Synthesis of novel redox systems having thiophenes highly integrated with quinone methides structure

我们对所有氢原子都被2,6-二叔丁基-4-亚甲基环己-2,5-二烯酮（醌-甲基）结构取代的共轭噻吩体系很感兴趣。我们已经制备了噻吩和二噻吩衍生物(分别命名为“四喹诺噻吩”（1)和“六喹诺噻吩”(2)）。动态多级氧化还原体系和采用硫原子的交叉共轭体系都引起了人们的关注。化合物1和2由溴噻吩衍生物经Suzuki-Miyaura偶联合成。通过x射线分析确定了1的结构。夹紧键的扭转很小，中心五元环形成扭船状构象。用循环伏安法检测了1和2的电化学性能，观察到它们的第一还原波是不可逆的。它表明1和2的构象都发生了单电子还原。

We have been interested in conjugated thiophene systems whose all hydrogen atoms are substituted by 2,6-di-tert-butyl-4-methylenecyclohexa-2,5-dienone (quinone-methide) structure. We have prepared thiophene and bithiophene derivatives (we named them "tetraquinothiophene"(1) and "hexaquinobithiohene"(2), respectively). These attract attention in term of dynamic multi-stage redox system as well as cross conjugated system adopting sulfur atom. Compounds 1 and 2 were synthesized from bromothiophene derivatives via Suzuki-Miyaura coupling. The structure of 1 was determined by X-ray analysis. There were little torsion of pinch-bonds and central five membered ring formed twist boat like conformation. The electrochemical properties of 1 and 2 were examined by cyclic voltammetry and the first reduction waves of them were observed irreversibly. It indicates conformational changes occur with one-electron reduction about both 1 and 2.