The long-standing challenge in the synthesis of polyrotaxanes with a defined number of rings has been cracked! The collaborative efforts of Postdoctoral Fellow Yunyan Qiu and two world-renowned experts in mass spectrometry, Bo Song, currently also a Postdoctoral Fellow in the group, and Xiaopeng Li from University of South Florida, as well as the molecular-machine theorist R. Dean Astumian from University of Maine, have led to a report being published in the June 12th Issue of Science. See Publication #1193 or Science 2020, 368, 1247–1253.
This report describes the assembly line–like emergence of polyrotaxanes with increasingly higher energies by harnessing artificial molecular pumps situated at each end of a poly(ethylene glycol) chain to deliver rings in pairs by chemical or electrochemical redox-driven processes. Polyrotaxanes with 2 / 4 / 6 / 8 / 10 rings carrying 8+ / 16+ / 24+ / 32+ / 40+ charges, respectively, have been made. We are one step closer to having a wholly synthetic molecular pump, that operates in a similar way as do the ion-pumps inside us.
Pictured below – Graphic describing the process of assembling polyrotaxanes with a defined number of rings:
Pictured below – Animation describing the process of assembling polyrotaxanes with a defined number of rings: