Semi-crystalline alkali-metal salt complexes with poly(oligooxyethyleneoxy-1,2-phenylene)s

Abstract

A series of poly(oligooxyethyleneoxy-1,2-phenylene)s having the formula [graphic omitted] where n= 2, 3 and 5, have been synthesised with molecular weights of ca. 10 000. Although the pure polymers are fully amorphous, thermal analysis and X-ray scattering show that the polyether with n= 2 forms a well organised complex with NaSCN, with a stoichiometry of three oxygens per Na⁺ ion. The melting temperature of the new complex (187 °C) is similar to that of the analogous complex with poly(ethylene oxide)(PEO). Comparison with the PEO–NaSCN complex suggests that the new polymer may enclose the Na⁺ ions to form a 2₁ helix with 18 bonds per repeat. A plausible 2₁ helical structure for this new polyether complex has been computed. A crystalline complex between the polyether with n= 5 and NaSCN is also observed but no organised complexes with the n= 3 system or with Nal, LiClO₄ or KSCN were obtained with any of the polyethers.