Experimental and theoretical study of the complexation of the thallium cation with a hexaarylbenzene-based receptor

Abstract  

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of a hexaarylbenzene-based receptor. Tl⁺ complex species dissolved in nitrobenzene saturated with water was determined. By using the quantum-mechanical density functional level of theory calculations, the most probable structure of this complex was derived.     

Extraction and DFT study of complexation of the cesium cation with beauvericin

Abstract  

From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of the beauvericin–Cs⁺ complex species dissolved in nitrobenzene saturated with water was determined. By using quantum–mechanical density functional level of theory (DFT) calculations, the most probable structure of this complex was derived.     

On the protonation of dibenzo-18-crown-6

Abstract  

The stability constant of the dibenzo-18-crown-6·H₃O⁺ cationic complex species dissolved in nitrobenzene saturated with water has been determined from extraction experiments in the two-phase water–nitrobenzene system and from γ-activity measurements. Various structures of protonated dibenzo-18-crown-6 are discussed.     

Solvent extraction of silver trifluoromethanesulfonate from water into nitrobenzene in the presence of silver ionophore?IV

Abstract  

From extraction experiments in the two-phase water/nitrobenzene system, the stability constant of the silver ionophore IV (i.e., 5,11,17,23-tetra-tert-butyl-25,27-bis[2-(methylthio)ethoxy]calix[4]arene)–Ag⁺ complex in nitrobenzene saturated with water was determined. Furthermore, the most probable structure of the resulting complex was derived by means of density functional level of theory calculations.     

On the complexation of the sodium cation with beauvericin: experimental and theoretical study

Abstract  

From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of the beauvericin·Na⁺ complex species dissolved in nitrobenzene saturated with water was determined. By using quantum mechanical density functional level of theory (DFT) calculations, the most probable structure of this complex species was derived.     

A combined experimental and theoretical study on the complexation of Li+ with valinomycin

Abstract  

From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of the valinomycin–lithium complex in nitrobenzene saturated with water was determined. Further, the structure of the resulting complex was indicated by means of the density functional level of theory (DFT) calculations.     

A combined extraction and DFT study on the complexation of the silver cation with dibenzo-18-crown-6

Abstract  

Extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements were used to determine the stability constant of the dibenzo-18-crown-6·Ag⁺ complex species in nitrobenzene saturated with water. Furthermore, the structure of the resulting complex was derived by means of theoretical calculations at the density functional level.     

Extraction and DFT study on the complexation of H3O+ ion with tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalix[4]arene

Abstract  

Extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements were used to determine the stability constant of protonated tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalix[4]arene in nitrobenzene saturated with water. Density functional theory (DFT) calculations were applied to derive the most probable structure of the tetrakis(2-ethoxyethoxy)-tetra-p-tert-butylcalix[4]arene·H₃O⁺ complex species.     

A combined extraction and DFT study on the complexation of K+ with valinomycin

Abstract  From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of protonated tetraethyl p-tert-butylcalix[4]arene tetraacetate in nitrobenzene saturated with water was determined. By using DFT calculations, the most probable structure of the tetraethyl p-tert-butylcalix[4]arene tetraacetate·H₃O⁺ complex species was derived. Graphical Abstract        

On the protonation of dibenzo-18-crown-6

Abstract  The stability constant of the dibenzo-18-crown-6·H₃O⁺ cationic complex species dissolved in nitrobenzene saturated with water has been determined from extraction experiments in the two-phase water–nitrobenzene system and from γ-activity measurements. Various structures of protonated dibenzo-18-crown-6 are discussed. Graphical abstract        

Experimental evidence, stability, and the most probable structure of protonated p-tert-butylcalix[4]arenetetrakis(N,N-dimethylacetamide)

Abstract  

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H₃O⁺(aq) + 1·Na⁺(nb) \leftrightarrows \leftrightarrows 1·H₃O⁺ (nb) + Na⁺ (aq) taking place in the two-phase water–nitrobenzene system (1 = p-tert-butylcalix[4]arenetetrakis(N,N-dimethylacetamide); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex (H₃O⁺, 1·Na⁺) = −0.1 ± 0.1. Further, the stability constant of the 1·H₃O⁺ complex in water-saturated nitrobenzene was calculated for a temperature of 25 °C as log β _nb (1·H₃O⁺) = 10.9 ± 0.2. By using quantum mechanical DFT calculations, the most probable structure of the 1·H₃O⁺ cationic complex species was derived. In this complex, the hydroxonium ion H₃O⁺ is bound partly to one phenoxy oxygen atom and partly to two carbonyl oxygens of 1 by strong hydrogen bonds and obviously by other electrostatic interactions.     

Extraction and DFT study on the complexation of the cesium cation with a hexaarylbenzene-based receptor

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Cs⁺(aq) + A⁻(aq) + 1(nb) ⇆ 1·Cs⁺(nb) + A⁻ (nb) taking part in the two-phase water–nitrobenzene system (A⁻ = picrate, 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex (1·Cs⁺, A⁻) = 2.8 ± 0.1. Further, the stability constant of the hexaarylbenzene-based receptor·Cs⁺ complex (abbrev. 1·Cs⁺) in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β _nb (1·Cs⁺) = 4.7 ± 0.1. By using quantum mechanical DFT calculations, the most probable structure of the 1·Cs⁺ complex species was solved. In this complex having C ₃ symmetry, the cation Cs⁺ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom via cation–π interaction. Finally, the calculated binding energy of the resulting complex 1·Cs⁺ is −220.0 kJ/mol, confirming relatively high stability of the considered cationic complex species.     

A combined experimental and theoretical study on the complexation of Li<Superscript>+</Superscript> with valinomycin

Abstract  From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constant of the valinomycin–lithium complex in nitrobenzene saturated with water was determined. Further, the structure of the resulting complex was indicated by means of the density functional level of theory (DFT) calculations. Graphical abstract        

Stability constants of the Li+, Na+, H3O+, NH4+, Ag+, and K+ complexes of the cone conformer of tetraethyl p-tert-butyltetrathiacalix[4]arene tetraacetate in nitrobenzene saturated with water

Abstract  

From extraction experiments in the two-phase water–nitrobenzene system and γ-activity measurements, the stability constants of the tetraethyl p-tert-butyltetrathiacalix[4]arene tetraacetate (cone)·M⁺ complexes (M⁺ = Li⁺, H₃O⁺, NH₄ ⁺, Ag⁺, or K⁺) were determined in water-saturated nitrobenzene. It was found that these constants increase in the cation order NH₄ ⁺ < K⁺ < H₃O⁺ < Ag⁺ < Li⁺ < Na⁺.     

Experimental and theoretical study on the complexation of the cesium cation with dibenzo-30-crown-10

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Cs⁺ (aq) + A⁻ (aq) + 1(nb) \rightleftarrows \rightleftarrows 1·Cs⁺(nb) + A⁻(nb) taking place in the two-phase water–nitrobenzene system (A⁻ = picrate, 1 = dibenzo-30-crown-10; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex (1·Cs⁺, A⁻) = 4.0 ± 0.1. Further, the stability constant of the 1·Cs⁺ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β _nb (1·Cs⁺) = 5.9 ± 0.1. Finally, by using quantum–mechanical DFT calculations, the most probable structure of the resulting cationic complex species 1·Cs⁺ was derived.     

A Combined Experimental and Theoretical Study on the Complexation of Ag<Superscript>+</Superscript> with a Hexaarylbenzene-Based Receptor

From extraction experiments and γ-activity measurements, the exchange extraction constant corresponding to the equilibrium Ag⁺(aq) + 1⋅Cs⁺(nb) ⇆ 1⋅Ag⁺(nb) + Cs⁺(aq) taking part in the two-phase water–nitrobenzene system (where 1 = hexaarylbenzene-based receptor; aq = aqueous phase, nb = nitrobenzene phase) was evaluated to be log ₁₀ K _ex(Ag⁺, 1⋅Cs⁺) = −1.0±0.1. Further, the stability constant of the hexaarylbenzene-based receptor⋅Ag⁺ complex (abbreviation 1⋅Ag⁺) in nitrobenzene saturated with water, was calculated at a temperature of 25 °C: log ₁₀ β _nb(1⋅Ag⁺) = 5.5±0.2. By using quantum mechanical DFT calculations, the most probable structure of the 1⋅Ag⁺ complex species was solved. In this complex having C₃ symmetry, the cation Ag⁺ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene ring via cation–π interaction.     

Kinetics and mechanism of the reaction between chromium(III) and picolinic acid in weak acidic aqueous solution

Abstract  

The interaction between chromium(III) and picolinic acid in weak acid aqueous solution was studied, resulting in the formation of a complex upon substitution of water molecules in the chromium(III) coordination sphere. Experimental results show that the reaction takes place in multiple steps. The first step is the formation of an ion pair, the second step (two consecutive steps) is the slow one corresponding to substitution of the first water molecule from the chromium aqueous complex coordination sphere by a picolinic acid molecule via oxygen atom of the carboxylic acid group and substitution of the second water molecule via nitrogen of the pyridine ring forming an 1:1 complex. Both consecutive steps were independent of chromium concentration. The rate constants of the 1st and 2nd consecutive steps were increased by increasing picolinic acid concentration. The corresponding activation parameters are ∆H _1obs ^* = 28.4 ± 4 kJ mol⁻¹, ∆S _1obs ^* = −202 ± 26 J K⁻¹ mol⁻¹, ∆H _2obs ^* = 39.6 ± 5 kJ mol⁻¹, and ∆S _2obs ^* = −175 ± 19 J K⁻¹ mol⁻¹. The third step is fast, corresponding to formation of the final complex [Cr(pic)₃]. The logarithms of the formation constants of 1:1 and 1:3 complexes were found to be 1.724 and 4.274, respectively.     

A combined experimental and DFT study on the complexation of Mg<Superscript>2+</Superscript> with beauvericin

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Mg²⁺(aq) + 1·Sr²⁺(nb) ⇆ 1·Mg²⁺(nb) + Sr²⁺(aq) taking place in the two-phase water–nitrobenzene system (1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex (Mg²⁺, 1·Sr²⁺) = 0.0 ± 0.1. Further, the stability constant of the 1·Mg²⁺ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C as log β_nb (1·Mg²⁺) = 9.1 ± 0.2. By using quantum mechanical DFT calculations, the most probable structures of the non-hydrated 1·Mg²⁺ and hydrated 1·Mg²⁺·3H₂O complex species were predicted.     

Extraction and DFT study on the complexation of the cesium cation with dibenzo-21-crown-7

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium \textCs ⁺ ( \textaq ) + \textA ^- ( \textaq ) + 1( \textnb )\underset \rightleftharpoons 1·\textCs ⁺ ( \textnb ) + \textA ^- ( \textnb ) {\text{Cs}}^{ + } \left( {\text{aq}} \right) + {\text{A}}^{ - } \left( {\text{aq}} \right) + {\mathbf{1}}\left( {\text{nb}} \right)\underset {} \rightleftharpoons {\mathbf{1}}\cdot{\text{Cs}}^{ + } \left( {\text{nb}} \right) + {\text{A}}^{ - } \left( {\text{nb}} \right) taking place in the two-phase water-nitrobenzene system (A⁻ = picrate, 1 = dibenzo-21-crown-7; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K _ex (1·Cs⁺, A⁻) = 4.4 ± 0.1. Further, the stability constant of the 1·Cs⁺ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β_nb (1·Cs⁺) = 6.3 ± 0.1. Finally, by using quantum mechanical DFT calculations, the most probable structure of the resulting cationic complex species 1·Cs⁺ was solved.     

A combined extraction and DFT study on the complexation of H3O+ with a hexaarylbenzene-based receptor

Abstract  

By means of theoretical calculations at density functional level, the complex structure of a hexaarylbenzene-based receptor with Na⁺ was derived. In the resulting complex having C ₃ symmetry, the sodium cation synergistically interacts with the hydrophilic polar ethereal oxygen fence and with the central hydrophobic benzene bottom of the parent receptor via cation–π interaction.