Solubilization of NaX Salts in Chloroform by Bifunctional Receptors

Scheerder, Jürgen; Duynhoven, John van; Engbersen, Johan F.J.; Reinhoudt, David N.

doi:10.1002/anie.199610901

Cited by 208 publications

(110 citation statements)

References 18 publications

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“…39 These researchers attached either two or four urea moieties to the upper rim of a calix [4]arene core that possessed the cation-recognizing tetra(ethyl ester) groups on the lower rim.…”

Section: Ion Pair Receptors Based On Urea Groups For Anion Recognitionmentioning

confidence: 99%

Calix[4]pyrrole-Based Ion Pair Receptors

2014

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Ion pair receptors, which are able to bind concurrently both a cation and an anion, often display higher selectivity and affinity for specific ion pairs than simple ion receptors capable of recognizing primarily either a cation or an anion. This enhancement in recognition function is attributable to direct or indirect cooperative interactions between cobound ions via electrostatic attractions between oppositely charged ions, as well as to positive allosteric effects. In addition, by virtue of binding the counterions of the targeted ion, ion pair receptors can minimize the solvation of the counterions, which can otherwise have a negative effect on the interactions between the receptors and the targeted ions. As a result of their more favorable interactions, ion pair receptors are attractive for use in applications, such as extraction and sensing, where control of the binding interactions is advantageous. In this Account, we illustrate this potential in the context of ion pair receptors based on the calix[4]pyrrole scaffold. Both simple ditopic ion pair receptors, containing sites for the recognition of a single anion and single cation, and so-called multitopic ion pair receptors will be discussed. The latter systems differ from conventional, so-called ditopic ion pair receptors in that they contain more than one binding site for a given targeted ion (e.g., a cation). This permits a level of selectivity and control over binding function not normally seen for simple ion or ion pair receptors containing one or two binding sites, respectively. Calix[4]pyrroles are macrocyclic compounds consisting of four pyrrole units linked via fully substituted sp 3 hybridized meso carbon atoms. They are effective receptors for Lewis basic anions (e.g., halides) in typical organic media and under certain conditions will recognize ion pairs containing charge diffuse cations, such as a small alkylammonium, imidazolium, or cesium cations. The calix[4]pyrrole framework is further attractive in that it is relatively easy to modify. In particular, functionalization of the β-pyrrolic carbon and meso-carbon atoms with simple crown ethers or calix[4]arene crown ethers can produce heteromultitopic ion pair receptors containing more than two cation binding sites. This allows the interactions between receptors and ions to be manipulated on a higher level than can be achieved using simple ion receptors or heteroditopic ion pair receptors and has made these systems attractive for use in ion transport, recognition, and extraction. Recent progress in developing calix[4]pyrroles as both multitopic and more conventional ion pair receptors is summarized in this Account. The emphasis will be on our own work.

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“…39 These researchers attached either two or four urea moieties to the upper rim of a calix [4]arene core that possessed the cation-recognizing tetra(ethyl ester) groups on the lower rim.…”

Section: Ion Pair Receptors Based On Urea Groups For Anion Recognitionmentioning

confidence: 99%

Calix[4]pyrrole-Based Ion Pair Receptors

2014

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“…The anion binding properties were examined by 1 H NMR titration experiments in CDCl 3 . Substantial down field shift of urea NH signal was observed when tetrabutylammonium acetate, dihydrogen phosphate, hydrogen sulfate, chloride and bromide salts were added, indicating that anion binding is taking place at the urea vicinity.…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Anion Binding Properties of Bifunctional Urea Derivative of Calix[4]diquinone

Oh¹,

Cho²,

Ryu³

et al. 2003

Bulletin of the Korean Chemical Society

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The simultaneous binding of cationic and anionic guest species by ditopic receptors is a rapidly developing new field for ion pair recognition of environment and biological importance. By taking advantage of calix[4]arene framework, a few neutral bifunctional receptors 1-4 were developed and showed the enhanced binding constants of hydrophilic anions in the presence of cations in organic media. As a consequence of their upper and lower rim of topologies the calixarenes are attractive host molecules to modify and so create unique geometries for the multifunctional receptors. The combination of two binding sites, urea for anions and two podand groups for cations, yields receptor that is capable of binding anions and alkali metal cations simultaneously. In addition to ion binding ability, two quinone moieties are introduced for the redox switchable receptors. [5][6][7] We report here the synthesis of a new bifunctional receptor calix[4]-diquinone 4 containing two urea moieties and two podand groups and the simultaneous binding properties of cation and anion guests were studied.

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“…[1][2][3][4][5] The selective recognition of these hydrophilic inorganic salts can thus only be achieved under conditions where their inherently high energy of hydration is overcome and selectivity-inducing interactions are used.…”

Section: Introductionmentioning

confidence: 99%

“…The solutions were magnetically stirred during the recording of all emf Scheme 1. Synthesis of salphenH2 derivatives (2) and its uranyl complex as ionophores (3). values.…”

mentioning

confidence: 99%

Beryllium(II) Recognition by Allosteric Effects in 1,2-Ethylenedioxybenzene Based Ditopic Receptors

Kim¹,

Kim²,

Hwang³

et al. 2011

Bulletin of the Korean Chemical Society

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Efficient ditopic receptor, uranyl(II) N,N'-(ethylenedioxy)benzenebis(salicylideneimine) (3) for beryllium ion has been obtained upon functionalization of 1,2-ethylenedioxybenzene (1) with a uranyl-salphen (salphen = N,N'-phenylenebis(salicylideneimine)) unit. Binding affinities of the receptor, 3 in AN-DMSO (v/v 95:5) solution have been measured for alkali and alkaline earth metal ions by conductometry comparing 1. The results showed that both monotopic 1 and ditopic receptor 3 were selective for Be 2+ ions over other cations, while especially 3 that can complex both with cations (coordinated to basic oxygen of ethylenedioxybenzene) and anions (coordinated to the Lewis acidic uranyl center) results in an increase of the stability constants by a factor of 10 2.42 with respect to 1. Furthermore, the Be 2+-3 interactions are demonstrated by 1 H NMR experiments in highly polar solvent medium, DMSO-d 6 . Higher selectivities were also observed for Be 2+ when the ditopic receptor, 3 was incorporated into PVC membranes and tested as ion selective electrodes at neutral pH.

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Solubilization of NaX Salts in Chloroform by Bifunctional Receptors

Cited by 208 publications

References 18 publications

Calix[4]pyrrole-Based Ion Pair Receptors

Calix[4]pyrrole-Based Ion Pair Receptors

Synthesis and Anion Binding Properties of Bifunctional Urea Derivative of Calix[4]diquinone

Beryllium(II) Recognition by Allosteric Effects in 1,2-Ethylenedioxybenzene Based Ditopic Receptors

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