Construction of supramolecular system toward the investigation of biological events

以主客体复合物形成为基础的分子识别是一个基本的化学过程。酶、抗体、受体和载体都使用分子识别事件。为了理解和模拟分子识别过程，主客体化学起着非常重要的作用，简化的人工受体有助于在分子水平上理解结合的性质。我们已经成功地合成了几种人工受体，用于结合非极性有机客体，如富勒烯和几种杂环。杯芳烃作为空穴载体。结果表明，杯[5]芳烃是富勒烯的有效受体，通过共价键或非共价键连接两个受体单元，可使富勒烯与杯[5]芳烃发生强结合。富勒烯的吸收和释放都可以使用具有脲官能团的自组装杯芳烃主体在有机介质中用或不用质子酸容易地控制。我们还合成了几种具有极性官能团的杯芳烃主体，考察了氢键和其他非定向力（货车del Waals和CH-π相互作用等）对极性客体（如环脲和二酮哌嗪）有效结合的协同作用。通过分子动力学模拟和核磁共振化学位移模拟分析了束缚客体的运动自由度。为了研究平面客体在有机介质中的电荷转移型相互作用，还合成了分子钳型主体。在超分子配合物中观察到了给体-受体-给体和给体-受体-受体三明治结构。

Molecular recognition based on the formation of host-guest complex is a fundamental chemical process. Enzymes, antibodies, receptors, and carriers all use the molecular recognition events. For the purpose of understanding and mimicking molecular recognition processes, host-guest chemistry playing a very important roll and simplified artificial receptors are useful to understand the nature of the binding on a molecular level. We have succeeded in synthesizing several artificial receptors for binding apolar organic guests such as fullerenes and several heterocycles. Calixarenes were employed as the cavity carrying unit. It was found that the calix[5]arene is a useful receptor for fullerene and connecting the two units of the receptor by covalent or non-covalent bonds resulted in the strong binding of the fullerenes. Both the uptake and release of the fullerene can be easily controlled with or without the protic acid in organic media using a self-assembling calixarene host having urea functionality. Several calixarene hosts having polar functionalities were also synthesized to examine the cooperative role of the hydrogen bonding and other non-directional forces (van del Waals and CH-π interactions and so on) for the effective binding of the polar guest such as cyclic ureas and diketopiperazines. The freedom of movement of the bound guests was analyzed by both the molecular dynamic simulation and nmr chemical shift simulation procedure. Molecular tweezers type hosts were also synthesized in order to study the effective binding the planar guests with charge transfer type interaction in organic media. Both donor-acceptor-donor and donor-acceptor-acceptor sandwich type layered arrangements were observed in the supramolecular complexes.