Abstract
From extraction experiments in the two-phase water/nitrobenzene system and γ-activity measurements, the stability constant of a hexaarylbenzene-based receptor. Tl+ complex species dissolved in nitrobenzene saturated with water was determined. By using the quantum-mechanical density functional level of theory calculations, the most probable structure of this complex was derived. 相似文献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Abstract
The stability constant of the dibenzo-18-crown-6·H3O+ 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·H3O+ complex species. 相似文献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Abstract
From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium H3O+(aq) + 1·Na+(nb) \leftrightarrows \leftrightarrows 1·H3O+ (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 (H3O+, 1·Na+) = −0.1 ± 0.1. Further, the stability constant of the 1·H3O+ complex in water-saturated nitrobenzene was calculated for a temperature of 25 °C as log β nb (1·H3O+) = 10.9 ± 0.2. By using quantum mechanical DFT calculations, the most probable structure of the 1·H3O+ cationic complex species was derived. In this complex, the hydroxonium ion H3O+ 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+, H3O+, NH4 +, Ag+, or K+) were determined in water-saturated nitrobenzene. It was found that these constants increase in the cation order NH4 + < K+ < H3O+ < Ag+ < Li+ < Na+. 相似文献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