Abstract
Pillar[n]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 1H NMR, 13C 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.
Highlights
Interlocked molecules (MIMs) are a type of “star” molecule due to their beautiful and interesting architectures and wide applications in the area of biology and nanoscience (Bissell et al, 1994; Brouwer et al, 2001; Zhu and Chen, 2005; Crowley et al, 2009; Yonath, 2010; Zhang et al, 2011; Li et al, 2014; Wang et al, 2015, 2018)
P[5]nRs and mono-ferrocene modified pillar[5]arene were successfully synthesized by P[5]nPRs reacted with ferrocene-carboxylic acid as the stopper under the catalysis of HOBT/EDCL
P[5]4R was prepared from P[5]4PR reacted with ferrocenecarboxylic acid as the stopper. 1H NMR spectra of monomer M3 and [1] rotaxane P[5]4R in CDCl3 at 293 K are shown in Figure 1
Summary
Interlocked molecules (MIMs) are a type of “star” molecule due to their beautiful and interesting architectures and wide applications in the area of biology and nanoscience (Bissell et al, 1994; Brouwer et al, 2001; Zhu and Chen, 2005; Crowley et al, 2009; Yonath, 2010; Zhang et al, 2011; Li et al, 2014; Wang et al, 2015, 2018). Among various MIMs, rotaxanes, which have dumbbell-like structures with a wheel sliding along an axle, have attracted great interest due to their wide application in preparation of artificial molecular machines (Green et al, 2007; Lewandowski et al, 2013; Zhang et al, 2013). [1]rotaxanes, whose wheels and axles are connected in one molecule. The efficient synthesis of [1]rotaxanes is very difficult due to their subtle structure. To the best of our knowledge, there are very limited studies about the synthesis and properties of macrocycle based [1]rotaxanes. Qu et al fabricated a novel [1]rotaxane-based molecular motion modified with ferrocene groups (Li et al, 2012)
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
