Yusuke Ishigaki

Associate Prof. Yusuke Ishigaki is a chemist at Hokkaido University, Japan. He works on the creation of fundamental chemistry based on original molecular design.

Theme: Preparation of Redox-active Highly Strained Molecules with a Novel Functionality
Field: Structural Organic Chemistry, Organic Chemistry, Physical Organic Chemistry
Keyword: Highly 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.

Education and Working Experiences

2008.3 B.S. Department of Chemistry, Faculty of Science, Hokkaido University (Prof. Takanori Suzuki)
2009.9 M.S. Department of Chemistry, Graduate School of Science, Hokkaido University (Prof. Takanori Suzuki)
2012.9 Ph.D. Department of Chemistry, Graduate School of Science, Hokkaido University (Prof. Takanori Suzuki)
2010.4-2012.9 Research Fellow (DC1), Japan Society for the Promotion of Science (JSPS)
2012.10-2013.3 Postdoctoral Research Fellow (Prof. Peter Bäuerle, University of Ulm, Germany), JSPS (PD)
2013.4-2015.12 Nippon Steel & Sumikin Chemical Co., Ltd. (Japan)
2016.1-2021.3 Assistant Professor, Department of Chemistry, Faculty of Science, Hokkaido University
2021.4-present Associate Professor, Department of Chemistry, Faculty of Science, Hokkaido University

Representative Achievements

2020.1 Special Lecturer for Young Chemists in the 100th CSJ Annual Meeting (by The Chemical Society of Japan)
2020.3 The Encouragement Award from Hokkaido Branch of the Chemical Society of Japan (by Hokkaido Branch of The Chemical Society of Japan)

Selected publications

Hysteretic Three-State Redox Interconversion among Zigzag Bisquinodimethanes with Non-fused Benzene Rings and Twisted Tetra-/Dications with [5]/[3]Acenes Exhibiting Near-Infrared Absorptions.
Y. Ishigaki,* T. Harimoto, K. Sugawara, T. Suzuki*
J. Am. Chem. Soc. 2021, 143, 3306-3311. DOI: 10.1021/jacs.1c00189
Molecular Recognition by Chalcogen Bond: Selective Charge‐transfer Crystal Formation of Dimethylnaphthalene with Selenadiazolotetracyanonaphthoquinodimethane.
Y. Ishigaki, K. Asai, H.-P. Jacquot de Rouville, T. Shimajiri, V. Heitz, H. Fujii-Shinomiya, T. Suzuki*
Eur. J. Org. Chem. 2021, 990-997. DOI: 10.1002/ejoc.202001554
Flexible C–C Bonds: Reversible Expansion, Contraction, Formation, and Scission of Extremely Elongated Single Bonds.
T. Shimajiri, T. Suzuki, Y. Ishigaki*
Angew. Chem. Int. Ed. 2020, 59, 22252-22257. DOI: 10.1002/anie.202010615
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. 2020, 59, 6581-6584. DOI: 10.1002/anie.201916089
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. DOI: 10.1002/asia.201901816
H₂S-activatable near-infrared afterglow luminescent probes for sensitive molecular imaging in vivo.
L. Wu,^# Y. Ishigaki,^# Y. Hu, K. Sugimoto, W. Zeng, T. Harimoto, Y. Sun, J. He, T. Suzuki,* X. Jiang, H.-Y. Chen, D. Ye* (^#These authors contributed equally.)
Nat. Commun. 2020, 11, 446. DOI: 10.1038/s41467-020-14307-y
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）DOI: 10.1021/jacs.9b09646
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) DOI: 10.1246/bcsj.20190094
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) DOI: 10.1016/j.chempr.2018.01.011