Synthesis and properties of pteridine-2,4-dione-functionalised oligothiophenes

The synthesis of acceptor-functionalised oligothiophene derivatives (t3, t6, t7, t8) is described, where the pteridine-2,4-dione acceptor units are arranged symmetrically in derivatives t6–t8. The symmetrical arrangement of acceptor units stems from the ability to selectively brominate the conjugated thiophene moiety of building block t3. Upon increasing the conjugation by going from t3 to t8, a significant increase in absorption toward the near-infrared region and a simultaneous narrowing of the HOMO/LUMO gap occurs, which may promote their future application as optoelectronic materials.