Researcher Information


Associate 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

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)
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)
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.
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)
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
2021年- Associate 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, The Japanese Photochemistry Association
Room addressScience Building 6 #6-509

Department of Chemistry, Organic and Biological Chemistry


Associate Professor

What made you decide to become a researcher?

Once I start doing something, I get absorbed in it, and I have always thrown myself into everything I decided to do. I think this personality is one of the reasons why I continued to learn calligraphy during the time from elementary school to high school for more than 10 years, and soft tennis from junior high school to a club team for another 10 years. In addition, I have aspired to create new things with my own hands, so I am sure it was inevitable that I would meet chemistry and become a chemist. I believe that being a researcher is an ideal job of mine, because it allows me to create molecules that I have designed myself and that no one else in the world has had yet. I am pursuing a phenomenon that has never been seen before.

What is your dream that you want to achieve through your research?

As mentioned in ” What made you decide to become a researcher?”, I would like to elucidate undiscovered phenomena that have not been clarified yet and to conduct research that will lead to unexplored functions (applications), by using my own molecules. One of my dreams for the future is to leave my mark on history. Such a dream has been partially accomplished by my discovery being published in a textbook for graduate students (a technical book), in addition to each of papers with my colleagues published in international journals. In the future, I would like to continue to perform impactful research that will widely catch the attention.

Unlocking Carbon’s Mysteries
Please tell us your memories until you became a researcher.

After receiving my PhD, I have studied in Germany for six months. There were a lot of difficulties living abroad, but it was definitely a wonderful experience for me. It was hard to decide whether to study in an English-speaking country or in Europe, but now I am sure that I was right in deciding to go to Germany. I cannot write it all down here, so if you would like to hear more about my experience, please contact me directly via email or Twitter (@ysk_isgk). After returning to Japan, I worked at a private company and was able to learn about another field of research, which is far different from university. In particular, thanks to my supervisor at the company, I think I was also able to learn what is important in managing a group. I am convinced that my experiences in various places have helped me to become the person I am today.

Pictures taken during my stay in Germany (Ulm University)
Please tell us about yourself; things you are good at, your favorites, hobbies, and daily routines.

I am always taking care of my plants at home. I grow a variety of vegetables while looking forward to harvesting them with my son and daughter. The most popular vegetables so far are asparagus and green soybeans. They are always eaten up as soon as they are harvested, and thus, I continue to increase the amount I grow year by year.