Radical Reactivity of Thioimidates for Diversified Polymeric Amidines with Tunable Properties

Thioimidates serve as a synthetic branch point for other functional groups but are relatively unexplored in radical and polymer chemistry. This study marks the first investigation of thioimidate radical chemistry and subsequent elaboration into diverse polymeric amidines.

Abstract

The first reactions of thioimidates under radical-mediated conditions are described along with the delineation of structural factors that impact radical reactivity and possible side reactions. Thioimidate-containing copolymers with methylmethacrylate (MMA) are synthesized through radical-mediated, chain-growth polymerization. These materials serve as a synthetic branch point for facile conversion into amidines by treatment with a weak acid and an external amine. Our approach allows for more diverse amidine structures than have been previously reported in polymers. This chemistry also enables crosslinking to form novel hydrogels with finely tuned acid–base behavior. Subsequent examination of the acid–base properties revealed that these features are preserved across linear, soluble amidine polymers to cross-linked amidine gel polymer architectures.

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