Fine Chemistry and Engineering Research Institute, College of Chemistry and Chemical Engineering, Henan University, Kaifeng, 475004, People's Republic of China.
J Fluoresc. 2012 Jan;22(1):201-12. doi: 10.1007/s10895-011-0947-7. Epub 2011 Aug 9.
Five benzimidazole compounds containing pyrazole group were synthesized via one-step reaction of o-phenylenediamine and 1-arylpyrazole-4-carbaldehyde in ethanol under mild conditions. The composition and structure of resultant benzimidazole compounds were analyzed by means of elemental analysis, mass spectrometry, (1)H-nuclear magnetic resonance spectroscopy and X-ray single crystal diffraction. The ultraviolet-visible light spectra and fluorescent spectra of the products were measured. Their ground-state (S(0)) equilibrium geometries and vibrational frequencies were determined based on B3LYP method, and their first excited-state (S(1)) geometries were fully optimized based on 6-31G (d, p) basis set of TD-B3LYP method. Besides, the spectroscopic properties of the products were computed based on cc-pVTZ basis set of TD-B3LYP method and compared with corresponding experimental data. It has been found that benzimidazole compounds containing pyrazole group can be readily synthesized in a high yield via one-step reaction of o-phenylenediamine and 1-arylpyrazole-4-carbaldehyde in ethanol solvent. The fluorescence properties of the five synthesized compounds are closely related to their molecular structure; and their computed fluorescence spectra well correspond to their experimental values. Moreover, they have stable structure and strong fluorescence, showing potential application in time-resolved fluoroimmunoassay and DNA probe.
五种含吡唑基团的苯并咪唑化合物通过邻苯二胺和 1-芳基吡唑-4-甲醛在乙醇中的一步反应温和条件下合成。通过元素分析、质谱、（1）H 核磁共振波谱和 X 射线单晶衍射对所得苯并咪唑化合物的组成和结构进行了分析。测量了产物的紫外-可见光谱和荧光光谱。基于 B3LYP 方法确定了它们的基态（S(0))平衡几何形状和振动频率，并基于 TD-B3LYP 方法的 6-31G(d,p)基组对它们的第一激发态（S(1))几何形状进行了全优化。此外，基于 TD-B3LYP 方法的 cc-pVTZ 基组计算了产物的光谱性质，并与相应的实验数据进行了比较。结果表明，含吡唑基团的苯并咪唑化合物可以通过邻苯二胺和 1-芳基吡唑-4-甲醛在乙醇溶剂中的一步反应很容易以高产率合成。五种合成化合物的荧光性质与其分子结构密切相关；并且它们的计算荧光光谱与实验值很好地对应。此外，它们具有稳定的结构和较强的荧光，在时间分辨荧光免疫分析和 DNA 探针中显示出潜在的应用前景。
