Hierarchical assembly involving hydroxyethyl-substituted imidazolium cations and p-sulfonatocalix[4]arenes

A multiple-component bilayer involving four different ions has preferential binding of functionalized 3-(2-hydroxyethyl)-1-methylimidazolium in the cavity of bowl-shaped p-sulfonatocalix[4]arene, with the supermolecule being capped by a water molecule involving an O-H⋯π(imidazolium) interaction, an O⋯HO H-bond involving the hydroxyethyl group, and an SO⋯HO H-bond. The nature of the interplay of the components has been mapped out using Hirshfeld surface analysis. The [imidazolium ∩ calixarene] supermolecule persists in solution.