Efficient oxidative coupling of thiols and oxidation of sulfides using UHP in the presence of Ni or Cd salen complexes immobilized on MCM-41 mesoporous as novel and recoverable nanocatalysts

• Ni or Cd-Salen-MCM-41 was prepared via post-grafting method.
• Ni or Cd -Salen-MCM-41 was characterized by FT-IR, XRD, BET and TGA techniques.
• Ni or Cd -Salen-MCM-41 was evaluated as catalyst for the oxidation of sulfides and thiols.

Oxidation of sulfides to sulfoxides and oxidative coupling of thiols into their corresponding disulfides were carried out using urea-hydrogen peroxide (UHP) as oxidizing agent and immobilized Ni or Cd complexes on MCM-41 as stable, heterogeneous, efficient and recoverable catalysts under mild reaction conditions. These supported complexes were characterized by FT-IR spectroscopy, thermogravimetric analysis (TGA), powder X-ray diffraction (XRD) and N2 adsorption–desorption isotherms. A variety of aromatic and aliphatic sulfides and thiols with different functional groups were successfully oxidized with short reaction times in good to excellent yields at room temperature. Catalysts were easily recovered and reused for several consecutive runs without significant loss of their catalytic activity and efficiency.

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