Self-assembly provides access to non-covalently synthesized supramolecular materials with distinct properties from a single building block. However, dynamic switching between functional states still remains challenging, but holds enormous potential in material chemistry to design smart materials. Herein, we demonstrate a chemical fuel-mediated strategy to dynamically switch between two distinctly emissive aggregates, originating from the self-assembly of a naphthalimide-appended peptide building block. A molecularly dissolved building block shows very weak blue emission, whereas, in the assembled state (Agg-1), it shows cyan emission through π stacking-mediated excimer emission. The addition of a chemical fuel, ethyl-3-(3-(dimethylamino)propyl)carbodiimide (EDC), converts the terminal aspartic acid present in the building block to an intra-molecularly cyclized anhydride in situ forming a second aggregated state, Agg-2, by changing the molecular packing, thereby transforming the emission to strong blue. Interestingly, the anhydride gets hydrolyzed gradually to reform Agg-1 and the initial cyan emission is restored. The kinetic stability of the strong blue emissive aggregate, Agg-2, can be regulated by the added concentration of the chemical fuel. Moreover, we expand the scope of this system within an agarose gel matrix, which allows us to gain spatiotemporal control over the properties, thereby producing a self-erasable writing system where the chemical fuel acts as the ink.

中文翻译：

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装配编码发射之间的化学燃料动态切换

自组装提供了非共价合成的超分子材料，其具有与单一构建块不同的特性。然而，功能状态之间的动态切换仍然具有挑战性，但在材料化学设计智能材料方面具有巨大的潜力。在此，我们展示了一种化学燃料介导的策略，可在两种明显发射的聚集体之间动态切换，该策略源自萘酰亚胺附加肽构建块的自组装。分子溶解的结构单元显示出非常弱的蓝色发射，而在组装状态（Agg-1）下，它通过π堆积介导的准分子发射显示出青色发射。添加化学燃料乙基-3-(3-(二甲基氨基)丙基)碳二亚胺 (EDC)，将结构单元中存在的末端天冬氨酸原位转化为分子内环化酸酐，形成第二聚集态Agg -2，通过改变分子堆积，从而将发射转变为强蓝色。有趣的是，酸酐逐渐水解，重新形成Agg-1，并恢复了最初的青色发射。强蓝光发射聚集体Agg-2的动力学稳定性可以通过化学燃料的添加浓度来调节。此外，我们在琼脂糖凝胶基质内扩展了该系统的范围，这使我们能够获得对其特性的时空控制，从而产生一种可自擦除的书写系统，其中化学燃料充当墨水。