Metalloporphyrins as biomimetic models for cytochrome P-450 in the oxidation of atrazine

The aim of this work was to evaluate whether metalloporphyrin models could mimic the action of cytochrome P-450 in the oxidation of atrazine, a herbicide. The commercially available second-generation metalloporphyrins 5,10,15,20-tetrakis(2,6-dichlorophenyl)porphyrin metal(III) chloride [M(TDCPP) Cl] and 5,10,15,20-tetrakis(pentafluorophenyl)porphyrin metal(III) chloride [M(TFPP)Cl] (metal = Fe or Mn) and the oxidants iodosylbenzene and metachloroperbenzoic acid were employed in this study. Results showed that the metalloporphyrins used here can oxidize atrazine. Yields as high as 32% were obtained for the Mn(TFPP)Cl/PhlO system, which shows that these catalysts can mimic both the in vivo and the in vitro action of cytochrome P-450, with formation of the metabolites DEA and DIA. The formation of five other unknown products was also detected, but only one of them could be identified, since the other four were present in very low concentrations. The compound COA, identified by mass spectrometry, was the main product in most of the oxidation reactions.