Intercalation of p-Aminobenzylated and Dimethylammoniomethylated Calix[4]areneoctols by Cu(II)–Montmorillonite

Abstract

Abstract The uptake of two different types of cationic calix[4]areneoctols by Cu(II)–montmorillonite was studied at 25 °C. p-Aminobezylated calix[4]areneoctol 1 forms an intercalated phase in which the guest molecules are arranged as a 10.8 Å thick monolayer, with a cone-type conformation and with their cavity axes perpendicular to the inorganic layers. Thermogravimetric and copper(II) release data suggest that the calixareneoctol molecules are taken up in their divalent form and act as a prop to yield a vacant space of 42% in interlayer porosity. The molecules of dimethylammoniomethylated calix[4]areneoctol 2 are also intercalated as a monolayer, but initially in their divalent form and finally in the di- and mono-valent mixed form to fully occupy the interlayer space. The striking contrast between the two calixareneoctols as guest species is substantially due to the difference in bulkiness of their ammonio-substituted groups.