Activated carbon functionalized with Mn(II) Schiff base complexes as efficient alkene oxidation catalysts: Solid support matters

• Mn-catalysts were synthesized by covalent grafting onto activated carbon.
• These catalysts are effective and selective towards epoxides with H2O2 and CH3COONH4.
• They are re-usable and provide considerably high TOFs.
• The function of CH3COONH4 which is determinant for the catalysis is proposed.

A new synthetic methodology to covalently anchor MnII-Schiff-base catalysts onto activated carbon (ACox) has been applied, resulting in heterogeneous MnII-L@ACox materials. These catalysts are effective and selective towards epoxides with H2O2, in the presence of CH3COONH4, as co-catalyst, providing TONs equivalent-to/or higher than the homologous MnII-L@SiO2 catalysts for certain substrates. Moreover MnII-L@ACox catalysts are re-usable and kinetically faster than the corresponding MnII-L@SiO2 catalysts resulting in considerably higher TOFs. Combining catalytic and EPR spectroscopic data we propose a catalytic reaction mechanism which elucidates the co-catalytic function of CH3COONH4 which is of key importance for the successful performance of the studied MnII-catalysts.

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