Mechanical interlocking of molecules (catenation) is a nontrivial challenge in modern synthetic chemistry and materials science1,2. One strategy to achieve catenation is the design of pre-annular molecules that are capable of both efficient cyclization and of pre-organizing another precursor to engage in subsequent interlocking3–9. This task is particularly difficult when the annular target is composed of a large ensemble of molecules, that is, when it is a supramolecular assembly. However, the construction of such unprecedented assemblies would enable the visualization of nontrivial nanotopologies through microscopy techniques, which would not only satisfy academic curiosity but also pave the way to the development of materials with nanotopology-derived properties. Here we report the synthesis of such a nanotopology using fibrous supramolecular assemblies with intrinsic curvature. Using a solvent-mixing strategy, we kinetically organized a molecule that can elongate into toroids with a radius of about 13 nanometres. Atomic force microscopy on the resulting nanoscale toroids revealed a high percentage of catenation, which is sufficient to yield ‘nanolympiadane’10, a nanoscale catenane composed of five interlocked toroids. Spectroscopic and theoretical studies suggested that this unusually high degree of catenation stems from the secondary nucleation of the precursor molecules around the toroids. By modifying the self-assembly protocol to promote ring closure and secondary nucleation, a maximum catenation number of 22 was confirmed by atomic force microscopy. Nanoscale toroids with a high percentage of poly-catenation and radii of up to about 13 nm are kinetically organized using fibrous supramolecular assemblies with intrinsic curvature and a solvent-mixing strategy.

中文翻译：

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来自超分子环形构件的自组装聚链烷烃

分子的机械联锁（链）是现代合成化学和材料科学中的一项重大挑战1,2。实现连锁的一种策略是设计能够有效环化和预组织另一种前体以参与后续互锁的预环分子3-9。当环形目标由大量分子组成时，即当它是超分子组装时，这项任务尤其困难。然而，这种前所未有的组件的构建将能够通过显微镜技术实现非平凡的纳米拓扑结构的可视化，这不仅可以满足学术好奇心，还可以为开发具有纳米拓扑衍生特性的材料铺平道路。在这里，我们报告了使用具有固有曲率的纤维超分子组装体合成这种纳米拓扑。使用溶剂混合策略，我们在动力学上组织了一个分子，该分子可以伸长成半径约为 13 纳米的环形。对所得纳米级环面的原子力显微镜显示出高百分比的链，这足以产生“nanolympiadane”10，一种由五个互锁环面组成的纳米级链。光谱和理论研究表明，这种异常高的连锁程度源于环面周围前体分子的二次成核。通过修改自组装协议以促进环闭合和二次成核，原子力显微镜证实了最大链数为 22。