Sulfate anion templated synthesis of a triply interlocked capsule

Li, Yitong; Mullen, Kathleen M.; Claridge, Tim D. W.; Costa, Paulo J.; Félix, Vítor; Beer, Paul D.

doi:10.1039/b915548a

Cited by 91 publications

(52 citation statements)

References 17 publications

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“…Directed attractive interactions between the substrate and binding sites located inside the cavity as in the active centers of enzymes are, however, relatively rare. Notable examples of containers with functionalized interiors are two independently described coordination cages for sulfate ions,9a,b an interlocked sulfate‐binding capsule,9c self‐assembled phenylalanine‐substituted resorcarene dimers,9d–f and a few other systems 9g–i. In addition, bicyclic and tricyclic ammonium‐ or amide‐based anion receptors possess cavities lined by properly arranged hydrogen‐bond donors 9j,k…”

Section: Introductionmentioning

confidence: 99%

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Chronic pain 5 years after randomized comparison of laparoscopic and Lichtenstein inguinal hernia repair (Br J Surg 2010; 97: 600–608)

Hussain

El-Hasani

2010

British Journal of Surgery

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Ganz einfach: Erstmals gelang eine präparativ nützliche intermolekulare oxidative Heterokupplung von Imiden und Oxindolen an Ester, Ketone und Lactone. Das strategisch geschickte Nutzen der ursprünglichen Oxidationsstufe der Reaktanten ermöglicht den Verzicht auf Präfunktionalisierungsschritte (Halogenierung, Enolsilan‐Bildung) und erlaubt so eine rasche Synthese unsymmetrischer Lignane wie (−)‐Bursehernin (1).

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Section: Introductionmentioning

confidence: 99%

“…This reaction, often referred to as a click reaction,11b–c has been shown to be immensely useful for a variety of purposes. However, to the best of our knowledge it has only rarely been applied to the synthesis of molecular containers or cages so far 9c. 12 …”

Section: Introductionmentioning

confidence: 99%

Chronic pain 5 years after randomized comparison of laparoscopic and Lichtenstein inguinal hernia repair (Br J Surg 2010; 97: 600–608)

Hussain

El-Hasani

2010

British Journal of Surgery

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“…Indeed, impressive examples of such species have been assembled using cationic [3,4] and neutral [5] templates. [8,9] A "handcuff" catenane is an example of a higher-order interlocked architecture where two covalently linked macrocycles have a single macrocycle passing through both rings ( Figure 1). In particular, almost all reports of anion templation of interlocked molecules involve the construction of either [2]catenane or [2]rotaxane structures.…”

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confidence: 99%

“…In contrast, the use of anion templation to generate interlocked structures, whilst having been demonstrated by us [6] and others, [7] remains in its infancy. [8,9] A "handcuff" catenane is an example of a higher-order interlocked architecture where two covalently linked macrocycles have a single macrocycle passing through both rings ( Figure 1). [8,9] A "handcuff" catenane is an example of a higher-order interlocked architecture where two covalently linked macrocycles have a single macrocycle passing through both rings ( Figure 1).…”

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confidence: 99%

Chloride Anion Templated Synthesis and Crystal Structure of a Handcuff Catenane

Evans,

Serpell,

Beer

2011

Angew Chem Int Ed

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Catenanes and rotaxanes are highly attractive synthetic targets in supramolecular chemistry due, in part, to their potential uses as molecular machines [1] or as selective hosts for ionic and molecular guests. [2] The preparation of higherorder interlocked architectures provides a much greater synthetic challenge than the construction of the prototypical [2]catenanes and [2]rotaxanes, but can allow for functionality not open to simpler systems. Indeed, impressive examples of such species have been assembled using cationic [3,4] and neutral [5] templates. In contrast, the use of anion templation to generate interlocked structures, whilst having been demonstrated by us [6] and others, [7] remains in its infancy. In particular, almost all reports of anion templation of interlocked molecules involve the construction of either [2]catenane or [2]rotaxane structures. [8,9] A "handcuff" catenane is an example of a higher-order interlocked architecture where two covalently linked macrocycles have a single macrocycle passing through both rings ( Figure 1). To the best of our knowledge, only two examples of such species-constructed using cationic templation-have been described in the chemical literature to date. [10,11] Here, we detail the preparation and characterization of a novel chloride anion templated handcuff catenane, along with its crystal structure-this being the first handcuff catenane crystal structure to be determined.The synthetic strategy undertaken to prepare the target handcuff catenane is illustrated in Figure 2. Two identical Nmethyl pyridinium molecules thread, by anion templation, through a handcuff-like bis(macrocycle), where each macrocycle contains an isophthalamide group able to hydrogen bond to the chloride anion. Pseudorotaxane formation is also supported by p-p stacking between the electron-rich hydroquinone groups of the bis(macrocycle) and electron-poor pyridinium rings of the threading components. Subsequent cyclization will lead to the formation of the desired handcuff catenane.The actual detail of the synthesis of novel bis(macrocycle) 4 and handcuff catenane 6 2+ (Cl À ) 2 is shown in Schemes 1 and 2. The bis(macrocycle) was synthesized by reacting 2 equivalents of bis(amine) 1 with tetraacid chloride 2 [12] in the presence of 2 equivalents of the N-methyl pyridinium template 3 + Cl À and NEt 3 in dry CH 2 Cl 2 . [13] After aqueous workup and silica gel chromatography, 4 was isolated in a 15 % yield. [14] Subsequently, 4 was suspended in dry CH 2 Cl 2 , and two equivalents of the bis(vinyl) precursor 5 + Cl À [6b] added, which led to the solubilization of the bis(macrocycle) indicating that the prerequisite pseudorotaxane complex was formed. Addition of 10 % (by wt) Grubbs secondgeneration catalyst, followed by stirring at room temperature for 16 hours under a nitrogen atmosphere allowed ringclosing metathesis (RCM) to occur. After solvent removal, preparative silica gel thin layer chromatography (TLC) was undertaken, whereupon a new yellow band was separated from the crude reaction mixtu...

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“…ATRP is strongly influenced by the values of the rate constants, k act , 40 and k deact , 41 and their ratio, K ATRP . 40,42 Rates of ATRP increase with catalysts activity (K ATRP ) but /L] ratio, and build-up in the concentration of deactivator via the persistent radical effect.…”

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Synthesis of cyclic macromolecular architectures

Hossain¹

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Design and synthesis of complex polymer architectures is a promising field in polymer chemistry to produce new materials with unprecedented macroscopic properties. Recent advances in 'living' radical polymerization and polymer coupling chemistries has facilitated the fabrication of new polymer topologies. The main goal of this thesis is to develop novel methods to fabricate cyclic polymers with pendent functional groups, and use them as building blocks in the synthesis of complex polymer topologies. The 'click' reaction used to couple the cyclic polymers was by copper-catalyzed azide/alkyne cycloaddition reaction (CuAAC). The thermal properties of the resultant complex structures were investigate by Differential Scanning Calorimetry to determine the effect of topology on the glass transition temperature (T g ).First, the combination of RAFT polymerization and CuAAC reaction were used for the synthesis of cyclic polymer with pendent hydroxyl group. An alkyne functional RAFT agent was used for the synthesis of linear polystyrene (PSTY), in which the RAFT moiety was then converted to an azide moiety and a free OH group via a two step synthetic reaction.This linear polymer was cyclized in high yield and considered as a highly efficient method, and has the potential to be applied to a wide range of polymers made by RAFT. Although the monocyclic polymer was synthesized in high yield, we observed ester cleavage during the synthesis of more complex topologies from the monocyclic precursor building blocks. A detail degradation study was conducted using different catalyst/ligand complexes, and finally the methodology for the synthesis of different topologies of cyclics was amended to reduce this degradative side reaction. However, for the fabrication of more complex topologies, the synthetic methodology was redirected towards a more stable synthetic approach.A modular approach was followed for the synthesis of multifunctional linear polymer precursors through modulating the Cu(I) activity towards the click reaction over radical formation. The post-modification approach allowed for the synthesis of α, ω-heterotelechelic linear polymer precursors which was cyclised by using a modified CuAAC cyclization reaction in which the hydroxyl functional groups were equally spaced. The hydroxyl groups were converted to azides or alkynes and then further coupled together through the CuAAC reaction to produce complex structures, including a spiro tricyclic and 1 st generation dendritic structures. All these structures were produced in high yields with good 'click' efficiencies. The purity and 'click' efficiencies were calculated by fitting the experimental SEC traces with a log-normal distribution (LND) model based on fitting iii multiple Gaussiun functions for each polymer species. The crude polymer was purified by preparative SEC that essentially removes all the unreacted species and by-products.In the follow up work, a range of different topologies of cyclic homo and copolymers were synthesized by combining of ATRP, SET-LRP a...

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Sulfate anion templated synthesis of a triply interlocked capsule

Abstract: Sulfate templation has been used in the synthesis of a novel tris-urea-based triply interlocked capsule, whose structure has been verified by DOSY NMR, mass spectrometry and molecular modelling investigations.

Cited by 91 publications

References 17 publications

Chronic pain 5 years after randomized comparison of laparoscopic and Lichtenstein inguinal hernia repair (Br J Surg 2010; 97: 600–608)

Chronic pain 5 years after randomized comparison of laparoscopic and Lichtenstein inguinal hernia repair (Br J Surg 2010; 97: 600–608)

Chloride Anion Templated Synthesis and Crystal Structure of a Handcuff Catenane

Synthesis of cyclic macromolecular architectures

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