Green oxidation of sulfides to sulfoxides and sulfones with H2O2 catalyzed by ionic liquid compounds based on Keplerate polyoxometalates

The hybrid catalyst of (NH4)(2)(MimAm)(40)[Mo132O372(CH3COO)(30)(H2O)(72)] (MimAm = 3-Aminoethyl-1-methy-limidazolium) was synthesized by self-assembly strategy. Catalyst was successfully used in the selective oxidation of various sulfides to corresponding sulfoxides and sulfones. All reactions were performed in water as a green solvent by 30% aqueous hydrogen peroxide as a green oxidant under mild reaction conditions. The catalyst showed high conversion and excellent selectivity toward a varied range of substrates and demonstrates excellent chemoselectivity in which other active functional groups such as hydroxyl and C=C bond have been tolerated. Also, this hybrid catalyst could be simply separated by filtration, and showed excellent reusability without loss of activity after seven cycles.