Front Cover: In article number 1900374 by Akimitsu Narita, Klaus Müllen, and co‐workers, a new synthetic approach toward lateral extension of polyphenylenes is developed. This strategy bases on a stepwise Diels‐Alder reaction between cyclopentadienone‐based building blocks, and ethynyl groups rationally appended on a starting polyphenylene. The strategy enables syntheses of a series of laterally extended polymers, which can potentially serve as precursors of graphene nanoribbons wider than 2 nm.

中文翻译：

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苯取代的线性聚苯撑的逐步侧向延伸

封面：成田明光，KlausMüllen和他的同事们在编号1900374的文章中，开发了一种新的合成方法来横向延伸聚苯撑。该策略基于基于环戊二烯酮的结构单元之间的逐步Diels-Alder反应，以及合理地附加在起始聚苯撑上的乙炔基。该策略可以合成一系列横向延伸的聚合物，这些聚合物可以潜在地用作宽于2 nm的石墨烯纳米带的前体。