A Light-Driven Molecular Shuttle Based on a Rotaxane

Murakami, Hiroto; Kawabuchi, Atsushi; Kotoo, Kengo; Kunitake, Masashi; Nakashima, Naotoshi

doi:10.1021/ja971438a

Cited by 444 publications

(242 citation statements)

References 14 publications

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“…The foot component and anchorage groups for both fabrication targets may be implemented by using a variety of molecular systems, including DNA (1-5), peptides, and synthetic molecules (8)(9)(10)(11)(12)(13)(14). Nearly all bipedal walkers implemented thus far (1-4) have used DNA strands to make the foot and anchorage groups.…”

Section: Discussion Motor Fabrication By Dimerization Of Identical Momentioning

confidence: 99%

“…The alignment-gated selective detachment being likely a demanding experimental issue can be implemented via a rather general strategy by exploiting the unique motor-track mechanics in the regime of the asymmetric ground state. Two basic categories of synthesis targets for the motor-track were outlined, and these may be implemented by using a variety of candidate systems from engineered biomolecules (1-5) to synthetic molecules (8)(9)(10)(11)(12)(13)(14). This study thus points to a systematic approach to developing a large class of new-generation bipedal nanomotors operating on the same core mechanism.…”

Section: Discussionmentioning

confidence: 99%

“…How a nanomotor comprising two such incapable pedal components can gain the synergic capability of directional movement as a whole is the central issue in fabricating bipedal nanotransporters. This also is a thermodynamically intricate problem that may bear general relevance to driven nanosystems (8)(9)(10)(11)(12)(13)(14).…”

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Synergic mechanism and fabrication target for bipedal nanomotors

Wang

2007

Proc. Natl. Acad. Sci. U.S.A.

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Inspired by the discovery of dimeric motor proteins capable of undergoing transportation in living cells, significant efforts have been expended recently to the fabrication of track-walking nanomotors possessing two foot-like components that each can bind or detach from an array of anchorage groups on the track in response to local events of reagent consumption. The central problem in fabricating bipedal nanomotors is how the motor as a whole can gain the synergic capacity of directional track-walking, given the fact that each pedal component alone often is incapable of any directional drift. Implemented bipedal motors to date solve this thermodynamically intricate problem by an intuitive strategy that requires a hetero-pedal motor, multiple anchorage species for the track, and multiple reagent species for motor operation. Here we performed realistic molecular mechanics calculations on moleculescale models to identify a detailed molecular mechanism by which motor-level directionality arises from a homo-pedal motor along a minimally heterogeneous track. Optimally, the operation may be reduced to a random supply of a single species of reagents to allow the motor's autonomous functioning. The mechanism suggests a distinct class of fabrication targets of drastically reduced system requirements. Intriguingly, a defective form of the mechanism falls into the realm of the well known Brownian motor mechanism, yet distinct features emerge from the normal working of the mechanism. molecular devices ͉ molecular mechanics theory ͉ nanotechnology ͉ Brownian motor

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Section: Discussion Motor Fabrication By Dimerization Of Identical Momentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

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Synergic mechanism and fabrication target for bipedal nanomotors

Wang

2007

Proc. Natl. Acad. Sci. U.S.A.

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“…Using the photoisomelism characteristics of Az, Nakashima et al have demonstrated a light-driven molecular shuttle utilizing ix-CD and an azobenzenecontaining polymer capped with 1,4-dinitrobenzene. 15 They clarified that Az moiety is captured in the cavity of ix-CD when Az forms trans isomer, and that ix-CD exists on the polymer chain beside Az moiety when Az forms cis isomer. This report indicates that a change in the geometrical shape of Az plays an important role to regulate the position of ix-CD on the Az-containing polymer.…”

mentioning

confidence: 99%

Regulation of pseudo-Polyrotaxane Formation between α-Cyclodextrins and Azobenzene-Terminated Poly(ethylene glycol)

Ikeda

Ooya

Yui

1999

Polym J

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ABSTRACT:Regulation of pseudo-polyrotaxane formation between ix-cyclodextrins (ix-CDs) and azobenzene(Az)-terminated poly(ethylene glycol) (PEG) was studied in terms of the photoisomerization of the terminal Az groups. pseudo-Polyrotaxane formation was analyzed by a change in the transmittance at 550nm in water. It was found that the rate of transmittance change was decreased with an increase in the cis isomer content in Az-PEG. The cis-isomerization effect was quantitatively evaluated, assuming that Az-PEG having two cis-isomerized Az groups does not participate in the pseudo-polyrotaxane formation. From this analysis, it is suggested that pseudo-polyrotaxane formation between ix-CDs and PEG was hindered when the both terminal Az groups were isomerized to cis isomer. The content of Az-PEG in the pseudo-polyrotaxane aggregate and the content of cis-isomerized Az-PEG in the supernatant were measured by 'H NMR and UV-Vis absorption spectrum, respectively, and the obtained results supported our suggestion. It is concluded that the terminal Az groups act as a gate to regulate the pseudo-polyrotaxane formation.KEY WORDS pseudo-Polyrotaxane Formation / Photoisomerization / ix-Cyclodextrin / Poly(ethylene glycol) / Azobenzene / Over the past two decades, new synthetic methods have been investigated in order to design "intelligent" or "smart" materials which exhibit large property change in response to small physical or chemical stimuli. 1 In particular, the progress in supramolecular chemistry has introduced a new fascinating field of nano-organized systems mimicking nanostructures in nature. 2 • 3 The nano-organized systems have been focused on a key technology to realize high-performance smart materials, micromachines and so on. Molecular assemblies organized by their intermolecular forces are believed to be essential for the construction of the nano-organized systems. 4 pseudo-Polyrotaxanes in which many cyclic molecules are threaded onto a linear polymer have been recently studied as a novel molecular assembly. 5 -8 Harada et al. demonstrated pseudo-polyrotaxane formation between cyclodextrins (CDs) and a linear polymer in high yield.It was found that ix-, /3-, or y-CDs were selectively threaded onto various linear polymers. 9 For instance, when ix-CD saturated aqueous solution is mixed with poly(ethylene glycol) (PEG) aqueous solution, the solutions become turbid. 10 This phenomenon is caused by the formation of pseudo-polyrotaxane and its aggregation. Further, when bulky-terminal groups are introduced to the terminals of the polymer, the sterical hindrance for pseudo-polyrotaxane forµiation is changed in relation to the shape of the bulky-terminal groups. For instance, Harada et al. reported that bis(2-naphthylacetyl)-terminated PEG forms a pseudo-polyrotaxane with ix-CD, whereas bis(l-naphthylacetyl)-terminated PEG does not. 11 This report indicates that the pseudo-polyrotaxane formation is affected by the mobility or shape of the terminals of the linear polymer. If stimuli-responsible moieties, which can con...

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“…而且在药物传递 [5] 和光电子学 [6] 方面也显示出较好的前景. 特别是由于芳香偶氮化合物具有在光和热的作用下可以发生顺反异构现象的特性和优良的光致变色性能, 其在现代高技术领域中的研究也开始倍受人们的青睐, 相继在非线性光电信息材料 [7] 、光学存储介质 [8] 、化学传感器 [9] 、液晶材料 [10,11] 、光化学分子开关 [12,13] 、生物荧光显影成像剂 [14] 、分子机器 [15] 、纳米管 [16] 和防护眼镜过滤器 [17] 的制造等领域有广泛的应用潜力. 此外, 光驱动偶氮苯顺式和反式之间可逆的异构化使它们成为调节不同基团相对运动的极佳的候选者.…”

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Novel Progresses in Synthesis Strategies of Aromatic Azo Derivatives

Qin¹,

Li²,

Li³

et al. 2013

Chin. J. Org. Chem.

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Aromatic azo derivatives possess a particular character that is the light driven reversible isomerization between their cis-and trans-forms, which makes them excellent candidates to modulate the relative movement of different moieties. They are widely used not only in the traditional chemical industry, but also in many newly rising areas of science, such as photochemical molecular switch, super-molecular chemistry of host-guest recognition, self-assembly liquid crystal material, analysis of biomedical imaging and chemical, light driven molecular motor, and so on. The development of chromophores with characteristics, like high chemical stability, thermal stability over a wide temperature range and having two forms easily detectable by a method that does not cause irreversible molecular alterations, is a major challenge for researchers who focus their interest in this area. With the increasing need for investigating unknown aromatic azo derivatives, many novel efficient synthesis strategies are recently innovated and developed in succession. This critical review covers the various synthetic methods of aromatic azo derivatives reported more recently, with special emphasis on application of arylhydrazine, arylamine, nitroarene, azoxyarene, arylazide, and their derivatives.

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A Light-Driven Molecular Shuttle Based on a Rotaxane

Cited by 444 publications

References 14 publications

Synergic mechanism and fabrication target for bipedal nanomotors

Synergic mechanism and fabrication target for bipedal nanomotors

Regulation of pseudo-Polyrotaxane Formation between α-Cyclodextrins and Azobenzene-Terminated Poly(ethylene glycol)

Novel Progresses in Synthesis Strategies of Aromatic Azo Derivatives

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