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Photochemistry in Confined Environments for Single-Chain Nanoparticle Design
- Frisch, Hendrik, Menzel, Jan P., Bloesser, Fabian R., Marschner, David E., Mundsinger, Kai, Barner-Kowollik, Christopher
- Journal of the American Chemical Society 2018 v.140 no.30 pp. 9551-9557
- nanoparticles, photochemistry, polymers
- Emulating nature’s protein paradigm, single-chain nanoparticles (SCNP) are an emerging class of nanomaterials. Synthetic access to SCNPs is limited by ultralow concentrations, demanding reaction conditions, and complex isolation procedures after single-chain collapse. Herein, we exploit the visible light photodimerization of styrylpyrene units as chain folding mechanism. Critically, their positioning along the polymer chain creates a confined environment, increasing the photocycloaddition quantum yields dramatically, enabling single-chain folding at unrivaled high concentrations without subsequent purification. Importantly, the enhanced photoreactivity allows for single-chain folding at λ = 445 nm LED-irradiation within minutes as well as via ambient light, enabling an unprecedented folding system. The herein demonstrated enhancement of quantum yields by steric confinement serves as a blueprint for all photochemical ligation systems.