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2007 Fiscal Year Final Research Report Summary

Molecular designing for Intensely emissive transition metal complexes

Research Project

Project/Area Number 18550054
Research Category

Grant-in-Aid for Scientific Research (C)

Allocation TypeSingle-year Grants
Section一般
Research Field Inorganic chemistry
Research InstitutionUniversity of Toyama (2007)
Osaka University (2006)

Principal Investigator

NOZAKI Koichi  University of Toyama, Graduate School of Science and Engineering, Professor (20212128)

Project Period (FY) 2006 – 2007
Keywordstransition-metal complex / OLED / phosphorescence / MLCT / dd state / spin-orbit coupling
Research Abstract

Molecular designing of transient-metal compounds with blue phosphorescence is one of the most important problems in recent development of phosphorescent OLED devices. While pyrazole ligands have been often used to increase emission energy of phosphorescent iridium(III) complexes, introduction of these ligands is known to increase nonradiative transition rates remarkably. In this work, kinetic parameters for the nonradiative process have been determined from emission lifetimes of iridium complexes with two pyrazole-iridium bonds were measured over a wide temperature range. The obtained activation energy of 1800 cm-1 indicates that the emissive phosphorescent state is quenched via closely lying dd state.
To get insights into the quenching process, the potential energy surface of the lowest triplet state of this complex was calculated using unrestricted DFT calculation and the geometrical changes associated with the quenching via the dd state were studied. It was revealed that at the geometry where the iridium-pyrazole bonds are elongated by 0.6nm compare to that for the phosphorescent state the energies of both the triplet excited state and the ground state become degenerating and therefore very fast deactivation occurs. Both the calculated emission energy and activation energy were in good agreement with those observed, which greatly validates the DFT calculations.

  • Research Products

    (11 results)

All 2008 2007 2006

All Journal Article (6 results) (of which Peer Reviewed: 3 results) Presentation (4 results) Book (1 results)

  • [Journal Article] Syntheses and Phosphorescent Properties of Blue Emissive Iridium Complexes with Tridentate Pyrazolyl Ligands.2008

    • Author(s)
      Yang, Lifen
    • Journal Title

      Inorganic Chemistry 47(印刷中)

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Journal Article] Synthesis and Characterization of Luminescent Zinc(II) and Cadmium(II) Complexes with N,S-Chelating Schiff Base Ligands2008

    • Author(s)
      Kawamoto, Tatsuya
    • Journal Title

      Inorganic Chemistry 47

      Pages: 3095-3104

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Syntheses and Phosphorescent Properties of Blue Emissive Iridium Complexes with Tridentate Pyrazolyl Ligands2008

    • Author(s)
      Lifen, Yang
    • Journal Title

      Inorganic Chemistry 47(in press)

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Rates of Electronic Excitation Hopping in Anisotropic Ionic Crystals of[Ru(2,2^1-bipyridine)_3]X_2(X=ClO_4^-,PF_6^-,SbF_6^-);Monte Carlo Simulation of Single-and Mufti-Exponential Emission Decays.2007

    • Author(s)
      Ohno, Takeshi
    • Journal Title

      Inorganic Chemistry 46

      Pages: 8859-8870

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Journal Article] Rates of Electronic Excitation Hopping in Anisotropic Ionic Crystals of [Ru(2,2'-bipyridine) _3]X_2(X = ClO4^-, PF6^-, SbF6^- ); Monte Carlo Simulation of Single- and Multi-Exponential Emission Decays2007

    • Author(s)
      Ohno, Takeshi
    • Journal Title

      Inorganic Chemistry 46

      Pages: 8859-8870

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] Highly phosphorescent iridium complexes containing both tridentate bis(benzimidazolyl)-benzene or-pyridine and bidentate phenylpyridine: synthesis, photophysical properties, and theoretical study of Ir-bis(benzimidazolyl)benzene complex.2006

    • Author(s)
      Obara, S.
    • Journal Title

      Inorganic Chemistry 46

      Pages: 8907-8921

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Presentation] ピラゾールが配位したイリジウム(III)錯体の発光状態の熱失活機構の解明2008

    • Author(s)
      野崎浩一
    • Organizer
      日本化学会春期年会
    • Place of Presentation
      立教大学
    • Year and Date
      2008-03-26
    • Description
      「研究成果報告書概要(和文)」より
  • [Presentation] Theoretical studies on thermal deactivation mechanism of MLCT state in[Ru(terpy)_2]^<2+>(terpy=2,2':6,2"-terpyridine)2007

    • Author(s)
      Nozaki, Koichi
    • Organizer
      17th International Symposium on the Photochemistry and Photophysics of Coordination Compounds
    • Place of Presentation
      Dublin, Ireland
    • Year and Date
      20070624-28
    • Description
      「研究成果報告書概要(和文)」より
  • [Presentation] Theoretical studies on thermal deactivation mechanism of MLCT state in [Ru(terpy)2]^<2+>(terpy=2,2':6,2"-terpyridine)2007

    • Author(s)
      Nozaki, Koichi
    • Organizer
      17th International Symposium on the Photochemistry and Photophysics of Coordination Compounds
    • Place of Presentation
      Dublin, Ireland
    • Year and Date
      20070624-28
    • Description
      「研究成果報告書概要(欧文)」より
  • [Presentation] Proton-induced switching of luminescent properties in two isomeric iridium complexes bearing with bis(benzimidazolyl) pyridine and-benzene derivatives2007

    • Author(s)
      Haga, Masa-aki
    • Organizer
      17th International Symposium on the Photochemistry and Photophysics of Coordination Compounds
    • Place of Presentation
      Dublin, Ireland
    • Year and Date
      20070624-28
    • Description
      「研究成果報告書概要(欧文)」より
  • [Book] 遷移金属錯体の光化学2007

    • Author(s)
      佐々木陽一
    • Total Pages
      348
    • Publisher
      三共出版
    • Description
      「研究成果報告書概要(和文)」より

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Published: 2010-02-04  

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