Multivalent Crown Ether Receptors Enable Allosteric Regulation of Anion Exchange in an Fe4 L6 Tetrahedron.
Multivalent Crown Ether Receptors Enable Allosteric Regulation of Anion Exchange in an Fe4 L6 Tetrahedron.
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DOI：
10.1002/anie.201808534
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发表时间：
2018-09
影响因子：
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通讯作者：
Larissa K. S. von Krbek;D. Roberts;B. S. Pilgrim;C. Schalley;J. Nitschke
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文献类型：
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作者：
Larissa K. S. von Krbek;D. Roberts;B. S. Pilgrim;C. Schalley;J. Nitschke
我们报道了一种通过三脚架三(烷基铵)阳离子的外部配位来调节Fe4 L6金属-有机四面体内部结合阴离子交换速率的策略。笼子的每个FeII顶点都有三个灵活的18-冠-6受体，促进了与三(铵)阳离子的强烈三向相互作用，以“封顶”四面体的顶点。这种封顶机制限制了笼架的灵活性，从而将其中心空腔内的阴离子交换速度降低了20倍。因此，我们展示了首次使用外部结合的多价效应器来变构控制分子笼中的内部客体结合。
We report a strategy for regulating the rate of internally bound anion exchange within an Fe4 L6 metal-organic tetrahedron through external coordination of tripodal tris(alkylammonium) cations. The cage features three flexible 18-crown-6 receptors at each of its FeII vertices, facilitating strong tritopic interactions with tris(ammonium) cations to "cap" the vertices of the tetrahedron. This capping mechanism restricts the flexibility of the cage framework, thereby reducing the rate of anion exchange within its central cavity by 20-fold. Thus, we demonstrate the first use of an externally bound multivalent effector to allosterically control internal guest binding in a molecular cage.