Iridium-Catalyzed Direct C-H Amidation Polymerization: Step-Growth Polymerization by C-N Bond Formation via C-H Activation to Give Fluorescent Polysulfonamides.

We report a powerful strategy for activation of C-H bonds to produce polysulfonamides by an atom-economical and green method using iridium-catalyzed direct C-H amidation polymerization (DCAP). After screening various directing groups, additives, silver salts, concentrations, and temperatures to optimize DCAP, high-molecular-weight (up to 149 kDa) and defect-free polysulfonamides were synthesized from various bis-sulfonyl azides. Although these polymers do not have conventional fluorescent conjugated cores, they emit blue light with large Stokes shifts and high quantum yields upon photoexcitation owing to an excited-state intramolecular proton-transfer process.