Beneficial Effect of Acetic Acid on the Formation of FeIII(OOH) Species and on the Catalytic Activity of Bioinspired Nonheme FeII Complexes. |
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Authors: | Roxanne Bercy Dr Jean-Noël Rebilly Dr Christian Herrero Dr Régis Guillot Hélène Maisonneuve Prof Frédéric Banse |
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Institution: | Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Saclay, CNRS, 91400 Orsay, France |
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Abstract: | Three new amine/pyridine FeII complexes bearing pentadentate ligand with one, two or three electron enriched 4-methoxy-3,5-dimethylpyridine were used as catalysts for the oxidation of small organic molecules by hydrogen peroxide. The distribution of products formed suggests that these ligands are not enough electron donating to promote the O?O heterolytic cleavage of the oxidant in order to generate selective FeV(O) species. Using acetic acid in the reaction mixtures results in a significant increase of the efficiency of these catalytic systems. Our investigations show that the use of AcOH leads to the protonation/dissociation of a pyridyl moiety and the formation of (N4)FeII(OAc)(OH) species. These complexes readily react with excess hydrogen peroxide to yield (N4)FeIII(OAc)(OOH) intermediates. These latter intermediates are proposed to evolve into (N4)FeIV(OAc)(O), which are more efficient than the usual (N4)FeIV(O) and (N5)FeIV(O). |
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Keywords: | nonheme iron hydroperoxo O?O activation reaction mechanisms |
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