An increasingly wide variety of fluorescent compounds is used in biotechnology, genomics, immunoassays, array technologies, imaging, and drug discovery. Therefore, synthesis of fluorophores with novel structural features can be interesting and useful in various fields. In this paper, four new fluorescent heterocyclic compounds with high quantum yields are introduced. These new fluorophores are synthesized in moderate to high yields via regioselective nitration of 3-alkyl-8-(4-chlorophenyl)-3 H-imidazo[4′,5′:3,4]benzo[c]isoxazoles. The latter compounds are obtained from the reaction of 1-alkyl-5-nitro-1 H-benzoimidazoles with (4-chlorophenyl)acetonitrile in basic MeOH solution. Physical spectral (UV-vis, IR, 1HNMR, 13C NMR, NOESY and fluorescence) and analytical data have established the structures of synthesized compounds. The fluorescence properties of new fluorescent heterocyclic compounds are studied. The fluorescence of all compounds is very intense and fluorescence quantum yields are high (> 0.52). Density functional theory (DFT) calculations are performed to provide the optimized geometries, relevant frontier orbitals and the prediction of 1H NMR chemical shifts for confirming the exact structure of fluorescent compounds. Calculated electronic absorption spectra were also obtained by time-dependent density functional theory (TD-DFT) method.
越来越多种类的荧光化合物被用于
生物技术、
基因组学、免疫测定、阵列技术、成像和药物发现等领域。因此,合成具有新结构特征的荧光团在各个领域都非常有趣和有用。本文介绍了四种具有高量子产率的新型荧光
杂环化合物。这些新的荧光团是通过 3-烷基-8-(4-
氯苯基)-3 H-
咪唑并[4′,5′:3,4]苯并[c]
异恶唑的区域选择性硝化以中等到高产率合成的。后一种化合物是由 1-烷基-5-硝基-1 H-
苯并咪唑与(4-
氯苯基)
乙腈在碱性 MeOH 溶液中反应得到的。物理光谱(紫外-可见光、红外、1HNMR、13C NMR、NOESY 和荧光)和分析数据确定了合成化合物的结构。研究了新荧光
杂环化合物的荧光特性。所有化合物的荧光都非常强烈,荧光量子产率也很高(0.52)。密度泛函理论(DFT)计算提供了优化的几何结构、相关的前沿轨道和 1H NMR
化学位移预测,以确认荧光化合物的确切结构。此外,还通过时间相关密度泛函理论(TD-DFT)方法获得了电子吸收光谱。