Background and overview[1]
3-Bromophenylboronic acid pinacol ester, also known as 3-bromophenylboronic acid pinacol ester, can be used to synthesize a green light-emitting iridium (III) complex with high luminous efficiency.
Preparation[1]
Synthesis of 3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)bromobenzene:
Place 4.24mmol of m-dibromobenzene, 4.24mmol of pinacol diborate, 0.212mmol of 1,1′-bis(diphenylphosphine)ferrocene dichloride palladium dichloromethane complex, 600mg Add potassium acetate and 20 mL of 1,4-dioxane into a double-necked reaction flask, vacuum-fill nitrogen-evacuate the double-row tube, cycle three times, and finally use nitrogen to protect the reaction system at 85°C. The reaction was stopped after 10 hours of reflux reaction. The solvent coating additive was removed using a rotary evaporator, and a white solid was obtained by column chromatography. The obtained intermediate product 1 (3-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)bromobenzene) was treated with 1H NMR was verified and the results showed that the structure is correct. The data are as follows:
1H NMR (MHz, CDCl3)δ (ppm) = 7.93 (s, 1H), 7.71 (d, J = 7.6Hz, 1H), 7.58 (ddd, J=8.0, 2.0, 1.2Hz, 1H), 7.23 (t, J=7.6Hz, 1H), 1.34 (s, 12H).
Apply [1]
3-Bromophenylboronic acid pinacol ester can be used to synthesize a green light-emitting iridium (III) complex with high luminous efficiency. It contains a special functional group, namely a fluorophenyl group with electron transport properties. Clusters are conducive to the balanced transmission of carriers in the recombination region, thus making the organic electroluminescent device have better performance. The synthesis route is as follows:
Add 2.26mmol of 2-bromopyridine, 2.49mm of the intermediate product 1 of Huntsman metal complex dye ol, namely 3-bromophenylboronic acid pinacol ester, and 0.04mmol of tetrakis triphenylphosphorus palladium into the bis In the bottle, after vacuuming-nitrogen filling-vacuuming cycle three times, use nitrogen to protect the reaction system, add the mixed solvent (toluene: ethanol: sodium carbonate aqueous solution, V/V/ V) was poured into the reaction bottle, and the reaction system was reacted at 80°C for 6 hours. Extract three times with dichloromethane and water, combine the organic phases, remove the solvent with a rotary evaporator, and separate by column chromatography to obtain the intermediate product 2 (2-(3-bromo-phenyl)-pyridine);
Add 1.28 mmol of intermediate product 2, 1.41 mmol of 2,4-difluorophenylboronic acid and 0.03 mmol of tetrakis triphenylphosphorus palladium into a double-necked flask, and cycle three times of vacuuming, nitrogen filling and vacuuming. , use nitrogen to protect the reaction system, and pour the mixed solvent (toluene: ethanol: sodium carbonate aqueous solution, V/V/V) with a pre-deoxygenated ratio of 3:1:1 into the reaction bottle. The reaction system is heated at 80°C. React for 6 hours, extract three times with dichloromethane and water, combine the organic phases, remove the solvent with a rotary evaporator, and separate by column chromatography to obtain the intermediate product 3(2-(3-(2,4-difluorophenyl)-phenyl) )-pyridine);
Weigh IrCl3·3H2O (0.288mmol) and intermediate product 3 (0.72mmol) into a double-necked flask, evacuate and fill with nitrogen – Vacuum cycle three times and protect the reaction system with nitrogen. After injecting a mixture of 2-ethoxyethanol and water (3:1, v/v), the reaction mixture was heated to 110°C and stirred for about 24 hours. After the reaction stopped, the reaction mixture was lowered to room temperature and filtered to obtain a precipitate. The resulting precipitate was washed with water and ethanol respectively to obtain the intermediate product 4 ([Ir(dfbppy)2]2Cl2);
Weigh 0.02 mmol of the iridium dichloride bridge compound obtained above, 0.05 mmol of acetylacetone and 20 times the equivalent of potassium carbonate powder and add them to a double-necked bottle. After vacuuming-nitrogen filling-vacuuming, cycle three times. The reaction system was protected with nitrogen, 5 mL of 2-ethoxyethanol was added, and the reaction was carried out in a dry nitrogen atmosphere for 6 hours. After the reaction, the solvent was removed with a rotary evaporator, and the target product Ir(dfbppy)2acac was separated by column chromatography.
Main reference materials
[1] CN201410201799.0 Green iridium (III) complex and its preparation method and application
