2-糠醛缩N-乙基-3,6-二氨基咔唑双席夫碱的合成及其性能

以咔唑为起始原料经N-取代、硝化和还原反应制备中间体N-乙基-3,6-二氨基咔唑,然后以其与2-糠醛发生缩合反应制得新型双席夫碱化合物N-乙基-3,6-二(2-亚糠基亚氨基)咔唑,产率为72.36%。通过元素分析、FTIR、UV-Vis、1H NMR、溶液及固体荧光光谱、循环伏安(CV)和TG-DTA分析研究了标题化合物的分子结构、光物理特性、电化学特性和热稳定性。结果表明,化合物的DMF稀溶液在200~400 nm波段有较宽较强的紫外吸收;在365nm波长激发下,溶液发射深蓝色荧光,λem为446nm,固体荧光为λem=467nm的蓝色荧光,与溶液荧光相比固体荧光红移了21nm。由循环伏安测试得到产物的Eg=2.19e V,IP=4.99e V以及EA=2.80e V,说明其具有良好的空穴和电子传输材料性能。TG-DTA测试显示目标产物具有良好的热稳定性。该化合物在有机荧光、空穴注入传输材料以及电子传输材料方面具有潜在应用前景。

Synthesis and Properties of A Novel Bis-Schiff Base Derived from 2-Furaldehyde and N-ethyl-3,6-diaminocarbazole

With carbazole as raw material, the intermediate N-ethyl-3,6-diaminocarbazole was synthesized through N-alkyl substitution, nitration and reduction reaction successively. Then a novel bis-Schiff base N-ethyl-3,6-bis(2-furalideneimino)carbazole was synthesized from 2-furaldehyde and N-ethyl-3,6-diaminocarbazole with a yield 72.36%. Its structure was characterized by elemental analysis, FT-IR, UV-Vis, 1H NMR and EIS-MS. Solution fluorescence, solid fluorescence spectroscopy, cyclic voltammetry electrochemical analysis (CV) and TG-DTA thermal analysis were used to study its optical properties, electrochemical properties and thermal stability. The results showed that the target compound has a strong and wide UV absorption band from 200 nm to 400 nm in the dilute solution of DMF, and a deep blue fluorescence emission peak at 446 nm excited by 365 nm. Solid fluorescence spectroscopy indicated that the Schiff base has an emission peak at 467nm with a 21 nm red shift compared to the solution fluorescence. The optical band gap (Eg ), ionization potential (Ip) and electron affinity (EA) of the target compound are 2.19, 4.99 and 2.80 eV, respectively, calculated from UV-Vis and CV test, which indicated that it has excellent performance of hole transporting and electron transporting. TG/DTA analysis showed that the target compound possess good thermal stability. This compound has potential for use in organic luminescent material and hole and electron transport layer materials.