Uses
4,4''-Dibromo-2,2''-bipyridine is used as a reagent in the synthesis of benzodifuran based ruthenium dyes which show high efficiency of energy conversion when used in thin film dye sensitized solar cells.
Synthesis
The general procedure for the synthesis of 4,4'-dibromo-2,2'-dipyridine using the compound (CAS: 84175-09-7) as starting material was as follows: firstly, 37 g of compound 4-c (0.1 mol) was added to a 2 L round bottom flask under nitrogen protection, followed by the addition of 950 mL of chloroform to dissolve it completely. After cooling the reaction system to -3°C, 297 g of phosphine tribromide (1.1 mol) was slowly added dropwise. After the dropwise addition, the reaction mixture was heated to 60 °C and stirred continuously for 2 hours. After completion of the reaction, the mixture was cooled to room temperature, slowly poured into 1 L of water and the pH was adjusted with sodium hydroxide solution to 11. Subsequently, the organic layer was separated by extraction with dichloromethane. The organic layer was dried over anhydrous sodium sulfate and concentrated under reduced pressure by rotary evaporator to remove the solvent. The resulting solid was washed with ethanol and filtered to give the light yellow solid product 4-d in 26 g yield, giving 77% yield.
References
[1] Inorganic Chemistry, 2011, vol. 50, # 8, p. 3271 - 3280
[2] Patent: US2012/247546, 2012, A1. Location in patent: Page/Page column 35
[3] European Journal of Organic Chemistry, 2009, # 28, p. 4777 - 4792
[4] Heterocycles, 2008, vol. 75, # 1, p. 57 - 64
[5] Journal of the American Chemical Society, 1958, vol. 80, p. 2745,2747
