Kinetic Evidence for Reactive Dimeric TAML Iron Species in the Catalytic Oxidation of NADH and a Dye by O2 in AOT Reverse Micelles

The efficacy of the iron(III) TAML activator [Fe{C6H4-1,2-((NCOCMe2NCO)-C-1-C-2)(2)CMe2(Fe-N1)(Fe-N2)}(OH2)]- (1) for the catalytic activation of dioxygen in reverse micelles of Aerosol OT (AOT) in n-octane has been studied. Kinetic evidence is presented for the existence of unusual second-order catalytic pathways in the oxidation of NADH to NAD(+) and the bleaching of blue pinacyanol chloride (PNC) dye. Depending on the substrate and reaction conditions, a second-order pathway in [1] either dominates or proceeds in obvious combination with a first-order pathway in [1]. Detailed kinetic analysis of the experimental data supports the previously made hypothesis that the reactive intermediate is associated with the mixed-valent dimer system [(LFeOFeL)-O-III-L-IV](3-)/[LFeIII(OH)(FeL)-L-IV](2-).