含偶氮基团的不对称弯曲型液晶分子的合成及其光谱特性  

Synthesis and UV-Vis Absorption of Asymmetric Bent-Core Liquid Crystals Containing Azo Linkage

作　　者：李增俊[1] 沈冬[1] 

机构地区：[1]华东理工大学理学院化学物理研究室,上海200237

出　　处：《液晶与显示》2011年第3期274-280,共7页Chinese Journal of Liquid Crystals and Displays

基　　金：国家自然科学基金(No.60878047)

摘　　要：合成了6个含偶氮基团的具有不同苯环个数的不对称弯曲型液晶分子,用1 H NMR、HRMS表征其结构,采用差示扫描量热法(DSC)和偏光显微镜(POM)研究其液晶性能。考察结果表明:所有化合物均出现了液晶相,特别是含有3个苯环的分子在较低温度下出现了向列相;偶氮基团的吸收光谱在330～360nm出现了较强的由π-π*电子跃迁引起的吸收,在430～450nm出现了较弱的由n-π*电子跃迁引起的吸收,其吸收波长的变化表明分子的弯曲形状和电子分布使分子吸收波长有较大的变化。Six asymmetric bent-core liquid crystals with different aromatic rings containing azo linkage were synthesized.Their chemical structures were confirmed by 1H NMR and HRMS spectra and the liquid crystalline property was studied with polarizing optical microscopy and differential scanning calorimeter.All of the synthesized compounds exhibit liquid crystalline phases and the compound containing three aromatic rings has nematic phase at low temperature.The absorption spectra of the azo-benzene groups display a high-intensity π-π＊ transition at about 330~360 nm and a low-intensity n-π＊ transition at around 430~450 nm.The result that the three ring compounds have longer π-π＊ transition absorption waves than those of the four and five ring compounds may be caused by the bent shape of the molecules.

关 键 词：不对称 偶氮 弯曲型液晶 向列相 紫外-可见光吸收 

分 类 号：O753.2[理学—晶体学]