Selective Oxidation of Thioanisole with Hydrogen Peroxide using Copper Complexes Encapsulated in Zeolite: Formation of a Thermally Stable and Reactive Copper Hydroperoxo Species

[Cu(terpy)]2+ complexes encapsulated into Na-Y zeolite ([Cu(terpy)]2+@Y) were prepared, and their catalytic activities for the oxidation of sulfides using hydrogen peroxide were investigated. Several spectroscopic results, as well as elemental analysis, demonstrated the formation of [Cu(terpy)]2+ complexes in supercages of Y-zeolite. [Cu(terpy)]2+@Y exhibited high selectivity for the oxidation of thioanisole into methylphenylsulfoxide when H2O2 was used. The kinetic study of this oxidation at the catalyst [Cu(terpy)]2+@Y suggests that the reaction of [Cu(terpy)]2+ species with H2O2 is the rate-determining step. The oxidation of thioanisole, benzene, and 2-phenylethylamine using [[Cu(terpy)]2+@Y]*, which was prepared from the reaction between [Cu(terpy)]2+@Y and H2O2, quantitatively proceeded to methylphenylsulfoxide, phenol, and 2-amino-1-phenylethanol, respectively. The reaction of [Cu(terpy)]2+@Y and H2O2 was found to yield thermally stable but active CuII-OOH species in [Cu(terpy)]2+@Y.