Photocontrolled reversible release of guest molecules from coumarin-modified mesoporous silica
Photocontrolled reversible release of guest molecules from coumarin-modified mesoporous silica
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DOI：
10.1038/nature01362
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发表时间：
2003-01-23
期刊：
影响因子：
64.8
通讯作者：
Tanaka, Y
中科院分区：
文献类型：
--
作者：
Mal, NK;Fujiwara, M;Tanaka, Y
自从十多年前发现MCM-41以来，许多研究已经探索了六方介孔二氧化硅对于潜在实际应用的适用性（2-4）。这些范围从催化（5，6）和光学活性材料（7，8）到聚合科学（9-12），分离技术（3，13，14）和药物递送（15-18），最近在制造混合介孔有机二氧化硅（19-21）方面的成功有望开辟进一步的应用可能性。由于这类材料的孔隙空隙表现出直径在2-4 nm范围内的相对窄的孔径分布，因此中孔二氧化硅可以选择性地包括有机化合物并在稍后阶段连续释放它们。用光活性衍生物（22-25）官能化MCM-41孔隙提供了对材料吸收行为的影响，但对释放过程的完全控制仍然困难。在这里，我们表明，在MCM-41中的有机分子的吸收，存储和释放可以通过连接到孔出口的香豆素衍生物的光控和可逆的分子间二聚化26，27来调节。成功的功能化需要未煅烧的MCM-41仍然充满了引导其孔形成的模板分子，以确保香豆素衍生物优先附着到孔出口，而不是它们的内壁。我们发现，这种功能和一维的，孤立的性质的个别孔允许有效的和可逆的光控客人访问材料的内部。
Since the discovery(1) of MCM-41 more than ten years ago, many investigations have explored the suitability of hexagonal mesoporous silicas for potential practical applications(2-4). These range from catalysis(5,6) and optically active materials(7,8) to polymerization science(9-12), separation technology(3,13,14) and drug delivery(15-18), with recent successes in the fabrication of hybrid mesoporous organosilicas(19-21) expected to open up further application possibilities. Because the pore voids of this class of materials exhibit relatively narrow pore size distributions in the range of 2-4 nm in diameter, mesoporous silicas can selectively include organic compounds and release them continuously at a later stage. The functionalization of MCM-41 pore voids with photoactive derivatives(22-25) provides influence over the material's absorption behaviour, but full control over the release process remains difficult. Here we show that the uptake, storage and release of organic molecules in MCM-41 can be regulated through the photocontrolled and reversible intermolecular dimerization 26,27 of coumarin derivatives attached to the pore outlets. Successful functionalization requires uncalcined MCM-41 still filled with the template molecules that directed the formation of its pores, to ensure that coumarin derivatives attach preferentially to the pore outlets, rather than their inside walls. We find that this feature and the one-dimensional, isolated nature of the individual pores allow for efficient and reversible photocontrol over guest access to the material's interior.