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Interaction of the univalent silver cation with [Gly6]-antamanide: Experimental and theoretical study

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ag+(aq) + 1.Na+(nb) ⇄ 1.Ag+ (nb) + Na+(aq) occurring in the two–phase water – nitrobenzene system (1 = [Gly6]-antamanide; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (Ag+,1·Na+) = 1.5 ± 0.1. Further, the stability constant of the 1·Ag+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Ag+) = 4.5 ± 0.2. Finally, by using quantum chemical DFT calculations, the most probable structure of the cationic complex species 1·Ag+ was derived. In the resulting complex, the “central” cation Ag+ is coordinated by four noncovalent interactions to the corresponding four carbonyl oxygen atoms of the parent ligand 1. Besides, the whole 1·Ag+ complex structure is stabilized by two intramolecular hydrogen bonds. The interaction energy of the considered 1·Ag+ complex was found to be −465.5 kJ/mol, confirming also the formation of this cationic species.

Extraction and DFT study on complexation of the barium cation with [Gly6]-antamanide

On the basis of 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 = [Gly6]-antamanide; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (Ba2+,1·Sr2+) = 0.6 ± 0.1. Further, the stability constant of the 1·Ba2+ complex 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 chemical 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 bonding 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 −943.5 kJ/mol, confirming the formation of this cationic species as well

Experimental and theoretical study on complexation of the calcium cation with [Gly6]-antamanide

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ca2+(aq)+1∙Sr2+(nb)⇄1∙Ca2+ (nb)+Sr2+(aq) occurring in the two–phase water–nitrobenzene system (1=[Gly6]-antamanide; aq=aqueous phase, nb=nitrobenzene phase) was determined as log Kex (Ca2+,1·Sr2+)=0.6±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+)=10.2±0.2. Finally, by using quantum chemical DFT calculations, the most probable structure of the cationic complex species 1∙Ca2+ was derived. In the resulting complex, the “central” cation Ca2+ is bound by six bonding interactions to the corresponding six carbonyl oxygen atoms of the parent ligand 1. The interaction energy of the considered 1∙Ca2+ complex was found to be −1221.2kJ/mol, confirming the formation of this cationic species as well.

Protonation of calix[4]arene-(2,3-naphthylene-crown-6,crown-6): 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 = calix[4]arene-(2,3-naphthylene-crown-6,crown-6); aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex(H3O+,1·Na+) = −0.2 ± 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+) = 5.9 ± 0.2. Finally, applying quantum chemical 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 three strong hydrogen bonds to two phenoxy oxygen atoms and to one ethereal oxygen from the crown-6 moiety of the parent ligand 1. The interaction energy, E(int), of the considered 1·H3O+ complex was found to be −416.0 kJ/mol, confirming the formation of this cationic species as well.

Calix[4]arene-(1,2-phenylene-crown-6,crown-6) as an extraordinarily effective macrocyclic receptor for the univalent silver cation

ABSTRACTOn the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ag+(aq) + 1·Cs+ (nb) 1·Ag+(nb) + Cs+ (aq) occurring in the two-phase water–nitrobenzene system (1 = calix[4]arene-(1,2-phenylene-crown-6,crown-6); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex(Ag+, 1·Cs+) = −1.3 ± 0.1. Further, the very high stability constant of the 1·Ag+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb(1·Ag +) = 9.3 ± 0.2. Finally, by using quantum mechanical DFT calculations, the most probable structures A and B of this cationic complex species, which are obviously in a dynamic equilibrium, were derived.

Complexation of the lithium cation with N,N,N’,N’-tetracyclohexyl-1,2-phenylenedioxydiacetamide: experimental and theoretical study

ABSTRACTOn the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Li+ (aq) + 1·Na+ (nb) 1·Li+ (nb) + Na+ (aq) taking part in the two-phase water–nitrobenzene system (1 = N,N,N’,N’-tetracyclohexyl-1,2-phenylenedioxydiacetamide called Sodium ionophore III; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (Li+,1·Na+) = 0.7 ± 0.1. Further, the stability constant of the 1·Li+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb (1·Li+) = 8.1 ± 0.2. Finally, applying quantum mechanical DFT calculations, the most probable structures of the nonhydrated 1·Li+ and the hydrated 1·Li+·H2O cationic complex species were derived. In both of these complexes, the ‘central’ cation Li+ is bound by four bonding interactions to the corresponding four oxygen atoms of the parent ligand 1. Besides, in case of the 1·Li+·H2O complex, the considered hydrated structure is stabilised by one water molecule bound to the ‘central’ lithium cation.

Complexation of the strontium cation with a macrocyclic lactam receptor: Experimental and theoretical study

On the basis of 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=macrocyclic lactam receptor — see Scheme 1; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log Kex (1·Sr2+, 2A−)=−4.0±0.1. Further, the stability constant of the 1·Sr2+ cationic complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·Sr2+)=5.1±0.1. Finally, applying quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·Sr2+ was derived. In the resulting complex, which is most energetically favored, the “central” cation Sr2+ is bound by five bonding 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 interaction of the silver cation with nonactin

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium occurring in the two-phase water–nitrobenzene system (1 = nonactin, aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (Ag+, 1 ⋅ Na+) = 0.6 ± 0.1. Furthermore, the stability constant of the 1 ⋅ Ag+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb(1 ⋅ Ag+) = 6.6 ± 0.2. Finally, employing quantum mechanical calculations, the most probable structure of the cationic complex species 1 ⋅ Ag+ was derived. In the resulting complex, having a tennis-ball-seam conformation with the C2 symmetry, the ‘central’ cation Ag+ is bound by eight relatively strong bonding interactions to eight oxygen atoms of the parent nonactin ligand. The interaction energy of the considered 1 ⋅ Ag+ complex was found to be –468.5 kJ/mol, confirming also the formation of this cationic species.

Experimental and DFT study on complexation of the strontium cation with cyclosporin A

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 = cyclosporin A; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (1·Sr2+,2A−) = 0.1 ± 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+) = 9.2 ± 0.1. Finally, applying quantum mechanical DFT calculations, the most probable structure of the proven 1·Sr2+ cationic complex was derived. In the resulting complex, the “central” cation Sr2+ is bound by five bonds to the corresponding five oxygen atoms of the parent cyclosporin A ligand. The interaction energy, E(int), of the investigated 1·Sr2+ complex, involving the 7-point correction for the basis set superposition error, was calculated as −894.5 kJ/mol.

Interaction of the cesium cation with hexaethyl calix[6]arene hexaacetate: Extraction and DFT study

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Cs+(aq)+A−(aq)+1(nb)⇄1·Cs+(nb)+A−(nb) occurring in the two-phase water–nitrobenzene system (1=hexaethyl calix[6]arene hexaacetate; A−=picrate, aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log Kex (1·Cs+, A−)=6.8±0.1. Further, the very high stability constant of the 1·Cs+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·Cs+)=8.7±0.1. Finally, applying quantum mechanical DFT calculations, the most probable structure of the proven 1·Cs+ cationic complex species was derived. In the resulting complex, the “central” cation Cs+ is bound by six very strong bonding interactions to the corresponding six oxygen atoms of the parent ligand 1. The interaction energy of the considered 1·Cs+ complex was found to be −308.0kJ/mol, confirming the formation of this complex as well.

Complexation of the calcium cation with antamanide: an experimental and theoretical study

By using extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Ca2+(aq) + 1 ·Sr2+(nb) 1 ·Ca2+(nb) + Sr2+(aq) occurring in the two-phase water–nitrobenzene system (1 = antamanide; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (Ca2+, 1 ·Sr2+) = 1.6 ± 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+) = 10.9 ± 0.2. Finally, applying quantum mechanical density functional level of theory calculations, the most probable structure of the cationic complex species 1 ·Ca2+ was derived. In the resulting complex, the ‘central’ cation Ca2+ is bound by six strong bonding interactions to the corresponding six carbonyl oxygen atoms of the parent ligand 1. Besides, the whole 1 ·Ca2+ complex structure is stabilised by two intramolecular hydrogen bonds. The interaction energy of the considered 1 ·Ca2+ complex, involving the Boys–Bernardi counterpoise corrections of the basis set superposition error, was found to be −1219.3 kJ/mol, confirming the formation of this cationic species.

Calix[4]arene-(2,3-naphthylene-crown-6,crown-6) as an extraordinarily efficient macrocyclic receptor for the univalent thallium cation

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Tl+ (aq) + 1·Cs+ (nb) 1·Tl+ (nb) + Cs+ (aq) taking place in the two-phase water–nitrobenzene system (1 = calix[4]arene-(2,3-naphthylene-crown-6,crown-6); aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex(Tl+,1·Cs+) = 0.3 ± 0.1. Further, the extremely high stability constant of the 1·Tl+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log βnb(1·Tl+) = 10.0 ± 0.2. Finally, applying quantum mechanical 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 eight strong bonds to six oxygen atoms of the crown-6 moiety and to two carbons from the respective two benzene rings of the parent ligand 1 via cation-π interaction. The interaction energy, E(int), of the considered 1·Tl+ complex was found to be −305.7 kJ/mol, also confirming the formation of this cationic species.

Experimental and theoretical study on complexation of the ammonium cation with enniatin B

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium NH4+(aq)+1·Na+(nb)⇆1·NH4+(nb)+Na+(aq) taking place in the two-phase water–nitrobenzene system (1=enniatin B; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as log Kex (NH4+, 1·Na+)=1.9±0.1. Further, the stability constant of the 1·NH4+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·NH4+)=6.4±0.2. Finally, applying quantum mechanical DFT calculations, the most probable structure of the cationic complex species 1·NH4+ was derived. In the resulting 1·NH4+ complex, the “central” cation NH4+ is bound by three relatively strong hydrogen bonds to the corresponding three carbonyl oxygens of the parent enniatin B ligand. The interaction energy, E(int), of the considered complex 1·NH4+ was found to be −305.5kJ/mol, confirming also the formation of this investigated complex.

Lithium ionophore VIII as an extraordinarily strong receptor for the trivalent europium cation

On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Eu3+(aq) + 3A−(aq) + 1(nb) ⇆ 1·Eu3+(nb) + 3A‑(nb) occurring in the two-phase water–nitrobenzene system (A− = CF3SO−3; 1 = lithium ionophore VIII; aq = aqueous phase, nb = nitrobenzene phase) was determined as log Kex (1·Eu3+, 3A‑) = 2.5 ± 0.1. Furthermore, the extremely high stability constant of the 1·Eu3+ complex in nitrobenzene saturated with water was calculated: log βnb (1·Eu3+) = 15.6 ± 0.1. Finally, by using DFT calculations, the most probable structure of the cationic complex species 1·Eu3+ was derived. In the resulting complex, the ‘central’ cation Eu3+ is bound by six very strong bond interactions to the corresponding six oxygen atoms of the parent ligand 1. It is evident that this exceptionally effective receptor 1 for the Eu3+ cation could be considered as a potential extraction agent for nuclear waste treatment.

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.

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.

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.

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 cooperative interaction of the ethanolammonium cation with a hexaarylbenzene-based receptor

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+=ethanolammonium, 1=hexaarylbenzene-based receptor; aq=aqueous phase, nb=nitrobenzene phase) was evaluated as logKex(HL+,1·Cs+)=−1.1±0.1. Further, the stability constant of the 1·HL+ complex in nitrobenzene saturated with water was calculated for a temperature of 25°C: log βnb (1·HL+)=5.4±0.2. Finally, by using quantum mechanical DFT calculations, the most probable structures A and B of the 1·HL+ complex species, which are obviously in a dynamic equilibrium, were indicated. In both of these structures of the resulting complex 1·HL+, the cation HL+ synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene bottom of the parent receptor 1 via cation–π interaction.