School of Chemistry and Chemical Engineering, Beijing Key Laboratory of Photoelectronic/Electrophotonic Conversion, Materials, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China.
Materials Science and Engineering, Beijing Institute of Technology, 5 South Zhongguancun Street, Beijing, 100081, China.
Chemistry. 2019 Jan 7;25(2):573-581. doi: 10.1002/chem.201804074. Epub 2018 Dec 13.
Five organic luminophores, 1,2,5-triphenylpyrrole (TPP) derivatives 3 a-e bearing electron-withdrawing or electron-donating groups, have been synthesized by Pd-catalyzed Suzuki coupling of 1-phenyl-2,5-di(4'-bromophenyl)pyrrole and para-substituted phenylboronic acid derivatives. They possess good thermal stabilities with high decomposition temperatures above 310 °C. Investigation of the photophysical properties of the luminogens 3 a-e indicated that they exhibited dual intense photoluminescence in both solution and the solid state due to their twisted conformations, and their fluorescence quantum yields (Φ ) were determined as 68.7-94.9 % in THF solution and 19.1-52.0 % in solid powder form. Compounds 3 a-c bearing electron-accepting groups exhibited remarkable solvatochromism with large Stokes shifts, attributable to their D-π-A structure and intramolecular charge-transfer effect. In particular, 3 a, bearing aldehyde groups, displayed an obvious red-shift of the emission band from 445 to 564 nm with increasing solvent polarity. However, no obvious solvatochromic behavior was observed for compounds 3 d,e bearing electron-donating groups. The luminophore 3 a exhibited polymorphic luminescence properties and crystallization-induced emission enhancement.
五种有机发光体，1,2,5-三苯基吡咯（TPP）衍生物 3a-e，带有吸电子或供电子基团，通过钯催化的 1-苯基-2,5-二（4'-溴苯基）吡咯和对取代苯基硼酸衍生物的 Suzuki 偶联反应合成。它们具有良好的热稳定性，分解温度高于 310°C。对发光体 3a-e 的光物理性质的研究表明，由于它们的扭曲构象，它们在溶液和固态中都表现出双重强烈的光致发光，并且它们的荧光量子产率（Φ）在 THF 溶液中为 68.7-94.9％，在固体粉末形式中为 19.1-52.0％。带有吸电子基团的化合物 3a-c 表现出显著的溶剂化变色现象，具有较大的斯托克斯位移，归因于它们的 D-π-A 结构和分子内电荷转移效应。特别是，带有醛基的 3a，随着溶剂极性的增加，发射带从 445nm 明显红移至 564nm。然而，带有供电子基团的化合物 3d,e 则没有明显的溶剂化变色行为。发光体 3a 表现出多晶态发光特性和结晶诱导的发射增强。
