Efficient Catalytic Epoxidation in Water by Axial N-Ligand-Free Mn-Porphyrins within a Micellar Capsule

Epoxidation of styrenes is efficiently catalyzed by micelle-like molecular capsules providing Mn-porphyrins in water at room temperature. In contrast to usual Mn-porphyrin catalysts, the encapsulated Mn-porphyrin catalysts show higher reactivities (up to 1350 TON for 1 h) even without the addition of imidazole ligands. Spectroscopic studies and competitive-binding experiments demonstrate that the efficient catalytic cycle stems from the enforced proximity of the catalyst and substrates as well as the smooth replacement of the products by substrates in the hydrophobic cavity of the capsule.