Design, Synthesis And Recognition Performance Of Probes For Metal Ions Based On Coumarin

Selective recognition and detection of some metal ions in biological or environmental systems are of importance due to their board applications in the areas of life sciences, environmental science and medicine. The fluorescent probes are widely used for the detection of metal ions because they are highly sensitive, selective and easy too perate. In this thesis, the coumarin-based fluorescent acceptors were designed and deeply studied for several metal ions recognition.Three Fe³⁺ fluorescent probes A1-A3 with the amide bond linker at C-3 position of coumarin bearing different length of phenyl thiourea were developed. The probes exhibit high selectivity and anti-disturbance for Fe³⁺ in presence of other common metal ions by the experiment of metal ion titration. The fluorescence quenching effect for 7-?diethylamino?-2-oxo-N-?6-?3-phenylthioureido?hexyl?-2H-chromene-3-carboxamide?A3? to Fe³⁺?99.2 %? was observed.Metal ion probes B1-B4 bearing the thiourea group at C-3 position of coumarin were designed and synthesized later. In acetonitrile, the probes 1-?2-oxo-2H-chromen-3-yl?-3-phenylthiourea?B1? and 1-?7-hydroxy-2-oxo-2H-chromen-3-yl?-3-phenylthio-urea?B2? have certain selectivity to Mg²⁺ over other coexistent metal ions with blue-shift. Probes N-??2-oxo-2H-chromen-3-yl?carbamothioyl?benzamide?B3? and N-??7-hydroxy-2-oxo-2Hchromen-3-yl?carbamothioyl?benzamide?B4? with phenyl thiourea show selective fluorescence enhancement with Ag⁺ in acetonitrile.We also introduced the pyridine group as the recognition group at C-3 position of the coumarin. Considering the influences of coordination number of metal ion and spatial factor, we developed the probes C1-C5 with "single" and "double" pyridine, which can selectively identify Fe³⁺ in EtOH/HEPES?v/v = 1:1?. The recognition effect of 3-?bis?pyridin-2-ylmethyl? amino?-7- hydroxy-2H-chromen-2-one?C3? displayed excellent selectivity for Zn²⁺ and Fe³⁺ over a number of metal ions in acetonitrile and EtOH/HEPES?v/v = 1:1?.