| Summary: | 碩士 === 國立臺灣大學 === 化學研究所 === 88 === An efficient one-pot synthetic strategy has been developed to introduce different alkynes regioselectively to the 2- and 5-position of 5-bromo-2-iodopyrimidine in the presence of catalytic amount of Pd-catalyst (consecutive Sonogashira reaction). A series of conjugated oligomers were synthesized by further couple pyrimidine containing building block with di-iodoarenes. Different alkyl substituents were introduced for increasing the solubility towards organic solvents. Moreover, the regioselectivity of 5-bromo-2-iodopyrimidine towards Pd-catalyzed Sonogashira coupling reaction was applied to control the arrangement of the dipolar pyrimidine moiety in the backbone with defined conjugated length. Three different arrangements have been successfully achieved. For comparison, a model compound with the same skeleton but without pyrimidine moiety was also synthesized. The photophysical properties of these conjugated compounds were investigated by UV-VIS absorption and photoluminescence in solution, thin film or in PVK matrix. Introducing pyrimidine into the conjugated system reduces the HOMO-LUMO band gap was confirmed by these photophysical studies. We also applied these conjugated oligomers as a dopant in PVK for light-emitting diode. There is no significant difference in device characteristics upon introducing oligomers with different arrangement of dipolar pyimidine. However, oligomers with pyrimidine moiety enhance the efficiency of light emitting devices was observed. .
|
|---|
