136630-39-2

One of the most popular products made available from 2,7-dibromocarbazole is PCDTBT, a well-known polymer semiconductor used for polymer solar cells. A good example for adjusting the solubility of the carbazole compounds by using 2,7-dibromocarbazole as the starting materials is the synthesis of 2,7-dibromo-9-heptadecanylcarbazole.

301-13-3

439797-69-0

136630-39-2

544436-46-6

Reaction of 4,4'-dibromo-2-nitro-1,1'-biphenyl (0.004 mol) and 4-nitrotoluene (0.006 mol) with an excess of tris(2-ethylhexyl) phosphite (0.05 mol) was carried out at 160 °C for 5 h (for the specific compounds j, k) or 17 h (for the specific compounds i, m), protected by argon gas. Upon completion of the reaction, the reaction was cooled to room temperature and the excess tris(2-ethylhexyl) phosphite and the resulting tris(2-ethylhexyl) phosphate were subsequently removed under vacuum. The reaction mixture was purified by silica gel column chromatography with the eluent of toluene/heptane (1:1, v/v) and the column size of 3 cm × 60 cm. The major product 2,7-dibromo-9-(2-ethylhexyl)-9H-carbazole (Rf = 0.8-0.9) was effectively separated from the by-product 2,7-dibromocarbazole (Rf = 0.5-0.6). The resulting compounds 7a-m were characterized by thin layer chromatography (TLC), elemental analysis, melting point determination, 1H NMR, 13C NMR and Fourier transform infrared spectroscopy (FTIR). Chromatographically purified compound 7 was used for melting point determination and further purified by methanol recrystallization. Non-alkylated carbazoles 8 (including 2,7-diiodocarbazole 10 (8a-c), 2,7-dibromocarbazole 8 (8d-f), 2,7-dichlorocarbazole 7 (8g-i), and commercial carbazole 11 (8j-m)) were obtained either by independent preparation or by commercial purchase and used for structural characterization.