Self-Assembly of ROMP-Derived Block Copolymers into Vesicles and Micelles for Photocatalytic Oxidation of Anilines to Azobenzenes in Aqueous Media

Aqueous photocatalysis offers a sustainable and environmentally benign platform for promoting chemical transformations under visible light and mild conditions. However, the limited water solubility of many high-performance photocatalysts restricts their use in aqueous systems. Herein, we report the synthesis of amphiphilic copolymers incorporating the photosensitizer 4CzIPN via ring-opening metathesis polymerization. These copolymers self-assemble into vesicles or micelles, exhibiting excellent dispersibility in water and effectively overcoming the solubility limitations of 4CzIPN. Moreover, the assembly morphology can be precisely tuned by adjusting the block ratio and monomer sequence. Among the synthesized series, P1 45 - b -P2 30 formed uniform vesicles in water and displayed the highest photocatalytic activity in the oxidation of anilines to azobenzenes under aqueous conditions. This polymeric catalyst outperformed the small-molecule 4CzIPN by 5-fold and retained catalytic activity over multiple catalytic cycles. This work underscores the potential of amphiphilic copolymers bearing organic photosensitizers as robust and effective platforms for photocatalytic organic transformations in aqueous media.