Photo-control of Separation and Determination of Metal Ion using Micelle Solutions Containing Crowned Spirobenzopyran Derivatives

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Fluorescence spectra of the micelle solutions, which consist of dodecylsulfate as a surfactant, containing spirobenzopyran derivatives bearing a crown ether moiety and an octadecyl group, what we call crowned spirobenzopyran, were investigated on addition of different metal ions. The remarkable increase in relative fluorescence intensity of spirobenzopyran derivative bearing monoaza-12-crown-4 was observed on addition of lithium ion under alkaline conditions. The most increase in the relative fluorescence intensities of spirobenzopyran derivatives bearing monoaza-15-crwn-5 and-18-crown-6 were also realized when added sodium and potassium ions, respectively, which form the most stable complexes with those crown ether moieties.It is very important to determine the basic properties, such as the shape and the critical micelle concentration (cmc), of the micelle composed of anionic surfactant and crowned spirobenzopyran for the molecular design of the surfactant as the constituent of micelle and as the trapping agent for organic molecules. From this point of view, the critical micelle concentrations of the micelle containing crowned spirobenzopyran, which has a monoaza-12-crown-4, were measured under the dark and the light-irradiation conditions. The values of cmc increased in the following order : without crowned spirobenzopyran < with crowned spirobenzopyran under visible-light irradiation < with crowned spirobenzopyran under dark conditions. On the other hand, the aggregation numbers of the micelle were increased in the reverse of the tendency of cmc. It was realized from the observation using the dynamic light scattering and the transmission electron microscope that the micelles have the spherical shape and the spherical diameter is changed by photo-irradiation. Moreover, the dissolving abilities of the micelles for organic compounds were also altered with the change in polarity of the micelle by photo-irradiation.