The reaction between the peroxide VO(η²-O₂)(pyridine-2-carboxylate)·2H₂O and Fe^II_aq is not a Fenton-like reaction

Abstract

The reduction of VO(η²-O₂)(pyridine-2-carboxylate) by Fe(H₂O)₆²⁺ proceeds via formation of the transient complex (pyridine-2-carboxylate)(O)V^V(μ-η²: η²-O₂)Fe^II(H₂O)₃²⁺ that is transformed via intramolecular electron transfer into (pyridine-2-carboxylate)(O)V^IV(μ-η²: η²-O₂)Fe^III(H₂O)₃²⁺. The latter transient reacts with another Fe(H₂O)₆²⁺ to yield 2Fe(H₂O)₆³⁺ + V^VO(OH)(pyridine-2-carboxylate)⁺. These results point out that: (1) V^V does not activate the η² bound peroxide toward the Fenton-like reaction. In this aspect, V^V differs from Fe^III in (H₂O)₅Fe–OOH²⁺ and (2) transients of the type L_mMⁿ(μ-η²: η²-O₂)M′L″_l have to be considered in the reductions of complexes of η²-bound peroxides.

Keywords:

• DFT
• Fenton reaction
• kinetics and mechanism
• μ-η²: η²-O₂ binuclear complexes
• vanadium