Zhang Runmiao, Wang Chenwei, Long Renhua, Chen Tingting, Yan Chaoguo, Yao Yong
College of Chemistry, Nantong University, Nantong, China.
College of Chemistry, Yangzhou University, Yangzhou, China.
Front Chem. 2019 Jul 23;7:508. doi: 10.3389/fchem.2019.00508. eCollection 2019.
Pillar[]arenes are a new type of macrocyclic compounds, which were first reported in 2008 by Ogoshi. They not only have cylindrical, symmetrical, and rigid structures, but also have many advantages, including easy functionalization and rich host-guest properties. On the other hand, mechanically interlocked molecules (MIMs) exist extensively in nature which have been artificially synthesized and widely applied in the fields of nanotechnology and biology. Although pillar[5]arene-based MIMs have been investigated much over recent years, pillar[5]arene-based [1]rotaxanes are very limited. In this report, we synthesized a series of amide-linked pillar[5]arene-based [1]rotaxanes with ferrocene unit as the stopper. Under the catalysis of HOBT/EDCL, the mono-amido-functionalized pillar[5]arenes were amidated with ferrocene carboxylic acid to constructed ferrocene-based [1]rotaxanes, respectively. The structure of the [1]rotaxanes were characterized by H NMR, C NMR, 2D NMR, mass spectroscopy, and single-crystal X-ray structural determination. In the experiment, the monofunctionalized pillar[5]arene was synthesized with a self-inclusion property, which allows for forming a pseudo-rotaxane. The key role is the length of the imine chain in this process. The formation of a rotaxane was realized through amidation of ferrocene dicarboxylic acid, which acted as a plug. In addition, due to the ferrocene units, the pillar[5]arene-based [1]rotaxanes perform electrochemically reversible property. Based on this nature, we hope these pillar[5]arene-based [1]rotaxanes can be applied in battery devices in the future.
柱芳烃是一类新型大环化合物，由小宫等人于2008年首次报道。它们不仅具有柱状、对称且刚性的结构，还具有许多优点，包括易于功能化和丰富的主客体性质。另一方面，机械互锁分子（MIMs）在自然界中广泛存在，已被人工合成并广泛应用于纳米技术和生物学领域。尽管近年来基于柱[5]芳烃的MIMs已得到大量研究，但基于柱[5]芳烃的[1]轮烷却非常有限。在本报告中，我们合成了一系列以二茂铁单元为封端基的酰胺连接的基于柱[5]芳烃的[1]轮烷。在1-羟基苯并三唑（HOBT）/1-乙基-3-（3-二甲氨基丙基）碳二亚胺盐酸盐（EDCL）的催化下，单酰胺功能化的柱[5]芳烃分别与二茂铁羧酸酰胺化，构建了基于二茂铁的[1]轮烷。通过氢核磁共振（H NMR）、碳核磁共振（C NMR）、二维核磁共振（2D NMR）、质谱和单晶X射线结构测定对[1]轮烷的结构进行了表征。在实验中，合成了具有自包结性质的单功能化柱[5]芳烃，这使得能够形成准轮烷。在此过程中，关键作用在于亚胺链的长度。通过作为塞子的二茂铁二羧酸的酰胺化实现了轮烷的形成。此外，由于二茂铁单元，基于柱[5]芳烃的[1]轮烷具有电化学可逆性质。基于这一性质，我们希望这些基于柱[5]芳烃的[1]轮烷未来能够应用于电池装置。
