含不同基团偶氮苯化合物的合成及其光致异构化性质

以苯胺或对硝基苯胺为起始原料,通过重氮偶合法合成了4种分别含有硝基、氨基和不同数目偶氮基的偶氮苯化合物(1~4),其结构经1H NMR和FT-IR确证。研究了1~4在紫外灯(12 W)照射下随时间变化的UVVis谱图。结果表明:含有给电子基团(NH2)偶氮苯的光致异构化速率较含有吸电子基团(NO2)时更快,NO2对分子的异构化有一定抑制作用;分子中偶氮基的数目增加时,顺反异构化过程也受到影响。

Synthesis and Photoisomerization Behavior of Azobenzene Compounds Containing Various Groups

Four kinds of azobenzene compounds(1~4) containing nitro, amino, and different number of azo groups were synthesized by diazo coupling reaction from aniline or 4-nitroaniline.The structures were confirmed by 1 H NMR and FT-IR.The UV-Vis spectra of 1~4 under UV irradiation were investi-gated.The results showed that the photoisomerization rate of the compounds linked with electron-dona-ting group( NH2 ) was faster than those linked with electron withdrawing group ( NO2 ) .The photoi-somerization was therefore restrained by NO2 .The cis/trans isomerization process was also affected by the number of azo couples.