Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Požar, Josip; Horvat, Gordan; Čalogović, Marina; Galić, Nives; Frkanec, Leo; Tomišić, Vladislav

doi:10.5562/cca2172

Cited by 8 publications

(5 citation statements)

References 30 publications

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“…A notably more favorable solvation of alkali metal cation complexes with other carbonyl-containing lower-rim calix[4]arene derivatives in MeCN as compared to MeOH was previously reported. , This was ascribed, at least partly, to the inclusion of the solvent molecule in the macrocycle hydrophobic cavity. Namely, the affinity for MeCN inclusion into the aromatic basket of the free calixarene was found to be much lower as a result of its flattened cone conformation. ,,,, In contrast, the corresponding cation complexes adopted the square cone conformation, suitable for the solvent molecule inclusion. ,,,,,, …”

Section: Discussionmentioning

confidence: 99%

Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative

et al. 2017

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The medium effect on the complexation of alkali metal cations with a calix[4]arene ketone derivative (L) was systematically examined in methanol, ethanol, N-methylformamide, N,N-dimethylformamide, dimethyl sulfoxide, and acetonitrile. In all solvents the binding of Na cation by L was rather efficient, whereas the complexation of other alkali metal cations was observed only in methanol and acetonitrile. Complexation reactions were enthalpically controlled, while ligand dissolution was endothermic in all cases. A notable influence of the solvent on NaL complex stability could be mainly attributed to the differences in complexation entropies. The higher NaL stability in comparison to complexes with other alkali metal cations in acetonitrile was predominantly due to a more favorable complexation enthalpy. The H NMR investigations revealed a relatively low affinity of the calixarene sodium complex for inclusion of the solvent molecule in the calixarene hydrophobic cavity, with the exception of acetonitrile. Differences in complex stabilities in the explored solvents, apart from N,N-dimethylformamide and acetonitrile, could be mostly explained by taking into account solely the cation and complex solvation. A considerable solvent effect on the complexation equilibria was proven to be due to an interesting interplay between the transfer enthalpies and entropies of the reactants and the complexes formed.

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Section: Discussionmentioning

confidence: 99%

Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative

et al. 2017

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“…18 It should be noted that the process of calixarene-cation complex formation in solution is oen strongly inuenced by solvation of the reactants and the complex formed. [19][20][21][22][23][24][25] In addition, in non-aqueous solutions ion-pairing between free and complexed cation and an anion can signicantly affect the cation-binding reaction. 19,26 As already mentioned, the unique topology of calixarenes offers a wide range of scaffolds, making them perfect platforms for sensors.…”

Section: Introductionmentioning

confidence: 99%

Fluorescent phenanthridine-based calix[4]arene derivatives: synthesis and thermodynamic and computational studies of their complexation with alkali-metal cations

et al. 2015

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“…The receptor affinity toward particular cation is affected by several factors, the most important being the nature of the substituents on phenolic oxygen atoms forming the cation-binding site, and the compatibility of the size of this site with that of the metal ion. In addition, the binding process is often strongly influenced by the solvation of the reactants and the complex(es) formed. , In this respect, the specific solvent–ligand and solvent–complex interactions, that is, inclusion of the solvent molecule in a calixarene hydrophobic cavity, can play a very important role in determining the complexation equilibrium. ,, …”

Section: Introductionmentioning

confidence: 99%

The Effect of Specific Solvent–Solute Interactions on Complexation of Alkali-Metal Cations by a Lower-Rim Calix[4]arene Amide Derivative

et al. 2013

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Complexation of alkali-metal cations with calix[4]arene secondary-amide derivative, 5,11,17,23-tetra(tert-butyl)-25,26,27,28-tetra(N-hexylcarbamoylmethoxy)calix[4]arene (L), in benzonitrile (PhCN) and methanol (MeOH) was studied by means of microcalorimetry, UV and NMR spectroscopies, and in the solid state by X-ray crystallography. The inclusion of solvent molecules (including acetonitrile, MeCN) in the calixarene hydrophobic cavity was also investigated. The classical molecular dynamics (MD) simulations of the systems studied were carried out. By combining the results obtained using the mentioned experimental and computational techniques, an attempt was made to get an as detailed insight into the complexation reactions as possible. The thermodynamic parameters, that is, equilibrium constants, reaction Gibbs energies, enthalpies, and entropies, of the investigated processes were determined and discussed. The stability constants of the 1:1 (metal:ligand) complexes measured by different methods were in very good agreement. Solution Gibbs energies of the ligand and its complexes with Na(+) and K(+) in methanol and acetonitrile were determined. It was established that from the thermodynamic point of view, apart from cation solvation, the most important reason for the huge difference in the stability of these complexes in the two solvents lay in the fact that the transfer of complex species from MeOH to MeCN was quite favorable. That could be at least partly explained by a more exergonic inclusion of the solvent molecule in the complexed calixarene cone in MeCN as compared to MeOH, which was supported by MD simulations. Molecular and crystal structures of the lithium cation complex of L with the benzonitrile molecule bound in the hydrophobic calixarene cavity were determined by single-crystal X-ray diffraction. As far as we are aware, for the first time the alkali-metal cation was found to be coordinated by the solvent nitrile group in a calixarene adduct. According to the results of MD simulations, the probability of such orientation of the benzonitrile molecule included in the ligand cone was by far the largest in the case of LiL(+) complex. Because of the favorable PhCN-Li(+) interaction, L was proven to have the highest affinity toward the lithium ion in benzonitrile, which was not the case in the other solvents examined (in acetonitrile, sodium complex was the most stable, whereas in methanol, complexation of lithium was not even observed). That could serve as a remarkable example showing the importance of specific solvent-solute interactions in determining the equilibrium in solution.

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Complexation of Oxonium and Ammonium Ions by Lower-rim Calix[4]arene Amino Acid Derivatives

Abstract: Abstract. Complexation of oxonium and ammonium cations with two calix4arene amino acid derivatives, namely 5,11,17,23-tetra-tert-butyl-26,28,25,27-tetrakis-(O-methyl-D-α-phenylglycylcarbonylmethoxy)-calix[4]arene (1) and 5,11,17,23-tetra-tert-butyl-26,28,25,27-(O-

Cited by 8 publications

References 30 publications

Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative

Solvation Effect on Complexation of Alkali Metal Cations by a Calix[4]arene Ketone Derivative

Fluorescent phenanthridine-based calix[4]arene derivatives: synthesis and thermodynamic and computational studies of their complexation with alkali-metal cations

The Effect of Specific Solvent–Solute Interactions on Complexation of Alkali-Metal Cations by a Lower-Rim Calix[4]arene Amide Derivative

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