On the microenvironments surrounding dansyl sequestered within class I and II xerogels
On the microenvironments surrounding dansyl sequestered within class I and II xerogels
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DOI：
10.1021/cm000580z
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发表时间：
2000-12-01
影响因子：
8.6
通讯作者：
Bright, FV
中科院分区：
文献类型：
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作者：
Pandey, S;Baker, GA;Bright, FV
我们报告了丹磺酰螯合在两种干凝胶中的静态和时间分辨荧光光谱，这两种干凝胶是由四乙基原硅烷（TEOS）与 ppm 水平的丹磺酰胺或丹磺酰三乙氧基硅烷混合形成的。它们分别被称为 I 类和 II 类干凝胶。在一年的时间内，对这些样品从液体转变为干凝胶进行了实验。结果表明，I 类和 II 类干凝胶中丹磺酰掺杂剂周围的平均局部微环境是不同的。具体来说，尽管随着两个样品从液体发展到干凝胶，丹磺酰掺杂剂周围的偶极性增加，但与 I 类干凝胶相比，II 类干凝胶内的局部丹磺酰微环境总是更加异质。在老化的干凝胶中，I类干凝胶中丹磺酰掺杂剂周围的局部偶极性大于II类干凝胶。这些结果根据一个模型进行了讨论，该模型的丹酰基分别优先位于 I 类和 II 类干凝胶的 Si-OH 和 SiO2 富集区域内。
We report on the static and time-resolved fluorescence spectroscopy of dansyl sequestered within two xerogels that were formed from tetraethylorthosilane (TEOS) mixed with ppm levels of dansylamide or dansyltriethoxysilane. These are referred to as class I and II xerogels, respectively. Experiments were performed on these samples as they progressed from liquids to xerogels over a period of 1 year. The results show that the average local microenvironment surrounding the dansyl dopant is different in the class I and II xerogels. Specifically, even though the dipolarity surrounding the dansyl dopant increases as both samples progress from liquids to xerogels, the local dansyl microenvironment within a class II xerogel is always more heterogeneous in comparison to the class I xerogel. In an aged xerogel, the local dipolarity surrounding the dansyl dopant is greater for the class I xerogel than for the class II xerogel. These results are discussed in terms of a model that has the dansyl locating preferentially within Si-OH- and SiO2-rich regions for the class I and II xerogels, respectively.