Methyl-substituted cucurbit[6]uril-based microporous supramolecular frameworks for highly selective Et2O/CH3OH adsorption

Abstract

The interaction and supramolecular assemblies of two alkaline earth metal ions, Ca²⁺ and Ba²⁺, with methyl-substituted cucurbit[6]uril derived from 3α-methyl-glycoluril (HMeQ[6]) in aqueous HCl solution have been investigated. X-ray diffraction analysis revealed that coordination of HMeQ[6] with these metal ions resulted in the formation of one-dimensional coordination polymers in the presence of polychloride transition metal anions, such as [CdCl₄]²⁻, as structure-directing agents. The supramolecular frameworks exhibit excellent thermal stability as well as permanent porosity. The activated desolvated materials show high Et₂O and CH₃OH adsorption capacity and selectivity compared with other porous organic materials assembled solely through hydrogen bonding under ambient conditions.