We report the synthesis of a new perylene-diimide-based helical nanoribbon, which exhibits the largest molar electronic circular dichroism in the visible range of any molecule. This nanoribbon also displays a substantial increase in molar circular dichroism relative to a smaller helical analogue, even though they share a similar structure: both nanoribbons incorporate two conformationally dynamic double-[4]helicene termini and a rigid [6]helicene-based core within their helical superstructures. Using DFT and TDDFT calculations, we find that the double-[4]helicenes within both nanoribbons orient similarly in solution; as such, conformational differences do not account for the disparities in circular dichroism. Instead, our results implicate the configuration of the double-[6]helicene within the larger nanoribbon as the source of the observed chiroptical amplification.

中文翻译：

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摆动的螺旋纳米带中强烈圆二色性的结构起源

我们报告了一种新的基于苝二亚胺的螺旋纳米带的合成，该纳米带在任何分子的可见光范围内表现出最大的摩尔电子圆二色性。与较小的螺旋类似物相比，该纳米带还显示出摩尔圆二色性显着增加，即使它们具有相似的结构：两种纳米带都包含两个构象动态双 [4] 螺旋末端和刚性 [6] 螺旋基核心他们的螺旋上层建筑。使用 DFT 和 TDDFT 计算，我们发现两个纳米带内的双 [4] 螺旋在溶液中的取向相似；因此，构象差异不能解释圆二色性的差异。反而，