JST-ERATO, Itami Molecular Nanocarbon Project, Chikusa, Nagoya 464-8602, Japan.
Graduate School of Science, Nagoya University, Chikusa, Nagoya 464-8602, Japan.
Science. 2019 Jul 19;365(6450):272-276. doi: 10.1126/science.aav5021.
The generation of topologically complex nanocarbons can spur developments in science and technology. However, conventional synthetic routes to interlocked molecules require heteroatoms. We report the synthesis of catenanes and a molecular trefoil knot consisting solely of -connected benzene rings. Characteristic fluorescence of a heterocatenane associated with fast energy transfer between two rings was observed, and the topological chirality of the all-benzene knot was confirmed by enantiomer separation and circular dichroism spectroscopy. The seemingly rigid all-benzene knot has rapid vortex-like motion in solution even at -95°C, resulting in averaged nuclear magnetic resonance signals for all hydrogen atoms. This interesting dynamic behavior of the knot was theoretically predicted and could stimulate deeper understanding and applications of these previously untapped classes of topological molecular nanocarbons.
拓扑复杂纳米碳的生成能够推动科学技术的发展。然而，传统的互锁分子的合成路线需要杂原子。我们报告了仅由 - 连接的苯环组成的轮烷和三叶结分子的合成。观察到与两个环之间快速能量转移相关的杂轮烷的特征荧光，并且通过对映体分离和圆二色性光谱证实了全苯结的拓扑手性。即使在-95°C 下，溶液中看似刚性的全苯结也具有快速的漩涡状运动，导致所有氢原子的核磁共振信号平均化。这种结的有趣动态行为在理论上进行了预测，并且可能激发对这些以前未开发的拓扑分子纳米碳的更深入理解和应用。
