Institute of Inorganic Chemistry, Georg-August-University Göttingen , Tammannstraße 4, 37077 Göttingen, Germany.
J Am Chem Soc. 2015 Jan 28;137(3):1060-3. doi: 10.1021/ja5130379. Epub 2015 Jan 16.
Molecular encapsulation processes under the control of an external trigger play a major role in biological signal transduction processes and enzyme catalysis. Here, we present an artificial mimic of a controllable host system that forms via self-assembly from a simple bis-monodentate ligand and Pd(II) cations. The resulting interpenetrated double cage features three consecutive pockets which initially contain one tetrafluoroborate anion, each. Activation of this host system with two halide anions triggers a conformational change that renders the central pocket susceptible to the uptake of small neutral guest molecules. Thereby, the pentacationic cage expels the central anion and replaces it with a neutral molecule to give a hexacationic species. The cage structures prior and after the halide triggered binding of benzene were examined by X-ray crystallography, ESI MS, and NMR techniques. The kinetics and thermodynamics of the encapsulation of benzene, cyclohexane, and norbornadiene are compared.
分子包封过程受外部触发的控制在生物信号转导过程和酶催化中起着重要作用。在这里，我们提出了一种可控主体系统的人工模拟，该系统通过简单的双单齿配体和 Pd(II)阳离子自组装形成。所得的互穿双笼具有三个连续的口袋，最初每个口袋中都含有一个四氟硼酸根阴离子。用两个卤化物阴离子激活这个主体系统会触发构象变化，使中心口袋易受小分子中性客体分子的进入。由此，五价阳离子笼排出中心阴离子并用中性分子取代它，得到六价阳离子物种。通过 X 射线晶体学、ESI-MS 和 NMR 技术研究了在卤化物触发苯结合前后的笼状结构。比较了苯、环己烷和降冰片二烯的包封的动力学和热力学。
