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Synthesis, Structure, and Reactivity of Stable Silabenzenes

Research Project

Project/Area Number 10440184
Research Category

Grant-in-Aid for Scientific Research (B)

Allocation TypeSingle-year Grants
Section一般
Research Field Organic chemistry
Research InstitutionJapan Women's University

Principal Investigator

OKAZAKI Renji  Department of Chemical and Biological Sciences, Japan Women's University, 理学部, 教授 (70011567)

Project Period (FY) 1998 – 1999
Project Status Completed (Fiscal Year 1999)
Budget Amount *help
¥11,400,000 (Direct Cost: ¥11,400,000)
Fiscal Year 1999: ¥5,600,000 (Direct Cost: ¥5,600,000)
Fiscal Year 1998: ¥5,800,000 (Direct Cost: ¥5,800,000)
Keywordssilabenzene / silabenzvalene / X-ray crystallography / kinetic stabilization / aromaticity / theoretical caluculations / ィイD129ィエD1Si NMR / 立体保護 / ^<29>Si-NMR
Research Abstract

Since silicon is located immediately below carbon in the periodic table, organosilicon chemists have been interested in the synthesis of important classes of compounds where carbon atoms are replaced by silicon. Silaaromatic compounds have particularly been attracting the attension of organosilicon chemists because of great importance of aromatic compounds in organic chemistry. Silaaromatic compounds have eluded isolation although some compouns of such sort have been spectroscopically observed in low temperature matrices. In this study, we have succeeded in the synthesis of the first stable silabenzene by taking advantage of a very efficient steric protection group, 2, 4, 6-tris [bis (trimethylsilyl) methyl] phenyl (abbreviated to Tbt group) which was developed by us. The precursor of the silabenzene was prepared from a stanna-1, 4-diene via a reaction of a silicon hydride with TbtLi and dehydrochlorinated by lithium diisopropyl amide to give the silabezene. The silabenzene has been shown to be a delocalized aromatic system from ィイD129ィエD1Si NMR (92.5 ppm), ィイD11ィエD1JィイD2Si-CィエD2 (83 Hz), and UV (301, 323, 331 nm). The X-ray crystallographic data also corroborate this conclusion ; the Si=C bond lengths are almost identical to each other (1.765 and 1.770 Å) and in the middle between normal Si-C double and single bonds. The C-C bond lengths are also close to that of benzene. The silabenzene undergoes interesting photchemical valence isomerization to the corresponding silabenzvalene. This is the first stable silabenzvalene and reverts to the silabenzene upon heating.

Report

(3 results)
  • 1999 Annual Research Report   Final Research Report Summary
  • 1998 Annual Research Report
  • Research Products

    (11 results)

All Other

All Publications (11 results)

  • [Publications] K.Wakita: "An Unexpected Elimination of Cyclopentadienide Anion in the Reaction of Silacyclohexadienes with a Bulky Aryllithium"Chemistry Letters. 687-688 (1998)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K.Wakita: "Synthesis of Stable 2-Silanaphthalenes and Their Aromaticity"J. Am. Chem. Soc.. 121. 11336-11344 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K.Wakita: "Synthesis and Properties of an Overcrowded Silabenzene Stable at Ambient Temperature"Angew.Chem., Int. Ed.. 39. 634-636 (1999)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K.Wakita: "Crystal Structure of a Stable Silabenzene and Its Photochemical Valence Isomerization into the Corresponding Silabenzvalene"J.Am.Chem.Soc.. 122(印刷中). (2000)

    • Description
      「研究成果報告書概要(和文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Wakita: "An Unexpected Elimination of Cycloheptadienide Anion in the Reaction of Silacyclohexadiene with a Bulky Aryllithium"Chemistry Letters. 687-688 (1998)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Wakita: "Synthesis of Stable 2-Sialnaphthalenes and Their Aromaticity"Journal of Americal Chemical Society. 121. 11336-11344 (1999)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Wakita: "Synthesis and Properties of a Overcrowded Silabenzene Stable at Ambient Temperature"Angewandte Chemie, International Edition. 39. 634 (2000)

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Wakita: "Crystal Structure of a Stable Silabenzene and Its photochemical Valance Isomerization into the Corresponding Silabenzvalene"Journal of American Chemical Society. (in press).

    • Description
      「研究成果報告書概要(欧文)」より
    • Related Report
      1999 Final Research Report Summary
  • [Publications] K. Wakita: "Synthesis of Stable 2-Silanaphthalenes and Their Aromaticity"J. Am. Chem. Soc.. 121. 11336-11344 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] K. Wakita: "Synthesis abd Properties of an Overcrowded Silabenzene Stable at Ambient Temperature"Angew. Chem.. 39. 634-636 (1999)

    • Related Report
      1999 Annual Research Report
  • [Publications] K.Wakita: "An Unexpected Elimination of Cyclopentadienide Anion in the Reaction of Silacyclohexadienes with a Bulky Aryllithium" Chemistry Letters. 687-688 (1998)

    • Related Report
      1998 Annual Research Report

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Published: 1998-04-01   Modified: 2016-04-21  

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