Novel polyurethanes with macroheterocyclic (crown-ether) structures in the polymer backbone

The synthesis of a functionalized crown ether was accomplished in two steps by condensing 3,4-dihydroxybenzaldehyde with bis(2-chloroethyl)ether and subsequent reduction of the reaction product, bis(formylbenzo)-18-crown-6 (4) to a diol (5). Polyurethanes that bear the dibenzo-18-crown-6 moiety in the polymer backbone were synthesized from bis(methylolbenzo)-18-crown-6 (5), a polypropylene glycol, and methylene bis(4-cyclohexyl isocyanate). The resulting polymers were fibrous white solids with glass transitions from ca. 15–120°C, depending on the starting diol composition. The thermomechanical spectra of melt pressed or solvent cast films of several crown-ether-bearing polyurethanes showed evidence of multiphase character. The polymers failed to complex effectively with sodium ions. However, their complexing ability with potassium ion was similar in magnitude to that observed with relatively simple crown ethers.