New Coumarin Mannich Bases Fluorescent Synthesis And Fluorescence Properties Of Functional Molecules

Fluorescence analysis, as a kind of the visual research method, could be used to analyze quantitatively and qualitatively for a target. It has many advantages in varies aspects such as high sensitivity, high selectivity, real-time in-situ test, wide linear range optional parameters and so on. Recently, it has been widely applied in many areas including Physiology, Pharmacology, molecular biology and information science. It has already become an important tool for scientists to study microscopic life activities and explore the world. Complete fluorescent signal system generally consists of three parts:identify group, fluorescence group and connection group, wherein, the study of the fluorophores which are the signal corresponding portions has been a hotpot in the last few years. Fluorophore could be defined as coumarin, fluorescein, naphthamide, rhodamine, cyanine and BODIPY, and the coumarin-based fluorescent probe has gradually become a kind of novel research subject in recent years.As an important class of organic heterocyclic dyes, coumarin (2H-1-benzopyran-2-one) and its derivatives can be found in many natural or synthetic drug molecules and possess versatile bioactivities, such as ani-HIV, anticoagulant, antibacterial, anticancer, anthelminthic, anti-inflammatory and antioxidant activities. Moreover, coumarins which have been modified by introducing electron-donor group at6-and7-position and electron-withdrawing group at3-and4-position have outstanding optical properties including high fluorescence quantum yield, large Stokes shift, excellent photostability and good solubility in common solvents. In view of these excellent photochemical and photophysical properties, the coumarins are extensively studied, and often used as biological and chemical sensors, fluorescent probes, nonlinear optical chromophores, and laser dyes. For these advantages motioned above, there remain some interests in the molecular design and synthesis of novel coumarin derivatives with excellent optical properties and greater stability.In this paper, we have designed and synthesized twelve novel coumarin-based Mannich base functional molecules and studied the fluorescent properties.(1) The synthesis of novel coumarin-based Mannich base functional molecules:Taking4-halo resorcinol as primary material, coumarin-based Mannich bases were synthesized in three steps by means of formylation, Knoevenagel condensation and Mannich reaction, and all the structures of the compounds were confirmed by IR,1H NMR, MS and EA.(2) We have studied the fluorescent properties of the novel coumarin-based Mannich base functional molecules:correlation between quencher HOMO level and fluorescence intensity; the influence of heavy atom effect; conformational analysis; correlation between conformation and fluorescence; the influence of different pH to the fluorescence intensity.