Researcher Information

Yusuke Ishigaki

Assistant Professor

Creating Fundamental Chemistry Based on Our Original Molecular Design

Department of Chemistry, Organic and Biological Chemistry


Preparation of Redox-active Highly Strained Molecules with a Novel Functionality

FieldStructural Organic Chemistry, Organic Chemistry, Physical Organic Chemistry
KeywordHighly strained compounds, Redox systems, Electrochromism, Mechanochromism, Long bond, Hyper covalent bond

Introduction of Research

The carbon–carbon covalent bond is one of the most basic concept in organic chemistry. Bond length, bond angle, and torsion angle among carbon atoms are nearly constant on the basis of their hybrid orbitals. On the other hand, highly strained hydrocarbons such as sterically-congested and/or curved polycyclic aromatic hydrocarbons as well as cyclic π-conjugated molecules have attracted much attention with regard to their characteristic features. We focused on two types of redox-active molecules with a extremely elongated C-C single bond (Hyper covalent bond with a bond length beyond 1.8 Å) or a strained double bond, for which unique electrochromic behavior was observed upon oxidation to give deeply colored cationic species.

Unusual geometric features in highly strained molecules.
Hyper covalent bond in dihydropyracylene derivative: an extremely expanded C-C single bond with a bond length of 1.806(2) Å and X-ray crystal structure (at 400 K).

Representative Achievements

Switching of Redox Properties Triggered by a Thermal Equilibrium between Closed-shell Folded and Open-shell Twisted Species
Y. Ishigaki, T. Hashimoto, K. Sugawara, S. Suzuki, T. Suzuki
Angew. Chem. Int. Ed., in press.
Hexaarylbutadiene: a versatile scaffold with tunable redox properties towards organic near-infrared electrochromic material
Y. Ishigaki, T. Harimoto, K. Sugimoto, L. Wu, W. Zeng, D. Ye, T. Suzuki
Chem. Asian J. 2020, 15, 1147-1155.
Photo- and Thermal Interconversion of Multiconfigurational Strained Hydrocarbons Exhibiting Completely Switchable Oxidation to Stable Dicationic Dyes
Y. Ishigaki, Y. Hayashi, T. Suzuki
J. Am. Chem. Soc. 2019, 141, 18293-18300. (Chem-Station Spotlight Research No. 244)
Two-way Chromic Systems Based on Tetraarylanthraquinodimethanes: Electrochromism in Solution and Mechanofluorochromism in a Solid State
Y. Ishigaki, K. Sugawara, M. Yoshida, M. Kato, T. Suzuki
Bull. Chem. Soc. Jpn. 2019, 92, 1211-1217. (Selected Paper)
Longest C–C Single Bond among Neutral Hydrocarbons with a Bond Length beyond 1.8 Å
Y. Ishigaki, T. Shimajiri, T. Takeda, R. Katoono, T. Suzuki
Chem 2018, 4, 795-806. (Selected as the Editors' Favorite Chem Articles from 2018)

Related industries

Functional Materials, Molecular Device, Optical Element
Academic degreePh.D.
Academic background2008 B.S. Department of Chemistry, Faculty of Science, Hokkaido University
2009 M.S. Department of Chemistry, Graduate School of Science, Hokkaido University
2012 Ph.D. Department of Chemistry, Graduate School of Science, Hokkaido University
2012-2013 JSPS Research Fellow (PD), Ulm University, Germany
2013-2015 Nippon Steel & Sumikin Chemical Co., Ltd.
2016- Assistant Professor, Department of Chemistry, Faculty of Science, Hokkaido University
Affiliated academic societyThe Chemical Society of Japan, The Society of Physical Organic Chemistry, Japan, The Society of Synthetic Organic Chemistry, Japan
Room addressScience Building 6 #6-509