三苯基咪唑共轭Schiff碱的合成及其光学性能

Synthesis and Spectroscopic Properties of Triphenylimidazole Conjugated Schiff Bases

联苯甲酰、对硝基苯甲醛和乙酸铵在冰乙酸介质中经缩合反应制得2-(4-硝基苯基)-4,5-二苯基咪唑(1);1经铁粉还原制得2-(4-氨基苯基)-4,5-二苯基咪唑(2);2与4-二甲氨基苯甲醛经缩合反应合成了一种具有D-π-A结构的新型三苯基咪唑Schiff碱(3),其结构经~1H NMR,^(13)C NMR,IR和MS(ESI)表征。利用紫外-可见吸收光谱和荧光光谱研究了3在不同溶剂中的光物理行为。结果表明:3的最大吸收峰位于311~332 nm和378~380 nm,荧光发射峰位于433~436 nm和457~461 nm。由于具有D-π-A结构,3表现出明显的扭曲分子内电荷转移现象。

The reaction of 4-nitrobenzaldehyde with benzil in the presence of ammonium acetate affor- ded 2- （4-nitrophenyl） -4,5-diphenylimidazole （ 1 ）, which was reduced by iron powder to afford 2- （4- aminophenyl）-4,5-diphenylimidazole （2）. A novel D-＇rr-A structural triphenylimidazole conjugated Schiff base（3） was synthesized by condensation reactions of 2 with 4-dimethylaminobenzaldehyde. The structure was characterized by 1H NMR, 13C NMR, IR and MS（ESI）. UV-Vis and fluorescence spec- tra of 3 in different solution were investigated. The results indicated that the maximum UV-Vis absorp- tion peaks for 3 locate at 311 -332 nm and 378 -380 nm, and the fluorescence emission peaks locate at 433 - 436 nm and 457 - 461 nm, respectively. 3 showed obvious twisted internal charge transfer （TICT） due to the donor-π-acceptor structures.