Yousuke Ooyama

Graduate School of Engineering, Hiroshima University

Research AreasFunctional Dye Chemistry, Organic Materials Chemistry
Participating Group (2018-2019)

Development of Soft Crystals Based on Mechanofluorochromism of D-π-A Fluorescent Dyes

Fluorescent Dye, Soft Crystal, Mechanofluorochromism, Dipole Moment, Fluorescent Clathrate
Co-Researcher: Keiichi Imato (Graduate School of Engineering, Hiroshima University,Assistant professor)

Research Outline

This researcher found that newly developed heteropolycyclic donor-acceptor π-conjugated (D–π–A) fluorescent dyes with electron-withdrawing substituents as acceptor and thus moderate dipole moments (ca. 5 Debye) show mechanofluorochromism (MFC); grinding of as-recrystallized dyes induces a bathochromic shift of fluorescent maximum wavelength, followed by a reversion to the original fluorescent maximum wavelength by heating or exposure to solvent vapor. In this work, the research subjects to create external stimulus-responsive soft crystals based on MFC are to direct the molecular design toward developing new-type D–π–A mechanofluorochromic dyes to be finely controlled the molecular orientation and arrangement by external stimulus, and to develop fluorescent clathrate compounds for water or carboxylic acid based on photo-induced electron transfer (PET). The mechanofluorochromic dyes and the fluorescent clathrate compounds can be a promising class of fluorescent soft crystals for rewritable photoimaging and next generation optoelectronic devices.

Mechanofluorochromism (MFC) of D-π-A fluorescent dye
MFC of D-π-A fluorescent dye in cast film
Molecular orientation and arrangement in the aggregate state for MFC of D-π-A fluorescent dye



Academic papers/reviewed


  1. "Fluorescent sensor for water based on photo-induced electron transfer and Förster resonance energy transfer: anthracene-(aminomethyl)phenylboronic acid ester-BODIPY structure" D. Jinbo, K. Imato and Y. Ooyama, RSC Adv., 2019, 9, 15335-15340.
  2. "Phenazine-Based Photosensitizers for Singlet Oxygen Generation" K. Imato, K. Ohira, M. Yamaguchi, T. Enoki and *Y. Ooyama, Mater. Chem. Front., 2020,4, 589-596
  3. "Development of an intramolecular charge transfer-type colorimetric and fluorescence sensor for water by fusion with juloidine structure and complexation with boron trifluoride" K. Imato, T. Enoki and *Y. Ooyama, RSC Adv., 9, 31466-31473 (2019).
  4. "Synthesis and Photophysical and Electrochemical Properties of Pyridine-, Pyrazine- and Triazine-based (D-π-)2A Fluorescent Dyes" K. Imato, T. Enoki, K. Uenaka and *Y. Ooyama, the thematic issue “Dyes in modern organic chemistry” in Beilstein J. Org. Chem., 15, 1712-1721 (2019). (Invited Article).
  5. "A colorimetric and fluorescent sensor for water in acetonitrile based on intramolecular charge transfer: D-(π-A)2-type pyridine-boron trifluoride complex" S. Tsumura, T. Enoki, Y. Ooyama, Chem. Commun., 2018, 54, 10144-10147.
  6. "Colorimetric and ratiometric fluorescence sensing of water based on 9-methyl pyrido[3,4-b]indole-boron trifluoride complex" Y. Ooyama, T. Enoki, Dalton Trans., 2019, 48, 2086-2092.
  7. "Tetraphenylethene– and diphenyldibenzofulvene–anthracene-based fluorescence sensors possessing photo-induced electron transfer and aggregation-induced emission enhancement characteristics for detection of water" Y. Ooyama, R. Sagisaka, T. Enoki, N. Tsunoji, J. Ohshita, New J. Chem., 2018, 42, 13339-13350.

Review article, commentary, criticism etc.


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