Research Theme

Design and synthesis of three-dimensional organic structures

Keywords

π-conjugated molecules, molecular topology, 3D network polymer

Aromatic compounds are potentially useful as functional electronic materials. However, the design and control of three-dimensional molecular assembly are still very difficult, especially for the crystal engineering of organic molecules. This group aims to create novel topological and reticular organic structures by using synthetic organic chemistry and geometric insight. To achieve our purpose, this group will start electron-diffraction crystallography (MicroED) for the rapid structure determination of three-dimensional covalent organic frameworks.

1) Design and synthesis of π-conjugated organic molecules
2) Development of novel molecular topology
3) Construction of 3D network polymers

Selected Publications

1. Synthesis, structure, and properties of twisted π-conjugated molecules featuring three-dimensional π-π interactions in solid states
   Mai Nagase, Ryu Yoshida, Sachiko Nakano, Takashi Hirose, Yasutomo Segawa*
   Chem. Commum. 2025, 61, 11187-11190.
2. Diverse tetracyanodihydrodipyrazinopyrazine clathrate crystals assembled from weak intermolecular interactions
   Kosuke Watanabe, Haruki Sugiyama, Yasutomo Segawa*
   CrystEngComm 2025, 27, 3552-3559.
3. Synthesis of fully fused tetrapyrazinoporphyrazine polymers bearing three-dimensional structures controlled by steric repulsion
   Kosuke Watanabe, Teruki Toya, Yuto Toyota, Yoichi Kobayashi, Junichi Usuba, Yuh Hijikata, Ryotaro Matsuda, Katsuyuki Nishimura, Haruki Sugiyama, Yasutomo Segawa*
   Chem. Commun. 2025, 61, 2822-2825.
4. Synthesis, structure, and properties of a bay-fluorinated triphenylene
   Ryu Yoshida, Haruki Sugiyama, Yasutomo Segawa*
   Chem. Lett. 2024, 53, upae048.
5. Synthesis of Polycyclic Arenes Composed of Four-, Five-, Six-, and Eight-Membered Rings via an Unexpected Four-Membered Ring Formation Reaction
   Soshi Hirota, Sachiko Nakano, Haruki Sugiyama, Yasutomo Segawa*
   Org. Lett. 2023, 25, 8062–8066.
6. Synthesis of penta- and hexa(3,4-thienylene): Size-dependent structural properties of cyclic oligothiophenes
   Mai Nagase, Sachiko Nakano, Yasutomo Segawa*
   Chem. Commun. 2023, 59, 11129-11132.
7. Nonplanar Aromatic Hydrocarbons: Design and Synthesis of Highly Strained Structures
   Yasutomo Segawa*
   Bull. Chem. Soc. Jpn. 2022, 95, 1600–1610.
8. Topological Molecular Nanocarbons: All-benzene Catenane and Trefoil Knot
   Yasutomo Segawa,* Motonobu Kuwayama, Yuh Hijikata, Masako Fushimi, Taishi Nishihara, Jenny Pirillo, Junya Shirasaki, Natsumi Kubota, Kenichiro Itami*
   Science 2019, 365, 272-276.
9. Synthesis of a Carbon Nanobelt
   Guillaume Povie, Yasutomo Segawa,* Taishi Nishihara, Yuhei Miyauchi, Kenichiro Itami*
   Science 2017, 356, 172–175.
10. Metal-free Hydrogenation Catalysis of Polycyclic Aromatic Hydrocarbons
    Yasutomo Segawa, Douglas W. Stephan*
    Chem. Commun. 2012, 48, 11963–11965.
11. Boryllithium: Isolation, Characterization, and Reactivity as a Boryl Anion.
    Yasutomo Segawa, Makoto Yamashita,* Kyoko Nozaki*
    Science 2006, 314, 113–115.