水溶性萘酰亚胺类荧光探针对Fe^(3+)和Cr_(2)O_(7)^(2-)的特异性检测

A Water-Soluble Naphthalimide-Based Fluorescent Probe for Specific Sensing of Fe^(3+) and Cr_(2)O_(7)^(2-)

合成了一种能选择性识别Fe^(3+)和Cr_(2)O_(7)^(2-)的探针N-(2-(2-(2-羟基乙氧基)乙基)-1,3-二氧基-2,3-二氢-1H-苯并[de]异喹啉-6-基)呋喃-2-甲酰胺(1),这是首个基于萘酰亚胺检测Cr_(2)O_(7)^(2-)的小分子探针.pH滴定表明,分子内电荷转移(intramolecular charge transfer,ICT)效应增强引起的光谱红移是酰胺负离子形成的结果,还研究了探针1在CH_(3)CN/N-2-羟乙基哌嗪-N'-2-乙磺酸(HEPES)缓冲溶液中对Fe^(3+)和Cr_(2)O_(7)^(2-)的选择性、浓度滴定、时间依赖性、猝灭常数、检测限和识别机理等.研究表明,Fe^(3+)和Cr_(2)O_(7)^(2-)通过内滤效应(IFE)快速猝灭探针1的荧光,猝灭在30 s后恒定,猝灭常数分别为6.14×103和6.55×103 L•mol^(-1);探针1对Fe^(3+)和Cr_(2)O_(7)^(2-)的检测限分别为1.62和1.56μmol/L;水样中Fe^(3+)和Cr_(2)O_(7)^(2-)的测定结果表明,探针1可以作为一种在实际应用中的潜在检测工具.

N-(2-(2-(2-Hydroxyethoxy)ethyl)-1,3-dioxo-2,3-dihydro-1H-benzo[de]isoquinolin-6-yl)furan-2-carboxamide(1)that can selectively recognize Fe^(3+)and Cr_(2)O^(2-)_(7) was synthesized,which was the first small molecule probe based on naphthalimide to detect Cr_(2)O^(2-)_(7).The pH titration showed that the spectral red shift caused by the enhancement of intramolecular charge transfer(ICT)effect was as a result of formation of amide anion.Besides,the selectivity,concentration titration,time dependence,quenching constant,detection limit and recognition mechanism of probe 1 to Fe^(3+)and Cr_(2)O^(2-)_(7) were also studied in CH3CN/N-2-hydroxyethylpiperazine-N'-2-ethanesulfonic acid(HEPES)buffer solution.The results showed that Fe^(3+)and Cr_(2)O^(2-)_(7) could rapidly quenched the fluorescence of probe 1 through the inner filter effect.The quenching effects remained constant after 30 s,and the quenching constants were 6.14×103 and 6.55×103 L•mol–1,respectively.The detection limits of probe 1 for Fe^(3+)and Cr_(2)O^(2-)_(7) were 1.62 and 1.56μmol/L,respectively.The determination of Fe^(3+)and Cr_(2)O^(2-)_(7) in water samples made it clear that probe 1 could be used as a potential detection tool in practical application.