Two compounds with a tri-carbazole (3Cz) structure, namely 3,6-di(carbazol-9-yl)-N-(4-nitrophenyl)carbazole (NO₂-3Cz) and 3,6-di(carbazol-9-yl)-N-(4-aminophenyl)carbazole (NH₂-3Cz), were synthesized and electropolymerized into robust polymer films on the electrode surface in an electrolyte solution via the oxidative coupling reactions. The electro-generated polymer films exhibited reversible electrochemical oxidation processes, with significant electrochromic behaviour. The colour of P(NO₂-3Cz) films changed from the pale yellow neutral state to yellow-green as a radical cation and then to blue when fully oxidized. Upon oxidation, the colour of P(NH₂-3Cz) films changed from colourless to pale green and finally to blue. Furthermore, we also synthesized and characterized some N-phenylcarbazoles with different substituents on the phenyl group. Based on a comparative study, the possible electropolymerization mechanisms of the NO₂-3Cz and NH₂-3Cz monomers are suggested; that of the former is through carbazole–carbazole coupling, and the latter is through both carbazole–carbazole and NH₂–carbazole coupling.

中文翻译：

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由N-苯基-3,6-双（N-咔唑基）咔唑电化学合成电致变色聚咔唑薄膜†

具有三咔唑（3Cz）结构的两种化合物，即3,6-二（咔唑-9-基）-N-（4-硝基苯基）咔唑（NO ₂ -3Cz）和3,6-二（咔唑-9）合成了-基）-N-（4-氨基苯基）咔唑（NH ₂ -3Cz），并通过氧化偶联反应在电解质溶液中的电极表面上将其电聚合成坚固的聚合物膜。电产生的聚合物膜表现出可逆的电化学氧化过程，具有显着的电致变色行为。P（NO ₂ -3Cz）膜的颜色从浅黄色变为中性状态，变为黄绿色作为自由基阳离子，然后在完全氧化时变为蓝色。氧化后，P（NH ₂-3Cz）胶片从无色变为浅绿色，最后变为蓝色。此外，我们还合成并表征了一些在苯基上具有不同取代基的N-苯基咔唑。在比较研究的基础上，提出了NO ₂ -3Cz和NH ₂ -3Cz单体可能的电聚合机理。前者是通过咔唑-咔唑偶联，后者是通过咔唑-咔唑和NH _2-咔唑偶联。