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1.
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. 相似文献
2.
Abstract The stability constant of the dibenzo-18-crown-6·H 3O + 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. 相似文献
3.
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. 相似文献
4.
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. 相似文献
5.
Abstract From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of the benzo-18-crown-6–ammonium complex in nitrobenzene saturated with water
was determined. Furthermore, the structure of the resulting complex was derived by means of theoretical calculations at the
density functional level. 相似文献
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. 相似文献
7.
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·H 3O + complex species. 相似文献
8.
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·H 3O + complex species was derived.
Graphical Abstract
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9.
Abstract From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H 3O +(aq) + 1·Na +(nb)
\leftrightarrows \leftrightarrows
1·H 3O + (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 (H 3O +, 1·Na +) = −0.1 ± 0.1. Further, the stability constant of the 1·H 3O + complex in water-saturated nitrobenzene was calculated for a temperature of 25 °C as log β
nb ( 1·H 3O +) = 10.9 ± 0.2. By using quantum mechanical DFT calculations, the most probable structure of the 1·H 3O + cationic complex species was derived. In this complex, the hydroxonium ion H 3O + 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. 相似文献
10.
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. 相似文献
11.
Abstract The stability constant of the dibenzo-18-crown-6·H 3O + 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
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12.
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 +, H 3O +, NH 4
+, Ag +, or K +) were determined in water-saturated nitrobenzene. It was found that these constants increase in the cation order NH 4
+ < K + < H 3O + < Ag + < Li + < Na +. 相似文献
13.
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. 相似文献
14.
On the basis of extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Pb2+(aq) + 1·Sr2+(nb) ? 1·Pb2+(nb) + Sr2+(aq) occurring in the two-phase water–nitrobenzene system (1 = cyclosporin A; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K
ex (Pb2+, 1·Sr2+) = 0.1 ± 0.1. Further, the stability constant of the 1·Pb2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β
nb (1·Pb2+) = 9.2 ± 0.2. Finally, applying quantum chemical DFT calculations, the most probable structure of the proven 1·Pb2+ cationic complex species was derived. In the resulting complex, the “central” cation Pb2+ is bound by four bonding interactions to the corresponding four oxygen atoms of the parent cyclosporin A ligand. The interaction energy, E(int), of the considered 1·Pb2+ complex was found to be ?1016.3 kJ/mol, confirming also the formation of this complex. 相似文献
15.
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. 相似文献
16.
Solvent extraction of microamounts of europium and cerium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H +B −) in the presence of polyethylene glycol PEG 1000 (L) has been investigated. The equilibrium data have been explained assuming
that the species H 2L 2+ and ML 3+ (M 3+ = Eu 3+, Ce 3+) are extracted into the organic phase. The values of extraction and stability constants of the complexes in nitrobenzene
saturated with water have been determined. It was found that the stability constants of the cationic complex species EuL 3+ and CeL 3+ in water-saturated nitrobenzene are practically the same. 相似文献
17.
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 C 3 symmetry, the cation Ag + synergistically interacts with the polar ethereal oxygen fence and with the central hydrophobic benzene ring via cation– π interaction. 相似文献
18.
Solvent extraction of microamounts of europium and cerium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H +B −) in the presence of polyethylene glycol PEG 600 (L) has been investigated. The equilibrium data have been explained assuming
that the complexes HL +, H 2L 2+ and ML 3+ (M 3+ = Eu 3+, Ce 3+; L = PEG 600) are extracted into the organic phase. The values of extraction and stability constants of the species in nitrobenzene
saturated with water have been determined. It was found that the stability constants of the EuL 3+ and CeL 3+ cationic complex species (L = PEG 600) in water-saturated nitrobenzene are the same. 相似文献
19.
Extraction of microamounts of calcium and strontium by a nitrobenzene solution of hydrogen dicarbollylcobaltate (H +B −) in the presence of 1,2-(diphenylphosphino)ethylene dioxide (DPPEDO, L) has been investigated. The equilibrium data have
been explained assuming that the species HL +, HL 2
+, CaL 2
2+, CaL 3
2+, CaL 4
2+, SrL 2
2+ and SrL 3
2+ are extracted into the organic phase. The values of extraction and stability constants of the cationic complexes in nitrobenzene
saturated with water have been determined. In the considered nitrobenzene medium, it was found that the stability constants
of the CaL
n
2+ complexes, where n = 2, 3 and L is DPPEDO, are somewhat higher than those of the corresponding complex species SrL
n
2+. 相似文献
20.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Mg 2+(aq) + 1·Sr 2+(nb) ⇆ 1·Mg 2+(nb) + Sr 2+(aq) taking place in the two-phase water–nitrobenzene system ( 1 = beauvericin; aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K
ex (Mg 2+, 1·Sr 2+) = 0.0 ± 0.1. Further, the stability constant of the 1·Mg 2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C as log β nb ( 1·Mg 2+) = 9.1 ± 0.2. By using quantum mechanical DFT calculations, the most probable structures of the non-hydrated 1·Mg 2+ and hydrated 1·Mg 2+·3H 2O complex species were predicted. 相似文献
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