EPR INVESTIGATION ON RADICAL TRAP REACTIONS OF 2-METHYL-2-NITROSOPROPANE ENCAPSULATED BY CYCLODEXTRINS WITH EXTERNAL ORGANIC RADICALS PRODUCED BY PHOTOLYSIS OF COENZYME B-12 AND ITS ANALOGS

H-1 NMR studies reveal that 2-methyl-2-nitrosopropane (MNP) in the dim eric state can decompose into monomer effectively in the presence of c yclodextrins (Cds) in aqueous solution. The inclusion complexes formed are more soluble than MNP itself and stable to light. MNP-Cds are use d as radical traps in the photolysis of coenzyme B-12 and alkylcobalam ins in the present study. The N and H hyperfine splitting parameters o f the spin adducts are obtained by the EPR technique. Models for the i nteraction between Cds and aminoxyls are proposed, which mimic coenzym e B-12-enzyme interactions to a certain extent.