2,2,2′,2′-四(苯并咪唑-2-基)-1,4-二乙烯基苯的合成及其光电性能

Synthesis and Photoelectronic Properties of 2,2,2′,2′-tetra(benzimidazole-2-yl)-1,4-divinylbenzene

以邻苯二胺、丙二酸及对苯二甲醛为原料,通过Knoevenagel反应合成了一种多苯并咪唑有机光电材料2,2,2′,2′-四(1H-苯并咪唑-2-基)-1,4-二乙烯基苯。采用包括元素分析、FTIR和1 H NMR分析在内的方法对其结构进行了表征,并测试研究了产物的光物理性能、电化学特性和热稳定性。结果表明:该化合物的最大紫外吸收谱在398nm附近的近紫外光区。其溶液荧光为λem≈500nm的蓝绿色光,固体薄膜荧光为λem=554nm的绿色光,且具有明显的聚集诱导发光增强(AIEE)效应。通过CV测得其Eg=3.10eV,IP=5.57eV,EA=2.47eV,表明该化合物是一种潜在空穴传输材料。测得其热分解温度接近500℃,具有良好的热稳定性。采用密度泛函(DFT)理论计算其主要光电性能参数,与实验结果相符,量化计算证明该分子具有显著的非共平面性的π共轭体系以及分子内电荷转移特性。

A novel photoelectric material 2,2,2′,2′-tetra(benzimidazole-2-yl)-1,4-divinylbenzene was synthesized through Knoevenagel reaction.Its structure was characterized by various methods including elemental analysis,etc.Measurements and tests for photophysical properties,electrochemical properties and thermal stability were carried out.The results showed that the compound has two UV absorption peaks locating at 280 nm and 398 nm and a blue-green fluorescenceλem,max=500 nm excited by 365 nm in DMF.A significant AIEE effect of the compound was found with different DMA/H2O ratio inmixed solvent.It has a green fluorescence(λem,max=554 nm)in solid with a 54 nm red shift compared to the solution fluorescence.Eg=3.10 eV,Ip=5.57 eV and EA=2.47 eV calculated from CV test indicated the compound may be a potential hole transporting material.TG-DTA analysis showed that the compound with a thermal decomposition temperature(500℃)possess good thermal stability.The optimized ground-state geometry,HOMO and LUMO distributions of the compound were obtained by DFT.The results from DFT calculation is consistent with that of experiments and revealed that the compound has a largely nonplanarπelectron conjugated system and notable intramolecular charge transferring performance.