Dipotassium salt of a double-armed terephthalic acid derivative: dipotassium 2,5-bis(2-{2-[2-(2-{2-[2-(2-hydroxyethoxy)phenoxy]ethoxy}phenoxy)ethoxy]phenoxy}methyl)terephthalate methanol tetrasolvate

Abstract

Single crystals of the the title compound, 2K+·C58H56O18 2−·4CH3OH, were obtained from a methanol solution. The anion is centrosymmetric; consequently the asymmetric unit contains one-half of the salt and two methanol molecules. Each polyether chain contains one K+, which is coordinated by eight O atoms belonging to the carboxylate, terminal hydroxy and six ether groups. The structure of the entire anion is such that the two K+ are enclosed in the shape of an S. One methanol molecule forms hydrogen bonds with the O atom of the carboxylate group that does not participate in the coordination. The other methanol molecule forms hydrogen bonds with the other O atom of the carboxylate group that coordinates with K+ and also with the terminal hydroxy group of an adjacent salt unit.