Design,Synthesis And Recognition Performance Of Probes For Fe(?) Ion Based On Coumarin-Quinoline

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,easy operation and real time monitoring.Iron is the most abundant transition metal element and an essential trace element in the human body.In this thesis,the fluorescent probes based on coumarin-quinoline were designed and deeply studied for metal ions recognition.Two fluorescent probes A1-A2 have been developed via integrating coumarin with8-hydroxylquinoline by hydrazide,the A1 is named 2-oxo-N'-?2-?quinolin-8-yloxy?acetyl?-2H-chromene-3-carbohydrazide and the A2 is named 7-?diethylamino?-2-oxo-N'-?2-?quinolin-8-yloxy?acetyl?-2H-chromene-3-carbohydrazide.The probe A1 selectively responded to Fe³⁺in the mixture of solution CH₃CN/H₂O?1:9,v/v?.Fluorescence studies showed that fluorescent emission peak red shifts 64 nm with fluorescent intensity enhancing 3.6-fold in the presence of 10 equiv.of Fe³⁺.Job's plot analysis indicated a 1:1 binding stoichiometry between the probe A1 and Fe³⁺.Fluorescence titration curve demonstrated the detection limit on fluorescence response of the probe A1 to Fe³⁺was down to 1.22×10^-7 M.The association constant Ka was 7.33×10⁴ M^-1.In this study,two novel probes B1-B2 composed of coumarin and quinoline linked by1,2,3-triazole were designed and synthesized,the B1 is named N-?2-oxo-2H-chromen-3-yl?-2-?4-??quinolin-8-yloxy?methyl?-1H-1,2,3-triazol-1-yl?acetamide and the B2 is named N-?6-?diethylamino?-2-oxo-2H-chromen-3-yl?-2-?4-??quinolin-8-yloxy?methyl?-1H-1,2,3-triaz ol-1-yl?acetamide.The probe B1 selectively responded to Fe³⁺in CH₃CN/H₂O?2:8,v/v?.Fluorescence studies showed that fluorescent intensity quenching 84.62%at 391 nm,fluorescent intensity enhancing 2.08-fold with fluorescent emission peak red shifts 15 nm at470 nm in the presence of 10 equiv.of Fe³⁺.The solution color under illumination with a UV lamp changed from blue to yellow green.Job's plot indicated the formation of 1:1 complex between B1 and Fe³⁺.Fluorescence titration curve demonstrated the detection limit on fluorescence response of the probe to Fe³⁺was down to 2.75×10^-7 M.The association constant Ka was 1.74×10⁴ M^-1.