RIKEN

The University of Tokyo

Japan Science and Technology Agency

Summary

Hiroshi Sato, Unit Leader of the Emergent Molecular Integration Research Unit, Integrated Molecular Science Program, RIKEN Center for Emergent Matter Science, (Visiting Researcher at the Graduate School of Engineering, The University of Tokyo, JST PRESTO Researcher), Takuzo Aida, Vice Director of the Emergent Molecular Integration Research Unit, RIKEN Center for Emergent Molecular Science (RIKEN Center for Emergent Molecular Science) (Professor at the Graduate School of Engineering, The University of Tokyo), and Wenjin Meng, Research Fellow at the Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo. (RIKEN Center for Emergent Matter Science), and Wenjin Meng, JSPS Research Fellow (at the time of the research) at the Department of Chemistry and Biotechnology, Graduate School of Engineering, The University of Tokyo, have successfully developed a soft crystal that responds to external forces by precisely arranging "catenane" molecules in a three-dimensional arrangement. The research group has succeeded in developing soft crystals that respond to external forces by precisely arranging "catenane" molecules in three dimensions.

The research results are expected to lead to applications such as innovative porous materials that can absorb and desorb gas molecules such as carbon dioxide by pinching and releasing them with a finger.

In this study, the joint research group prepared crystals in which catenane molecules, which are two ring-shaped molecules linked in a chain, and cobalt ions ( ^{Co2+) are} heated in a solvent to form a three-dimensional arrangement of catenane molecules through coordination bonds. The structure of these crystals was investigated using single-crystal X-ray structure analysis, which revealed that more than 90% of the crystals are composed of catenane molecules, that they have a structure with many microscopic holes, and that they change their structure with temperature change. Furthermore, it was found that the crystal changes its shape when force is applied from the outside and returns to its original shape when the force is removed, indicating that it has rubber-like properties despite being a crystal.

Figure: Crystal made by precisely arranging molecular chains "catenanes" in three dimensions

This research was published online in the scientific journal Nature on October 13 (Japan time), prior to its publication in the journal.

Associate Professor Issei Komatsu of the Geochemical Research Center participated in this research.
For more information, please visit the RIKEN website.