Reactions of Low Valent Transition-Metal Complexes with Hydrogen Peroxide. Are they “Fenton-Like” or Not? 3. The Case of Fe(II){N(CH2CO2)3}(H2O)2

Abstract

The reaction of Fe(II){N(CH₂CO₂)₃}(H₂O)₂ with H₂O₂ in neutral and slightly acidic solutions was studied. The results indicate that the transient complex formed between these reagents, (nta)(H,O)-Fe²⁺ · O₂H, (where nta = N(CH,CO₂)₃) reacts either directly with ≫ 0.175 M 2-propanol or 2-methyl-2-propanol, or decomposes into the corresponding tetra-valent iron complex which then reacts with these alcohols. The nature of the final products in this system containing iron ions and nta depends on the pH, thus indicating that the nature of the transient complexes formed, or their relative yields, depend on the pH. The results prove that free hydroxyl radicals are not the major product of this “Fenton like” reaction under the experimental conditions. The implications of these results on the understanding of biological processes is discussed.