We introduce visible light induced dynamic covalent chemistry as a powerful reversible ligation tool based on a wavelength-dependent photon efficiency analysis (WPEA). We demonstrate by a monochromatic wavelength scan of the reversible dimerization of styrylpyrene at constant photon count that the system is most effective in its forward reaction at 435 nm, while the highest reverse reaction efficiency is observed at 330 nm. Critically, these optimum wavelengths are not accessible by inspection of the UV/vis spectra of the monomer and the dimer. Application of the identified reaction conditions enabled an entirely λ-orthogonal photoreversible polymer ligation using visible light, including with readily available light sources. The current study thus makes a [2 + 2] reaction system applicable in the critical visible light regime based on quantitative wavelength resolved data for applications in recodeable surface design in biological environments as well as reprogrammable materials systems.

We pioneer the synthesis of fluorescent single chain nanoparticles (SCNPs) via UV-light induced folding based on tetrazole chemistry directly in pure water. Water-soluble photoreactive precursor polymers based on poly(acrylic acid) (PAA) bearing tetrazole, alkene and tetraethylene glycol monomethyl ether moieties, (PAA n (Tet/p-Mal/TEG)), or simply tetrazoles moieties, PAA n (Tet), were generated via RAFT polymerization. While tetrazole, ene, and acrylic acid containing polymers fold via dual nitrile imine-mediated tetrazole-ene cycloaddition (NITEC) as well as nitrile iminecarboxylic acid ligation (NICAL), tetrazole and acrylic acid only functional prepolymers fold exclusively via NICAL. A detailed study of the underpinning photochemistry of NITEC and NICAL is also included. The resulting water-soluble SCNPs were carefully characterized via analytical techniques such as NMR, UV−vis, and fluorescence spectroscopy, as well as SEC and DLS.

We introduce the facile synthesis of fluorescent single-chain nanoparticles (SCNPs) based on chain-shattering acyclic diene metathesis (ADMET) polymers featuring self-immolative azobenzene motifs. An electrophilic alkoxyetherification is utilized to introduce the photoreactive moieties required for the subsequent chain collapse via UV-induced nitrile imine-mediated tetrazole-ene cycloaddition (NITEC).