Water and hydrogen halides serve the same structural role in a series of 2+2 hydrogen-bonded dimers based on 2,6-bis(2-anilinoethynyl)pyridine sulfonamide receptors
Water and hydrogen halides serve the same structural role in a series of 2+2 hydrogen-bonded dimers based on 2,6-bis(2-anilinoethynyl)pyridine sulfonamide receptors
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DOI：
10.1002/anie.200703971
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发表时间：
2008-01-01
影响因子：
16.6
通讯作者：
Johnson, Darren W.
中科院分区：
文献类型：
--
作者：
Berryman, Orion B.;Johnson, Charles A., II;Johnson, Darren W.
水分子复杂的氢键相互作用是显著的：水在许多系统中起着至关重要的作用，从形成氢键水低聚物[1]到提高蛋白质的构象稳定性[2]，以及在酶[3]或仿生[4]活性部位形成关键的协同氢键。在许多情况下，这些氢键既决定了结构，也决定了功能。在超分子化学中，水和有机分子之间的协同氢键有助于稳定有机分子主体的花瓶状构象[5]，并诱导形成在8个水分子的帮助下缝合在一起的错综复杂的六聚体纳米胶囊。在这两种情况下，这些主体都可以在潮湿的有机或纯水溶剂中稳定下来。另一方面，阴离子往往不具有水的结构氢键多样性，部分原因是阴离子的弱碱性，而且通常是因为它们的氢键形成缺乏方向性。在自组装反应中，出现了阴离子作为导向元件的新用途。值得注意的例子包括包裹在两个硫酸盐阴离子周围的双链螺旋；[10]通过与阴离子形成氢键而形成模板的链烷和其他结构；[11]和通过阴离子连接在一起的超分子二聚体、齐聚物和聚合物。[12]在这里，我们报道了基于2，6-双(2-苯乙基)吡啶支架的新受体，这种支架出人意料地与水、卤化物或两者都形成了2+2二聚体，这取决于受体的质子化状态。据我们所知，这是第一个卤化物和水分子在合成的自组装系统中起到相同的结构氢键作用的例子。
The complex hydrogen-bonding interactions of the water molecule are remarkable: water plays a vital role in a number of systems ranging from the formation of hydrogen-bonded water oligomers [1] to the increased conformational stability of proteins [2] and the crucial synergistic hydrogen bonds formed in enzymatic [3] or biomimetic [4] active sites. In many cases these hydrogen bonds dictate both structure and function. In supramolecular chemistry, synergistic hydrogen bonding between water and organic molecules has helped to stabilize vase-like conformations of hosts for organic molecules [5] and to induce the formation of intricate hexameric nanoscale capsules stitched together with the aid of eight water molecules.[6] In both cases these hosts can be stabilized in wet organic or purely aqueous solvents.[7] Anions, on the other hand, tend not to share the structural hydrogen-bonding diversity of water, in part as a result of the weak basicity of anions and often because of a lack of directionality in their hydrogen-bond formation.[8, 9] Nevertheless, there is an emerging use of anions as directing elements in self-assembly reactions. Notable examples include a double-stranded helix wrapped around two sulfate anions;[10] catenanes and other structures templated by the formation of hydrogen bonds to anions;[11] and supramolecular dimers, oligomers, and polymers linked together by anions.[12] Herein we report new receptors based on a 2, 6-bis (2-anilinoethynyl) pyridine scaffold that surprisingly form 2+ 2 dimers with either water, halides, or both, depending on the protonation state of the receptor. To our knowledge, this is the first example of both halides and water molecules serving the same structural hydrogen-bonding role in a synthetic self-assembled system.[13]