Takashi Hirano

Graduate School of Informatics and Engineering, The University of Electro-Communications

Research AreasPhysical Organic Chemistry, Organic Photochemistry

Synthesis and Development of Chemiluminescent Soft Crystals for Spatiotemporal Control of the Stimulus-responsive Functions

Soft Crystal, Chemiluminescence, Time-resolved Spectroscopy, Organic Peroxide, Phosphorescent Metal Complex, Electron Transfer, Ultra-High-Resolution Microscope, Crystal Structure Analysis, External Stimulus-responsive Function, Spatiotemporal Control
Co-Investigator: Tomoyoshi Suenobu (Graduate School of Engineering, Osaka University, Assistant Professor)
Co-Researcher: Chiharu Matsuhashi (Graduate School of Informatics and Engineering, The University of Electro-Communications, Researcher)

Research Outline

Chemiluminescence (CL) is a phenomenon in which excited molecules are generated by thermochemical reactions to emit light. It would be possible to detect extremely minute structural changes in a soft crystal at the atomic and molecular levels as CL changes, since ultrahigh sensitivity analysis is made possible by observing CL as a probe. In this research, we will create soft crystal CL systems that initiate luminescence by external stimulations to crystals. By elucidating the mechanism of stimulus-responsive CL with thermodynamic, kinetic, and quantum theoretical approaches, we also aim for spatiotemporal control of CL produced at arbitrary position and time in soft crystals. Specifically, we will conduct our research in the following two ways, (1) organic peroxides and luminescent redox-active metal complexes will be prepared for CL in soft crystals to establish the requirements for CL-active crystal structures and elucidate the CL reaction mechanisms; (2) We will take advantage of recently-developed ultra-high-resolution microscopy and time-resolved spectroscopy based on full-time “in-situ” observations of stimulus CL responses.

Creation of Chemiluminescent Soft Crystals
“In-situ” Observation of Stimulus-responsive Chemiluminescence of Soft Crystals
Luminescent Chromism of Soft Crystals Composed of Transition Metal Complexes in Response to External Stimulations

Representative Achievements

  • Spectroscopic Properties of Amine-substituted Analogues of Firefly Luciferin and Oxyluciferin
    Kakiuchi, M.; Ito, S.; Yamaji, M.; Viviani, V. R.; Maki, S.; Hirano, T. Photochem. Photobiol. 2017, 93, 486–494.
    DOI: 10.1111/php.12654
  • Spectroscopic Properties of BF2 Complexes of N-(5-Phenyl-2-pyrazinyl)pivalamides Exhibiting Fluorescence in Solution and Solid State
    Hachiya, S.; Hashizume, D.; Ikeda, H.; Yamaji, M.; Maki, S.; Niwa, H.; Hirano, T. J. Photochem. Photobiol. A 2016, 331, 206–214.
    DOI: 10.1016/j.jphotochem.2015.10.014
  • Catalytic Formation of Hydrogen Peroxide from Coenzyme NADH and Dioxygen with a Water-Soluble Iridium Complex and a Ubiquinone Coenzyme Analogue
    Suenobu, T.; Shibata, S.; Fukuzumi, S. Inorg. Chem. 2016, 55, 7747–7754.
    DOI: 10.1021/acs.inorgchem.6b01220
  • Catalytic hydrogen Production from Paraformaldehyde and Water Using an Organoiridium Complex
    Suenobu, T.; Isaka, Y.; Shibata, S.; Fukuzumi, S. Chem. Commun. 2015, 51, 1670–1672.
    DOI: 10.1039/C4CC06581F
  • Chemiluminescent 2,6-Diphenylimidazo[1,2-a]pyrazin-3(7H)-ones: a New Entry to Cypridina Luciferin Analogues
    Ishii, Y.; Hayashi, C.; Suzuki, Y.; Hirano, T. Photochem. Photobiol. Sci. 2014, 13, 182–189.
    DOI: 10.1039/C3PP50197C



Related Website(s)
thirano [at] uec.ac.jp