A simple synthesis of luminescent π-conjugated materials having fDTBT derivatives

Abstract We developed a simple and rapid process for synthesizing dithieno[3′,2′:3,4;2″,3″:5,6]benzo[1,2-c][1,2,5]thiadiazole (fDTBT) derivatives using crystalline sulfur and internal alkynes, wherein thiophene is cyclized to benzothiadiazole. Cyclized derivatives were synthesized in 3 or 5 steps using this reaction, whereas the conventional synthesis methods involved 7 steps and hazardous reactions with explosive properties. The absorption spectra of the synthesized fDTBT derivatives in chloroform solution revealed a new absorption band owing to the cyclization. All 3 compounds exhibited orange-to-red luminescence, and the maximum absolute quantum yield was determined to be 67%, demonstrating excellent luminescence.