Showing papers by "Yoshihisa Inoue published in 1988"
TL;DR: In this article, the conductivities of alkali metal salts in the presence of 15-crown-5 (15C5), 16c5 (16C5) and benzo-15crown -5 (B15c5) were measured at 25 °C in acetonitrile, propylene carbonate, and methanol formation constants (KML+) of 1:1 complexes of 15C5 and 16C5 with alkali ion and conductance parameters (λ0 and a) of the Na+ complexes of Na+ complex of 15
Abstract: Conductivities of alkali metal salts in the presence of 15-crown-5 (15C5), 16-crown-5 (16C5), and benzo-15-crown-5 (B15C5) were measured at 25 °C in acetonitrile, propylene carbonate, and methanol Formation constants (KML+) of 1:1 complexes of 15C5 and 16C5 with alkali metal ions and conductance parameters (λ0 and a) of the Na+ complexes of 15C5, 16C5, and B15C5 were determined, λ0 and a being limiting ionic molar conductivity and distance of closest approach of ions, respectively In general, selectivities of 15C5 and 16C5 for alkali metal ions show the size-fit correlation In contrast to 15C5, 16C5 forms much the most stable complex with Na+ in every solvent Generally, KML+-value sequences of a given crown ether complex for the solvents are the reverse of donor-number sequences of the solvents Value of a increases with an increase in the cationic size (Na+→Na(15C5)+→Na(16C5)+→Na(B15C5)+) Mobility of the Na+–crown ether complex decreases with an increase in the size of the crown ether From λ0 value
46 citations
TL;DR: In this article, a constant set of stabilite et parametres thermodynamiques for the complexation of K + + were presented. Formation of complexes 1:2. Effets de la longueur de la chaine sur la stabilite des complexes
Abstract: Constantes de stabilite et parametres thermodynamiques pour la complexation de K + . Formation de complexes 1:2. Effets de la longueur de la chaine sur la stabilite des complexes
34 citations
TL;DR: In this paper, an overwhelming preference for the sandwich complexation and unique cation selectivities were observed for aqueous lanthanoid picrates with 15crown-5 and 18crown6 in the absence of background salts.
Abstract: Quantitative solvent extractions of aqueous lanthanoid picrates with 15-crown-5 and 18-crown-6 were conducted at low ionic strength in the absence of background salts. An overwhelming preference for the sandwich complexation and unique cation selectivities were observed. The peak extraction constants were found for samarium with 15-crown-5 (1:2 stoichiometry) and for cerium and praseodymium with 18-crown-6 (1:1 and 1:2 stoichiometries, respectively). The facile sandwich complexation and unique cation selectivities are interpreted in terms of the heavy hydration of lanthanoid ions of high charge density.
30 citations
TL;DR: In this article, a solvent extraction study with 18crown-6, 24c Crown-8, and their dibenzo-derivatives has revealed that the following ligand-cation combinations give dicationic complexes in the solution phase.
Abstract: A solvent extraction study with 18-crown-6, 24-crown-8, and their dibenzo-derivatives has revealed that the following ligand–cation combinations give dicationic complexes in the solution phase: 18-crown-6 with Li+; 24-crown-8 with Li+, Na+, K+; dibenzo-24-crown-8 with Na+, K+, Ag+, Sr2+. The facile formation of dicationic complexes in the solvent extraction is attributed to the effective charge-shielding co-ordination by the bulky, lipophilic picrate anions in the contact ion-pair complex extracted.
13 citations
TL;DR: The 14,16,16-crown-5 derivatives possess unusually high cation-binding abilities for most cations, maintaining the original relative cation selectivity for Na+ and Ag+ for which the fixed conformation is responsible.
Abstract: 14,16-Bridged 16-crown-5 derivatives possess unusually high cation-binding abilities for most cations, maintaining the original relative cation-selectivity for Na+ and Ag+, for which the fixed conformation is responsible.
4 citations