alkyl(aryl)-3,5-bis(3,4,5-trialkoxyphenyl)-4H-1,3,4-triazoles are reported. These heterocyclic compounds were derived from unsaturated 1,3,4-oxadiazoles and 1,2,4-triazoles as the core group, and obtained by condensation reaction of 3,4,5-trialkoxybenzoic acid N-(3,4,5-Trialkoxybenzoyl)hydrazides. These compounds were characterized by 1H- and 13C-NMR spectroscopy and elemental analysis. The mesomorphic properties of these compounds was characterized and studied by different scanning calorimetry(DSC) and polarized optical microscope.The primation of mesophases was found to be dependent of the numbers of alkoxy sidechains attached. Some compounds exhibited hexagonal columnar(Colh) phases, however, the others formed crystalline phases regardless of the carbon length on the sidechains. The compounds with shorter carbon sidechains were room temperature liquid crystals. Thepolar induction by nitrogen or/and oxygen atoms on the heterocyclic core ring might be responsible for the formation and beter observed mesomorphic properties in this type of compounds.