“Click”able monomer and polymers based on Azide-functionalized 3,4-Propylenedioxythiophene with tunable processibility

This research introduces 3,3-bis(azidomethyl)-3,4-dihydro-2H-thieno[3,4-b][1,4]dioxepine (ProDOT-AM2) as a versatile building block monomer for the synthesis of variously functionalized monomers and copolymers via “click”able 1,3-dipolar cycloaddition. The efficiency of this building block as a precursor to a wide range of ProDOT-based monomers is demonstrated by click reaction with various alkynes. The 1,3-dipolar cycloaddition of ProDOT-AM2 with different alkynes in the presence of a catalyst yields a novel class of ProDOT derivatives via a “triazole-locker” mechanism. Depending on the bases utilized, two distinct types of functionalized monomers, namely bistriazole and triazole, are obtained. The resulting polymers from the oxidative polymerization of selected monomers exhibit high solution processability and stability under multiple chemical redox processes, demonstrating potential applications in chemical chromics. Additionally, a conjugated copolymer containing ProDOT-AM2 is synthesized via Stille reaction conditions and subsequently post-functionalized with alkynes via a “triazole-locker” mechanism. Characterization studies via IR and ¹H NMR confirm the successful post-functionalization of the polymer. Electropolymerization of ProDOT-AM2 yields an electroactive polymer (PProDOT-AM2), indicating its potential utility in conducting polymers to be further post-functionalized. Overall, this methodology presents a straightforward approach for synthesizing a new class of monomers for conducting polymers and polymer modification using click chemistry.