Two-phase Water-nitrobenzene System Research Articles

Protonation of sodium ionophore III: Extraction and DFT study

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq)+1⋅Na+(nb)⇆1⋅H3O+(nb)+Na+(aq) occurring in the two-phase water–nitrobenzene system (1=sodium ionophore III; aq=aqueous phase, nb=nitrobenzene phase) was determined as logKex (H3O+, 1⋅Na+)=0.0±0.1. Further, the stability constant of the 1⋅H3O+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: logβnb(1⋅H3O+)=6.4±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1⋅H3O+ was derived. In the resulting complex, the “central” cation H3O+ is bound by two linear hydrogen bonds and one bifurcated hydrogen bond to the corresponding four oxygens of the parent ligand 1. The interaction energy of the considered 1⋅H3O+ complex was found to be −556.6kJ/mol, confirming also the formation of this cationic species.

Interactions of some protonated α-amino acid methyl esters with hexaethyl p-tert-butylcalix[6]arene hexaacetate in nitrobenzene saturated with water

The exchange extraction constants corresponding to the general equilibrium C+(aq) + 1·Cs+(nb) ⇔ 1·C+ (nb) + Cs+(aq) occurring in the two-phase water–nitrobenzene system (C+ = protonated α-amino acid methyl ester, 1 = hexaethyl p-tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were evaluated on the basis of extraction experiments and γ-activity measurements. Further, the stability constants of the 1·C+ cationic complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: protonated l-tryptophan methyl ester < protonated l-phenylalanine methyl ester < protonated l-leucine methyl ester < protonated l-methionine methyl ester < protonated l-valine methyl ester.

Protonation of antamanide: Experimental and theoretical study

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq)+1·Na+(nb)⇆1·H3O+(nb)+Na+(aq) occurring in the two-phase water–nitrobenzene system (1=antamanide; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log Kex (H3O+, 1·Na+)=−0.4±0.1. Further, the stability constant of the 1·H3O+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·H3O+)=5.7±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·H3O+ was derived. In the resulting complex, the “central” cation H3O+ is bound by two linear hydrogen bonds and one bifurcated hydrogen bond to the corresponding four oxygens of the parent ligand 1. Besides, the whole 1·H3O+ complex structure is stabilized by two intramolecular H-bonds. The interaction energy of the considered 1·H3O+ complex was found to be −458.7kJ/mol, confirming also the formation of this cationic species.

Extraction and theoretical study on complexation of the strontium cation with antamanide

By using extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Sr2+(aq) + 2A−(aq) + 1(nb) ⇔ 1·Sr2+(nb) + 2A−(nb) occurring in the two-phase water–nitrobenzene system (A− = picrate, 1 = antamanide; aq = aqueous phase, nb = nitrobenzene phase) was determined as log K ex (1·Sr2+, 2A−) = −0.3 ± 0.1. Further, the stability constant of the 1·Sr2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β nb (1·Sr2+) = 8.8 ± 0.1. Finally, applying quantum mechanical density functional level of theory calculations, the most probable structure of the cationic complex species 1·Sr2+ was derived. In the resulting complex, the “central” cation Sr2+ is bound by six bond interactions to the corresponding six oxygen atoms of the parent ligand 1. The interaction energy of the considered 1·Sr2+ complex was found to be −1,114.9 kJ/mol, confirming the formation of this cationic species as well.

Experimental and theoretical study on interaction of the barium cation with antamanide

By using extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ba2+(aq)+1⋅Sr2+(nb)⇄1⋅Ba2+(nb)+Sr2+(aq) occurring in the two-phase water–nitrobenzene system (1=antamanide; aq=aqueous phase, nb=nitrobenzene phase) was determined as logKex (Ba2+, 1⋅Sr2+)=0.2±0.1. Further, the stability constant of the 1⋅Ba2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: logβnb (1⋅Ba2+)=8.8±0.2. Finally, applying quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1⋅Ba2+ was derived. In the resulting complex, the “central” cation Ba2+ is bound by six bond interactions to the corresponding six carbonyl oxygen atoms of the parent ligand 1. The interaction energy of the considered 1⋅Ba2+ complex was found to be −964.9kJ/mol, confirming the formation of this cationic species as well.

Experimental and theoretical study on interaction of the potassium cation with antamanide

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium K+ (aq)+1·Na+ (nb) ⇄1·K+ (nb)+Na+ (aq) taking part in the two-phase water–nitrobenzene system (1=antamanide; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log Kex (K+,1·Na+)=0.2±0.1. Further, the stability constant of the 1·K+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·K+)=4.7±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·K+ was derived. In the resulting complex, the “central” cation K+ is bound by four bond interactions to the corresponding four carbonyl oxygen atoms of the parent ligand 1. Besides, the whole 1·K+ complex structure is stabilized by two intramolecular hydrogen bonds. The interaction energy of the considered 1·K+ complex was found to be −346.6kJ/mol, confirming also the formation of this cationic species.

Interaction of the univalent thallium cation with antamanide: Experimental and theoretical study

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Tl+(aq) + 1·Na+(nb) ⇔1·Tl+ (nb) + Na+(aq) occurring in the two-phase water–nitrobenzene system (1=antamanide; aq=aqueous phase, nb=nitrobenzene phase) was determined as logKex (Tl+, 1·Na+)=0.7±0.1. Further, the stability constant of the 1·Tl+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·Tl+)=4.5±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·Tl+ was derived. In the resulting complex, the “central” cation Tl+ is bound by four bond interactions to the corresponding four carbonyl oxygen atoms of the parent ligand 1. Besides, the whole 1·Tl+ complex structure is stabilized by two intramolecular hydrogen bonds. The interaction energy of the considered 1·Tl+ complex was found to be −359.0kJ/mol, confirming also the formation of this cationic species.

Complexation of the cesium cation with lithium ionophore VIII: extraction and DFT study

From extraction experiments and c-activity measurements, the extraction constant corresponding to the equilibrium Cs ? (aq) ? 1� Na 1 (nb) = 1� Cs ? (nb) ? Na ? (aq) taking place in the two-phase water-nitrobenzene system (1 = lithium ionophore VIII; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (Cs ? , 1� Na ? ) =- 0.5 ± 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 bnb (1� Cs ? ) = 4.8 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1� Cs ? was derived. In the resulting complex, the ''central'' cation Cs ? is bound by six bond interactions to the corresponding six oxygen atoms of the parent ligand 1.

Interaction of protonated tyramine with a hexaarylbenzene-based receptor: Extraction and DFT study

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium HL+(aq)+1·Cs+(nb)⇔1·HL+(nb)+Cs+(aq) taking place in the two-phase water–nitrobenzene system (HL+=protonated tyramine, 1=hexaarylbenzene-based receptor; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex(HL+, 1·Cs+)=−0.3±0.1. Further, the stability constant of the 1·HL+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C as logβnb(1·HL+)=4.7±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the 1·HL+ complex species was predicted. In the resulting “asymmetrical” cationic complex 1·HL+, the cation HL+ synergistically interacts with the polar ethereal oxygen fence by means of the corresponding three H-bonds and with the central hydrophobic benzene bottom of the parent receptor 1 via cation – π interaction.

Complexation of some protonated α-amino acid methyl esters with benzo-18-crown-6 in nitrobenzene saturated with water

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C+(aq)+1·Na+(nb)⇔⟺1·C+ (nb)+Na+ (aq) taking place in the two-phase water–nitrobenzene system (C+=protonated α-amino acid methyl ester, 1=benzo-18-crown-6; aq=aqueous phase, nb=nitrobenzene phase) were evaluated. Furthermore, the stability constants of the 1·C+ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: protonated l-tryptophan methyl ester<protonated l-phenylalanine methyl ester<protonated l-leucine methyl ester, protonated l-methionine methyl ester<protonated l-valine methyl ester.

Complexation of Eu3+ with a macrocyclic lactam receptor: Experimental and theoretical study

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Eu3+(aq)+3A−(aq)+1 (nb) ⇔1·Eu3+(nb)+3A−(nb) taking place in the two-phase water–nitrobenzene system (A-=CF3SO3-; 1=macrocyclic lactam receptor – see Scheme 1; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex(1·Eu3+, 3A−)=−4.1±0.1. Further, the stability constant of the 1·Eu3+ cationic complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: logβnb(1·Eu3+)=9.0±0.1. Finally, by using DFT calculations, the most probable structure of the cationic complex species 1·Eu3+ was derived. In the resulting 1·Eu3+ complex, the “central” cation Eu3+ is bound by five bond interactions to two ethereal oxygen atoms and two carbonyl oxygens, as well as to one carbon atom of the corresponding benzene ring of the parent macrocyclic lactam receptor 1 via cation–π interaction.

Experimental and theoretical study on the complexation of Ca2+ with beauvericin

From extraction experiments and γ-activity measurements, the exchange extraction constant corresponding to the equilibrium Ca2+(aq) + 1·Sr2+(nb) ⇔ 1·Ca2+(nb) + Sr2+(aq) taking place in the two-phase water–nitrobenzene system (1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex(Ca2+, 1·Sr2+) = 1.1 ± 0.1. Further, the stability constant of the 1·Ca2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb(1·Ca2+) = 10.1 ± 0.2. Finally, by using quantum mechanical density functional level of theory calculations, the most probable structures of the non-hydrated 1·Ca2+ and hydrated 1·Ca2+·H2O complex species were predicted.

Complexation of valinomycin with some univalent organic cations in nitrobenzene saturated with water

From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C+(aq)+1·Cs+(nb)⇔1·C+(nb)+Cs+(aq) taking place in the two-phase water–nitrobenzene system (C+ = methylammonium, ethylammonium, propylammonium, ethanolammonium, diethanolammonium, triethanolammonium, protonated tyramine, protonated dopamine, or protonated dl-noradrenaline; 1 = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the 1·C+ complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: propylammonium<ethylammonium<protonated tyramine<methylammonium<protonated dopamine<triethanolammonium<diethanolammonium<ethanolammonium<protonated dl-noradrenaline.

Experimental and DFT study on the complexation of Ba2+ with beauvericin

From extraction experiments and γ-activity measurements, the exchange extraction constant corresponding to the equilibrium Ba2+(aq) + 1·Sr2+(nb) ⟺1·Ba2+(nb) + Sr2+(aq) taking place in the two-phase water–nitrobenzene system (1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (Ba2+, 1·Sr2+) = 1.2 ± 0.1. Further, the stability constant of the beauvericin–barium complex (abbrev. 1·Ba2+) in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Ba2+) = 9.5 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structure of the 1·Ba2+ complex species was predicted.

Experimental and theoretical study on the complexation of the strontium cation with nonactin

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Sr2+(aq)+2A-(aq)+1(nb)⇔1·Sr2+(nb)+2A-(nb) taking place in the two-phase water-nitrobenzene system (A−=picrate, 1=nonactin; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex(1·Sr2+, 2A−)=−2.0±0.1. Further, the stability constant of the 1·Sr2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·Sr2+)=7.1±0.1. Finally, by using DFT calculations, the most probable structure of the cationic complex species 1·Sr2+ was derived. In the resulting complex having S4 symmetry, the “central” cation Sr2+ is bound by eight relatively strong bond interactions to eight oxygen atoms of the parent nonactin ligand 1.

Complexation of some univalent organic cations with benzo-18-crown-6 in nitrobenzene saturated with water

Abstract From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C+(aq) + 1·Na+(nb) 1·C+ (nb) + Na+(aq) taking place in the two-phase water-nitrobenzene system (C+ = methylammonium, ethylammonium, propylammonium, ethanolammonium, diethanolammonium, triethanolammonium, cation TRIS+, hydrazinium, hydroxylammonium; 1 = benzo-18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the 1·C+ cationic complex species in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: triethanolammonium +

Extraction and theoretical study on the complexation of the strontium cation with beauvericin

From extraction experiments and c-activity measurements, the extraction constant corresponding to the equilibrium Sr(aq) ? 2A(aq) ?1(nb) , 1 Sr(nb) ? 2A(nb) taking place in the two-phase water–nitrobenzene system (A = picrate, 1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex(1 Sr,2A) = -0.6 ± 0.1. Further, the stability constant of the 1 Sr complex in nitrobenzene saturated with water was calculated for a temperature of 25 C: log bnb(1 Sr) = 8.5 ± 0.1. Finally, by using quantummechanical DFT calculations, the most probable structure of the resulting cationic complex 1 Sr was derived.

Synergistic extraction of some univalent cations into nitrobenzene by using cesium dicarbollylcobaltate and calix[4]arene-bis(t-octylbenzo-18-crown-6)

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M+ (aq) + CsL+ (nb) , ML+ (nb) + Cs+ (aq) taking place in the two-phase water nitrobenzene system (M+ = K+, Rb+, NH+4,Ag+, Tl+; L = calix[4]arene-bis(t-octylbenzo-18-crown-6); aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML+ complexes in nitrobenzene saturated with water were calculated; they were found to increase in the following cation order: NH+4 < K+ < Ag+ < Rb+ < Tl+.

On the complexation of some univalent cations with 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown-6 in nitrobenzene saturated with water

From extraction experiments and c-activity measurements, the exchange extraction constants corresponding to the general equilibrium M (aq) ? 1 Cs (nb) , 1 M (nb) ? Cs (aq) taking place in the two-phase water–nitrobenzene system (M = Ag, K, Rb, Tl; 1 = 1,3-alternate-25,27-bis(1-octyloxy)calix[4]arene-crown6; aq is aqueous phase, nb is nitrobenzene phase) were determined. Moreover, the stability constants of the 1 M complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of K \ Rb \ Ag \ Tl.

Complexation of the lithium cation with beauvericin: Experimental and DFT study

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Li+(aq)+1·Na+(nb)⇆1·Li+(nb)+Na+(aq) taking place in the two-phase water–nitrobenzene system (1=beauvericin; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex (Li+, 1·Na+)=0.5±0.1. Further, the stability constant of the 1·Li+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C as log βnb (1·Li+)=5.6±0.2. By using DFT calculations, the most probable structures of the non-hydrated 1·Li+ and hydrated 1·Li+·3H2O complex species were predicted.