Organic Cages as Building Blocks for Mechanically Interlocked Molecules: Towards Molecular Machines

ChemPlusChem ◽  
2020 ◽  
Vol 85 (6) ◽  
pp. 1145-1155
Author(s):  
Sonia La Cognata ◽  
Ana Miljkovic ◽  
Riccardo Mobili ◽  
Greta Bergamaschi ◽  
Valeria Amendola
Keyword(s):  
Molecular Machines ◽  
Building Blocks ◽  
Interlocked Molecules

scholarly journals Tetrathiafulvalene – a redox-switchable building block to control motion in mechanically interlocked molecules

2018 ◽  
Vol 14 ◽  
pp. 2163-2185 ◽  
Author(s):  
Hendrik V Schröder ◽  
Christoph A Schalley
Keyword(s):  
Molecular Motion ◽  
Functional Unit ◽  
Molecular Machines ◽  
Building Blocks ◽  
Interlocked Molecules ◽  
The Past ◽  
Research Challenge ◽  
And Control ◽  
Redox Switches ◽  
Selection Of

With the rise of artificial molecular machines, control of motion on the nanoscale has become a major contemporary research challenge. Tetrathiafulvalenes (TTFs) are one of the most versatile and widely used molecular redox switches to generate and control molecular motion. TTF can easily be implemented as functional unit into molecular and supramolecular structures and can be reversibly oxidized to a stable radical cation or dication. For over 20 years, TTFs have been key building blocks for the construction of redox-switchable mechanically interlocked molecules (MIMs) and their electrochemical operation has been thoroughly investigated. In this review, we provide an introduction into the field of TTF-based MIMs and their applications. A brief historical overview and a selection of important examples from the past until now are given. Furthermore, we will highlight our latest research on TTF-based rotaxanes.

scholarly journals Rotaxane synthesis exploiting the M(i)/M(iii) redox couple

2017 ◽  
Vol 46 (35) ◽  
pp. 11645-11655 ◽  
Author(s):  
Jack Emerson-King ◽  
Richard C. Knighton ◽  
Matthew R. Gyton ◽  
Adrian B. Chaplin
Keyword(s):  
Building Blocks ◽  
Redox Couple ◽  
Interlocked Molecules

In the context of advancing the use of metal-based building blocks for the construction of new and interesting mechanically interlocked molecules, we herein describe the preparation of rhodium and iridium containing [2]rotaxanes.

A Dynamic Route to Structure and Function: Recent Advances in Imine-Based Organic Nanostructured Materials

2013 ◽  
Vol 66 (1) ◽  
pp. 9 ◽  
Author(s):  
Yi Liu ◽  
Zhan-Ting Li
Keyword(s):  
Self Assembly ◽  
Reaction System ◽  
Functional Materials ◽  
Building Blocks ◽  
The Self ◽  
Interlocked Molecules ◽  
Functional Aspects ◽  
Imine Bond ◽  
And Function ◽  
Dynamic Route

The chemistry of imine bond formation from simple aldehyde and amine precursors is among the most powerful dynamic covalent chemistries employed for the construction of discrete molecular objects and extended molecular frameworks. The reversible nature of the C=N bond confers error-checking and proof-reading capabilities in the self-assembly process within a multi-component reaction system. This review highlights recent progress in the self-assembly of complex organic molecular architectures that are enabled by dynamic imine chemistry, including molecular containers with defined geometry and size, mechanically interlocked molecules, and extended frameworks and polymers, from building blocks with preprogrammed steric and electronic information. The functional aspects associated with the nanometer-scale features not only place these dynamically constructed nanostructures at the frontier of materials sciences, but also bring unprecedented opportunities for the discovery of new functional materials.

scholarly journals Beyond switches: Rotaxane- and catenane-based synthetic molecular motors

2008 ◽  
Vol 80 (1) ◽  
pp. 17-29 ◽  
Author(s):  
Euan R. Kay ◽  
David A. Leigh
Keyword(s):  
Molecular Motors ◽  
Physical Science ◽  
Statistical Physics ◽  
Biological Process ◽  
Molecular Level ◽  
Molecular Machines ◽  
Interlocked Molecules ◽  
Recent Developments ◽  
New Generation ◽  
First Time

Nature uses molecular motors and machines in virtually every significant biological process, but learning how to design and assemble simpler artificial structures that function through controlled molecular-level motion is a major challenge for contemporary physical science. The established engineering principles of the macroscopic world can offer little more than inspiration to the molecular engineer who creates devices for an environment where everything is constantly moving and being buffeted by other atoms and molecules. Rather, experimental designs for working molecular machines must follow principles derived from chemical kinetics, thermodynamics, and nonequilibrium statistical physics. The remarkable characteristics of interlocked molecules make them particularly useful for investigating the control of motion at the molecular level. Yet, the vast majority of synthetic molecular machines studied to date are simple two-state switches. Here we outline recent developments from our laboratory that demonstrate more complex molecular machine functions. This new generation of synthetic molecular machines can move continuously and progressively away from equilibrium, and they may be considered true prototypical molecular motors. The examples discussed exemplify two, fundamentally different, "Brownian ratchet" mechanisms previously developed in theoretical statistical physics and realized experimentally in molecular-level devices for the first time in these systems.

scholarly journals A precise polyrotaxane synthesizer

Science ◽  
2020 ◽  
Vol 368 (6496) ◽  
pp. 1247-1253 ◽  
Author(s):  
Yunyan Qiu ◽  
Bo Song ◽  
Cristian Pezzato ◽  
Dengke Shen ◽  
Wenqi Liu ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Assembly Line ◽  
Molecular Machines ◽  
One Pot ◽  
Interlocked Molecules ◽  
Design And Synthesis ◽  
Redox Cycles

Mechanically interlocked molecules are likely candidates for the design and synthesis of artificial molecular machines. Although polyrotaxanes have already found niche applications in exotic materials with specialized mechanical properties, efficient synthetic protocols to produce them with precise numbers of rings encircling their polymer dumbbells are still lacking. We report the assembly line–like emergence of poly[n]rotaxanes with increasingly higher energies by harnessing artificial molecular pumps to deliver rings in pairs by cyclical redox-driven processes. This programmable strategy leads to the precise incorporation of two, four, six, eight, and 10 rings carrying 8+, 16+, 24+, 32+, and 40+ charges, respectively, onto hexacationic polymer dumbbells. This strategy depends precisely on the number of redox cycles applied chemically or electrochemically, in both stepwise and one-pot manners.

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

2019 ◽  
Author(s):  
Andrew Heard ◽  
Stephen Goldup
Keyword(s):  
Active Site ◽  
Molecular Machines ◽  
Enantioselective Catalysis ◽  
Interlocked Molecules ◽  
End Groups ◽  
Mechanical Bond

<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

2019 ◽  
Author(s):  
Andrew Heard ◽  
Stephen Goldup
Keyword(s):  
Active Site ◽  
Molecular Machines ◽  
Enantioselective Catalysis ◽  
Interlocked Molecules ◽  
End Groups ◽  
Mechanical Bond

<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

A Mechanically Planar Chiral Rotaxane Ligand for Enantioselective Catalysis

2019 ◽  
Author(s):  
Andrew Heard ◽  
Stephen Goldup
Keyword(s):  
Active Site ◽  
Molecular Machines ◽  
Enantioselective Catalysis ◽  
Interlocked Molecules ◽  
End Groups ◽  
Mechanical Bond

<p> <b>Rotaxanes are interlocked molecules in which a molecular ring is trapped on a dumbbell-shaped axle due to its inability to escape over the bulky end groups, resulting in a so-called mechanical bond. Interlocked molecules have mainly been studied as components of molecular machines, but the crowded, flexible environment created by threading one molecule through another, reminiscent of the active site of an enzyme, has also been explored in catalysis and sensing. However, so far the applications of one of the most intriguing properties of interlocked molecules, their ability to display stereogenic units that do not rely on the stereochemistry of their covalent subunits, termed "mechanical chirality", have yet to be properly explored and prototypical demonstration of the applications of mechanically chiral rotaxanes remain scarce. Here we describe a mechanically planar chiral rotaxane-based Au complex that mediates a cyclopropanation reaction with stereoselectivities that are comparable with conventional covalent catalyst reported for this reaction.</b></p>

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