Synthesis And Fluorescence Spectral Properties Of7-diethylamino-coumarin Derivatives

Coumarin-derived compounds, as a class of lactones with unique biologicalactivities and good photochemical and photophysical properties, have been applied invarious fields like chemistry, biology and medicine, and well concerned by domesticand foreign scholars. Coumarin fluorophores are excellent candidate fluorophores inthe design of fluorescent probes and fluorescent dyes because of their uniqueadvantages, such as excellent photostability, high fluorescence quantumyield andlarge Stokes shifts. Here, we designed and synthesized four fluorescent compoundsby coumarin with diethylamino in position7along with3-bromophenol,p-trifluoromethyl-phenol,8-hydroxyquinoline and2-thiophene methanol in position3, respectively. The details as following:1. Four7-diethylamino-coumarin compounds were designed and synthesized bythree steps: Knoevenagal reaction, alkaline hydrolysis and condensation reactions. Allcompounds obtained were characterized by1H NMR,13C NMR, and FT-IR, and thetarget compounds were also confirmed by HR MS spectra.2. Study of UV-visible spectroscopy and fluorescence spectra of the four newcompounds showed that, Stokes shift of compounds Ⅲa～Ⅲdwere relatively small,and they had stable fluorescence in a long time, and over a wide temperature and pHrange.3. The responses of Ⅲa～Ⅲdto metal ions were studied by fluorescence spectra.The results indicated that, Ⅲaand Ⅲbcouldn’t recognized any metal ions well,however, Ⅲchad both fluorescence quenching response and fluorescenceenhancement response to Cu2+, and Ⅲdshowed good selectivity to Fe3+throughfluorescence quenching. Corresponding changes in fluorescence spectra were inducedby complexes of Ⅲcwith Cu2+, and Ⅲdwith Fe3+, which provide a reliableexperimental and theoretical basis for further design and synthesis of new coumarinfluorescent probes.