Hydrophobic vitamin B12.: Part 20:: Supernucleophilicity of Co(I) heptamethyl cobyrinate toward various organic halides
Hydrophobic vitamin B12.: Part 20:: Supernucleophilicity of Co(I) heptamethyl cobyrinate toward various organic halides
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DOI：
10.1246/bcsj.78.859
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发表时间：
2005-05-15
影响因子：
4
通讯作者：
Hisaeda, Y
中科院分区：
文献类型：
--
作者：
Shimakoshi, H;Maeyama, Y;Hisaeda, Y
七甲基钴氨酸盐，疏水性维生素B-12，通过与四氢硼酸钠反应被还原成其Co（I）物种。其与各种有机卤化物如CH 2Cl 2、CHCl 3、CCl 4、CHBrCl 2、CHBr 3、CCl 3CH 3、CFCl 3和BrCH 2CH 2CH 3反应，形成相应的烷基化配合物并脱卤。通过元素分析和ESI-MS对烷基化配合物进行了表征，并通过紫外-可见吸收光谱的变化证实了烷基化配合物的光不稳定性。用ESR自旋捕获技术研究了钴碳键在可见光照射下的断裂方式。用循环伏安法研究了一系列烷基化配合物的氧化还原行为。烷基化配合物在-1.21 ~-1.29V（相对于A1-AgCl）处有一不可逆还原峰，表明钴-碳键被电解裂解。
Heptamethyl cobyrinate, hydrophobic vitamin B-12, was reduced to its Co(I) species by a reaction with sodium tetrahydroborate. which reacted with various organic halides, such as CH2Cl2, CHCl3, CCl4, CHBrCl2, CHBr3, CCl3CH3, CFCl3, and BrCH2CH2CH3, 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 A,-AgCl, which showed cleavage of the cobalt-carbon bond by electrolysis.