Thienopyrrolo[3,2,1-]carbazoles: Building Blocks for Functional Organic Materials.

The facile preparation of three regioisomeric thienopyrrolo[3,2,1-]carbazoles applying a convenient C-H activation approach is presented. The incorporation of thiophene into the triarylamine framework significantly impacted the molecular properties in comparison to the analogous indolo[3,2,1-]carbazole scaffold. Dependent on the exact substitution pattern, the absorption onsets of the new materials are shifted toward slightly higher wavelengths compared to the analogous indolo[3,2,1-]carbazole, whereas the emission maxima of the sulfur derivatives is shifted from 375 to 410 nm. In analogy, the HOMO-LUMO energy gap of the thienopyrrolo[3,2,1-]carbazoles is reduced compared to indolo[3,2,1-]carbazole. Therefore, the developed thienopyrrolo[3,2,1-]carbazoles enrich the family of triarylamine donors and constitute a novel building block for functional organic materials.