Biomimetic oxidation of diphenyl sulfide with electrochemical p-450 model system in CH2Cl2 treated with alkaline solution

Dichloromethane containing metalloporphyrins [meso-tetraphenylporphyrinatom anganese(III)chloride (1) or meso-tetraphenylporphyrinatoiron (III) chlorid e (2)] and Bu4NClO4 was treated with an aqueous solution of NaOH (5%), and subjected to controlled potential electrolysis at - 1.0 V (vs. S.C.E. (satu rated calomel electrode)) in a divided cell after addition of diphenyl sulf ide (3). Diphenyl sulfoxide (4) and diphenyl sulfone (5) were found in an e lectrolyzed solution as the reaction products. Results obtained from cyclic voltammetry and visible spectrometry suggested that the treatment of dichl oromethane containing metalloporphyrins with the aqueous solution of NaOH d id not change the fifth ligand of metalloporphyrins from Cl to OH. On the e lectrode, dissolved dioxygen was reduced to hydrogen peroxide. Compounds 1 and 2 catalyze the oxidation of 3 by hydrogen peroxide without imidazole. C ompound 2 showed higher selectivity than compound 1.