摘要/Abstract

自由基既是新型功能材料的构筑基元，也是常见的反应中间体.调控自由基的活性，具有重要的理论意义和应用价值.为此，我们提出了"超分子自由基"的概念，系指通过非共价作用稳定或活化的自由基.基于葫芦脲的主客体化学，构筑了不同结构的超分子自由基，借助葫芦脲分子的结构特征，从三个方面对自由基的活性进行调控：（1）利用葫芦脲的空间位阻效应和静电效应，稳定自由基阴离子，从而构筑了新型有机近红外光热转换材料，并应用于选择性抗菌；（2）利用葫芦脲的静电效应，活化自由基阳离子，实现了对芬顿氧化反应的显著加速；（3）利用葫芦脲主客体化学的动态可逆性，实现了对反应中间体活性的自适应调控，从而显著地提升了醇氧化反应的催化效率.上述研究表明，构筑简便、活性可调的超分子自由基在功能材料和超分子催化领域具有广阔的应用潜力，未来有望得到进一步的发展.
关键词: 超分子自由基, 葫芦脲, 主客体相互作用, 近红外光热转换, 超分子催化
Modulating the activity of radicals is of great importance for the applications in radical-based materials and radical-mediated reactions. To this end, we have proposed a new concept of "supramolecular free radicals", which refers to the free radicals stabilized or activated through supramolecular approaches. Based on the host-guest chemistry of cucurbiturils (CB), we have fabricated three kinds of supramolecular free radicals to modulate the activity and realize diverse functions. Firstly, radical anions can be stabilized by the steric effect and electrostatic effect of CB. As a result, we have constructed a highly efficient near-infrared photothermal conversion system, which displays selective antibacterial performance. Secondly, owing to the electrostatic effect of CB, radical cations can be activated to induce a significant acceleration of Fenton oxidation reaction. Thirdly, by taking advantage of the dynamic nature of host-guest interactions, we can endow the reaction intermediate with adaptive reactivity, which greatly improves the catalytic efficiency of alcohol oxidation. It is highly anticipated that this series of research opens a new horizon in supramolecular materials and supramolecular catalysis.
Key words: supramolecular free radicals, cucurbiturils, host-guest interactions, near-infrared photothermal conversion, supramolecular catalysis


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