EPR investigation on radical trap reactions of 2-methyl-2-nitrosopropane encapsulated by cyclodextrins with external organic radicals produced by photolysis of coenzyme B12 and its analogues

Abstract

¹ H NMR studies reveal that 2-methyl-2-nitrosopropane (MNP) in the dimeric state can decompose into monomer effectively in the presence of cyclodextrins (Cds) in aqueous solution. The inclusion complexes formed are more soluble than MNP itself and stable to light. MNP–Cds are used as radical traps in the photolysis of coenzyme B₁₂ and alkylcobalamins in the present study. The N and H hyperfine splitting parameters of the spin adducts are obtained by the EPR technique. Models for the interaction between Cds and aminoxyls are proposed, which mimic coenzyme B₁₂–enzyme interactions to a certain extent.