Recognition of chiral anions using calix[4]arene-based ureido receptor in the 1,3-alternate conformation

Botha, F.; Budka, Jan; Eigner, Václav; Hudeček, Oldřích; Vrzal, Lukáš; Cı́sařová, Ivana; Lhoták, Pavel

doi:10.1016/j.tet.2013.11.030

Cited by 21 publications

(14 citation statements)

References 46 publications

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“…Calix[4]arenes have attracted interest due to their concave macrocyclic structure and hydrophobic cavity, despite their small cavity size, which can hamper the design of systems for anion recognition. Following subtle substitution and pre‐organization on the upper and lower rims, charged systems have been prepared and investigated. Different type of positively charged sites can be grafted onto the calixarene .…”

Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Positively Charged tris‐Imidazolium Calix[6]arene Hosts for Anion Recognition

et al. 2019

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The syntheses of new tripodal ligands with effective C 3 symmetry and anion recognition properties, are reported herein. The ligands have a 1,3,5-tris-methoxy-2,4,6-tris-(α,ωbromoalkoxy)calix- [6]arene as a backbone, and were prepared from 1,3,5-tris-methoxy-p-tert-butyl-calix [6]arene by alkylation with a series of α,ω-dibromo-alkanes [Br(CH 2 ) n Br] of different chain lengths (n = 2, 4 or 6). Further substitution of the bromo groups, via the use of 1-methyl-, 1-mesityl-or 2,6-diisopropylphenyl-1H-imidazole, led to alkylation by imidazole units and afforded tripodal and tricationic 1,3,5-tris-methoxy-2,4,6-trisimidazolium-p-tert-butyl-calix[6]arenes. These scaffolds provide a framework for H-bonded and electrostatic interactions with various anions and their anion binding properties were investigated by 1 H NMR and UV-visible spectroscopy. A sizeable selectivity for HSO 4 -(present as the n-Bu 4 N + salt) was demonstrated for most of the tripodal ligands considered in this work. Other anions such BF 4 -, ClO 4 -, PF 6 -, NO 3 -, Clexhibited weak to medium associations with the investigated ligands. A single crystal X-ray study, unfortunately of poor quality, corroborated the geometry of the calix [6]arenes that was previously established by 1 H NMR spectroscopy. The bindingsite geometry was more definitively probed by DFT calculations. IntroductionOver the last decades, the design of molecular receptors with high selectivity has been one of the goals and challenges in the field of supramolecular chemistry: [1] different functionalities and shapes [2][3][4] have been investigated to induce selective and efficient [5][6][7][8] recognition of charged and/or neutral species. [9] Due to their potential applications in the biological, environmental and industrial domains, [10][11][12][13][14] interest has also been focused on pre-organized hosts for anion coordination. [15,16] Nevertheless the selective coordination of anions remains a research area which has been less explored compared to that of cations. [17][18][19][20] The designed receptors can be neutral or cationic organic scaffolds or even metal-ligand complexes. [21][22][23][24][25] Calix[4]arenes have attracted interest due to their concave macrocyclic structure and hydrophobic cavity, despite their small cavity size, which can hamper the design of systems for anion recognition. Following subtle substitution and preorganization on the upper and lower rims, [26][27][28][29][30] charged systems have been prepared and investigated. Different type of positively charged sites can be grafted onto the calixarene. [31] Imidazolium groups, bound to different positions have been recently used. [32][33][34] The imidazolium proton's high acidity can promote efficient and strong C-H .… anion interactions and, in addition, the cationic imidazolium groups, may also induce strong electrostatic interactions with negatively charged anions. Secondary effects, such as anion-π interactions [35,36] could also take place. Overall, this series of complementary interactions makes c...

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Section: Resultsmentioning

confidence: 99%

Synthesis and Characterization of Positively Charged tris‐Imidazolium Calix[6]arene Hosts for Anion Recognition

et al. 2019

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“…[12][13][14] Sel 3 was prepared by synthesizing 2-methyl-1-butanol in calixarene, as follows. 15 Calix [4]arene (0.424 g, 1.00 mmol), triphenylphosphine (1.575 g, 6 mmol), and (S)-2-methylbutan-1-ol (1.08 mL, 10 mmol) were dissolved in dry toluene (30 mL), followed by the dropwise addition of DIAD (1.25 mL, 6 mmol) for 5 min at 0 C. Then, the reaction mixture was refluxed, and the reaction was monitored by TLC until no starting material remained. After completion of the reaction, the reaction mixture was cooled, and toluene was evaporated on a vacuum evaporator.…”

Section: Chemicals and Reagentsmentioning

confidence: 99%

Determination of Enantiomeric Purity for Chiral π‐Basic Aromatic Alcohols Chiral Samples by ¹H NMR Spectroscopy

Heo

Ryoo

2019

Bulletin Korean Chem Soc

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N-3,5-Dinitrobenzoyl(DNB)-(R)-phenylglycinol (Sel 1) and its silylation product (Sel 2) were used as the HPLC chiral stationary phase (CSP) for the resolution of racemic analytes. 2,2,2-Trifluoro-1-(9-anthryl) ethanol (S1), 1,1 0 -bi-2-naphthol (S2), and 6,6 0 -dibromo-1,1 0 -bi-2-naphthol (S3) were separated on the CSP, but the enantiomeric purities could not be accurately determined because of low resolution (Rs). In this study, the enantiomeric purity of S1-S3 were determined using Sel 1, Sel 2, and 1,3-bis[(S)methylbutoxy] calix[4]arene-2,4-diol (Sel 3). These were used for 1 H NMR experiments in three different solvents (CDCl 3 , DMSO-d 6 , and acetone-d 6 ). The accuracy of the enantiomeric purity of S1-S3 with Sel 2 was more than 98% when using CDCl 3 .

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“…The nitrogen atom of the amino acid was incorporated into an amide or urea group, while the carbon end was transformed into an amide or hydrazide moiety. Host 16 is an example where the functionalities were split, with the achiral anion binding groups and chiral selectors located on different arms of the calixarene core in an 1,3‐alternating mode. They remain far away in terms of chemical bond count but spatially close due to a rigid scaffold with appropriate geometry.…”

Section: Overview Of Receptor Constructionmentioning

confidence: 99%

Chiral Recognition of Carboxylates—Receptors, Analytical Tools, and More

Ulatowski

Jurczak

2016

Asian J Org Chem

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Mostc arboxylic acids, which are among the most common molecules in biological systems, are chiral. The enantiomers of these species are commonly distinguished in nature, but such recognitionh as provenq uite difficult to reproduce by using artificial receptors. Better knowledge of the chiral recognition of carboxylates is therefore crucial for af ullu nderstanding of host-guest phenomenai nn ature, and also for the design of new analytical devices.I nt his Focus Review we summarize andd iscuss the methods employed to evaluater eceptors, and present av ariety of structural designst hat have been utilized in chiral receptors. Some advanced functions of receptors in sensors and sensor arrays are also reviewed.

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Recognition of chiral anions using calix[4]arene-based ureido receptor in the 1,3-alternate conformation

Cited by 21 publications

References 46 publications

Synthesis and Characterization of Positively Charged tris‐Imidazolium Calix[6]arene Hosts for Anion Recognition

Synthesis and Characterization of Positively Charged tris‐Imidazolium Calix[6]arene Hosts for Anion Recognition

Determination of Enantiomeric Purity for Chiral π‐Basic Aromatic Alcohols Chiral Samples by ¹H NMR Spectroscopy

Chiral Recognition of Carboxylates—Receptors, Analytical Tools, and More

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Recognition of chiral anions using calix[4]arene-based ureido receptor in the 1,3-alternate conformation

Cited by 21 publications

References 46 publications

Synthesis and Characterization of Positively Charged tris‐Imidazolium Calix[6]arene Hosts for Anion Recognition

Synthesis and Characterization of Positively Charged tris‐Imidazolium Calix[6]arene Hosts for Anion Recognition

Determination of Enantiomeric Purity for Chiral π‐Basic Aromatic Alcohols Chiral Samples by 1H NMR Spectroscopy

Chiral Recognition of Carboxylates—Receptors, Analytical Tools, and More

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Determination of Enantiomeric Purity for Chiral π‐Basic Aromatic Alcohols Chiral Samples by ¹H NMR Spectroscopy