Film-forming polymers containing in the main-chain dibenzo crown ethers with aliphatic (C-10-C-16), aliphatic-aromatic, or oxyindole spacers
Zolotukhin, M.G., Hernandez, M.D.G., Lopez, A.M., Fomina, L., Cedillo, G., Nogales, A., Ezquerra, T., Rueda, D., Colquhoun, H.M., Fromm, K.M., Ruiz-Trevino, A. and Ree, M. (2006) Film-forming polymers containing in the main-chain dibenzo crown ethers with aliphatic (C-10-C-16), aliphatic-aromatic, or oxyindole spacers. Macromolecules, 39 (14). pp. 4696-4703. ISSN 0024-9297
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To link to this article DOI: 10.1021/ma052148e
Novel, linear, soluble, high-molecular-weight, film-forming polymers and copolymers in which main-chain crown ether units alternate with aliphatic (C-10-C-16) units have been obtained for the first time from aromatic electrophilic substitution reactions of crown ethers by aliphatic dicarboxylic acids followed by reduction of the carbonyl groups. The crown ether unit is dibenzo-18-crown-6, dibenzo-21-crown-7, dibenzo-24-crown-8, or dibenzo-30-crown-10; the aliphatic spacer is derived from a dicarboxylic acid (sebacic, 1,12-dodecanedicarboxylic, hexadecanedioic or 1,4-phenylenediacetic acids). The reactions were performed at 35 degrees C in a mixture of methanesulfonic acid (MSA) with phosphorus pentoxide, 12:1 (w/w), (Eaton's reagent). The carbonyl groups in the polyketones obtained were completely reduced to methylene linkages by treatment at room temperature with triethylsilane in a mixture of trifluoroacetic acid and dichloromethane. Polymers containing in the main chain crown ethers alternating with oxyindole fragments were prepared by one-pot condensation of crown ethers with isatin in a medium of Eaton's reagent. A possible reaction mechanism is suggested. According to IR and NMR analyses, the polyacylation reactions lead to the formation of isomeric (syn/anti-substituted) crown ether units in the main chain. The polymers obtained were soluble in the common organic solvents, and flexible transparent films could be cast from the solutions. DSC and X-ray studies of the polymers with "symmetrical" crown ethers reveal the presence of the endotherms corresponding to the supramolecular assemblies.