Single-Molecule Lactonization of Octadecylrhodamine B at a Liquid鈥揕iquid Interface

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• 作者：Tomoko Matsui ; Satoshi Tsukahara ; Hitoshi Watarai
• 刊名：Langmuir
• 出版年：2012
• 出版时间：November 6, 2012
• 年：2012
• 卷：28
• 期：44
• 页码：15428-15432
• 全文大小：258K
• 年卷期：v.28,no.44(November 6, 2012)
• ISSN：1520-5827

文摘

The total internal reflection laser fluorescence microscope method was used to observe the lateral diffusion of a single octadecylrhodamine B (C₁₈RB) molecule at the toluene鈥搘ater interface. The interfacial diffusion constant of single fluorescent cation C₁₈RB⁺ was obtained from the maximum residence time in a small observation area with pH <2. For pH >3, the maximum residence time was remarkably shortened, indicating that single fluorescent zwitterion C₁₈RB^卤 rapidly converted to the nonfluorescent lactone at the interface. The lactonization rate was completed within 0.13 ms at the toluene鈥搘ater interface but slowed to 67 ms at an interface saturated with dimyristoylphosphatidylcholine.