Topological molecular nanocarbons: All-benzene catenane and trefoil knot

• DOI: 10.1126/science.aav5021
• Publication Date: 2019-07-18T22:55:22Z
• Authors: Yasutomo Segawa; Motonobu Kuwayama; Yuh Hijikata; Masako Fushimi; Taishi Nishihara; Jenny Pirillo; Junya Shirasaki; Natsumi Kubota; Kenichiro Itami
• Keywords: Catenane; Catenation; Carbon fibers

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 catenanes a molecular trefoil knot consisting solely para-connected benzene rings. Characteristic fluorescence heterocatenane associated with fast energy transfer between two rings was observed, topological chirality all-benzene confirmed by enantiomer separation circular dichroism spectroscopy. seemingly rigid has rapid vortex-like motion solution even at -95°C, resulting averaged nuclear magnetic resonance signals for all hydrogen atoms. This interesting dynamic behavior theoretically predicted could stimulate deeper understanding applications these previously untapped classes nanocarbons.