Cobalt(II) phosphine complexes stable in aqueous solution: Spectroscopic and kinetic evidence for low-spin Co(II)P6 and Co(II)P3S3 with tripodal 1,1,1-tris(dimethylphosphinomethyl) ethane

Satoshi Iwatsuki, Hiroo Kato, Kenji Obeyama, Shigenobu Funahashi, Nobuyoshi Koshino, Kazuo Kashiwabara, Takayoshi Suzuki, Hideo D. Takagi

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Co(II) species produced by the controlled potential electrochemical reduction of Co(III)P3S3. and Co(III)P6 complexes with 1,4,7-trithiacyclononane and tripodal 1,1,1-tris(dimethylphosphinomethyl)ethane in aqueous solution were characterized at ambient temperature by the EPR and spectrophotometric methods: The Co(II)P6 and Co(II)P3S3 species are in the low-spin t(2g)/6e(g)/1 state with large Jahn-Teller distortion. Kinetic studies of the redox reactions involving these Co(III)/(II) species revealed that the electron self-exchange reactions for the Co(III)/(II) couples are very fast (k(ex) ~ 104 dm3 mol-1 s-1), which is consistent with the results for other low-spin/low-spin Co(III)/(II) couples. It was concluded that the nephelauxetic effect of the P donor atom stabilizes the low-spin state in Co(II). (C) 2000 Elsevier Science S.A.

Original languageEnglish
Pages (from-to)501-504
Number of pages4
JournalInorganic Chemistry Communications
Issue number10
Publication statusPublished - 2000
Externally publishedYes



  • Cobalt(II)
  • Electron transfer
  • EPR study
  • Kinetics
  • Spin state

ASJC Scopus subject areas

  • Biochemistry
  • Inorganic Chemistry
  • Physical and Theoretical Chemistry
  • Materials Chemistry

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