Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
10244434 | Journal of Catalysis | 2005 | 7 Pages |
Abstract
We report the kinetics of cyclohexane oxidation with iodosylbenzene, catalyzed by two supramolecular manganese(III) porphyrin isomers, containing four [Ru(bpy)2Cl]+ complexes attached to the pyridyl groups of meso-tetra(3-pyridyl)porphynatemanganese(III) or meso-tetra(4-pyridyl)porphynatemanganese(III) centers. An unusual pseudozero-order mechanism was observed by monitoring the formation of the cyclohexanol and cyclohexanone products, and a consistent oxygen-transfer mechanism, activated by the manganese center, was proposed on the light of the kinetic behavior. The kH/kD values suggested that in Mn(3-TRPyP) catalysis, the kinetics are favored by the stereochemical environment provided by the out-of-plane ruthenium complexes, whereas for the coplanar Mn(4-TRPyP) catalyst, the favorable electronic interaction of the ruthenium complexes with the metalloporphyrin center is the most relevant factor enhancing reactivity.
Related Topics
Physical Sciences and Engineering
Chemical Engineering
Catalysis
Authors
Genebaldo S. Nunes, Ildemar Mayer, Henrique E. Toma, Koiti Araki,