Study on Coenzyme B12 Model Compounds by Electrochemistry and Quantum Chemistry

It is now widely recognized that coenzyme B12-dependent rearrangements are caused by homolytic dissociation of the Co-C bond giving rise to a 5’-deoxyadenosyl radical. The Co-C bonding strength is related to the electronic and steric effect of the 5’-deoxyadenosyl radical and the axial organic base, playing a key role in the catalytic cycle. To clarify the mechanism of Co-C bond breaking in coenzyme B12, many experimental and theoretic researches on B12 model compounds have been conducted, especially on the effect