Intercalation of a Trimethylammoniomethylated Calix[4]arene by Cu(II)-Montmorillonite

Abstract

Abstract The uptake of 5,11,17,23-tetrakis(trimethylammoniomethyl)-25,26,27,28-tetramethoxycalix[4]arene tetrachloride by Cu(II)-montmorillonite was examined at 25 °C. The mineral forms an intercalated phase in which the calixarene molecules are arranged as a 9.5 Å thick monolayer, with a cone-type conformation, with their cavity axes perpendicular to the silicate layers. Thermogravimetric and copper(II) release data suggest that the guest molecules are taken up in their tetra- and tri-valent forms during the initial and final uptake stages, respectively.