Abstract
A series of new multi-functionalized indoles were designed and synthesized as blue-light emitting materials. Palladium-catalyzed coupling of methyl (3,4-dimethoxyphenyl)propiolates or a 9-anthraldehyde with 4-substituted-2-iodo-1- anilines in the presence of n-Bu4NBr (1.0 equiv) and NaOAc in DMF at 100–120 °C afforded the new indoles 1a–g and 13a,b, respectively, in 25–65% yields. Fine tune of their blue electroluminescence was performed by placement of elelctron-donating and -withdrawing substitutents at the C2-, C3-, and C5-positions. The quantum yields were measured between 0.41 and 0.59 by use of anthracene as the reference. These indole derivatives melted around 200 °C and were stable up to 250 °C. Results from spectroscopic measurements, molecular computations, and device manufacture indicate that the blue color of indoles can be successfully shifted to the desired chromaticity coordiates.