pH-Responsive Movement of Cucurbit[7]uril in a Diblock Polypseudorotaxane Containing Dimethyl β-Cyclodextrin and Cucurbit[7]uril

Ooya, Tooru; Inoue, Daisuke; Choi, Hak; Kobayashi, Yuichiro; Loethen, Scott; Thompson, David H.; Ko, Young Ho; Kim, Kimoon; Yui, Nobuhiko

doi:10.1021/ol060697e

Cited by 99 publications

(44 citation statements)

References 17 publications

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“…Higher rotaxanes are also accessible using bifunctional building blocks as well as under generation of rotaxanes with a pH-responsive moiety. [71] Another example of supramolecular compounds has been reported by Stoddart and co-workers. [72] The critical step in the formation of interlocked structures is the fixation of the intermediate supramolecular complexes.…”

Section: Rotaxanes P-cyclophanes and Calixarenesmentioning

confidence: 88%

‘Click’ Chemistry in Polymer and Materials Science

Binder

Sachsenhofer

2007

Macromol. Rapid Commun.

1,493

866

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IntroductionThe azide/alkyne 'click' reaction [1] (also termed the Sharpless 'click' reaction) is a recent re-discovery of a reaction fulfilling many requirements for the affixation of ligands onto polymers by post-modification processes, which include a) often quantitative yields, b) a high tolerance of functional groups, c) an insensitivity of the reaction to solvents, irrespective of their protic/aprotic or polar/ non-polar character, and d) reactions at various types of interfaces, such as solid/liquid, liquid/liquid, or even solid/ solid interfaces. The present review focuses on issues related to the reaction itself as well as on the wide applications in polymer science, material, and surface science.The basic reaction, which is nowadays summed up under the name 'Sharpless-type click reaction', is a variant of the Huisgen 1,3-dipolar cycloaddition reaction [2a,2b] between C-C triple, C-N triple bonds, and alkyl-/aryl-/ sulfonyl azides (see Scheme 1).The relevant outcomes of this reaction are tetrazoles, 1,2,3-triazoles, or 1,2-oxazoles (Scheme 1a-c, respectively). Besides the 1,3-dipolar cycloaddition reaction, classical Diels-Alder-type reactions (Scheme 1d) have been used extensively for the functionalization of polymeric materials and surfaces. [3] These reactions are located within a series of reactions named click reactions, which is defined by a gain of thermodynamic enthalpy of at least 20 kcal Á mol À1 , [1] thus leading to reactions characterized by high yields, simple reaction conditions, fast reaction times, and high selectivity. Among many reactions tested, the 1,3-dipolar cycloaddition process has emerged as the method of choice to effect the requirements of ligating two ReviewThe modification of polymers after the successful achievement of a polymerization process represents an important task in macromolecular science. Cycloaddition reactions, among them the metal catalyzed azide/alkyne 'click' reaction (a variation of the Huisgen 1,3-dipolar cycloaddition reaction between terminal acetylenes and azides) represents an important contribution towards this endeavor. They combine high efficiency (usually above 95%) with a high tolerance of functional groups and solvents, as well as moderate reaction temperatures (25-70 8C). The present review assembles recent literature for applications of this reaction in the field of polymer science (linear polymers, dendrimers, gels) as well as the use of this and related reactions for surface modification on carbon nanotubes, fullerenes, and on solid substrates, and includes the authors own publications in this field. A number of references (>100) are included.

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Section: Rotaxanes P-cyclophanes and Calixarenesmentioning

confidence: 88%

‘Click’ Chemistry in Polymer and Materials Science

Binder

Sachsenhofer

2007

Macromol. Rapid Commun.

1,493

866

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“…They can slip onto an ammonium ion guest as the pseudorotaxane wheel. Many different options for the construction of more complex architectures arise: (i) We can connect the 2 guests ''linearly'' (11)(12)(13)(14). (ii) The 2 crown ether hosts can be incorporated into dimers and-if connected through the anthracene core chosen here-are coplanar with each other.…”

Section: Resultsmentioning

confidence: 99%

Integrative self-sorting is a programming language for high level self-assembly

Jiang

Schalley

2009

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

169

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Starting from the basis of a simple 4-component self-sorting system of crown ethers and ammonium ions, we design 6 building blocks in which 2 identical or different binding sites are incorporated. These building blocks can be mixed in many different ways to yield quite distinctly different pseudorotaxane assemblies. The self-sorting process integrates all building blocks in specific places so that this approach permits us to exert positional control and can widely influence the resulting assemblies with respect to the details of their structures. At maximum, we report quadruply interlocked species with up to 5 subunits that form specific assemblies. Although NMR methods are limited to the analysis of simpler complexes, ESI-MS and, in particular, tandem mass spectrometry is highly useful to analyze the assemblies' connectivities.interlocked molecules ͉ pseudorotaxanes ͉ supramolecular chemistry ͉ tandem mass spectrometry ͉ crown ether T he ''bottom-up'' approach to the construction of molecular devices and machines through molecular self-assembly has attracted extensive attention in the past 2 decades (1-4). Molecular self-assembly (5-7) harnesses noncovalent interactions to organize discrete components into well-organized architectures. To achieve this, the necessary instructions must be written into the structures of the building blocks by chemical synthesis. Most artificial self-assembled architectures known today incorporate multiple copies of the same building blocks and thus are often highly symmetrical structures.In the macroscopic world, however, devices and machines are assembled from many different components cooperating with each other to perform complex functions. The same holds true for most biomolecules. Nature efficiently uses the principles of noncovalent self-assembly together with self-sorting (8, 9) phenomena to generate complex, functional architectures. DNA may serve as a prominent example whose function is information storage. Four bases (adenine (A), thymine (T), guanine (G), and cytosine (C)) self-sort to form base pairs (AT and GC) in their mixture. Integrating these bases to the polymer backbones of DNA in a specific sequence not only stores information but also allows the cell to replicate and transcribe the stored information.When complex functions are to be achieved in artificial molecular devices or machines, the self-assembly of highly symmetrical architectures from multiple identical building blocks is a severe restriction that can be overcome by applying the same strategy used by nature: The integration of different subunits into the architecture with precise positional control by combining the principles of self-assembly and self-sorting. We very recently coined this strategy, integrative self-sorting (10), and are convinced that it will not only enrich the world of supramolecular architectures from the point of view of structural variability but will also form the basis for the implementation of high-level functions in future assemblies.Herein, we present several strategies abou...

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“…Note that these induced NMR shifts of the AO protons in the presence of CB [7] were in sharp contrast with those associated with the inclusion of other organic molecules in the CB [7] cavity, with upfield shifts of their proton resonances. [26][27][28][29][30] It was known that Cob + could be completely included in the CB [7] cavity with an upfield shift of its proton resonance. [38] Upon addition of Cob + to the AO·CB [7] complex, the NMR spectrum of the aqueous AO solution was completely recovered, along with an upfield shift of the Cob + proton resonance.…”

Section: Resultsmentioning

confidence: 99%

“…[25] 1 H NMR spectroscopy is one of the most effective tools for studies of complex formation between CB[n]s and organic molecules. [26][27][28][29][30] In general, downfield shifts of the resonances of guests result from the deshielding effects of the carbonyl groups of the CB[n]s when the portions of the guests are located in the portals, whereas upfield shifts indicate that the guests are encapsulated in the shielding hydrophobic cavities. However, low dye concentrations commonly prevent detailed NMR characterization.…”

Section: Introductionmentioning

confidence: 99%

Insight into Unusual Downfield NMR Shifts in the Inclusion Complex of Acridine Orange with Cucurbit[7]uril

Liu

Jiang

et al. 2009

Eur J Org Chem

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This paper describes the structure and properties of the complex of acridine orange (AO) with cucurbit [7]uril (CB[7]) in aqueous solutions, studied by 1 H NMR spectroscopy, matrixassisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry, UV/Vis spectroscopy, and fluorescence spectroscopy with the aid of competitive binding methods. It was found that AO was included in the CB [7] cavity through strong ion-dipole interactions and hydrogen bonds. Theoretical studies based on calculations performed from first principles further confirmed this binding mode. Unusual downfield NMR shifts of the AO proton resonances in the presence of CB [7] were observed, in sharp contrast with cases of inclusion of other organic molecules in the CB [7]

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pH-Responsive Movement of Cucurbit[7]uril in a Diblock Polypseudorotaxane Containing Dimethyl β-Cyclodextrin and Cucurbit[7]uril

Cited by 99 publications

References 17 publications

‘Click’ Chemistry in Polymer and Materials Science

‘Click’ Chemistry in Polymer and Materials Science

Integrative self-sorting is a programming language for high level self-assembly

Insight into Unusual Downfield NMR Shifts in the Inclusion Complex of Acridine Orange with Cucurbit[7]uril

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