Experimental and theoretical study on the complexation of the cesium cation with dibenzo-30-crown-10

From extraction experiments and γ-activity measurements, the extraction constant corresponding to the equilibrium Cs+ (aq) + A− (aq) + 1(nb) \documentclass[12pt]{minimal} \usepackage{amsmath} \usepackage{wasysym} \usepackage{amsfonts} \usepackage{amssymb} \usepackage{amsbsy} \usepackage{mathrsfs} \usepackage{upgreek} \setlength{\oddsidemargin}{-69pt} \begin{document}$$ \rightleftarrows $$\end{document}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 Kex (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 βnb (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.