Synthesis of Novel Thiophene‐Based Oligomers and Polymers with Thienothiadiazole Units

Abstract

AbstractSummary: Novel non‐alkylated and alkylated quinquethiophenes were prepared by the Stille coupling reaction of bis(5‐bromo‐2‐thienyl)thieno[3,4‐c][1,2, 5]thiadiazole (TBr) with 2‐(tributylstannyl)thiophene. These compounds possess long wavelength absorption maxima around 700 nm in solution and 750 nm in thin films. Dibromo compound TBr is further employed as a building block in the syntheses of low‐bandgap copolymers with fluorene units. A soluble alternating copolymer was prepared by the Suzuki coupling of TBr with bis(propane‐1,3‐diyl) 9,9‐bis(2‐ethylhexyl)fluorene‐2,7‐diylbisboro‐nate. It shows the long‐wavelength absorption maximum at 747 nm in solution and at 764 nm in thin film, which indicates extensively conjugated system.