Carbonylation-Mediated End-Functionalization of Poly(3-hexylthiophene) with Broad Functional Group Compatibility

A novel strategy enables efficient end-functionalization of poly(3-hexylthiophene) (P3HT) with broad functional group tolerance under mild conditions. Following Kumada–Tamao catalyst-transfer condensation polymerization, the terminal nickel complex is converted to a reactive acyl intermediate through carbon monoxide insertion, which subsequently undergoes aminocarbonylation with various amines. This method successfully introduces functional groups incompatible with conventional Grignard-based approaches, including hydroxy, ester, carbonyl, and aryl halide moieties, achieving quantitative conversion within 1–12 h at room temperature. The strategy was successfully applied to synthesize well-defined P3HT-polyethylene glycol block copolymers, as confirmed by size-exclusion chromatography. Furthermore, the effective trapping of nickel(0) species by carbon monoxide prevents undesired side reactions, enabling unprecedented selective bifunctionalization of P3HT through sequential carbonylation and Suzuki–Miyaura coupling. This carbonylation-mediated approach significantly expands the structural diversity of end-functionalized conjugated polymers and provides a versatile platform for advanced materials design.