Sodium sulfide-promoted thiophene-annulations: Powerful tools for elaborating organic semiconducting materials

We describe herein facile thiophene annulation reactions promoted by sodium sulfide hydrate (Na₂S·9H₂O) for the synthesis of acene(di)thiophenes that can be further utilized as organic semiconductors or building blocks for the elaboration of semiconducting oligomers and polymers. Sodium sulfide hydrate is an efficient source of sulfur for both the aromatic nucleophilic substitution (S_NAr) reaction and the nucleophilic hydrogen substitution (S_NH) reaction to give a range of electron-donating acene(di)thiophenes and an electron-deficient naphtho[2,3-b:6,7-b′]dithiophene diimide (NDTI), respectively. We also describe organic semiconducting materials on the basis of these acene(di)thiophenes and their use in organic devices, such as organic field-effect transistors and organic photovoltaics, and demonstrate that synthetic evolution is one of the keys to promoting the field of organic semiconducting materials.