The mechanistic aspects of iron(III) porphyrin catalyzed oxidation reactions in mixed solvents

In the iron(III) porphyrin catalyzed oxidation reactions, the formation of various reactive intermediates have been observed to depend upon the nature of the catalyst, the oxidant and the solvent used for the study. The various iron(III) porphyrin catalysts such as F20TPPFeCl, F16TPPFeCl, F12TPPFeCl and F8TPPFeCl have been used in the present study to understand the effect of solvent system in the activation of the catalysts. As the terminal oxidant t-BuOOH has been used. It has been observed that acetonitrile contaminated with water activates all the catalysts. It has been noted that ∼9% of water in acetonitrile is the best solvent system for the activation of all the catalysts. The results obtained have been applied to successfully oxidize cyclohexene and cyclohexane by these oxidizing systems. It has also been observed that CH3OH mixed with CH2Cl2 play a very important role in the activation of catalyst in hydroperoxide oxidizing system. The 33 ± 3% ratio of CH3OH in CH2Cl2 acts as the most suitable solvent system to convert organopalladium compound 1a–c to 2a–c.

The various iron(III) porphyrin catalysts have been used to understand the effect of mixed solvent in the catalysts activation. The appropriate choice of the solvent, the catalyst and the oxidant significantly affect the formation of reactive intermediates. These findings have been used to oxidize the organopalladium compounds and cyclohexene at room temperature.Figure optionsDownload as PowerPoint slideHighlights
► CH3CN–H2O or CH2Cl2–CH3OH mixed solvent effect on iron(III) porphyrin catalyst activation.
► Iron(III) porphyrin oxidation reactions.
► Selective C–Pd bond oxidation.