Enantio-selective transportation of natural small chiral molecules via discrete access-controllable nanotubes based on pillararene

具有手性的亲水性天然分子通过人工通道进行选择性运输具有重要意义。然而，由于复杂的分子设计和长期的低效率，这项工作具有挑战性。为了实现这一目标，构建具有手性信息的通道是首要任务。利用柱状[n]芳烃具有可控的平面手性，我们首先在一个边缘上带有立体中心，另一个边缘上带有苯甲酸的边缘分化柱状[n]芳烃。柱状[5]芳烃的非对映体过剩是通过主客体与非手性线状客体相互作用产生的。通过预调控的边缘分化柱[5]芳烃与氨基柱[5]芳烃的离子相互作用，合成了具有特定螺旋度和稳定性的三聚体纳米管。另一种构建螺旋三聚体纳米通道的策略也被实践。首先将无立体中心的酸性边缘分化柱状[5]芳烃分离成两个对映体，并与氨基柱状[5]芳烃相互作用生成对映体纳米通道。所构建的通道具有纯左旋和右旋螺旋。这些三聚体纳米管有望作为人工通道，实现天然小手性分子的对映选择性运输，因为先前的工作已经揭示了柱[5]芳烃的对映选择性识别。

Selectively transporting hydrophilic natural molecules with chirality through artificial channels is of crucial importance. However, this work is challenging due to the sophisticated molecular design and standing low efficiency. To achieve this goal, the construction of channels with chiral information is the primary task.Taking advantage of the controllable planar-chiral properties of pillar[n]arenes, we started the project with a rim-differentiated pillar[5]arene bearing stereogenic centers on one rim and benzoic acids on the other rim. An diastereomeric excess of the pillar[5]arene was produced through the host-guest interaction with achiral linear guests. The trimeric nanotubes with specific helicity and stability were synthesized through the ionic interaction of the pre-regulated rim-differentiated pillar[5]arene with an amino pillar[5]arene.Another strategy on construction of helical trimeric nanochannels was also practiced. An acidic rim-differentiated pillar[5]arene without stereogenic centers was isolated into two enantiomers firstly, and interacted with the amino pillar[5]arene to produce enantiomeric nanochannels. The constructed channels possessed pure left- and right-handed helicity.These trimeric nanotubes were expected to work as artificial channels enabling enantio-selective transportation of natural small chiral molecules, because previous work has revealed the enantio-selective recognition of pillar[5]arenes.