Anodic oxidation of methionine under different pH conditions is reported. The results are compared with the oxidation process when the glycinic terminus of methionine is coordinated with Co(III). Synthesis of [Co(en)2(L-Met)](ClO4)2, [Co(trien)(L-Met)](CF3SO3)2, and [Co(trien)(OSO2CF3)2]CF3SO3 is reported where L-Met = L-methionine, en = ethylenediamine, trien = triethylenetetraamine. The triflato complex ([Co(trien)(OSO2CF3)2]CF3SO3) can serve as a starting material for synthesizing a variety of complexes. The x-ray structure of [Co(en)2(L-Met)](ClO4)2.H2O is also presented The complex crystallizes in space group P21 of the mono-clinic system with two independent molecules in the crystallographic asymmetric unit. The unit cell dimensions are a = 9.582 (2) Å, b = 11.554 (2) Å, c = 19.988 (6) Å, and f = 98.85 (2)°. The two molecular units are related by a pseudo-center of symmetry. The electrochemical data presented here suggest a major role of the neighboring group and pH in defining the ease of oxidation of methionine.
ASJC Scopus subject areas
- Inorganic Chemistry