可区别铁离子荧光探针异构体的合成及其水样分析

Synthesis of Isomers of Distinguishable Iron(Ⅲ) Fluorescent Probes and Application in Water Samples

分别以2-(2-氨基苯基)菲并咪唑和2-(3-氨基苯基)菲并咪唑为原料,与5-硝基水杨醛反应合成了两个菲并咪唑-苯酚异构体衍生物(PI-o-OH和PI-m-OH)。在水相体系中(V(DMF)∶V(HEPES)=1∶1,pH=7.4),两个异构体发射中等强度的荧光。Fe^(3+)存在下,两个异构体的荧光强度分别淬灭为原来的1/3和1/6,淬灭常数为4.8×10^(3)和4.6×10^(3)L/mol,且淬灭效果不受其它干扰离子和pH值变化的影响。间位异构体PI-m-OH与Fe^(3+)的荧光识别在2 min之内完成,配合速度明显优于邻位基异构体,且配合稳定性高于邻位异构体,配合常数为3.82×10^(3)L/mol。通过高分辨质谱和Job’s曲线,确定了两个异构体与Fe^(3+)识别配合比为1∶1,并建议了PI-m-OH-Fe^(3+)and PI-o-OH-Fe^(3+)两个配合物的结构。两个异构体均可实现实际水样中Fe^(3+)的定量检测,表明它们在实际水样的Fe^(3+)分析中具有一定的应用价值。

Two isomeric phenanthro[9,10-d]imidazole-phenol derivatives(PI-o-OH and PI-m-OH)were synthesized by the reaction of isomeric 2-aminophenyl and 3-aminophenyl phenanthro[9,10-d]imidazole and 5-nitro salicylaldehyde. In the aqueous medium(V(DMF)∶V(HEPES)= 1∶1,pH = 7. 4),fluorescent intensities for two isomers were observed and the fluorescence was quenched by the addition of Fe^(3+)with the quenching ratio of 1/3 and 1/6. The quenching effects are not disturbed by other metal ions and pH value with the quenching constants K;of 4. 8×10~3 L/mol and 4. 6×10~3 L/mol,respectively. Specially,PI-m-OH has the ability to respond to Fe^(3+)within 2 min,which is much quicker than that of PI-o-OH. Furthermore,the coordination constant K;between PI-m-OH and Fe^(3+)is 3. 82×10~4 L/mol and higher than that of PI-o-OH,which means that PI-m-OH has better stabilities of coordination with Fe^(3+). The complexation ratio between two compounds and Fe^(3+)is determined by HRMS and Job’s curves, based on which the structures for PI-m-OH-Fe^(3+)and PI-o-OH-Fe^(3+)are proposed. Besides,both isomeric probes could quantitatively detect the concentration of Fe^(3+)in real water sample by the fluorescence method,indicating that they have potential application in analyzing Fe^(3+).