Département de Chimie, Université de Montréal, CP 6128, succ. Centre-ville, Montréal, Québec, H3C 3J7, Canada.
Chemistry. 2011 Sep 19;17(39):10879-88. doi: 10.1002/chem.201101397. Epub 2011 Aug 31.
In the search of functional materials with improved electrochromic properties, thiophenes and asymmetric bipyrroles have been conjugated with azomethine units. 4-Methoxy-2,2'-bipyrroles 3-6 were first synthesized by a general route from 4-hydroxyproline and converted subsequently to dialdehydes 8-15, which underwent condensations with different aminothiophenes to provide azomethine conjugates 14-18 and 20-22. The crystallization and X-ray analysis of 20 showed the heterocycles and azomethine bonds were all co-planar with the heterocycles adopting an anti-parallel arrangement. These configurations result in extended conjugation and enhanced opto-electronic properties of the azomethines. Oxidation potential (E(pa)) was tailored by modification of the substitution pattern of the terminal thiophenes and central pyrroles of the azomethines. The combined low E(pa) and extended azomethine degree of conjugation resulted in stark color transitions occurring between their neutral and oxidized states. Reversible color formation was induced both electrochemically and by doping/de-doping with trifluoroacetic acid/triethylamine.
在寻找具有改进电致变色性能的功能材料的过程中，噻吩和不对称联吡啶已与亚甲胺单元共轭。通过从 4-羟基脯氨酸出发的一般路线首次合成了 4-甲氧基-2,2'-联吡啶 3-6，然后将其转化为二醛 8-15，与不同的氨噻吩缩合得到亚甲胺共轭物 14-18 和 20-22。20 的结晶和 X 射线分析表明，杂环和亚甲胺键均共面，杂环呈反平行排列。这些结构导致亚甲胺的共轭得到扩展，光电性能得到增强。通过修饰亚甲胺末端噻吩和中心吡咯的取代模式来调整氧化电势 (E(pa))。低 E(pa)和扩展的亚甲胺共轭度的结合导致其中性和氧化态之间发生明显的颜色转变。通过电化学和三氟乙酸/三乙胺掺杂/脱掺杂均可诱导可逆的颜色形成。
