Oxidation of sulfides with hydrogen peroxide catalyzed by 10,10′-linked bisflavinium perchlorates

A series of bisflavinium perchlorates linked with methylene spacer at N10-position exhibit high catalytic activities for the oxidation of sulfides with hydrogen peroxide affording the corresponding sulfoxides. The kinetic studies revealed that the reaction rates are dependent on the spacer length of the catalysts due to their specific intramolecular electrochemical behaviors.