Exploring Selectivity of 22 Acyclic Urea‐, Carbazole‐ and Indolocarbazole‐Based Receptors towards 11 Monocarboxylates

Martin, Kerli; Nõges, Juuli; Haav, Kristjan; Kadam, Sandip A.; Pung, Astrid; Leito, Ivo

doi:10.1002/ejoc.201700931

Cited by 20 publications

(30 citation statements)

References 29 publications

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“… a All anions were used as tetrabutylammonium salts at ambient temperatures. The standard uncertainties of the log K ass values, accounting for consistency of measurements, uncertainty of anchoring and possible systematic effects (see reference [ 8 ] for details) were in the range of 0.04 and 0.09; b solution not prepared due to low solubility of the receptor. …”

Section: Resultsmentioning

confidence: 99%

“…Cyclization of the receptor is possible via the positions 8 of the carbazole, using, e.g., amide bonds. Anion receptors containing carbazole and amide functionalities were investigated in numerous works [6][7][8][9]. In some cases, these functionalities were incorporated into macrocyclic systems, thereby offering valuable insight for design criteria.…”

Section: Introductionmentioning

confidence: 99%

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Design, synthesis and application of carbazole macrocycles in anion sensors

Rüütel¹,

Yrjänä²,

Kadam³

et al. 2020

Beilstein J. Org. Chem.

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Carboxylate sensing solid-contact ion-selective electrodes (ISEs) were created to provide a proof-of-concept ISE development process covering all aspects from in silico ionophore design to functional sensor characterization. The biscarbazolylurea moiety was used to synthesize methylene-bridged macrocycles of different ring size aiming to fine tune selectivity towards different carboxylates. Cyclization was achieved with two separate strategies, using either amide synthesis to access up to –[CH2]10– macrocycles or acyl halides to access up to –[CH2]14– macrocycles. Seventy-five receptor–anion complexes were modelled and studied with COSMO-RS, in addition to all free host molecules. In order to predict initial selectivity towards carboxylates, 1H NMR relative titrations were used to quantify binding in DMSO-d 6/H2O solvent systems of two proportions – 99.5%:0.5% m/m and 90.0%:10.0% m/m, suggesting initial selectivity towards acetate. Three ionophores were selected for successful sensor prototype development and characterization. The constructed ion-selective electrodes showed higher selectivity towards benzoate than acetate, i.e., the selectivity patterns of the final sensors deviated from that predicted by the classic titration experiments. While the binding constants obtained by NMR titration in DMSO-d 6/H2O solvent systems provided important guidance for sensor development, the results obtained in this work emphasize the importance of evaluating the binding behavior of receptors in real sensor membranes.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Design, synthesis and application of carbazole macrocycles in anion sensors

Rüütel¹,

Yrjänä²,

Kadam³

et al. 2020

Beilstein J. Org. Chem.

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“…) in which we found that out of 22 acyclic synthetic receptors with different numbers and geometric arrangements of hydrogen‐bond donors (HBD) and hydrophobic moieties, the receptor shown in Figure is the strongest binder for five monocarboxylates out of 11 in DMSO : H 2 O (99.5 % : 0.5 % m/m). The receptor molecule is based on 1,3‐bis(carbazolyl)urea and has eight NH groups that form a suitable binding pocket/cavity for smaller monocarboxylates like acetate . Therefore, this 1,3‐bis(carbazolyl)urea derivative (Figure ) was chosen as the ionophore for constructing SC‐ISEs in this work.…”

Section: Introductionmentioning

confidence: 99%

“…In this study, the ionophore (Figure ) was used to fabricate anion‐selective SC‐ISEs, utilizing PEDOT as the solid contact. This ionophore has been shown to have high binding affinity towards carboxylate ions . NMR experiments and computations have shown that 1,3‐bis(carbazolyl)urea derivatives bind carboxylates first of all via four hydrogen bonds donated by the two central urea NH groups and the two adjacent carbazole NH groups .…”

Section: Introductionmentioning

confidence: 99%

Solid‐contact Acetate‐selective Electrode Based on a 1,3‐bis(carbazolyl)urea‐ionophore

et al. 2019

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The construction and study of solid‐contact acetate‐selective electrodes is described using a 1,3‐bis(carbazolyl)urea derivative as a neutral hydrogen‐bonding ionophore and poly(3,4‐ethylenedioxythiophene) as the solid contact. It was shown recently that this ionophore binds acetate (logKass=4.98) that is used as primary ion in this study. The electrodes show linearity over the activity range of 10−4.50–10−1.10 with a sub‐Nernstian slope of −51.3 mV per decade and a detection limit of 10−5.00. The anion‐selectivity pattern of these electrodes deviates markedly from the Hofmeister pattern. When adding ionophore to the membrane the logarithm of the selectivity coefficient (logK) for SCN− decreased from 6.5 to 1.2, logK for I− decreased from 5.7 to 0.9, logK for NO3− decreased from 4.3 to 0.6 and logK for Br− decreased from 3.3 to 0.1. The selectivity coefficients of hydrophilic anions such as Cl−, F−, HPO42−, and SO42− are significantly lower than in case of the ionophore‐free membrane. It was discovered that the constructed electrodes are also relatively selective to bicarbonate. This work is an important step towards the further development of solid‐contact anion‐selective electrodes.

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“…62-65 • C) demonstrated by Ribeiro et al [26]. Tetrabutylammonium salt of ketoprofen is also known from the literature [27], but authors had not given the melting point of that. According to the confirmed definition, the synthesized KETO-ILs can be qualified as the protic ionic liquids [28].…”

Section: Synthesis Of the Amino-acid Ester-ketoprofenatementioning

confidence: 99%

Ketoprofen-Based Ionic Liquids: Synthesis and Interactions with Bovine Serum Albumin

et al. 2019

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The development of ionic liquids based on active pharmaceutical ingredients (API-ILs) is a possible solution to some of the problems of solid and/or hydrophobic drugs such as low solubility and bioavailability, polymorphism and an alternative route of administration could be suggested as compared to the classical drug. Here, we report for the first time the synthesis and detailed characterization of a series of ILs containing a cation amino acid esters and anion ketoprofen (KETO-ILs). The affinity and the binding mode of the KETO-ILs to bovine serum albumin (BSA) were assessed using fluorescence spectroscopy. All compounds bind in a distance not longer than 6.14 nm to the BSA fluorophores. The estimated binding constants (KA) are in order of 105 L mol−1, which is indicative of strong drug or IL-BSA interactions. With respect to the ketoprofen-BSA system, a stronger affinity of the ILs containing l-LeuOEt, l-ValOBu, and l-ValOEt cation towards BSA is clearly seen. Fourier transformed infrared spectroscopy experiments have shown that all studied compounds induced a rearrangement of the protein molecule upon binding, which is consistent with the suggested static mechanism of BSA fluorescence quenching and formation of complexes between BSA and the drugs. All tested compounds were safe for macrophages.

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Exploring Selectivity of 22 Acyclic Urea‐, Carbazole‐ and Indolocarbazole‐Based Receptors towards 11 Monocarboxylates

Cited by 20 publications

References 29 publications

Design, synthesis and application of carbazole macrocycles in anion sensors

Design, synthesis and application of carbazole macrocycles in anion sensors

Solid‐contact Acetate‐selective Electrode Based on a 1,3‐bis(carbazolyl)urea‐ionophore

Ketoprofen-Based Ionic Liquids: Synthesis and Interactions with Bovine Serum Albumin

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