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Artificial Molecular Machines.

Erbas-Cakmak S, Leigh DA, McTernan CT, Nussbaumer AL - Chem. Rev. (2015)

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.

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bonded molecules and on catenanes and rotaxanes in which switching of other protic solvents... This effect (listed in descending binding ability) stations on the thread, macrocycle In these systems, fast-responding reporters are preferred... practical applications by utilizing molecular scale changes to create macroscopic effects... The thread of these rotaxanes included an anthracene fluorophore similar application in synthetic polymers often furnishes a useful result... of Brownian motion can be exploited to great effect in the synthesis every aspect of functional molecule and materials design... An improved robotics” in which ratcheted motions of molecular components

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Photodriven directional translational motion in pseudorotaxanes 86–87. Reprinted with permission fromref (811). Copyright2013 American Chemical Society.
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fig30: Photodriven directional translational motion in pseudorotaxanes 86–87. Reprinted with permission fromref (811). Copyright2013 American Chemical Society.

Mentions: Directional translational motion along the axis of pseudorotaxanehas also been reported (Figure 30).553,811,812 Threading and dethreading of the macrocycle could be controlledby photochemical, chemical, or electrochemical redox reactions. Thepseudorotaxane axis has three different chemical motifs responsiblefor directional translocation. The first is a 2-isopropylphenyl group,a neutral energy barrier at one side of the axle. An electron-rich1,5-dioxynaphthaline occupied the center, and at the other end wasa positively charged 3,5-dimethylpyridinium station. A tetracationicelectron-poor cyclobis(paraquat-p-phenylene) macrocycleformed a π-complex with the electron-rich 1,5-dioxynaphthalinegroup. To form the complex, the macrocycle had to pass one of theenergy barriers, and the neutral 2-isopropylphenyl moiety presenteda lower energy barrier. Hence, threading took place selectively fromthis side of the axis. Upon one-electron reduction of the macrocycle,interaction with the 1,5-dioxynaphthaline station was weakened. Additionally,as a result of the reduced positive charge on the macrocycle, electrostaticrepulsion from the pyridinium site became less potent, allowing themacrocycle to pass over this barrier with greatly reduced activationenergy. Hence, once reduced, the macrocycle dethreaded over the pyridiniumgroup. The macrocycle threaded and dethreaded in a directional mannervia a ratcheting mechanism (flashing ratchet) acting on the potentialenergy surface of the pseudorotaxane axle. The same group later reporteda flashing ratchet based on similar principles, in a pseudorotaxanewith one stopper, where threading was driven by reduction, and dethreadingslowly occurred after rapid shuttling away from a reoxidized bipyridiniumstation.813 Recently, Credi et al. alsoreported the photodriven directional threading/dethreading of a crownether macrocycle on an axle using a flashing ratchet mechanism.814,815


Artificial Molecular Machines.

Erbas-Cakmak S, Leigh DA, McTernan CT, Nussbaumer AL - Chem. Rev. (2015)

Photodriven directional translational motion in pseudorotaxanes 86–87. Reprinted with permission fromref (811). Copyright2013 American Chemical Society.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4585175&req=5

fig30: Photodriven directional translational motion in pseudorotaxanes 86–87. Reprinted with permission fromref (811). Copyright2013 American Chemical Society.
Mentions: Directional translational motion along the axis of pseudorotaxanehas also been reported (Figure 30).553,811,812 Threading and dethreading of the macrocycle could be controlledby photochemical, chemical, or electrochemical redox reactions. Thepseudorotaxane axis has three different chemical motifs responsiblefor directional translocation. The first is a 2-isopropylphenyl group,a neutral energy barrier at one side of the axle. An electron-rich1,5-dioxynaphthaline occupied the center, and at the other end wasa positively charged 3,5-dimethylpyridinium station. A tetracationicelectron-poor cyclobis(paraquat-p-phenylene) macrocycleformed a π-complex with the electron-rich 1,5-dioxynaphthalinegroup. To form the complex, the macrocycle had to pass one of theenergy barriers, and the neutral 2-isopropylphenyl moiety presenteda lower energy barrier. Hence, threading took place selectively fromthis side of the axis. Upon one-electron reduction of the macrocycle,interaction with the 1,5-dioxynaphthaline station was weakened. Additionally,as a result of the reduced positive charge on the macrocycle, electrostaticrepulsion from the pyridinium site became less potent, allowing themacrocycle to pass over this barrier with greatly reduced activationenergy. Hence, once reduced, the macrocycle dethreaded over the pyridiniumgroup. The macrocycle threaded and dethreaded in a directional mannervia a ratcheting mechanism (flashing ratchet) acting on the potentialenergy surface of the pseudorotaxane axle. The same group later reporteda flashing ratchet based on similar principles, in a pseudorotaxanewith one stopper, where threading was driven by reduction, and dethreadingslowly occurred after rapid shuttling away from a reoxidized bipyridiniumstation.813 Recently, Credi et al. alsoreported the photodriven directional threading/dethreading of a crownether macrocycle on an axle using a flashing ratchet mechanism.814,815

View Article: PubMed Central - PubMed

Affiliation: School of Chemistry, University of Manchester , Oxford Road, Manchester M13 9PL, United Kingdom.

AUTOMATICALLY GENERATED EXCERPT
Please rate it.

bonded molecules and on catenanes and rotaxanes in which switching of other protic solvents... This effect (listed in descending binding ability) stations on the thread, macrocycle In these systems, fast-responding reporters are preferred... practical applications by utilizing molecular scale changes to create macroscopic effects... The thread of these rotaxanes included an anthracene fluorophore similar application in synthetic polymers often furnishes a useful result... of Brownian motion can be exploited to great effect in the synthesis every aspect of functional molecule and materials design... An improved robotics” in which ratcheted motions of molecular components

No MeSH data available.