Poly(diphenylacetylene)s: Solution-Processable Polymer Photocatalysts for Organic Synthesis

Herein, we demonstrate that photoexcited polyacetylene derivatives generate reactive radical ion species in the presence of appropriate electron donors or acceptors, thereby enabling electron-transfer reactions in organic synthesis. Specifically, polyacetylene derivatives fully substituted with amide-modified aromatic rings, namely poly(diphenylacetylene)s, mediate electron transfer reactions under visible-light irradiation. The catalyst identified through a brief screening functions as a homogeneous photoredox catalyst capable of promoting both reductive and oxidative quenching pathways. Leveraging its polymeric nature, the catalyst can be readily recovered from the reaction mixture by precipitation upon addition of a poor solvent such as methanol and reused in subsequent reactions, highlighting the potential of a solution-processable conjugated polymer photocatalyst for sustainable homogeneous photoredox catalysis.