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1.
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
2.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M 2+(aq)+SrL 2+(nb)⇔ML 2+(nb)+Sr 2+(aq) taking place in the two-phase water-nitrobenzene system (M 2+ = Ba 2+, Pb 2+, Cd 2+; L = tetramethyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants
of the ML 2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Ba 2+<Cd 2+<Pb 2+. 相似文献
3.
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
4.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M
2+ (aq) + 1 · Sr 2+ (nb) ⇄ 1 · M
2+ (nb) + Sr 2+ (aq) taking place in the two-phase water-nitrobenzene system ( M
2+ = Cu 2+, Zn 2+, Cd 2+, Pb 2+, UO 2
2+, Fe 2+, Co 2+, and Ni 2+; 1 = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1 · M
2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Fe 2+ < Cd 2+, Co 2+ < Ni 2+ < UO 2
2+, Zn 2+ < Cu 2+ < Pb 2+. 相似文献
5.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M
2+ (aq) + 1 · Sr 2+ (nb) ⇄ 1 · M
2+ (nb) + Sr 2+ (aq) taking place in the two-phase water-nitrobenzene system ( M
2+ = Cu 2+, Zn 2+, Cd 2+, Pb 2+, UO 2
2+, Fe 2+, Co 2+, and Ni 2+; 1 = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants of the 1 · M
2+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Fe 2+ < Cd 2+, Co 2+ < Ni 2+ < UO 2
2+, Zn 2+ < Cu 2+ < Pb 2+.
Correspondence: Emanuel Makrlík, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic. 相似文献
6.
Summary. From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H + (aq) + Na L+ (nb) = H L+ (nb) + Na + (aq) taking place in the two-phase water-nitrobenzene system ( L = valinomycin, aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log Kex (H +, Na L+) = −1.1 ± 0.1. Further, the stability constant of the valinomycin-proton complex in nitrobenzene saturated with water was
calculated as log β nb(H L+) = 5.3 ± 0.1. Finally, the stability constants of complexes of some univalent cations with valinomycin were summarized and
discussed. 相似文献
7.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H +(aq) + 1
·Na +(nb) ⇆ 1
·H +(nb) + Na +(aq) taking place in the two-phase water-nitrobenzene system ( 1 = p-tert-butylcalix[4]arene-tetrakis( N, N-diethylacetamide); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K
ex(H +, 1
·Na +) = −1.4 ± 0.1. Further, the stability constant of the p-tert-butylcalix[4]arene-tetrakis( N, N-diethylacetamide)-H + complex in water saturated nitrobenzene was calculated for a temperature of 25°C as log β nb( 1
· H +) = 8.1 ± 0.1. 相似文献
8.
Summary. From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H +(aq) + 1
·Na +(nb) ⇆ 1
·H +(nb) + Na +(aq) taking place in the two-phase water-nitrobenzene system ( 1 = p-tert-butylcalix[4]arene-tetrakis( N, N-diethylacetamide); aq = aqueous phase, nb = nitrobenzene phase) was evaluated as log K
ex(H +, 1
·Na +) = −1.4 ± 0.1. Further, the stability constant of the p-tert-butylcalix[4]arene-tetrakis( N, N-diethylacetamide)-H + complex in water saturated nitrobenzene was calculated for a temperature of 25°C as log β nb( 1
· H +) = 8.1 ± 0.1. 相似文献
9.
Summary From extraction experiments and<span style='font-size:12.0pt;font-family:Symbol; mso-bidi-font-family:Symbol'>g-activity measurements,
the extraction constant corresponding to the equilibrium Ba 2+(aq)+SrL 2+(nb)?BaL 2+(nb)+Sr 2+(aq) taking place in the two-phase water-nitrobenzene system (L= valinomycin; aq= aqueous phase,</o:p>nb= nitrobenzene phase)
was evaluated as log Kex(Ba 2+, SrL 2+)=1.3. Furthermore, the stability constant of the valinomycin-strontium complex in nitrobenzene saturated with water was calculated
for a temperature of 25 °C: log bnb(SrL 2+)=5.4. 相似文献
10.
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
11.
Summary From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Pb 2+(aq)+SrL 2+ (nb)↔PbL 2+ (nb)+Sr 2+ (aq) taking place in the two-phase water-nitrobenzene system (L=PEG 400; aq = aqueous phase, nb = nitrobenzene phase) was
evaluated as log Kex(Pb 2+, SrL 2+)=2.0±0.1. Further, the stability constant of the PEG 400 - lead complex in nitrobenzene saturated with water was calculated
for a temperature of 25 °C: log βnb(PbL 2+)=12.9±0.1. 相似文献
12.
From extraction experiments and γ-activity measurements, the exchange extraction constant corresponding to the equilibrium Ca 2+(aq) + 1·Sr 2+(nb) ? 1·Ca 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(Ca 2+, 1·Sr 2+) = 1.1 ± 0.1. Further, the stability constant of the 1·Ca 2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β nb( 1·Ca 2+) = 10.1 ± 0.2. Finally, by using quantum mechanical density functional level of theory calculations, the most probable structures of the non-hydrated 1·Ca 2+ and hydrated 1·Ca 2+·H 2O complex species were predicted. 相似文献
13.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium 2Li +(aq)+SrL 2
2+(nb) 2LiL +(nb)+Sr 2+(aq) taking place in the two-phase water-nitrobenzene system (L=15-crown-5; aq=aqueous phase, nb=nitrobenzene phase) was evaluated
as log K
ex
(2Li +;SrL 2
2+)=−3.7. Further, the stability constant of the 15-crown-5—lithium complex in nitrobenzene saturated with water was calculated:
log β nh(LiL +)=7.0. 相似文献
14.
From several strontium distribution experiments with 85Sr tracer, the extraction constant corresponding to the equilibrium Ca 2+(aq)+SrL 2+(nb) CaL 2+(nb)+Sr 2+ (aq) in the two-phase water-nitrobenzene system (L = 18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) was tentatively evaluated as log K
ex (Ca 2+,SrL 2+) = –1.9±0.1. Furthermore, the stability constant of the calcium — 18-crown-6 complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log nb(Cal 2+) = 10.1±0.1. 相似文献
15.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M 2+(aq)+SrL 2+(nb)⇔ML 2+(nb)+Sr 2+(aq) taking place in the two-phase water-nitrobenzene system (M 2+ = Mg 2+, Zn 2+, Mn 2+; L = valinomycin; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Further, the stability constants of the ML 2+ complexes in water saturated nitrobenzene were calculated. They were found to increase in the order of Mg 2+<Mn 2+<Zn 2+. 相似文献
16.
Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the Ag +(aq) + NaL +(nb)?AgL +(nb) + Na +(aq) equilibrium in the two-phase water-nitrobenzene system (L=valinomycin; aq=aqueous phase, nb=nitrobenzene phase) was evaluated
as log Kex(Ag +,NaL +)=-0.6±0.1. The stability constant of the valinomycin-silver complex in nitrobenzene saturated with water was calculated:
log bnb(AgL +)=4.6±0.1. The stability constants of complexes of some univalent cations with valinomycin were summarized and discussed. 相似文献
17.
Summary From extraction experiments andg-activity measurements, the extraction constant corresponding to the equilibrium Pb 2+(aq)+SrL(nb)?PbL(nb)+Sr 2+(aq)taking place in the two-phase water-nitrobenzene system (L = benzo-15-crown-5; aq = aqueous phase, nb = nitrobenzene phase)
was evaluated aslog Kex(Pb 2+,SrL)=0.1±0.1. Further, the stability constant of the benzo-15-crown-5-lead complex in nitrobenzene saturated with water was
calculated for a temperature of25 °C:log bnb(PbL)=13.2±0.1. 相似文献
18.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Pb 2+(aq)+SrL 2
2+(nb)⇆PbL 2
2+(nb)+Sr 2+(aq) taking place in the two-phase water-nitrobenzene system (L=15-crown-5; aq = aqueous phase, nb = nitrobenzene phase) was
evaluated: log K
ex (Pb 2+,SrL 2
2+)=3.0. Further, the stability constant of the PbL 2
2+ complex in nitrobenzene saturated with water was calculated: log β nb(PbL
2
2+
)=17.8 相似文献
19.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Sr 2+(aq) + 2A ?(aq) + 1(nb) ? 1·Sr 2+(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 K ex( 1·Sr 2+,2A ?) = ?0.6 ± 0.1. Further, the stability constant of the 1·Sr 2+ complex in nitrobenzene saturated with water was calculated for a temperature of 25 °C: log β nb( 1·Sr 2+) = 8.5 ± 0.1. Finally, by using quantum-mechanical DFT calculations, the most probable structure of the resulting cationic complex 1·Sr 2+ was derived. 相似文献
20.
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
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