Degradable <i>N</i>‑Vinyl Copolymers\nthrough Radical Ring-Opening Polymerization of Cyclic Thionocarbamates

A thiocarbonyl radical ring-opening polymerization approach\nwas\nimplemented with cyclic thionocarbamates to generate degradable copolymers\nwith <i>N</i>-vinyl monomers. The rigid structures of cyclic <i>N</i>-substituted thionocarbamates have been revealed by X-ray\ncrystallography and NMR spectroscopy. The corresponding copolymers\nshow incorporation of the thiocarbamates within the carbon backbone\nof polyvinylpyrrolidone influenced by acyl substituents through radical\nring-opening copolymerization. The phenyl-substituted cyclic thionocarbamate\ncopolymerized with <i>N</i>-vinyl carbazole and <i>N</i>-vinyl caprolactam, while little to no incorporation occurred\nwith <sup><i>t</i></sup>Bu acrylate and styrene, respectively.\nFurther, these copolymers can undergo hydrolytic degradation under\nmild conditions. A new family of cyclic thionocarbamates capable of\nradical ring-opening copolymerization with <i>N</i>-vinyl\nmonomers has been established.