Department of Experimental Physics, Taras Shevchenko National University of Kyiv, 01601 Kyiv, Ukraine.
Institute of Physics, National Academy of Sciences of Ukraine, 03028 Kyiv, Ukraine.
Int J Mol Sci. 2021 May 25;22(11):5592. doi: 10.3390/ijms22115592.
The electronic nature of 4-hydroxy-1H-pyrrolo[3,4-c]pyridine-1,3,6(2H,5H)-trione (HPPT) was comprehensively investigated in liquid media at room temperature using steady-state and time-resolved femtosecond transient absorption spectroscopic techniques. The analysis of the linear photophysical and photochemical parameters of HPPT, including steady-state absorption, fluorescence and excitation anisotropy spectra, along with the lifetimes of fluorescence emission and photodecomposition quantum yields, revealed the nature of its large Stokes shift, specific changes in the permanent dipole moments under electronic excitation, weak dipole transitions with partially anisotropic character, and high photostability. Transient absorption spectra of HPPT were obtained with femtosecond resolution and no characteristic solvate relaxation processes in protic (methanol) solvent were revealed. Efficient light amplification (gain) was observed in the fluorescence spectral range of HPPT, but no super-luminescence and lasing phenomena were detected. The electronic structure of HPPT was also analyzed with quantum-chemical calculations using a DFT/B3LYP method and good agreement with experimental data was shown. The development and investigation of new pyrrolo[3,4-c]pyridine derivatives are important due to their promising fluorescent properties and potential for use in physiological applications.
4-羟基-1H-吡咯并[3,4-c]吡啶-1,3,6(2H,5H)-三酮（HPPT）在室温下的液体介质中的电子性质使用稳态和时间分辨飞秒瞬态吸收光谱技术进行了全面研究。分析 HPPT 的线性光物理和光化学参数，包括稳态吸收、荧光和激发各向异性光谱，以及荧光发射和光分解量子产率的寿命，揭示了其大斯托克斯位移、电子激发下永久偶极矩的特定变化、具有部分各向异性特征的弱偶极跃迁以及高光稳定性的性质。使用飞秒分辨率获得了 HPPT 的瞬态吸收光谱，并且在质子性（甲醇）溶剂中没有揭示出特征溶剂化松弛过程。在 HPPT 的荧光光谱范围内观察到有效的光放大（增益），但没有检测到超发光和激光现象。还使用 DFT/B3LYP 方法进行了量子化学计算来分析 HPPT 的电子结构，并显示出与实验数据的良好一致性。开发和研究新的吡咯并[3,4-c]吡啶衍生物很重要，因为它们具有有前途的荧光性质，并且有可能用于生理应用。
