Catenanes and threaded systems: from solution to surfaces

Abstract

Functional catenanes and threaded systems able to perform controllable mechanical motions are ideally suited for the design of molecular devices displaying mechanical, electronic, information or sensing functions. These systems have been extensively studied in solution phase and numerous examples of stimuli-driven molecular shuttles have been reported. However, for fully developing their potential applications, they must be interfaced with the macroscopic world. To achieve this objective, in the last few years catenanes and rotaxanes have been organized over surfaces in the form of chemisorbed monolayers or physisorbed monolayers, multilayers and thin films. This tutorial review summarizes the different techniques for the deposition on surfaces and characterization of switchable catenanes and rotaxanes, and highlights the properties of these new functional surfaces and their potential applications.

A Highly Luminescent Tetramer from a Weakly Emitting Monomer: Acid‐ and Redox‐Controlled Multiple Complexation by Cucurbit[7]uril

“…Among the multitude of chromophoric moieties investigated, pyridinium and bipyridinium chromophores (also known as viologens, namely, 1,1′‐disubstituted‐4,4′‐bipyridinium salts) are some of the most extensively studied functional entities by virtue of their photochemical and electrochemical properties 13. 14 They are widely employed as electron‐acceptor recognition sites and redox switching units in supramolecular systems such as dendrimers,15–18 rotaxanes,19–21 and catenanes 22. 23 Moreover, they have been investigated as components for electrochromic displays,24, 25 molecular batteries,26 redox mediators,27, 28 and redox sensors 29.…”

Stable and Unconventional Conformation of Single PEG Bent γ‐CD‐Based Polypseudorotaxanes

“…α‐CDs were first reported to be threaded onto a polymeric chain to form polypseudorotaxanes (PPRs) and polyrotaxanes (PRs) after end‐capping with bulky stoppers which show a necklace‐like or channel‐type supramolecular structure in 1990 2. To date, various architectures of PPRs and PRs have been synthesized and exploited as building blocks to construct hierarchical nanostructures as well as to realize novel functions, such as dual thermo‐responsive triblock copolymers, slide‐ring gels, biosensors, vehicles for gene therapy, and electrospinning nanofibers 3–23…”

Bausteine mit Hohlräumen in supramolekularen Gelen

“…[31] Aufgrund der Spezifität des Wirts sind eine selektive Verkapselung, [32] Erkennung [33] und die katalytische Umsetzung von Gastmolekülen mög-lich. [34] Die Bildung von Rotaxanen [35] aus Polymeren und Cavitanden kann verwendet werden, um molekulare Motoren, Shuttles und Maschinen zu realisieren. [36,37] Rotaxane wurden auch für die Bildung von Gleitring-Gelen [38] verwendet; außerdem wurde über Organogele mit integrierten umschaltbaren Rotaxanen berichtet.…”