Grafted Disulfide-Linked Linear Polymers for Heterogeneous Thiyl Radical Photocatalysis

Dynamic disulfide bonds offer a promising avenue for developing robust and reversible photocatalysts. This study introduces a novel polymer, Poly-SS, designed for heterogeneous thiyl radical photocatalysis, leveraging the dynamic nature of disulfide linkages. Poly-SS features linear disulfide-containing polymers grafted onto a polyvinyl backbone, combining the photoactivity of disulfide with the structural integrity of polyvinyl. This design facilitates efficient thiyl radical generation upon photoirradiation, enabling challenging organic transformations. Poly-SS demonstrates exceptional photocatalytic efficiency for the aerobic oxidation of diarylalkynes to 1,2-diketones, achieving >99% conversion. The polyvinyl backbone plays a crucial role in maintaining polymer recyclability by promoting thiyl radical recombination and preserving disulfide linkages, addressing the inherent lability of molecular thiyl radicals. Furthermore, copolymerization with soluble monomer enhances the solubility of Poly-SS, enabling facile thin-film fabrication for diverse photoreactor designs. This work highlights a significant advancement in heterogeneous thiyl radical photocatalysis, showcasing the potential of carefully designed disulfide-linked polymers to overcome limitations associated with traditional molecular catalysts by integrating dynamic covalent chemistry with a robust polymer architecture.