The reaction between the peroxide VO(η 2 -O 2 )(pyridine-2-carboxylate)·2H 2 O and Fe II aq is not a Fenton-like reaction

The reduction of VO(η 2 -O 2 )(pyridine-2-carboxylate) by Fe(H 2 O) 6 2+ proceeds via formation of the transient complex (pyridine-2-carboxylate)(O)V V (μ-η 2 : η 2 -O 2 )Fe II (H 2 O) 3 2+ that is transformed via intramolecular electron transfer into (pyridine-2-carboxylate)(O)V IV (μ-η 2 : η 2 -O 2 )Fe III (H 2 O) 3 2+ . The latter transient reacts with another Fe(H 2 O) 6 2+ to yield 2Fe(H 2 O) 6 3+ + V V O(OH)(pyridine-2-carboxylate) + .

These results point out that: (1) V V does not activate the η 2 bound peroxide toward the Fenton-like reaction. In this aspect, V V differs from Fe III in (H 2 O) 5 Fe–OOH 2+ and (2) transients of the type L m M n (μ-η 2 : η 2 -O 2 )M′L″ l have to be considered in the reductions of complexes of η 2 -bound peroxides.