Catalytically active N-heterocyclic carbene release from single-chain nanoparticles following a thermolysis-driven Unfolding Strategy

The need for efficient, tailor‐made catalysts has inspired chemists to design synthetic macromolecular architectures for selective catalysis. To this purpose, herein the synthesis and in‐depth characterization of Ag(I)‐crosslinked single‐chain nanoparticles (SCNPs) is reported and their application as catalysts is demonstrated. Specifically, a copolymer of styrenic benzimidazolium chloride is synthesized as a linear precursor via reversible addition‐fragmentation chain‐transfer polymerization. Metalation of the benzimidazolium moieties by Ag(I) resulted in the intramolecular cross‐linking of single chains via the formation of silver‐N‐heterocyclic carbene (Ag‐NHC) linkages under dilute conditions. The successful formation of well‐defined, robust SCNPs is evidenced by size‐exclusion chromatography, dynamic light scattering, nuclear magnetic resonance spectroscopy, and transmission electron microscopy. Finally, it is demonstrated that the Ag‐SCNPs can be used as NHC pre‐catalysts, by first indirectly evidencing the formation of the corresponding unfolded NHC‐CS₂ polybetaine and then organocatalysing a benzoin condensation reaction.