Cation binding properties of polyanions bearing fluorescent crown ether units

✍ Scribed by Masamitsu Shirai; Yoshiki Matoba; Masahiro Tsunooka

• Publisher: Elsevier Science
• Year: 1995
• Tongue: English
• Weight: 457 KB
• Volume: 31
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(94)00209-6

✦ Synopsis

The cation-dependent decrease in fluorescence intensity of polyanions bearing 4'-acryloylbenzo-18-crown-6 (ACR18) or 4'-acryloylbenzo-15crown-5 (ACRIS) units was studied in water at 30°C. The polyanions were prepared by the radical copolymerization of methacrylic acid, acrylic acid, or itaconic acid and ACRl5 or ACR18. On excitation with 330 nm light the polymers showed fluorescence at 410 nm. The fluorescence intensity decreased on addition of alkali and alkaline earth metal cations, alkylammonium cations (C, H, + , -NH:, n = 2, 4, 6, and C,H,CH,-NH:), and alkyldiammonium cations [H,N+-(CH,),-NH: : n = 2,4,6]. The cation binding constants K for the polymers in water were determined from

the fluorescence change on addition of cations. The K values were much higher than that reported for the crown eth'ers with corresponding ring-size. The concentration effect of the cations in the neighborhood of the polymer-bound crown ether groups by electrostatic binding induced significant complex formation between cations and crown ether moiety in the polymer chain.