Hydrophobic vitamin B12. Part 20: Supernucleophilicity of Co(I) heptamethyl cobyrinate toward various organic halides

Hisashi Shimakoshi, Yasunori Maeyama, Takeshi Kaieda, Takashi Matsuo, Eiki Matsui, Yoshinori Naruta, Yoshio Hisaeda

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Abstract

Heptamethyl cobyrinate, hydrophobic vitamin B12, was reduced to its Co(I) species by a reaction with sodium tetrahydroborate, which reacted with various organic halides, such as CH2Cl2, CHCl 3, CCl4, CHBrCl2, CHBr3, CCl 3CH3, CFCl3, and BrCH2CH 2CH3, to form the corresponding alkylated complexes with dehalogenation. The alkylated complexes were characterized by elemental analyses and ESI-MS, and the photo-lability of the alkylated complexes was confirmed by the UV-vis absorption spectral change. The fashion for cleavage of the cobalt-carbon bond under irradiation with visible light was investigated by an ESR spin-trapping technique. The redox behavior of a series of alkylated complexes was investigated by cyclic voltammetry. The alkylated complexes showed an irreversible reduction peak at -1.21 to -1.29 V vs Ag-AgCl, which showed cleavage of the cobalt-carbon bond by electrolysis.

Original languageEnglish
Pages (from-to)859-863
Number of pages5
JournalBulletin of the Chemical Society of Japan
Volume78
Issue number5
DOIs
Publication statusPublished - May 15 2005

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All Science Journal Classification (ASJC) codes

  • Chemistry(all)

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