Nanosponges based on self-assembled starfish-shaped cucurbit[6]urils functionalized with imidazolium arms

A new porous material based on the first supramolecular cucurbituril-based nanosponge was synthesized by the functionalization of cucurbit[6]uril with twelve 1-(2-bromoethyl)-3-methyl-1H-imidazol-3-ium arms. The porous structure and the high adsorption capacity were demonstrated through surface area measurements and carbon dioxide adsorption. The new supramolecular sponge showed attractive properties such as (i) a highly porous structure that allowed CO₂ capture, (ii) the possibility to reuse the adsorbed CO₂ for organic synthesis, and (iii) an exciting thermal stability up to around 800 °C, with the potential use of this material in high temperature reactions. Finally, the reuse of CO₂ was successfully investigated in the carboxylation reaction of phenylacetylene.