Researcher Information

Yoshiyuki Kageyama

Assistant Professor

Chemistry becomes increasingly fun!

Department of Chemistry, Physical Chemistry

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Theme

We investigate dynamics in molecular systems, where many molecules play cooperatively. This insight is very far-from the classical chemistry. The self-organized behaviors like as the biological phenomena will be established from our research field.

FieldSystems Chemistry, Supramolecular Chemistry, Biomimetic Chemistry, Organic Chemistry, Chemical Physics
KeywordSelf-Organization (Dissipative Structure), Nonlinear Dynamics, Energy Conversion, Catalysis, Collective Dynamics of Molecules, Spontaneous Functions, Soft Matter, Active Matter

Introduction of Research

In our body, a large number of molecules work cooperatively. As the result of the cooperation, molecules show special functions that the molecule cannot realize by alone. The aim of our research is fully-artificial creation of such a “super function” due to networks in multi-molecular systems, in vitro. This novel research field is known as Systems Chemistry.
The best research result is shown in Figure 1. Generally, to make the repetitive motion of light-responsive materials, switching of light is required. However, the azobenzene crystals in the figure periodically flip under steady light irradiation. The mechanism for the self-continuous motion is shown in Figure 2. In the original phase of the crystal, the forward reaction (trans-to-cis photoisomerization) occurs, and the increasing in the cis-isomer ratio induces a subcritical phase transition to a metastable crystal phase. In the newly formed crystal, cis-to-trans photoisomerization occurs, and the decrease in the cis-isomer ratio induces the reverse phase transition to the original crystal phase. Repeating the dynamics spontaneously, the crystal flips repetitively. Hokkaido University press-released the result with the title of “On the path toward molecular robots”. The news was translated into more than ten languages by publishers. You may watch the movie of clione-like motion of crystal from YouTube (Figure 3).
When we construct such self-organized dynamics, self-assembly of molecules is also a key dynamics. As shown in Figure 4, the dynamics to form molecular assembly is quite interesting. The helical assembly, the size in the figure is several ten micrometers, grew to one centimeter-length assembly by 3-days incubation. The formation is involved with multi-molecular dynamics.
To investigate the feature of multi-molecular systems, the researcher applies his skill for organic synthesis. And home-made equipment is employed for physical measurements. An example of organic synthesis is shown in Figure 5.
The field of the research group is in multidiscipline area. All who interested in the research is welcomed to join.

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Figure 1. Periodic flipping motions of organic crystals under continuous light irradiation.
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Figure 2. Schematic illustration for self-oscillatory dynamics. Combination of the subcritical phase transition and the reversing of reaction by the phase transition causes the spontaneous periodic motion.
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Figure 3. Movie for clione-like behavior of an organic crystal is available from https://www.youtube.com/watch?v=M0epKeaS2_E
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Figure 4. Dynamics in molecular assembling is also an important topic for our study. The figure is spontaneous formation of a helical assembly in water.
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Figure 5. To achieve our goal, we synthesize organic compounds by ourselves.

Representative Achievements

Light‐Powered Self‐Sustainable Macroscopic Motion for the Active Locomotion of Materials, Y. Kageyama, ChemPhotoChem., 2019 (Minireview)
Dissipative and Autonomous Square-Wave Self-Oscillation of a Macroscopic Hybrid Self-Assembly under Continuous Light Irradiation, T. Ikegami, Y. Kageyama, K. Obara, S. Takeda, Angew. Chem. Int. Ed., 2016, 55, 8239–8243. (Hot Article, Press-Released Article)
Autocatalytic membrane-amplification on a pre-existing vesicular surface, H. Takahashi, Y. Kageyama, K. Kurihara, K. Takakura, S. Murata, T. Sugawara, Chem. Commun. 2010, 46, 8791–8793.
Mechanism of Macroscopic Motion of Oleate Helical Assemblies: Cooperative Deprotonation of Carboxyl Groups Triggered by Photoisomerization of Azobenzene Derivatives, Y. Kageyama, T. Ikegami, Y. Kurokome, S. Takeda, Chem. Eur. J. 2016, 22, 8669–8675.
Structure and growth behavior of centimeter-sized helical oleate assemblies formed with assistance of medium-length carboxylic acids, Y. Kageyama, T. Ikegami, N. Hiramatsu, S. Takeda, T. Sugawara, Soft Matter, 2015, 11, 3550–3558. (Back Cover Picture)

Related industries

Chemical Industry, Pharmacy
Academic degreePh. D. (Multidisciplinary Science)
Academic background2001. Graduated from the University of Tokyo
2003. Obtained Master-degree from the University of Tokyo
2006. Obtained Ph.D. from the University of Tokyo
2006-2007. Postdoctral Researcher in the University of Tokyo
2007-2009. Postdoctral Researcher in Tokyo University of Science
2009- current position
2013-2017. JST PRESTO researcher
Affiliated academic societyChemical Society of Japan
Project"Molecular Engine", Scientific Research on Innovative Areas, KAKENHI, MEXT
"Molecular Technology and Creation of New Functions", PRESTO, Japan Science and Technology Agency
Room addressBuilding 7 7-410