1,3-双(偶氮介晶基)-1,1,3,3-四甲基二硅氧烷的 合成、2D NMR结构分析和液晶性能

Synthesis, 2D NMR Analysis and Liquid Crystal Function of 1,3-Bis-(azomesogenes)-1,1,3,3-tetramethylsiloxane

合成了2个(CH3(C6H4)N2(C6H3A)COO(C6H4)OCH2-Si(CH3)2)2O化合物,其中A = H为1,A = CH3为2。经IR、1H NMR和元素分析表征,并用2D NMR1H-1H COSY记录了2个化合物中不同取代基苯环上所有质子的化学位移和相关-自旋偶合常数,对谱线的归属作了指认。通过偏光显微镜和DSC分析,1具有液晶性能,而2没有液晶性能。同时,用AM1方法计算了它们的电子结构,讨论了它们的结构与性能之间的关系。

Two new compounds (CH3(C6H4)N2(C6H3A)COO(C6H4)OCH2-Si(CH3)2)2O (1,2)(1,A=H;2,A=CH3) were synthesized and characterized by IR, 1H NMR and elemental analysis.The chemical shifts and spin-spin-coupling constant of protons on the different benzene rings of the two title compounds were recorded on 2D NMR 1H-1H COSY, and the attribute of the peaks was specified. Analysis with polarizing microscope and DSC show that 1 has liquid crystal property while 2 has not. The electronic structure was calculated by AM1 method, and the relationship between electronic structure and liquid crystal function was also discussed.