ISHIGAKI Yusuke

ISHIGAKI Yusuke
Associate Professor

Creating Fundamental Chemistry Based on Our Original Molecular Design

Department of Chemistry, Organic and Biological Chemistry

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.

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

Dibenzotropylium-Capped Orthogonal Geometry Enabling Isolation and Examination of a Series of Hydrocarbons with Multiple 14π-Aromatic Units
Y. Hayashi, S. Suzuki, T. Suzuki, Y. Ishigaki
J. Am. Chem. Soc. 2023, 145, 2596-2608. （Chem-Station Spotlight Research No. 501）

DOI: 10.1021/jacs.2c12574

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. （Chem-Station Spotlight Research No. 308）

DOI: 10.1021/jacs.1c00189

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

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

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

Related industries

Functional Materials, Molecular Device, Optical Element

Academic degree	Ph.D.
Academic background	2008 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 2021年- Associate Professor, Department of Chemistry, Faculty of Science, Hokkaido University
Affiliated academic society	The Chemical Society of Japan, The Society of Physical Organic Chemistry, Japan, The Society of Synthetic Organic Chemistry, Japan, The Japanese Photochemistry Association
Room address	Science Building 6 #6-509

Faculty of Science, Hokkaido University

Faculty of Science, Hokkaido University

Researcher Information

ISHIGAKI Yusuke
Associate Professor