Carbonized\nPolymer Dots-Promoted Photocatalytic Activation\nof Molecular Oxygen for Efficient and Selective Oxidation of Thioethers\nto Sulfoxides

Sulfoxides are essential in pharmaceuticals and chemicals,\nyet\ntraditional thioether oxidation struggles with selectivity and sustainability.\nThis study introduces carbonized polymer dots (CPDs) as effective\nphotocatalysts for ecofriendly thioether to sulfoxide oxidation, using\nwater and ethanol to enhance reaction selectivity and efficiency under\n455 nm blue light. These catalysts not only show remarkable efficacy\nunder mild conditions but also display high selectivity for sulfoxide\nformation, proving versatile across a broad range of substrates. We\n further elucidated the catalytic mechanism, confirming the predominant\nroles of singlet oxygen and superoxide anions through both spectroscopic\nevidence and quenching experiments. The method extends to the synthesis\nof pharmaceuticals such as oxfendazole, albendazole sulfoxide, and\nsulindac, highlighting its practical utility. Overall, our findings\npresent a sustainable and efficient avenue for sulfoxide synthesis,\nthereby broadening the practical utility of CPDs in photocatalytic\ntransformations.