Polystyrene-based eosin-Y as a photocatalyst for solar light-mediated NADH/NADPH regeneration and organic transformations

The development of a highly efficient, polymer-based photocatalyst for the solar light-mediated photocatalytic reaction is a key challenge in this era. In this study, we report an aminomethyl-polystyrene-based eosin-Y (PBE) solar light active photocatalyst in which polystyrene is covalently bonded to the light-harvesting organic dye, eosin-Y, by the condensation method. The covalent attachment of eosin-Y and polystyrene would enhance the molar extension coefficient and light-harvesting properties, making it serve as a more efficient photocatalyst than the pristine polystyrene. The new PBE photocatalyst exhibited excellent efficiencies for NADH/NADPH regenerations with yields of 65.19% and 75.56%, respectively, and for the synthesis of sulfoxide from alkenes and thiophenol it exhibited high yield and selectivity (99.8%). The optical character of the as-synthesized photocatalyst was characterized by density functional theory and optical spectroscopy. From these experimental analyses, it was expected that the formation of a charge-transferred state would facilitate the improvement of solar absorption ability and light-harvesting properties in the PBE photocatalyst. Moreover, the PBE photocatalyst can be reused more than six times without the degradation of the photocatalytic activity, confirming that PBE is a highly stable and reusable photocatalyst. Therefore, the current research work brings new insights into the potential application of the PBE photocatalyst in the field of solar light-mediated nicotinamide cofactor regeneration, along with organic transformations.