Room-Temperature Phosphorescence of 1-Bromonaphthalene upon Formation of Beta-Cyclodextrin Ternary Complexes with Alcohols and Surfactants: Optimization of Analytical Figures of Merit by Rigorous Equilibrium Studies

Abstract

Room-temperature phosphorimetry of ternary β-cyclodextrin complexes of the model compound 1-bromonaphthalene has been examined. The selected third partners were alcohols (cyclohexanol, cyclopentanol, and 1-pentanol) and surfactants (Triton X-100 and sodium dodecyl sulfate). A thorough analysis of all equilibria involved in the interaction between the components is performed and discussed. A computational procedure, not previously employed to study this type of complex systems, is used for the determination of the equilibrium constants and stoichiometries of the formed species. It is shown that a rigorous analysis of the equilibria is necessary for a proper optimization of analytical methods based on roomtemperature phosphorescence of ternary complexes. The best working conditions are inferred from the examination of three-dimensional and contour plots of the ternary complex concentration as a function of those of the reagents. The latter plots are constructed once the relative stabilities of all intervening species are known. On the basis of the calibration results, the relative advantages of employing the examined systems for determining the studied compound are presented.