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2007 Fiscal Year Final Research Report Summary

Energy-Controlled Spaces at the Single-Molecule Photo-Hydrogen-Evolving Devices

Research Project

Project/Area Number 16074216
Research Category

Grant-in-Aid for Scientific Research on Priority Areas

Allocation TypeSingle-year Grants
Review Section Science and Engineering
Research InstitutionKyushu University

Principal Investigator

SAKAI Ken  Kyushu University, Faculty of Science, Professor (30235105)

Co-Investigator(Kenkyū-buntansha) MASAOKA Shigeyuki  KYUSHU UNIVERSITY, Faculty of Science, Assistant Professor (20404048)
Project Period (FY) 2004 – 2006
KeywordsHydrogen evolution / Metal complexes / Photocatalysts / Energy
Research Abstract

Great attention has been paid to the studies on the photocatalytic systems promoting the solar-light-induced splitting of water into H_2 and 1/2O_2, because water and sunlight are abundant and such systems are free of the CO_2 emission. Since the original discovery in the H_2-evolving activities of amidate-bridged Pt(II)_2 dimers having a relatively strong metal-metal interaction, considerable efforts have been made to develop the 'photo-hydrogen-evolving (PHE)' molecular devices (MDs) that are made up of photosensitizing Ru(bpy)_3^<2+> derivatives and H_2-evolving Pt(II) catalysts. Such PHEMDs are expected to serve as an efficient 'photocatalyst'towards the visible-light-induced reduction of H_2_O by EDTA into H_2. As a result, we discovered that one particular molecular device consisting of a [Ru(bpy)_2(5-amino-phen)]^<2+> unit and a PtCl_2(bpy) unit evolves H_2 in the presence of EDTA under the visible light illumination.
In this project, several other related compounds have also been prepared and evaluated to better understand the factors affecting the PHE activities of such PHEMDs These studies suggested the following key factors: (i) destabilization of the HOMO corresponding to the filled Pt(II) dz^2 orbital enhances the PHE activity; (ii) steric hindrances around the axial site of the square-planar Pt(II) coordination sphere lower the PHE activity; (iii) an appropriate aromaticity is needed to enhance the intramolecular electron transfer processes; (iv) EDTA forms an adduct with a PHEMD before undertaking the H_2 generation; (v) the H_2 formation undergoes via a bimolecular process of the PHEMD. In addition to these results, the electrochemical studies, stopped flow experiments looking at the reactions between the Pt(II) complexes and a radical cation generated from methylviologen, and DFT MO investigations have been examined.

  • Research Products

    (7 results)

All 2007 2006

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

  • [Journal Article] Syntheses, Characterization, and Photo-Hydrogen-Evolving Properties of Tris (2, 2' - bipyridine)ruthenium(II) Derivatives Tethered to a cis-Pt(II)C12 Unit : Insights into the Structure-Activity Relationship2007

    • Author(s)
      Hironobu Ozawa, Yuki Yokoyama, Masa-aki Haga, Ken Sakai
    • Journal Title

      Dalton Trans.

      Pages: 1197-1206

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Journal Article] Homogeneous catalysis of platinum(II) complexes in photochemical hydrogen production from water2007

    • Author(s)
      Ken Sakai, Hironobu Ozawa
    • Journal Title

      Coord. Chem. Rev. 251

      Pages: 2753-2766

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Journal Article] An Effect of Structural Modification in the Photo-hydrogen-evoluting RuIIPtII Dimers2007

    • Author(s)
      Hironobu Ozawa, Ken Sakai
    • Journal Title

      Chem. Lett. 36

      Pages: 920-921

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Journal Article] Syntheses, Characterization, and Photo-Hydrogen-Evolving Properties of Tris(2,2'-bipyridine)ruthenium(II) Derivatives Tethered to a cis-Pt(II)C12 Unit : Insights into the Structure-Activity Relationship2007

    • Author(s)
      Hironobu Ozawa, Yuki Yokoyama, Masa-aki Haga, Ken Sakai
    • Journal Title

      Dalton Trans.

      Pages: 1197-1206

    • Description
      「研究成果報告書概要(欧文)」より
  • [Journal Article] A Photo-Hydrogen-Evolving Molecular Device Driving Visible-Light-Induced EDTA-Reduction of Water into Molecular Hydrogen2006

    • Author(s)
      Hironobu Ozawa, Masa-aki Haga, Ken Sakai
    • Journal Title

      J. Am. Chem. Soc. 128

      Pages: 4926-4927

    • Description
      「研究成果報告書概要(和文)」より
    • Peer Reviewed
  • [Journal Article] A Photo-Hydrogen-Evolving Molecular Device Driving Visible-Light-Induced EDTA-Reduction of Water into Molecular Hydrogen2006

    • Author(s)
      Hironobu Ozawa, Masa-aki Haga, Ken Sakai
    • Journal Title

      J. Am. Chem. Soc.

      Pages: 4926-4927

    • Description
      「研究成果報告書概要(欧文)」より
  • [Presentation] Photo-hydrogen-evolving molecular devices consisting of Ru(II) and Pt(II) centers2007

    • Author(s)
      Ken Sakai
    • Organizer
      The 17th International Symposium on the Photochemistry and Photophysics of Coordination Compounds (ISPPCC)
    • Place of Presentation
      Trinity College, Dublin, Ireland
    • Year and Date
      20070624-20070628
    • Description
      「研究成果報告書概要(和文)」より

URL: 

Published: 2010-06-09  

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