Polymeric pseudo-crown ether for cation recognition via cation template-assisted cyclopolymerization.

Terashima, Takaya; Kawabe, Minami; Miyabara, Yuichiro; Yoda, Hiroaki; Sawamoto, Mitsuo · Nat Commun · 2013

basic_science · Level V

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Abstract

Cyclopolymerization is a chain polymerization of bifunctional monomers via alternating processes of intramolecular cyclization and intermolecular addition, to give soluble linear polymers consisting of in-chain cyclic structures. Though cyclopolymers comprising in-chain multiple large rings potentially show unique functionality, they generally require the elaborate design of bifunctional monomers. Here we report cation template-assisted cyclopolymerization of poly(ethylene glycol) dimethacrylates as an efficient strategy directly yielding polymeric pseudo-crown ethers with large in-chain cavities (up to 30-membered rings) for selective molecular recognition. The key is to select a size-fit metal cation for the spacer unit of the divinyl monomers to form a pseudo-cyclic conformation, where the two vinyl groups are suitably positioned for intramolecular cyclization. The marriage of supramolecular chemistry and polymer chemistry affords efficient, one-pot chemical transformation from common chemical reagents with simple templates to functional cyclopolymers.