A butterfly-shaped pyrene derivative of cholesterol and its uses as a fluorescent probe.
A butterfly-shaped pyrene derivative of cholesterol and its uses as a fluorescent probe.
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DOI：
10.1021/jp312318b
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发表时间：
2013-05
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通讯作者：
Keru Zhao;Taihong Liu;Gang Wang;Xingmao Chang;D. Xue;K. Belfield;Yu Fang
中科院分区：
文献类型：
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作者：
Keru Zhao;Taihong Liu;Gang Wang;Xingmao Chang;D. Xue;K. Belfield;Yu Fang
设计并合成了胆固醇的蝴蝶形芘衍生物N，N'-（乙烷-1,2-二基）-双(N-（2-（胆-氨基）乙基）芘-1-磺酰胺（ECPS）。溶剂效应研究表明，在正己烷、苯和1,4-二恶烷等良好溶剂中，化合物的荧光发射轮廓以芘单体发射为特征，而在水等不良溶剂中，荧光发射以芘准分子发射为主。定量地说，当ECPS溶解于水和正己烷中时，准分子发射与单体发射的比值从50变化到0。相比之下，对于常用的极性探针芘，I3/I1的比值仅在~0.6 ~ ~1.7之间变化，其中I3和I1分别表示峰3和峰1的荧光发射强度。该值表明新化合物在极性传感方面具有更强的辨别能力。此外，与该化合物的主要成分芘和胆固醇不同，它的主链由多个亲水性结构组成，正是这种结构使得该化合物在有机溶剂中的释放对水的存在很敏感。据此，评价了该化合物在某些有机溶剂中痕量水测定中的适用性。正如预期的那样，该化合物对乙腈中水的检测限达到7ppm，这是以前从未达到的结果。此外，该化合物的荧光发射对粘度变化也很敏感。因此，假设ECPS既可以用作极性探针，也可以用作粘度探针。在一系列稳态和时间分辨荧光以及动态光散射研究的基础上，提出了一个结构模型来合理化该化合物在不同溶剂中的荧光行为及其极性和粘度探测性能。
A butterfly-shaped pyrene derivative of cholesterol, namely, N,N'-(ethane-1,2-diyl)-bis(N-(2-(chol-amino)ethyl)pyrene-1-sulfonamide) (ECPS), has been designed and synthesized. Solvent effect studies revealed that in good solvents such as n-hexane, benzene, and 1,4-dioxane, the profile of the fluorescence emission of the compound is characterized by pyrene monomer emission, but in poor solvent such as water, the emission is dominated by pyrene excimer emission. Quantitatively speaking, the ratio of the excimer emission to monomer emission changes from 50 to 0 when ECPS is dissolved in water and n-hexane, respectively. In contrast, for a commonly used polarity probe pyrene, the ratio of I3/I1 varies only from ~0.6 to ~1.7, where I3 and I1 stand for the intensities of the fluorescence emission at peak 3 and peak 1, respectively. This value suggests that a more powerful discriminating ability of the new compound in polarity sensing. Furthermore, unlike the main components of the compound, pyrene and cholesterol, its main chain is composed of multiple hydrophilic structures, and it is this structure that makes the emission of the compound in organic solvents sensitive to the presence of water. Accordingly, the applicability of the compound in determination of the trace amount of water in some organic solvents was evaluated. As expected, the detection limit of the compound toward water in acetonitrile reaches 7 ppm, a result never reached before. Furthermore, the fluorescence emission of the compound is also sensitive to viscosity variation. Therefore, it is assumed that ECPS may be used both as a polarity probe and a viscosity probe. On the bases of a series of steady-state and time-resolved fluorescence, as well as dynamic light scattering studies, a structural model was proposed to rationalize the fluorescence behavior of the compound in different solvents and its polarity and viscosity probing performances.