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首页> 外文期刊>Chemistry: A European journal >Dynamic equilibrium between a supramolecular capsule and bowl generated by inter- and intramolecular metal clipping
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Dynamic equilibrium between a supramolecular capsule and bowl generated by inter- and intramolecular metal clipping

机译：分子间和分子内金属夹持产生超分子囊与碗之间的动态平衡

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摘要

The metal-induced self-assembly of a resorcin[4]arene derivative 1 that has four pyridine units as pendent groups and two equivalents of [M(dppp)(OTf)(2)] (M=Pd, Pt) results in a dynamic equilibrium between an interclipped supramolecular capsule 3 and an intraclipped bowl 4 in nitromethane, although the interclipped capsule 3 is formed as a sole adduct in chloroform/methanol and the intraclipped bowl 4 is formed exclusively in an aqueous phase. This demonstrates how metal-induced self-assembly can be tuned by subtle changes in the solvent system. The coexistence of the two structures in nitromethane was characterized by NMR spectroscopy and coldspray ionization mass spectrometry (CSI-MS). The crystal structure of the interclipped capsule 3b, which is composed of two units of ligand 1 and four Pt-II ions, reveals the capsule cavity to have nanoscale dimensions of 15 x 20 Angstrom. NMR spectra show that the dynamic equilibrium between 3 and 4 is dependent on concentration and temperature. Temperature-dependent H-1 NMR spectroscopy was carried out from 273 to 343 K to verify the thermodynamic parameters that control the dynamic equilibrium process; the conversion from the interclipped supramolecular capsule 3a to the intraclipped bowl 4a is entropically favored and enthalpically disfavored. The rotational barrier of the restricted rotation of pyridine units in the intraclipped bowl 4 was determined by line-shape analysis.
机译：具有四个悬垂基团和两个当量[M（dppp）（OTf）（2）]（M = Pd，Pt）的间苯二酚[4]芳烃衍生物1的金属诱导自组装导致尽管夹层胶囊3在氯仿/甲醇中形成为唯一的加合物，而夹层碗4仅在水相中形成，但是夹层的超分子胶囊3和夹层碗4之间在硝基甲烷中具有动态平衡。这表明如何通过溶剂系统中的细微变化来调节金属诱导的自组装。通过NMR光谱和冷喷雾电离质谱（CSI-MS）表征了硝基甲烷中两种结构的共存。由两个单元的配体1和四个Pt-II离子组成的交错的胶囊3b的晶体结构揭示了胶囊腔具有15 x 20埃的纳米级尺寸。 NMR谱显示3和4之间的动态平衡取决于浓度和温度。在273至343 K范围内进行了温度依赖性H-1 NMR光谱分析，以验证控制动态平衡过程的热力学参数。从夹杂的超分子胶囊3a到夹杂的碗4a的转化在熵上是有利的，在焓上是不利的。通过线形分析确定内夹钳碗4中吡啶单元的受限旋转的旋转屏障。

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