Abstract

A new coumarin-fused quinoline push–pull fluorescent probe was designed, synthesized and characterized using \(^{\mathrm {1}}\)H NMR,\(^{\mathrm {13}}\)C NMR and mass spectrometry analysis. Electronic absorption and fluorescence studies of the synthesized probe were investigated in wide range of solvents of varying polarities, and the data were used to study its solvatochromic properties. The ground and excited state dipole moments of fluorescent probe were obtained from Bakhshiev’s and Bilot–Kawasaki’s equations by means of the solvatochromic shift method. The high value of dipole moment for the excited state over ground-state value was attributed to more polar excited state of molecule. Also, emission peak undergoes a bathochromic shift with an increase in the polarity of the solvent, confirming \({\varvec{\pi }} \rightarrow {\varvec{\pi }}{} \mathbf * \) transition. The ground-state and excited-state dipole moments were calculated and compared using DFT calculations. Both experimental and computational studies revealed that excited-state dipole moment values are higher than corresponding ground-state value of studied compound.

Graphical Abstract

A new coumarin-fused quinoline push–pull fluorescent probe was designed, synthesized and characterized. The ground-state and excited-state dipole moments were calculated and compared using DFT calculations.

中文翻译：

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香豆素稠合喹啉的合成，溶剂变色和电偶极矩研究：实验和量子化学计算研究

摘要

使用\（^ {\ mathrm {1}} \） H NMR，\（^ {\ mathrm {13}} \）设计，合成和表征了一种新型香豆素融合的喹啉推挽式荧光探针。13 C NMR和质谱分析。在各种极性不同的溶剂中研究了合成探针的电子吸收和荧光研究，并将数据用于研究其溶剂致变色性质。荧光探针的基态和激发态偶极矩是通过溶剂变色位移法从巴赫谢夫（Bakhshiev）方程和比洛特-川崎（Bilot-Kawasaki）方程获得的。激发态的偶极矩值高于基态值，这归因于分子的极性更强的激发态。另外，发射峰会随着溶剂极性的增加而发生红移，从而确定\（{\ varvec {\ pi}} \ rightarrow {\ varvec {\ pi}} {} \ mathbf * \）过渡。计算了基态和激发态偶极矩，并使用DFT计算进行了比较。实验和计算研究均表明，激发态偶极矩值高于所研究化合物的相应基态值。

图形概要

设计，合成和表征了一种新的香豆素融合的喹啉推挽式荧光探针。计算了基态和激发态偶极矩，并使用DFT计算进行了比较。