Quantum chemical study of the effects of interaction of polyhydrated Hg(II) with methylcobalamin — A derivative of vitamin B12

Quantum chemical methods were used to investigate the mechanism of interaction of polyhydrated Hg(II) with methylcobalamin — a derivative of vitamin B12. Migration of the methyl group in the B12·Hg(II) nH2O cluster, initiating the formation of methylmercury, is considered. The reaction of substitution of methylmercury for the cobalt atom in the corrin fragment of B12 has been studied. The thermodynamic and activation characteristics of these processes have been obtained. The mercury analog of vitamin B12 is shown to exist in two radically different conformations.