Issue 4, 2017

Radically promoted formation of a molecular lasso

Abstract

Two potential viologen-based molecular lasso precursors—both composed of a 4,4′-bipyridinium (BIPY2+) unit as part of a rope appended to a cyclobis(paraquat-p-phenylene) (CBPQT4+) loop—that have been designed to mimic the threading/unthreading motion of lasso peptides, have been synthesised and characterised. Solution and solid-state experiments reveal that, when the BIPY2+ unit in the rope and the CBPQT4+ loop are connected by a bulky linker, no lasso-like conformational transformation is observed between the different redox states on account of steric effects. In sharp contrast, when the linker size is small, the molecule can be switched between (i) a free rope-like conformation in its fully oxidised state and (ii) a self-entangled lasso-like conformation under reducing conditions employing either chemical or electrochemical stimuli: the BIPY˙+ unit in the rope resides inside the cavity of the CBPQT2(˙+) loop, forming a pseudo[1]rotaxane. The switching process is reversible and stereochemically unambiguous. This research shows how tiny structural differences can induce significantly different self-complexing properties and sheds light on designing functional artificial actuators.

Graphical abstract: Radically promoted formation of a molecular lasso

Supplementary files

Article information

Article type
Edge Article
Submitted
14 Nov 2016
Accepted
15 Jan 2017
First published
16 Jan 2017
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY-NC license

Chem. Sci., 2017,8, 2562-2568

Radically promoted formation of a molecular lasso

Y. Wang, J. Sun, Z. Liu, M. S. Nassar, Y. Y. Botros and J. F. Stoddart, Chem. Sci., 2017, 8, 2562 DOI: 10.1039/C6SC05035B

This article is licensed under a Creative Commons Attribution-NonCommercial 3.0 Unported Licence. You can use material from this article in other publications, without requesting further permission from the RSC, provided that the correct acknowledgement is given and it is not used for commercial purposes.

To request permission to reproduce material from this article in a commercial publication, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party commercial publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements