Under nitrogen protection, benzothiadiazole (6.81 g, 50 mmol) was dissolved in 200 mL of concentrated sulfuric acid. N-bromosuccinimide (18.71 g, 10⁵ mol) was added in three batches at 60 °C, and the mixture was stirred for 12 hours. The reaction solution was poured into 900 mL of ice water and filtered. The residue was washed three times each with deionized water, methanol, and n-hexane. This process was repeated three times. The final residue was dried to obtain a solid product with a yield of 69%. ¹H NMR, ¹³C NMR, MS, and elemental analysis showed that the obtained compound was the target product.
4,7-Dibromo-2,1,3-benzothiadiazole is a white to Light yellow to Light orange crystalline powder and needs to be stored in an inert gas. As an organic intermediate, it is widely used in organic synthesis and pharmaceutical production
This monomer is used in the synthesis of photoactive acceptor part in low band gap conjugated polymers and oligomers for high performance OPV devices
4,7-Dibromo-2,1,3-benzothiadiazole is the building block or monomer for the synthesis of light-emitting diodes and conducting polymers for organic electronics. It is used as an intermediate for the synthesis of poly[N-9'-heptadecanyl-2,7-carbazole-alt-5,5-(4',7'-di-2-thienyl-2',1',3'-benzothiadiazole)] (PCDTBT) and poly[2,1,3-benzothiadiazole-4,7-diyl[4,4-bis(2-ethylhexyl)-4H-cyclopenta[2,1-b:3,4-b']dithiophene-2,6-diyl]] (PCPDTBT).
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