Pseudorotaxanes Formed Between Secondary Dialkylammonium Salts and Crown Ethers

Ashton, Peter R.; Chrystal, Ewan J. T.; Glink, Peter T.; Menzer, Stephan; Schiavo, Cesare; Spencer, Neil; Stoddart, J. Fraser; Tasker, Peter A.; White, Andrew J. P.; Williams, David J.

doi:10.1002/chem.19960020616

Cited by 347 publications

(265 citation statements)

References 109 publications

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“…Neutral rotaxane monomer 6 was obtained in 84% yield by N-acetylation of 5 with excess acetic anhydride and triethylamine. [35][36][37] The structures of these monomers were determined by 1 H, 13 C NMR and IR spectral analyses along with mass spectra. 1 H NMR spectra of 5 and 6 clearly supported their structures as assigned in Rotaxane-tethering acetylene monomers and side chain-type polyrotaxanes K Nakazono et al presence of syn-anti isomers of the amide group, the spectrum confirmed the rotaxane structure of amide-type rotaxane monomer 6.…”

Section: Monomer Synthesismentioning

confidence: 99%

“…Splitting of the crown ether oxyethylene proton signals were characteristic of this type of rotaxane, as assigned in Figure 1. 30,[35][36][37] O-Benzylic proton signal, which is sensitive to the position of the crown ether wheel on the axle, moved to 5.9 p.p.m., indicating the localization of the wheel around the ester group. This result suggests that the wheel component gets considerably close to the acetylene moiety in comparison with that of 5.…”

Section: Monomer Synthesismentioning

confidence: 99%

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Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

Nakazono

Fukasawa

Sato

et al. 2010

Polym J

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A crown ether-ammonium salt-type rotaxane monomer was synthesized in a high yield using dibenzo-24-crown-8-ether and sec-ammonium salt having a hydroxy terminal by means of an end-capping reaction with an ethynyl benzoic acid. Its N-acetylated derivative was also synthesized in a quantitative yield using excess acetic anhydride and triethylamine. Novel side chain-type polyrotaxanes, that is, ammonium-type and neutral polyphenylacetylenes tethering rotaxane moieties in side chains with high molecular weights, were obtained in high yields by polymerizations with an Rh catalyst. The structures of the polymers were characterized by infrared, ultraviolet-visible (UV-vis) spectra and size exclusion chromatography. N-acetylation of the rotaxane moieties of the ammonium salt-type polymer resulted in the formation of a reddish-colored neutral polymer showing red-shifted UV-vis absorptions around 500 nm based on the conjugated main chain, according to the structural change of rotaxane side chains, that is, the change of the distance of the wheel component to the polyacetylene main chain. The solubility of the polymers was evaluated.

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Section: Monomer Synthesismentioning

confidence: 99%

Section: Monomer Synthesismentioning

confidence: 99%

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

Nakazono

Fukasawa

Sato

et al. 2010

Polym J

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“…Furthermore, blocked-axle 7 was investigated as the chloride salt, which will likely exist in biological environments. In CDCl3, the strong ion pairs greatly weakens pseudorotaxane 8 (KA = 17 ± 0.6 M −1 ) when compared to the typical association observed in the millimolar range for the complex of DB24C8 with R2NH2 + PF6 − salts [24][25][26]. Tighter association was observed in DMSO-d6 (KA = 250 ± 10 M −1 ).…”

Section: Measuring the Stability Of Pseudorotaxanementioning

confidence: 87%

A Versatile Axle for the Construction of Disassemblage Rotaxanes

Powers

Smithrud

2016

Molecules

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Rotaxanes are unique mechanical devices that hold great promise as sensors. We report on two new rotaxanes that contain an acid or base sensitive trigger and readily disassemble in a wide range of environments. Disassemblage was observed under TLC and 1 H-NMR analysis. The axle is highly charged, which enhances solubility in aqueous environments, and can be readily derivatized with sensor components. The trigger was swapped in a one-pot method, which is promising for the rapid production of a series of sensors.

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“…The end-cap proceeded efficiently via the Huisgen click reaction with terminal azide- The combination of a 24-membered crown ether, such as dibenzo-24-crown-8-ether (DB24C8), and sec-ammonium salt has been widely used for rotaxane synthesis. 38,42,50 Takata and colleagues [51][52][53] developed various sec-ammonium salt/DB24C8-based rotaxanes and applied them to rotaxane switches in which the mobility and relative position of the rotaxane components could be controlled. Therefore, M2R possessing the sec-ammonium salt/DB24C8 couple can be regarded as an ideal structure-definite polyrotaxane in which the mobility and position of the components should be stimuli responsive.…”

Section: Synthesis Of M2rmentioning

confidence: 99%

Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains

Takata

Aoki

2017

Polym J

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In this review article, we discuss the synthesis and dynamic nature of macromolecular systems that have mechanically linked polymer chains capable of undergoing a topology transformation driven by a rotaxane molecular switch. The rotaxane linking of polymer chains plays a crucial role in these systems. A linear polymer possessing a crown ether/sec-ammonium salt-type [1] rotaxane moiety at the axle chain terminal was prepared via the rotaxane linking of a single polymer chain. A linear-cyclic polymer topology transformation was achieved via the movement of the wheel component from one end to the other end of the axle component using the rotaxane macromolecular switch function. The successful synthesis of a macromolecular [2]rotaxane (M2R) possessing a single polymer axle and one crown ether wheel led to a variety of unique applications, such as the development of topology-transformable polymers and the synthesis of rotaxane crosslinked polymers (RCPs). The introduction of a polymer chain to the wheel component of M2R (rotaxane linking of two polymer chains) produced a rotaxane-linked AB block copolymer that transformed its topology from linear to branched. Furthermore, a rotaxane-linked three-component polymer and an ABC triblock copolymer were synthesized and transformed to the corresponding 3-arm star (co)polymers, and the transformation was confirmed by measuring the hydrodynamic volume change. The structural transformation of 4-arm and 6-arm star polymers was also accomplished using the dynamic mobility of a similar rotaxane. As a useful application, M2R-based vinylic crosslinkers (RCs) were prepared and applied to the synthesis of RCPs, whereby the addition of RCs into radical polymerization systems of vinyl monomers afforded polymers with excellent toughness by enhancing both of tradeoff properties that cannot be achieved using typical covalent crosslinkers.

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Pseudorotaxanes Formed Between Secondary Dialkylammonium Salts and Crown Ethers

Cited by 347 publications

References 109 publications

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

Synthesis of acetylene-functionalized [2]rotaxane monomers directed toward side chain-type polyrotaxanes

A Versatile Axle for the Construction of Disassemblage Rotaxanes

Topology-transformable polymers: linear–branched polymer structural transformation via the mechanical linking of polymer chains

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