A route to compounds with a 5,7-diazapentacene skeleton has been established involving a Friedländer reaction. A diaminodiketone 8 has been made by a novel method and reacted with cyclohexanone to prepare an octa-hydro-5,7-diazapentacene 7a and with tetralone to produce a dibenzotetrahydro-5,7-diazapentacene 7b. Reaction of the diaminodiketone with a diarylethanone followed by oxidation gave a tetrabenzo-5,7-diazapentacene 18b. Compound 7b undergoes solid-state dimerization during single-crystal X-ray analysis. These materials possess lower frontier orbitals than pentacene and show strong absorption and fluorescence which is affected by the presence of acid. In particular 18b shows a remarkable colour change in solution upon addition of acid. These results suggest that suitably functionalised 5,7-diazapentacenes could be promising candidates for optoelectronic applications.

中文翻译：

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弗里德兰德通往5,7-二氮杂戊烷的路线†

已经建立了涉及5,7-二氮杂戊并五烯骨架的化合物的方法，该方法涉及Friedländer反应。甲diaminodiketone 8已经取得了一种新颖的方法和与环己酮反应，制备八氢-5,7- diazapentacene 7A并与四氢萘酮以产生dibenzotetrahydro -5,7- diazapentacene 7B。二氨基二酮与二芳基酮的反应，然后氧化，得到四苯并-5,7-二氮杂戊并苯18b。化合物7b在单晶X射线分析过程中经历固态二聚化。这些材料比并五苯具有更低的前沿轨道，并且显示出强烈的吸收和荧光，这受酸的存在影响。特别是18b加入酸后溶液显示出显着的颜色变化。这些结果表明，适当官能化的5,7-二氮杂戊烷可以成为光电子应用的有前途的候选者。