Combining Click Sulfur(VI)-Fluoride Exchange with Photoiniferters: A Facile, Fast, and Efficient Strategy for...

"Click" type reactions represent the currently most prevalent postpolymerization strategy for the preparation of functional polymeric materials. Herein, a novel photoiniferter agent 4-(fluorosulfonyl)benzyl diethylcarbamodithioate (FSB-DECT) containing both dithiocarbamates and sulfonyl fluoride moieties is developed to act as both photoinitiator and click sulfur(VI)-fluoride exchange (SuFEx) agent. The photopolymerization behavior of FSB-DECT is demonstrated via standard photoiniferter-mediated polymerization for various types of monomer including N-isopropylacrylamide (NIPAAm), glycidyl methacrylate, and vinyl acetate (VAc). Gel permeation chromatography data show that the polymerization is relatively well controlled, with polydispersity indices of the product homopolymers in the range of 1.3-1.6. ¹ H and ¹⁹ F NMR spectra and "reinitiated" photopolymerization indicate that the sulfonyl fluoride and diethyldithiocarbamyl groups remain at the respective ends of the homopolymer chains. Furthermore, using the sulfonyl fluoride end-functionalized poly(N-isopropylacrylamide) as a model polymer, the utility of the SuFEx reaction for efficient postpolymerization functionalization is demonstrated.