Cooperative threading of asymmetric rings onto a linear chain

Horský, Jiřı́

doi:10.1002/1521-3919(20001201)9:9<759::aid-mats759>3.0.co;2-9

Cited by 7 publications

(3 citation statements)

References 14 publications

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“…In contrast to the extensive developments in the synthesis of rotaxanes 2 and their derivatives, as well as developments in their nanotechnology, computational studies aimed at rationalizing and predicting the underlying processes are rather scarce. In fact, there are few articles on computational studies on rotaxanes, , on pseudorotaxanes, , or on catenanes. , The largest number of such theoretical studies involve rotaxanes with cyclodextrins as the macrocycles . A recent study indicates that the macrocycle rotation around the thread depends on the experimental conditions, and these results have been confirmed by independent NMR measurements and by theoretical modeling .…”

Section: Introductionmentioning

confidence: 92%

Shuttling Process in [2]Rotaxanes. Modeling by Molecular Dynamics and Free Energy Perturbation Simulations

2003

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The first application of a methodology previously developed and tested on pseudorotaxanes is presented here in the study of the structure and the energetics of [2]rotaxane 1. The approach is based on the AMBER force field with RESP charges, and on an explicit solvent model for acetonitrile. With this model, the experimentally observed free energy difference (0.98 kcal mol -1 ) between the two translational isomers of 1 (computed ∆G ) 1.06 ( 0.04 kcal mol -1 ) was correctly reproduced. The linear component of the suprastructure adopts an extended conformation, as suggested by the free energy perturbation simulations.

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Section: Introductionmentioning

confidence: 92%

Shuttling Process in [2]Rotaxanes. Modeling by Molecular Dynamics and Free Energy Perturbation Simulations

2003

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“…These systems are essentially molecular "nanotubes" where the CD is threaded onto the PEG chains. While ß-CDs have been reported to not form inclusion complexes easily with PEG because of their larger size, threading of PEG molecules has been reported with a-CDs [24], and threading of ß-CDs has been reported with other hydrophilic materials including ethers, amines, and poly(ethylene glycol)-poly(propylene glycol)-poly(ethylene glycol) triblock copolymers (PEG-PPG-PEG) [25,26]. Therefore, for the reported experiments in solution, it is possible the CD had sufficient time before reaction to form molecular nanotubes with the PEG or the isocyanate endgroup and then was trapped as the material polymerized ( Figure 15).…”

Section: Hplc/contaminant Scavenging/renewability Studiesmentioning

confidence: 99%

Structure-Scavenging Abilities of Cyclodextrin-Based Polyurethanes

Young¹,

Vajda²,

Napadensky³

et al. 2002

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Cyclodextrins are ring-shaped molecules containing an apolar cavity with a diameter 4-8 Ä wide and approximately 8 Ä deep. Because of the hydrophilic nature of the surface, the materials are readily dispersed in water. However, hydrophobic groups on the inner surface of the nanoporous molecules attract hydrophobic organics that bind noncovalently to the apolar cavity. Recently, polycyclodextrins have been developed as binders for energetic materials and as sorbants for biological materials, and exhibit potential for development as sorbant materials for water filtration. Studies using these polymers have been reported in the literature and show that the polycyclodextrins are very effective scavengers of organic contaminants in water. Our work expands on the use of cyclodextrins in polymers through the synthesis of several organic cyclodextrinbased polymers. These filtering materials have been shown to scavenge several different kinds of contaminants up to parts per million concentrations from water. Some neutron work has been done to try to ascertain the nature of capture of these contaminants.u

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“…The literature offers articles where computational studies on rotaxanes are embedded into largely more detailed experimental results . Most of them are devoted to systems where cyclodextrins are the macrocycle, although catenanes have also been considered . However, several articles present computational studies on the complexation process between cyclobis(paraquat- p -phenylene) and aromatic guests and also phenyl glucosides .…”

Section: Introductionmentioning

confidence: 99%