Anion recognition through modified calixarenes: a highly selective sensor for monohydrogen phosphate

Gupta, Vinod K.; Ludwig, Rainer; Agarwal, Saurabh

doi:10.1016/j.aca.2005.02.008

Cited by 177 publications

(40 citation statements)

References 24 publications

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“…It is concluded that three nitrogen atoms are mainly involved in binding to TcO4-by means of ion-ion, cation-dipole and hydrogen bond interactions. The calix [4]arene backbone may be too rigid to allow the fourth nitrogen atom to rearrange into a position suitable for interaction.…”

Section: Resultsmentioning

confidence: 99%

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Solvent Extraction of Tc (VII) by Calixarenes Bearing Pyridino Groups

Ludwig

Dzung

2005

J. Nucl. Radiochem. Sci.

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The distribution of Tc(VII) between aqueous acidic solutions and organic solutions of nitrogen-containing extractants is investigated in order to establish the relationships between extraction power towards the Tc(VII) -anion, ligand molecular structure, influence of the media and the speciation in this ion-pair extraction. Ligands belonging to the class of calixarenes, derivatized with pyridino groups were newly devloped for these purposes. The number of substituents per calixarene, the position of the nitrogen and the size of calixarene are varying structural parameters. The nitrogen atoms are either protonated or quaternized to allow ion-pair extraction. The aqueous phase contains nitrate or chloride at varying or constant ionic strength. Experiments using Aliquat-336 were conducted under similar conditions.

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Section: Resultsmentioning

confidence: 99%

“…Figure la shows the distribution coefficients (D = Corg/Caq) for Tc(VII) in the extraction by calix [4]arenes bearing 2, 3, or 4 pyridino (py) substituents at the lower rim. In this series, the nitrogen atom is located ortho to the anchor group (2PyOC4), thus being located 'inside' the cavity.…”

Section: Resultsmentioning

confidence: 99%

Solvent Extraction of Tc (VII) by Calixarenes Bearing Pyridino Groups

Ludwig

Dzung

2005

J. Nucl. Radiochem. Sci.

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“…ISEs are also of obvious interest because they can help translate the chemistry of new substrate binding systems into tools that can be used to recognize selectively various targeted species in the presence of potentially interfering analytes. In the specific case of anion recognition, this approach has been explored extensively by Umezawa, Meyerhoff, Simon, Reinhoudt, Schmidtchen and others using a range of receptors including bis-guanidinium [1][2], porphyrins [3], protonated polyamines [4][5][6][7], and protonated sapphyrins [8][9][10], as well as a variety of Lewis acidic systems such as calixarenes [11][12][13][14][15], uranylsalenophenes [16][17], metalloporphyrins [18][19][20][21][22], metallocenes [23], other organometallic derivatives [24][25][26], and fluorinated compounds [27].…”

Section: Introductionmentioning

confidence: 99%

Potentiometric response and mechanism of anionic recognition of heterocalixarene-based ion selective electrodes

Shishkanova

Sýkora

Sessler

et al. 2007

Analytica Chimica Acta

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The ion selective electrode (ISE)-based potentiometric approach is shown to be an effective means of characterizing the anion recognition sites in the molecular receptor calix[2]pyridino[2]pyrrole (CPP). In particular, potentiometric pH-measurements involving the use of experimental PVCmembranes based on CPP revealed the existence of both mono-and diprotonated forms of the receptor under readily accessible conditions. Based on these analyses, apparent surface protonation constants for this heterocalixarene were found to lie between 8.5-8.9 (pK B1 ) and 3.3-3.8 (pK B2 ). CPP was found to interact with targeted anionic analytes based on both coulombic and hydrogen bond interactions, as inferred from varying the kinds of ionic sites present within the membrane phase. Potentiometric selectivity studies revealed that CPP preferred "Y-shaped" anions (e.g. acetate, lactate, benzoate) over spherical anions (e.g. fluoride and chloride), fluoride over chloride within the set of spherical anions, and the ortho-isomer over the corresponding meta-and para-isomers in the case of hydroxybenzoate (salicylate and congeners). In the context of this study the advantages of potentiometric determinations of acetylsalicylic acid using optimized PVC-membranes based on CPP relative to more conventional PVC-membrane ISEs based on traditional anion exchanger were also demonstrated.

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“…47 Furthermore, the anions complexation can be more difficult than that of cations, and a variety of considerations come into play, including (a) the charge, (b) the size, which is often larger than the metal cation one, (c) the shape; whereas the metal cations are spherical, the anions frequently are not, (d) pH dependence, often more critical than in the case of metal cations and (e) solvation, which has a strong influence on the binding strength. There are enormous reports on the recognition of various anions (inorganic) by the calix [4]arene derivatives in the organic solvents but there are only few reports on the anion complexation by the water-soluble calix [4]arenes in the aqueous medium, 48 which opens a new direction for such studies.…”

Section: Inorganic Anionsmentioning

confidence: 99%