Blesic Marijana, Lopes António, Melo Eurico, Petrovski Zeljko, Plechkova Natalia V, Canongia Lopes José N, Seddon Kenneth R, Rebelo Luís Paulo N
Instituto de Tecnologia Quimica e Biologica, ITQB 2, Universidade Nova de Lisboa, Apartado 127, 2780-901 Oeiras, Portugal.
J Phys Chem B. 2008 Jul 24;112(29):8645-50. doi: 10.1021/jp802179j. Epub 2008 Jul 1.
The aggregation behavior in aqueous solution of a number of ionic liquids was investigated at ambient conditions by using three techniques: fluorescence, interfacial tension, and (1)H NMR spectroscopy. For the first time, the fluorescence quenching effect has been used for the determination of critical micelle concentrations. This study focuses on the following ionic liquids: [Cnmpy]Cl (1-alkyl-3-methylpyridinium chlorides) with different linear alkyl chain lengths (n=4, 10, 12, 14, 16, or 18), [C12mpip]Br (1-dodecyl-1-methylpiperidinium bromide), [C12mpy]Br (1-dodecyl-3-methylpyridinium bromide), and [C12mpyrr]Br (1-dodecyl-1-methylpyrrolidinium bromide). Both the influence of the alkyl side-chain length and the type of ring in the cation (head) on the CMC were investigated. A comparison of the self-aggregation behavior of ionic liquids based on 1-alkyl-3-methylpyridinium and 1-alkyl-3-methylpyridinium cations is provided. It was observed that 1-alkyl-3-methylpyridinium ionic liquids could be used as quenchers for some fluorescence probes (fluorophores). As a consequence, a simple and convenient method to probe early evidence of aggregate formation was established.
在环境条件下，通过荧光、界面张力和¹H NMR光谱这三种技术，研究了多种离子液体在水溶液中的聚集行为。首次将荧光猝灭效应用于临界胶束浓度的测定。本研究聚焦于以下离子液体：具有不同线性烷基链长度（n = 4、10、12、14、16或18）的[Cnmpy]Cl（1-烷基-3-甲基吡啶鎓氯化物）、[C12mpip]Br（1-十二烷基-1-甲基哌啶鎓溴化物）、[C12mpy]Br（1-十二烷基-3-甲基吡啶鎓溴化物）和[C12mpyrr]Br（1-十二烷基-1-甲基吡咯烷鎓溴化物）。研究了阳离子（头部）中烷基侧链长度和环类型对临界胶束浓度的影响。提供了基于1-烷基-3-甲基吡啶鎓和1-烷基-3-甲基吡啶鎓阳离子的离子液体自聚集行为的比较。观察到1-烷基-3-甲基吡啶鎓离子液体可用作某些荧光探针（荧光团）的猝灭剂。因此，建立了一种简单方便的方法来探测聚集体形成的早期证据。
