Introducing Structural Diversity: Fe₂(MoO₄)₃ Immobilized in Chitosan Films as an Efficient Catalyst for the Selective Oxidation of Sulfides to Sulfones

This work reports how the immobilization of Fe-2(MoO4)(3) in chitosan films affects the oxidation reaction of sulfide derivatives to sulfates in the dark, resulting in good yields and excellent selectivity. As demonstrated, a variety of substituted sulfides were tolerated even in the presence of oxidativesensitive functional groups, leading to a regioselective application of the catalyst under mild reaction conditions and guaranteeing its reuse for at least 6 cycles without losing its catalytic performance. Specifically, films containing 1 mg of Fe-2(MoO4)(3) per ml of chitosan showed a yield and selectivity of 99%. The key success of the selective oxidation was associated with the presence of the hydroxyl radical, center dot OH, and the Fe3+/Fe2+ Fenton-like process. As a proof of concept, the selective oxidation of sulfides to the corresponding sulfones was performed to demonstrate the synergistic effect between Fe-2(MoO4)(3) and chitosan. This work offers a design strategy for efficient catalysts that may extend to other semiconductors and oxidation processes.