偶氮基杯[4]芳烃化合物的合成及其偶氮-醌腙互变异构性质

Synthesis and Azo-quinoid Tautomerizm of Azocalix[4]arene

通过芳胺的重氮化-偶合反应合成了8个偶氮基杯[4]芳烃化合物,其结构经IR,1H NMR,ESI-MS和元素分析表征.通过UV-V is,1H NMR和IR考察了溶液pH值对所合成化合物5,11,17,23-四[(2-苯并噻唑基)偶氮基]-25,26,27,28-四羟基杯[4]芳烃(3)和5,17-二[(1-萘基)偶氮基]-25,26,27,28-四羟基杯[4]芳烃(4)的偶氮-醌腙互变异构的影响.结果表明,随着溶液pH值增加,醌腙体在偶氮-醌腙互变异构平衡中的比例增加,当pH≥10时,几乎全部转变为醌腙体.特别当溶液pH=-1时,化合物4可以形成一种大的共轭体系,使其λm ax由477 nm红移至545 nm.

The introduction of chromophoric azo group into calixarene was of great value for the development of functional calixarenes, and the azo-coupled calixarene usually showed large UV-Vis band shifts when base was added. Eight azocalix [ 4 ] arene compounds were synthesized by diazo-coupling reaction. These compounds were characterized by IR, 1^H NMR, ESI-MS and elemental analysis. The effect of varying pH values upon the absorption ability of both 5,11,17,23 -tetra [ （ 2-benzothiazole ） azo ] -25,26,27,28-tetrahydroxyealix [ 4 ] arene and 5,17-di [ （1-naphthyl） azo ]-25,26,27,28-tetrahydroxycalix [ 4 ] arene was tested to study the azo-quinoid tautomerizm phenomena. Observed result exhibit that with the increasing of pH, the proportion of quinoid tau- tomer in azo-quinoid tautomerizm equilibrium is rised. Unexpectedly an conjugated system may be formed in the condition of pH = - 1 for 5,17-di [ （ 1 -naphthyl） -azo ] -25,26,27,28-tetrahydroxyealix [ 4 ] arene, of which the UV absorption spectra show substantial bathochromic shifts（ △λ = 477-545 nm）.