基于三苯胺-罗丹明染料荧光探针对pH和Cu^2+的选择性识别

基于罗丹明B酰肼和三苯胺染料合成了pH和Cu^2+双识别分子探针(RTPA),并利用核磁氢谱、核磁碳谱和高分辨质谱表征了RTPA的分子结构。通过紫外-可见光谱法和荧光光谱法研究了该荧光分子探针在极性不同的有机溶剂中的光谱性能以及在THF/H2O(V:V=1:1)溶液中对Cu^2+和质子的选择性识别性能。结果表明:随着溶剂的极性增大,化合物RTPA的最大发射波长发生红移,从419 nm红移到500 nm。该探针在水溶液中可以实现高选择性识别Cu^2+离子,不受其他常见金属离子的竞争性干扰。通过Job’s plot曲线证明了探针RTPA识别Cu^2+的化学计量比是1:1,Cu^2+的检出限为0.635μmol/L。当pH在1.87~4.48区间内,探针的荧光强度与pH呈良好的线性关系,线性相关系数为0.9957,其pKa为3.13。探针RTPA也可用于极酸性条件下(pH<4)质子浓度的定量检测。

Selective recognition of a fluorescence probe for pH and Cu^2+based on triphenylamine-rhodamine dyes

Based on rhodamine B hydrazide and triphenylamine dyes,a dual recognition molecular probe(RTPA)for pH and Cu^2+was synthesized.Its structure was characterized by1 H NMR,13 C NMR and high resolution mass spectrometer(HRMS).The absorption and fluorescence properties of this probe were investigated in various organic solvents,and the recognition of this probe for Cu^2+and H^+in THF/H2 O solution(V:V=1:1)were studied by UV-Vis and fluorescence spectrometry.The test results indicated that fluorescence spectra of compound RTPA were red shifted along with the increase of solvent polarity from 419 nm to 500 nm.The probe RTPA had good selectivity for Cu^2+in aqueous solution.The 1:1 complexation stoichiometry between Cu^2+ion and probe RTPA was confirmed by a Job’s plot.The detection limit of Cu^2+was 6.35×10-7 mol/L.When the pH was between 1.87 and 4.48,the fluorescence intensity of the probe showed a good linear relationship with the pH,and the linear correlation coefficient was 0.9957.Its acidity constant(p Ka)was 3.13 determined by fluorescence titration as a function of pH.The probe RTPA can be used for the quantitative detection of proton concentration under extremely acidic conditions(pH<4).