Publication Date

8-2014

Advisor(s) - Committee Chair

Rui Zhang (Director), Donald Slocum, Larry Byrd

Degree Program

Department of Chemistry

Degree Type

Master of Science

Abstract

The selective oxidation of organic compounds represents a leading technology for chemical industries. They are used in chemical synthesis in the pharmaceutical and petrochemicals industries, and possible the decontamination of harmful substances. However, oxidations reaction are among the most challenging processes to control. Many stoichiometric oxidants with heavy metals are expensive, or toxic maybe both, and therefore unfeasible to be utilized. The ideal processes for catalytic oxidation would use molecular oxygen or hydrogen peroxide as the primary oxygen source, with transition metal catalysts to mimic the predominant oxidation catalysts in Nature, the cytochrome P450 enzymes. This study focuses on the synthesis of porphyrin and corrole macrocyclic ligands and the corresponding iron(III) complexes which are fully characterized by UV-vis, GC/MS, and NMR spectroscopies. In this work, the potential of catalytic oxidation reactions towards organic sulfides by these metal complexes were studied. The iron(III) porphyrin and iron(III) corrole catalysts have shown excellent activity and selectivity for sulfoxidation reactions. Various reaction conditions and environmental effects were investigated including solvent, axial ligands, water, amounts of oxygen source, and substrate scope. The optimal conditions were determined for iron(III) porphyrin/ corrole-catalyzed sulfoxidations with PhI(OAc)2 as the mild oxygen source. Competitive catalytic oxidation of substituted thioanisoles versus thioanisole by iron(III) corrole with PhI(OAc)2 were studied. The spectral studies of iron(III) corrole with PhI(OAc)2 in the presence of organic sulfide showed that a well-known diiron(IV)-μ-oxo biscorrole was formed with a second-order rate constant of k2= (3.5 ± 0.3)×103 M-1·s-1. A catalytic cycle was proposed on the basis of the mechanistic study, suggesting a highly reactive iron(V)-oxo corrole as the active oxidizing intermediate.

Disciplines

Analytical Chemistry | Chemistry | Medicinal-Pharmaceutical Chemistry | Organic Chemistry

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