Bis-imidazolium cations, 1,1′-[1,4-phenylenebis(methylene)]bis(3-R-1H-imidazolium-1-yl), (R = methyl or n-butyl), form discrete multicomponent complexes in water with various phosphonium cations, anionic p-sulfonatocalixarene, and aquated gadolinium(III) ions. The terminal alkyl groups, R, reside in the cavities of the calixarenes, with two calixarenes either adjacent to each other, where they face the same direction and are in the same bilayer arrangement made of calixarenes and phosphonium cations, or where they face opposite directions. Here the calixarenes are similarly part of a bilayer arrangement, or they are part of an extended structure which can be regarded as being built from the assembly of supermolecules or “molecular capsules”, [(bis-imidazolium)(p-sulfonatocalixarene)2], which are π-stacked through the calixarenes in a head-to-tail fashion. The nature of the product depends on the length of the terminal alkyl group, and the choice of phosphonium cation.
Ling, I., Alias, Y., Sobolev, A., & Raston, C. (2009). Constructing Multicomponent Materials Containing Cavitands, and Phosphonium and Imidazolium Cations. Crystal Growth and Design, 9(10), 4497-4503. https://doi.org/10.1021/cg900710c