Mille Marion, Lamère Jean-François, Rodrigues Fernanda, Fery-Forgues Suzanne
Université Paul Sabatier, Laboratoire des Interactions Moléculaires Réactivité Chimique et Photochimique, and CNRS UMR 5623, 31062 Toulouse cedex 9, France.
Langmuir. 2008 Mar 18;24(6):2671-9. doi: 10.1021/la702197h. Epub 2008 Feb 1.
A solvent-exchange process was applied to three fluorescent dyes belonging to the 2-benzimidazolyl-7-diethylaminocoumarin series (namely Coumarin 7 (1), Coumarin 30 (2), and one of their derivatives bearing a butyl chain (3)). The three compounds only differ by the substitution of the nitrogen atom of the benzimidazolyl group. They were first dissolved in acetone and then suddenly placed in an aqueous environment where they generated molecular assemblies. The size and shape of the latter were studied by fluorescence microscopy and transmission and scanning electron microscopy. It appeared that 1 gave aggregates and flat microcrystals that evolved toward elongated structures. 2 formed straight nanofibers that are 10-20 microm long and exhibit a crystal structure. 3 gave short fibers (1 micromx25 nm), which finally arrange into entangled solid nanofibers. The formation of fibers arising from low-molecular-weight molecules was particularly interesting. The optical properties of the free-standing particles in suspension were analyzed and compared to those of highly dilute dyes, with the aim to get additional information about the dye arrangement in the nanostructures.
一种溶剂交换过程应用于三种属于2-苯并咪唑基-7-二乙氨基香豆素系列的荧光染料（即香豆素7（1）、香豆素30（2）以及它们带有丁基链的一种衍生物（3））。这三种化合物仅在苯并咪唑基的氮原子取代上有所不同。它们首先溶解在丙酮中，然后突然置于水环境中，在那里它们形成了分子聚集体。通过荧光显微镜、透射电子显微镜和扫描电子显微镜研究了后者的尺寸和形状。结果表明，1形成聚集体和平板微晶，这些微晶向细长结构演化。2形成了长10 - 20微米且具有晶体结构的直纳米纤维。3形成短纤维（1微米×25纳米），这些短纤维最终排列成缠结的固体纳米纤维。由低分子量分子形成纤维尤其有趣。分析了悬浮中独立颗粒的光学性质，并将其与高度稀释染料的光学性质进行比较，目的是获取有关纳米结构中染料排列的更多信息。
