Evaluating Host−Guest Interactions in a Metal−Organic Framework Using a Polarity-Sensitive Probe
Evaluating Host−Guest Interactions in a Metal−Organic Framework Using a Polarity-Sensitive Probe
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DOI：
10.1021/jz100243u
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发表时间：
2010-03
影响因子：
5.7
通讯作者：
Jungkweon Choi;T. Tachikawa;M. Fujitsuka;T. Majima
中科院分区：
文献类型：
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作者：
Jungkweon Choi;T. Tachikawa;M. Fujitsuka;T. Majima
报道了利用单分子、单粒子荧光光谱技术，在金属−有机骨架(MOF)中原位观察了极性敏感荧光染料4-二甲氨基-4‘-硝基二苯乙烯(DNS)的分子相互作用和光动力学。虽然吸附在MOF-177颗粒表面的DNS分子的荧光强度表现出强烈的溶剂极性依赖于外部溶剂交换，但当溶剂从甲苯切换到氯仿时，包裹在定义良好的MOF-177颗粒内部的分子的荧光强度略有变化。此外，通过掺入到MOF宿主中，DNS分子的光稳定性显著提高。这些观察结果强烈表明，包裹在MOF中的客体分子应该受到保护，不受外部溶剂和气体分子的影响。并用概率密度的方法观察和分析了包裹的单分子的光闪烁行为。
We report in situ observations of molecular interactions and photodynamics for the polarity-sensitive fluorescence dye 4-dimethylamino-4′-nitrostilbene (DNS) when encapsulated inside of metal−organic frameworks (MOFs) by utilizing single-molecule, single-particle fluorescence spectroscopy. While the fluorescence intensity from DNS molecules adsorbed onto the surface of MOF-177 particles exhibited a strong solvent polarity dependence toward external solvent exchanges, the intensity from molecules encapsulated inside of well-defined MOF-177 particles slightly changed when the solvent was switched from toluene to chloroform. Furthermore, the photostability of the DNS molecules was significantly enhanced by incorporation into the MOF host. These observations strongly suggest that guest molecules encapsulated in MOFs should be protected from external solvent and gas molecules. The photoblinking behavior of encapsulated single DNS molecules was also observed and analyzed in terms of the probability density.