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1.
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
2.
From extraction experiments and γ-activity measurements, the extraction constants corresponding to the general equilibrium M +(aq) + 1·Cs +(nb)
\rightleftarrows \rightleftarrows
1·M +(nb) + Cs +(aq) taking part in the two-phase water–nitrobenzene system ( 1 = hexaarylbenzene-based receptor; M + = H 3O +, NH 4
+, Ag +, K +, Rb +, Tl +; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the stability constants of the ML + complex species in nitrobenzene saturated with water were calculated; they were found to increase in the series of Rb + < K + < Ag +, Tl + < H 3O +, NH 4
+. 相似文献
3.
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
4.
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
5.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium C +(aq) + Cs +(nb) ⇔ C +(nb) + Cs +(aq) taking part in the two-phase water–nitrobenzene system (C + = organic cation; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Furthermore, the individual extraction constants
of 15 organic cations in the mentioned two-phase system were calculated. 相似文献
6.
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium
\text Cs + ( \text aq ) + \text A - ( \text aq ) + 1( \text nb )\underset \rightleftharpoons 1·\text Cs + ( \text nb ) + \text A - ( \text nb ) {\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. 相似文献
7.
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
8.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M + (aq) + 1·Na + (nb) ⇔ 1·M + (nb) + Na + (aq) taking place in the two-phase water–nitrobenzene system (M + = Li +, H 3O +, NH 4 + {\rm NH}_{4}^{ + } , Ag +, K +, Rb +, Tl +, Cs +; 1 = barium ionophore I; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the stability constants
of the 1·M + complexes in water-saturated nitrobenzene were calculated; they were found to increase in the series of Cs + < Rb + < NH 4 + {\rm NH}_{4}^{ + } , K + < H 3O + < Na + < Ag +, Tl + < Li +. 相似文献
9.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the equilibrium
M
+(aq) + 1 · Na + (nb) ⇄ 1 · M
+ (nb) + Na + (aq) taking place in the two-phase water-nitrobenzene system ( M
+ = Li +, H 3O +, NH 4
+, Ag +, K +, Rb +, Tl +, Cs +; 1 = tetraphenyl p-tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants
of the 1 · M
+ complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Cs + < Rb + < Tl + < K + < NH 4
+ < Ag + < H 3O + < Li +.
Correspondence: Emanuel Makrlík, Faculty of Applied Sciences, University of West Bohemia, Pilsen, Czech Republic. 相似文献
10.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M +(aq)+NaL +(nb)⇔ML +(nb)+Na +(aq) taking place in the two-phase water-nitrobenzene system [M +=Li +, K +, Rb +, Cs +; L = p-tert-butylcalix[4]arene-tetrakis (N, N-dimethylthioacetamide); aq = aqueous phase, nb = nitrobenzene phase] were evaluated. Furthermore,
the stability constants of the ML + complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Cs +<Rb +<K +<Li +<Na +. 相似文献
11.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M +(aq)+NaL +(nb)⇄ML +(nb)+Na +(aq) taking place in the two-phase water-nitrobenzene system (M +=Li +, K +, Rb +, Cs +; L=dibenzo-24-crown-8; aq=aqueous phase, nb=nitrobenzene phase) were evaluated. Further, the stability constants of the ML + complexes in nitrobenzene saturated with water were calculated; they were found to increase in the Cs +Rb +L +Na + order. 相似文献
12.
Summary From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Li +(aq)+NaL +(nb) ↔LiL +(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(Li +,NaL +)=-1.1. Further, the stability constant of the valinomycin-lithium complex species in nitrobenzene saturated with water was
calculated: log βnb(LiL +)=6.3. 相似文献
13.
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
14.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium M +(aq)+NaL +(nb)⇔ML +(nb)+Na +(aq) taking place in the two-phase water-nitrobenzene system (M + = H +, NH 4+, Ag +, Tl +; L = tetramethyl p- tert-butylcalix[4]arene tetraketone; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. Moreover, the stability constants
of the ML + complexes in water saturated nitrobenzene were calculated; they were found to increase in the order Tl +<NH 4+<Ag + <H + <Na +. 相似文献
15.
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
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.
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
18.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M +(aq)+NaL +(nb)⇄ML +(nb)+Na +(aq) taking place in the two-phase water-nitrobenzene system (M +=Li +, K +, Rb +, Cs +; L=18-crown-6; aq = aqueous phase, nb = nitrobenzene phase) were evaluated. The stability constants of the ML + complexes in nitrobenzene saturated with water were calculated; they are found to increase in the cation order Cs +Li +Na +Rb +K +. Further, the individual extraction constants for the NaL +, KL +, RbL + and CsL + complex species in the wate-nitrobenzene system were determined; their values increase in the series Na +Rb +Cs +K +. 相似文献
19.
From extraction experiments and γ-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 + = Li +, Na +, K +, Rb +; L = hexaethyl p- tert-butylcalix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were determined. Moreover, the stability constants
of the ML + complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order Rb +<Cs +<K +<Na +<Li +. 相似文献
20.
From extraction experiments and γ-activity measurements, the exchange extraction constants corresponding to the general equilibrium
M +(aq)+NaL +(nb)⇔ML +(nb)+Na +(aq) taking place in the two-phase water-nitrobenzene system (M + = Li +, H 3O +, NH 4+, Ag +; L = hexaethyl calix[6]arene hexaacetate; aq = aqueous phase, nb = nitrobenzene phase) were determined. Furthermore, the
stability constants of the ML + complexes in water saturated nitrobenzene were calculated; they were found to increase in the cation order H 3O +<NH 4+<Li +<Ag +. 相似文献
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