Visible‐Light‐Reactive Single‐Chain Nanoparticles

We introduce a single‐chain nanoparticle (SCNP) system capable of catalyzing the photooxidation of nonpolar alkenes up to three times more efficiently than an equivalent small‐molecule photosensitizer at an identical concentration. Specifically, we construct a polymer chain constituted of poly(ethylene glycol) methyl ether methacrylate and glycidyl methacrylate which we compact via multifunctional thiol‐epoxide ligation and functionalize with Rose Bengal (RB) in a one pot reaction, affording SCNPs with a hydrophilic shell and hydrophobic photocatalytic regions. Photooxidation of the internal alkene in oleic acid proceeds under green light. RB confined within the SCNP is three times more effective for nonpolar alkenes than free RB in solution, which we hypothesize is due to the spatial proximity of the photosensitizing units to the substrate in the hydrophobic region. Our approach demonstrates that SCNP based catalysts can afford enhanced photocatalysis via confinement effects in a homogeneous reaction environment. Photocatalytic activity can be enhanced up to three times by confining the catalyst within a compact single‐chain polymer nanoparticle environment, while retaining homocatalytic reaction conditions.