Series of dichloroiron(III) complexes of 1,3-bis(2′-arylimino) isoindoline, including a new structurally characterized ligand 1,3-bis(5′-methyl-2′-thiazolylimino)isoindoline and its complex, have been used as catalysts for the oxidative coupling of 2-aminophenol (OAPH) to 2-aminophenoxazine-3-one (APX) in DMF solution at ambient temperature. The complexes were suitable as catalyst, and depending on the oxidant used, two different mechanisms can be proposed, namely a metal-based oxidation for dioxygen, and a hydroxyl radical mediated process, including zero-order dependence on the concentration of the substrate, for H2O 2. In the former case a mechanism on the basis of kinetic data was proposed assuming ternary complex formation between catalyst, substrate and dioxygen, and a nice correlation was found between the reaction rate and the oxidation potential, E° ′pa of the iron center in the precursor complexes.
- Biomimetic oxidation
ASJC Scopus subject areas
- Process Chemistry and Technology
- Physical and Theoretical Chemistry