School of Chemistry and Chemical Engineering, Southeast University, Nanjing, 211189, PR China.
Luminescence. 2013 Sep-Oct;28(5):628-33. doi: 10.1002/bio.2404. Epub 2012 Jul 24.
1,3-Diphenyl-5-(9-anthryl)-2-pyrazoline and 1,3-diphenyl-5-(9-anthryl)-1H-pyrazole with an anthryl chromophore were synthesized and characterized using (1) H NMR, (13) C NMR, FT-IR, mass spectrometry and elemental analysis. Their optical properties were characterized by UV-vis absorption and fluorescence spectroscopy. It was observed that the absorption and fluorescence spectra of the two compounds showed a red shift with respect to that of anthracene. Pyrazole exhibited high fluorescent quantum yields (Φf = 0.90 in toluene) while pyrazoline showed nearly no fluorescence in solution. The significant fluorescence divergence of the two similar compounds was investigated theoretically through density functional theory (DFT) calculations. The energetically lowest-lying state S1 in the pyrazoline exhibited both characteristics of locally excited and electron-transfer states that resulted in the fluorescence quenching of anthryl chromophore whereas the S1 state in the pyrazole corresponded to an optically allowed state that led to high fluorescence quantum yields in solutions.
1,3-二苯基-5-(9-蒽基)-2-吡唑啉和 1,3-二苯基-5-(9-蒽基)-1H-吡唑啉具有蒽基发色团，使用 (1) H NMR、(13) C NMR、FT-IR、质谱和元素分析进行了合成和表征。通过紫外-可见吸收和荧光光谱研究了它们的光学性质。观察到两种化合物的吸收和荧光光谱相对于蒽发生了红移。吡唑啉表现出高荧光量子产率（在甲苯中为 0.90），而吡唑啉在溶液中几乎没有荧光。通过密度泛函理论（DFT）计算从理论上研究了两种相似化合物的显著荧光发散。在吡唑啉中，能量最低的 S1 态表现出局部激发态和电子转移态的特性，导致蒽基发色团的荧光猝灭，而吡唑啉的 S1 态对应于光学允许态，导致溶液中具有高荧光量子产率。
