Fluorescent organogels as templates for sol–gel transcription toward creation of optical nanofibers
Fluorescent organogels as templates for sol–gel transcription toward creation of optical nanofibers
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DOI：
10.1039/b501067e
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发表时间：
2005-07
影响因子：
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通讯作者：
K. Sugiyasu;Norifumi Fujita;S. Shinkai
中科院分区：
文献类型：
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作者：
K. Sugiyasu;Norifumi Fujita;S. Shinkai
合成了1，10-邻菲咯啉胆固醇基凝胶因子（1和2）及其非凝胶对照化合物（1′和2′）。结果表明，1和2的凝胶化能力是相当不同的，尽管它们的结构相似。化合物1可以与各种有机溶剂形成凝胶，而化合物2仅能够在酸性溶剂中凝胶化。凝胶化能力的这种差异似乎是由于菲咯啉部分的堆叠模式的差异，如CD光谱所证实的。TEM和AFM观察表明，纤维状聚集体缠结在一个三维的网络结构。凝胶还显示出美丽的荧光，其分子结构和凝胶化条件（在存在和不存在酸的情况下）的特征。因此，其特征在于，有机组件进行作为模板的金属醇盐，如正硅酸乙酯（TEOS）和钛酸四正丁酯的溶胶-凝胶缩聚。所得有机-无机复合材料显示出与有机凝胶相同的荧光性质。煅烧后，通过TEM观察发现，二氧化硅和二氧化钛材料具有中空结构，表明溶胶-凝胶缩聚反应在有机组装体的表面选择性地进行。的CD光谱的有机-无机复合物是类似的有机凝胶，表明聚集堆积模式的原始菲咯啉部分仍然保留，即使在硅胶相。所得到的有机-无机杂化物有望导致各种纳米结构的光电器件。
1,10-Phenanthroline-appended cholesterol-based gelators (1 and 2) and their non-gelling reference compounds (1′ and 2′) were synthesized. It was shown that the gelation abilities of 1 and 2 are quite different, in spite of their structural similarity. Compound 1 can form gels with various kinds of organic solvents, whereas 2 is capable of gelation only in acidic solvents. This difference in gelation abilities seems to be due to the difference in the stacking mode of the phenanthroline moieties, as confirmed by CD spectra. TEM and AFM observations showed that fibrillar aggregates are entangled in a three-dimensional network structure. The gels also showed beautiful fluorescence, characteristic of their molecular structures and gelation conditions (in the presence and the absence of acid). Organic assemblies thus characterized were subjected as templates for sol–gel polycondensation of metal alkoxide such as tetraethyl orthosilicate (TEOS) and tetra-n-butyl titanate. The resultant organic–inorganic composite materials showed the same fluorescence properties as the organic gels. After calcination, it was revealed by TEM observation that the silica and titania materials have a hollow structure, indicating that the sol–gel polycondensation reaction proceeds selectively at the surface of the organic assemblies. The CD spectrum of the organic–inorganic composite was similar to that of the organogel, indicating that the aggregation stacking mode of the original phenanthroline moieties is still retained even in the silica-gel phase. The organic–inorganic hybrids obtained are expected to lead to various nanostructured optoelectronic devices.