Selective Anion Receptor Research Articles

A theoretical insight into several common anion recognitions based on double‐dentate hydrogen bond and anion‐π coexistence

AbstractAnion recognitions of a pincer‐like receptor (N,N'‐bis‐(2‐fluoro‐benzoyl‐oxyethyl)‐urea, AR) for several common inorganic anions (F−, Cl−, Br−, I−, CN−, and SO42−) were theoretically explored and predicted at a molecular level in this paper. Geometric configurations of the complex (AR@X (X = F−, Cl−, Br−, and SO42−)) show that two N─H groups as a claw and two ─C6H4F rings on AR as a pair of tweezers simultaneously interact with the captured anions through cooperative double‐dentate hydrogen bond and double‐side anion‐π interactions. However, there is no anion‐π contact between AR and I− ion in AR@I− complex. In the system of AR@CN−, a stable single‐side CN−‐π is possible. The structure of stable 2:1 complex formed with two AR receptors and one SO42− is also predicted. The binding energies and thermodynamic information indicate that the recognitions of the above six anions by AR in the vacuum are spontaneously enthalpy‐driven and entropy‐opposed. The binding energy ΔEcp between SO42− and AR is higher than 340 kJ mol−1, suggesting that AR is an ideal selective anion receptor for SO42−. Additionally, energy decomposition analysis based on localized molecular orbital energy decomposition analysis (LMO‐EDA) was performed. Electronic properties and behaviors of the present systems were further discussed according to calculations on frontier molecular orbital, UV‐vis spectra, and visualized weak interaction regions.

A fluoride selective water-soluble anion receptor based on a 1,2-phenylenediacetic acid and calcium ion dimer

The dimeric receptor 1 from 1,2-phenylenediacetic acid and calcium ions recognized fluoride ions almost exclusively in 100% water.

A Hydrogen Pyrophosphate Selective Anion Receptor Based on Thiosemicarbazone

A novel rigid anion receptor 1 containing thiosemicarbazone groups were synthesized. Receptor 1 displayed competitive turn‐off fluorescence and colorimetric response for hydrogen pyrophosphate. This recognition process was confirmed by UV–vis, fluorescence titrations. A detailed analysis of the TD‐density functional theory calculations was consistent with the observed colorimetric experiments. These experiments revealed that the colorimetric and fluorescent response is triggered by thiourea/ HP2O73− hydrogen bonding.

Anion Recognition Based on a Combination of Double-Dentate Hydrogen Bond and Double-Side Anion-π Noncovalent Interactions.

Anion recognitions between common anions and a novel pincer-like receptor (N,N'-bis(5-fluorobenzoyloxyethyl)urea, BFUR) were theoretically explored, particularly on geometric features of the BFUR@X (X = F-, Cl-, Br-, I-, CO32-, NO3-, and SO42-) systems at a molecular level in this work. Complex structures show that two N-H groups as a claw and two -C6F5 rings on BFUR as a pair of tweezers simultaneously interact with captured anions through cooperative double-dentate hydrogen bond and double-side anion-π interactions. The binding energies and thermodynamic information indicate that the recognitions of the seven anions by BFUR in vacuum are enthalpy-driven and entropy-opposed, which occur spontaneously. Although the binding energy ΔEcp between F- and BFUR is relatively high (289.30 kJ·mol-1), ΔEcp, ΔG, and ΔH of the recognition for CO32- and SO42- are much larger than the cases of F-, Cl-, Br-, I-, and NO3-, suggesting that BFUR is an ideal selective anion receptor for CO32- and SO42-. Additionally, energy decomposition analysis based on localized molecular orbital energy decomposition analysis (LMO-EDA) was performed; electronic properties and behaviors of the present systems were further discussed according to calculations on frontier molecular orbital, UV-vis spectra, total electrostatic potential, and visualized weak interaction regions. The present theoretical exploration of BFUR@X (X = F-, Cl-, Br-, I-, CO32-, NO3-, and SO42-) systems is fundamentally crucial to establish an anion recognition structure-property relationship upon combination of different noncovalent interactions, that is, double-dentate hydrogen bond and double-side anion-π interactions.

Selective anion receptor for fluoride detection using ferrocenyl–boronate derivative

The reaction of ferrocenecarboxaldehyde with (2-aminoethoxy)diphenylborane led to the formation of ferrocenyl-substituted boronate receptor 1, which was characterized by IR, MS, HRMS, 11B, 1H and 13C NMR spectra. The signaling process was confirmed by UV–vis, electrochemistry measurements as well as 1H and 19F NMR spectroscopy. The receptor 1 exhibited high selectivity for F− in CH3CN solution over all the other anions in the DPVs (differential pulse voltammetry). 1H NMR titrations indicated that F− ion induced tautomerism of E- and Z-isomer transformations of the receptor 1 and there were three kinds of protons showing obvious highfield shifts for receptor 1 in DMSO-d6. UV–vis titrations demonstrated that the receptor 1 could bind F− ion forming 1:1 stoichiometric complexes and show high selectivity and sensitivity towards F− ion.

Nitrite selective anion receptor based on 1-methyl-1H-perimidine

A new anion receptor 1, which utilizes only C–H hydrogen bonding have been designed and synthesized. This receptor utilizes both aromatic C–H (two perimidine C2-H, anthracene 9-H) and aliphatic C–H (two perimidine 1-methyl C–H, two benzylic C–H) as hydrogen bonding moieties. The receptor 1 is found to have considerable binding affinity for weakly basic anions even in polar solvent such as DMSO. In addition, receptor 1 is selective for nitrite. The experimental data from UV–vis, fluorescence and 1H NMR titration are consistent with theoretical studies. The order of the interaction of the C–H groups of perimidine containing receptor with NO2− anion is found to be perimidine (C–H)>methylene (C–H)>methyl (C–H)>anthracene (C–H).

A dihydrogen phosphate selective anion receptor based on acylhydrazone and pyrazole

A novel chromogenic anion receptor 1 based on acylhydrazone and pyrazole has been designed and synthesized. Receptor 1 forms stable 1 : 1 complexes with dihydrogen phosphate and other halide anions in DMSO solution.

Dihydrogen Phosphate Selective Anion Receptor Based on Acylhydrazone

Anion receptor 1 based on acylhydrazone has been designed and synthesized. UV–vis and H NMR titration showed that receptor 1 is selective receptor for dihydrogen phosphate (H2PO4 −). Dihydrogen phosphate was complexed by the receptor 1 via at least 4 hydrogen bonding interactions, contributing from two amide N-Hs and two imine C-Hs. In addition, nitrogen in the aromatic ring could make 2 additional hydrogen bondings with OH groups in the dihydrogen phosphate. However, the receptor 1 could make only 4 hydrogen bonds with halides. Therefore, receptor 1 could bind anions through hydrogen bonds with a selectivity in the order of H2PO4 − > Br− > Cl− in highly polar solvent such as DMSO.

Synthesis and application of an efficient calix[4]arene-based anion receptor bearing imidazole groups for Cr(VI) anionic species

We synthesized the new calix[4]arene amines bearing two and four imidazole or tert-butylamine moieties (9a,b/10a,b) by the reaction of di- or tetra-tosylated calix[4]arene derivatives (7 and 8, respectively) with 1-(3-aminopropyl)imidazole and/or tert-butylamine, respectively. After the characterization of 9a,b/10a,b their extraction abilities toward Cr(VI) anionic species (CAS) was evaluated and compared by the liquid–liquid extraction method. The extraction results revealed that calix[4]arene amine having four imidazole groups (10a) was an efficient anion receptor for CAS. Moreover, the extraction of CAS by 10a in the presence of other anions such as Cl−, NO3−, and PO43− showed that 10a could be a selective anion receptor for CAS in the presence of those anions.

A new dihydrogen phosphate selective anion receptor utilizing carbazole and indole

Dihydrogen phosphate selective anion receptor 2 based on one carbazole and two indole moieties was designed and synthesized. Fluorescence and 1H NMR titration clearly showed that receptor 2 was a good sensor in the selective recognition for dihydrogen phosphate over other anions. Receptor 2 utilized two amide hydrogens, three amine hydrogens to bind anions. These five hydrogens formed concave structure for the selective recognition of dihydrogen phosphate.

A non-symmetric pillar[5]arene-based selective anion receptor for fluoride

A novel non-symmetric pillar[5]arene-based anion receptor containing multiple triazole anion-binding sites was designed and synthesized. It has high affinity and selectivity for the fluoride anion.

A New Carboxylate Selective Anion Receptor Utilizing Amide and Carbamate Hydrogens

E-mail: kangjm@sejong.ac.krReceived May 9, 2011, Accepted May 17, 2011A new anion receptor utilizing carbamate functionality as hydrogen bonding site has been designed andsynthesized. This new receptor 2 has two amide hydrogens and two carbamate hydrogens anchored at 1,8-position of anthracene. These four hydrogens form a concave structure for the anions and the receptor 2 wasfound to be a selective receptor for acetate among the anions investigated.Key Words : Anion receptor, Amide, Carbamate, Hydrogen bonds, AnthraceneIntroductionThere have been considerable efforts to develop efficientartificial receptors for anion recognition and sensing asanions play a major role in biological, medical, environ-mental, and chemical sciences.

Fine tuning of receptor polarity for the development of selective naked eye anion receptor

We designed and synthesized new anion receptors 1, 2, and 3, which have different N–H polarity. According to their N–H polarities, these receptors showed different selectivities for the anions they were interacting with. The difference of selectivity could be easily recognized from their color change during recognition events. Therefore, fine tuning of receptor polarity could be a good strategy for the designing of a selective anion receptor and made it possible to develop a selective naked eye anion receptor.

Carboxylate selective anion receptor based on two anthracenes with malonamide spacer

Acetate selective anion receptor 1 based on two anthracenes with malonamide spacer has been designed and synthesized. Fluorescence and 1H NMR titration clearly showed that receptor 1 is a good sensor in the selective recognition for carboxylate anions over other anions such as I −, Br −, Cl −, HSO 4 - , H 2 PO 4 - and NO 3 - . In this receptor 1, all the four hydrogens from amide and carbamate were involved in bonding with carboxylate ion.

Colorimetric response of spiropyran derivative for anions in aqueous or organic media

We previously found that a simple spiropyran derivative ( 1:1′,3′,3′-trimethyl-6-nitro-spiro-[2 H-1-benzopyran-2,2′-indoline]) behaves as a selective and sensitive cyanide anion (CN −) receptor in aqueous media under UV irradiation 13 . The receptor, when irradiated by UV light in a water/MeCN mixture, creates a CN −-selective absorption band via a nucleophilic addition of CN − to 1 (formation of the 1–CN − species) and allows quantitative determination of very low levels of CN −. In the present work, effects of pH and water content on the response of 1 to anions were studied to clarify the detailed properties of 1. In aqueous media, 1 reacts selectively with CN −regardless of pH and water content, but the reaction is suppressed by a decrease in pH and an increase in water content due to the protonation of CN −. In contrast, in pure MeCN, addition of F − also creates a new absorption band, as does CN −. This is promoted via a nucleophilic interaction between 1 and F − in a 1:2 stoichiometry (formation of the 1–2F − species). The 1–CN − and 1–2F − species have different photochemical properties; the 1–CN − species is stable upon UV irradiation, while the UV irradiation of the 1–2F − species leads to a decomposition of the spiropyran platform.

Spiropyran as a Selective, Sensitive, and Reproducible Cyanide Anion Receptor

A spiropyran derivative (1) behaves as a selective and sensitive cyanide anion receptor in aqueous media under UV irradiation. The receptor can be reproduced just by irradiation with visible light.

A Novel Selective Anion Receptor for Iodide Ion: Synthesis, Characterization and Anion Binding

A carbazole-based neutral anion receptor 3 has been designed and synthesized. Anion binding studies carried out using 1H NMR and UV-visible reveal that this compound showed good selectivity for the iodide ion over other anions. The high selectivity for iodide ion among the anions is attributed mainly to the complementarity of the geometries between the receptor 3 and iodide ion.

Synthesis and Anion Recognition of Cholic Acid-based Tripodal Receptor: A Chloride Selective Anion Receptor

Synthesis of cholic acid-based tripodal receptor (1) and its high chloride ion affinity in comparison with that of chenodeoxycholic acid (2) and lithocholic acid-based receptor (3) was achieved. Anion binding affinities of the receptors were evaluated <TEX>$by\;^1H$</TEX> NMR and ITC titrations. Tripodal receptor 1 showed a selective affinity for <TEX>$CI ^-$</TEX> over <TEX>$Br ^-$</TEX>, <TEX>$I^-$</TEX>, <TEX>$H_2 PO _4\;^-$</TEX>, and <TEX>$CH _3 CO_2\;^-$</TEX>. The selectivity of 1 for <TEX>$CI ^-$</TEX> is about 3 times that of <TEX>$Br ^-$</TEX>, and 17 times that for <TEX>$H_2 PO_4\;^-$</TEX>.

A hyodeoxycholic acid-based molecular tweezer: a highly selective fluoride anion receptor

A new molecular tweezer receptor Hc1 based on hyodeoxycholic acid has been synthesized and its binding properties were accessed by 1H NMR and isothermal titration calorimetry experiments. Molecular tweezer Hc1 shows a high selectivity toward F − over Cl −, Br −, I −, and H 2PO 4 −.

Iodide selective fluorescent anion receptor with two methylene bridged bis-imidazolium rings on naphthalene

We have designed and synthesized fluorescent anion receptor 2 , bearing two methylene bridged bis-imidazolium ring on 1,8-positions of naphthalene. Anion binding studies carried out using fluorescence spectroscopy and 1H NMR revealed that this compound displays selective affinities for iodide ion.