Dual-Functional Polystyrene-Based Borate Complexes: Recyclable Alkyl Radical Sources and Photodegradable Absorbents

Recyclable polymeric materials capable of generating radicals under mild conditions are valuable materials in synthetic chemistry. Herein, we report polystyrene-based copolymers bearing 2,2'-(pyridine-2,6-diyl)diphenol (PDP) moieties that form alkyl borate complexes and release alkyl radicals upon blue-light irradiation. The generated primary and secondary alkyl radicals efficiently participate in Giese-type addition reactions, affording products in good to excellent yields. The polymer-supported system enables straightforward purification by simple reprecipitation at both the borate complex formation and Giese reaction stages. Notably, the PDP polymer can be recovered through fluoride-mediated cleavage and regenerated via recomplexation, allowing reuse in subsequent reaction cycles. In addition, crosslinked PDP-borate networks function as photodegradable organogels that selectively absorb organic solvents from water and release them upon light irradiation. This polymer-supported strategy provides a versatile platform for photo-driven radical transformations and responsive materials applications, demonstrating proof-of-concept for polymer recovery (50% PDP regeneration) and practical advantages in product separation.