Enhancement of Anion Recognition Exhibited by a Halogen-Bonding Rotaxane Host System

Kilah, N. L.; Wise, Matthew D.; Serpell, Christopher J.; Thompson, Amber L.; White, Nicholas G.; Christensen, Kirsten E.; Beer, Paul D.

doi:10.1021/ja105263q

Cited by 254 publications

(200 citation statements)

References 26 publications

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“…However, in the past few years, a number of studies have demonstrated that XB anion receptors exhibit superior and contrasting recognition properties in comparison to their hydrogen‐bonding (HB) analogues 26. 27 For instance, we very recently reported that XB is remarkably effective for halide‐anion binding in water, and results in significantly enhanced recognition in acyclic and rotaxane‐based receptors compared to the analogous hydrogen‐bonding systems 28…”

Section: Introductionmentioning

confidence: 99%

Iodide Recognition and Sensing in Water by a Halogen‐Bonding Ruthenium(II)‐Based Rotaxane

Langton

Marques

Robinson

et al. 2015

Chemistry A European J

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The synthesis and anion‐recognition properties of the first halogen‐bonding rotaxane host to sense anions in water is described. The rotaxane features a halogen‐bonding axle component, which is stoppered with water‐solubilizing permethylated β‐cyclodextrin motifs, and a luminescent tris(bipyridine)ruthenium(II)‐based macrocycle component. 1H NMR anion‐binding titrations in D2O reveal the halogen‐bonding rotaxane to bind iodide with high affinity and with selectively over the smaller halide anions and sulfate. The binding affinity trend was explained through molecular dynamics simulations and free‐energy calculations. Photo‐physical investigations demonstrate the ability of the interlocked halogen‐bonding host to sense iodide in water, through enhancement of the macrocycle component’s RuII metal–ligand charge transfer (MLCT) emission.

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Section: Introductionmentioning

confidence: 99%

Iodide Recognition and Sensing in Water by a Halogen‐Bonding Ruthenium(II)‐Based Rotaxane

Langton

Marques

Robinson

et al. 2015

Chemistry A European J

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“…5 Many of these have shown enhanced binding properties over their hydrogen bonding (HB) analogues. 6,7 The electron-deficient 8 1,2,3-triazole motif has been exploited for anion recognition as an effective C-H hydrogen bond donor when integrated into multidentate macrocycles 9 and acyclic foldamers. [10][11][12] While the related 5-iodotriazole unit has been used as XB donor for anion binding, such XB anion hosts are rare in the literature.…”

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confidence: 99%

Neutral iodotriazole foldamers as tetradentate halogen bonding anion receptors

et al. 2017

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Neutral tetradentate halogen bond donor foldamers were synthesised and exhibit enhanced anion affinities over their hydrogen bonding analogues, displaying iodide selectivity over lighter halide, carboxylate and dihydrogen phosphate anions. A foldamer with a chiral (S)-binaphthol motif was demonstrated to distinguish between enantiomers of chiral anions.Halogen bonding (XB) is the attractive non-covalent interaction between a terminal s-hole on an electron deficient halogen atom and a Lewis base.1 Its strength and directionality have led to several applications in materials science and, more recently, in supramolecular chemistry 2,3 and organocatalysis. 4 In particular, XB donors have been successfully used in anion receptors for molecular recognition and sensing applications. 5 Many of these have shown enhanced binding properties over their hydrogen bonding (HB) analogues.6,7The electron-deficient 8 1,2,3-triazole motif has been exploited for anion recognition as an effective C-H hydrogen bond donor when integrated into multidentate macrocycles 9 and acyclic foldamers. [10][11][12] While the related 5-iodotriazole unit has been used as XB donor for anion binding, such XB anion hosts are rare in the literature. 13 No tetradentate XB donor foldamers have been described to date; the closest examples are a tridentate halopyridinium 14 and the use of triazole foldamers as XB acceptor hosts for organohalogens. 15Herein we sought to apply the potency of XB to enhance the anion affinity of the known triazole-based HB foldamer framework. Thus, XB foldamers with four 5-iodo-1,2,3-triazole XB donors were synthesized (Fig. 1) and their anion binding properties probed in comparison with HB analogues. A few variants were prepared: 1 and 2 contain triethylene glycol (TEG) chains for improved solubility, while in 3 and 4 9-anthrylmethyl termini have been introduced to provide a fluorescent response. 15,16 System 4 also includes a chiral (S)-binaphthol core in order to investigate XB chiral recognition, which has only previously been observed in a bidentate receptor. 17 Importantly, the XB foldamers exhibited overall stronger anion affinity than their HB analogs with the chiral XB host 4b displaying chiral discrimination with bulky amino acid anions. XB and HB foldamers 1-4 were synthesized via Cu(I)-catalysed azide-(iodo)alkyne cycloaddition (CuAAC) reactions (Scheme 1) using Cu(MeCN) 4 PF 6 in the presence of tris(benzyltriazolylmethyl) amine (TBTA) ligand. For the preparation of 1a and 2a an alternative benzyltriazolylmethylamine (BTA) ligand 18 was used as these compounds co-eluted with TBTA during chromatographic purification. As seen in Scheme 1, a terminal azide synthon 5-7 was reacted statistically with an excess of bis-alkyne 8a or 8b to afford an arm fragment 9-11. Two equivalents of 9-11 were then coupled under CuAAC conditions with a bis-azide core synthon 12 or 13 to give the anion receptors 1-4. The cycloadditions proceeded in moderate to high yields of 64-88% for 5H-triazole and 46-85% for 5I-triazole formation (s...

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“…Subsequently, a large number of MIMs have been prepared (Vickers & Beer 2007) using a range of anions as templates, including Cl − , Br − and SO 2− 4 , and most recently of all, the templation of MIMs involving halide anions has been invigorated by the newly discovered concept of halogen bonding (Kilah et al 2010). The development of functional devices, for example optical chloride sensors (Gassensmith et al 2010) based on anion-templated MIMs, underscores their potential for applications in the future.…”

Section: Synthetic Approaches To Mechanically Interlocked Moleculesmentioning

confidence: 99%

Mechanostereochemistry and the mechanical bond

2012

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The chemistry of mechanically interlocked molecules (MIMs), in which two or more covalently linked components are held together by mechanical bonds, has led to the coining of the term mechanostereochemistry to describe a new field of chemistry that embraces many aspects of MIMs, including their syntheses, properties, topologies where relevant and functions where operative. During the rapid development and emergence of the field, the synthesis of MIMs has witnessed the forsaking of the early and grossly inefficient statistical approaches for template-directed protocols, aided and abetted by molecular recognition processes and the tenets of self-assembly. The resounding success of these synthetic protocols, based on templation, has facilitated the design and construction of artificial molecular switches and machines, resulting more and more in the creation of integrated functional systems. This review highlights (i) the range of template-directed synthetic methods being used currently in the preparation of MIMs; (ii) the syntheses of topologically complex knots and links in the form of stable molecular compounds; and (iii) the incorporation of bistable MIMs into many different device settings associated with surfaces, nanoparticles and solid-state materials in response to the needs of particular applications that are perceived to be fair game for mechanostereochemistry.

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Enhancement of Anion Recognition Exhibited by a Halogen-Bonding Rotaxane Host System

Cited by 254 publications

References 26 publications

Iodide Recognition and Sensing in Water by a Halogen‐Bonding Ruthenium(II)‐Based Rotaxane

Iodide Recognition and Sensing in Water by a Halogen‐Bonding Ruthenium(II)‐Based Rotaxane

Neutral iodotriazole foldamers as tetradentate halogen bonding anion receptors

Mechanostereochemistry and the mechanical bond

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