Synthesis and Characterization of Alkali Metal Ion-Binding Copolymers Bearing Dibenzo-24-crown-8 Ether Moieties

Abstract

Dibenzo-24-crown-8 (DB24C8)-bearing copolymers were synthesized by radical copolymerization using a DB24C8-carrying acrylamide derivative and N-isopropylacrylamide monomers. The cloud point of the resulting copolymers changed in aqueous solution in the presence of cesium ions. In addition, the 1H NMR signals of DB24C8-bearing copolymers shifted in the presence of alkali metal. This shift was more pronounced following the addition of Cs+ compared to Rb+, K+, Na+, and Li+ ions due to recognition of the Cs+ ion by DB24C8.

Monosulfonated dibenzo-24-crown-8 and its properties

“…Notably, the binding preference of SDB24C8 (Na + > K + ≫ Cs + , Li + ) is very different from that of the parent dibenzo-24crown-8 ether (Cs + > K + > Na + > Li + ) 54,56 or systems containing the DB24C8 moiety. 57 DB24C8 clearly prefers the alkali metal cations with a relatively large ionic radius, i.e. K + and Cs + , albeit preference for Cs + is not very high, e.g.…”