Light-driven folding of single polymer chains via metal-complexation

We introduce a light-driven methodology (λ_max = 365 nm) to fold single polymer chains into single chain nanoparticles (SCNPs). Exploiting the photo-isomerization of spiropyran entities embedded into the backbone of polymer chains (ranging from 15 to 38 mol%) constituted of polyethylene glycol carrying monomer units (ranging from M_n = 28 500 g mol⁻¹ to 40 000 g mol⁻¹), we complex their open form using a range of metals, including iron, copper and cobalt. The approach offers the first direct avenue for incorporating metals into SCNPs via a photochemical folding mechanism in one step.