Synthesis of a thiophene-fused isoindigo derivative: a potential building block for organic semiconductors

Thiophene-fused isoindigo (TII) was synthesized from thieno[2,3-f]indol-6(7H)-one in a one-pot reaction, in which the alkylation, oxidation and condensation were finished in one step. It exhibits better intramolecular charge transfer properties and higher reductive potential compared with isoindigo(II), as evidenced by its optical and electrochemical properties, which shows that it might be used as a building block for n-type or ambipolar OFET materials.