Cation-sensitive fluorescence of anionic polymers bearing naphtho-18-crown-6 units.
Changes in the fluorescence intensity of anionic polymers bearing naphtho-18-crown-6 moieties on addition of cations were studied in water at 30 °C. On addition of alkali metal cations, the fluorescence intensity of the polymers decreased sharply for Tl(+) less for Cs(+) and little for Li(+), K(+) and Rb(+). On addition of alkaline earth metal cations, Ba(2+) caused the strongest decrease of the fluorescence intensity of the polymers. The decrease of the fluorescence intensity of the polymers was suggested to be caused by the external heavy-atom effect of the cations bound to the cavity of the crowned naphthalene moiety. The content of the crowned naphthalene units in the polymers affected the cation-dependent fluorescence change. The fluorescence change of the polymers based on the cation complexation competition was also studied.
Department of Applied Chemistry, College of Engineering, Osaka Prefecture University, Sakai, 593, Osaka, Japan.
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Shirai
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Murakami
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Tsunooka