Lanthanoid assisted self-assembly of imidazolium cations in organic bi-layers

Multi-component solutions containing 1-n-ethyl-3-methylimidazolium or 1-n-butyl-3-methylimidazolium cations, p-sulfonatocalix[4]arene and large mono- or bis-phosphonium cations, as well as lanthanide metal ions, afford self-assembled material incorporating all four components. The calixarenes and phosphonium cations are organized into bi-layers, with the imidazolium cations and gadolinium(iii) species incorporated between the bi-layers. The imidazolium cations are confined within essentially 'molecular capsules' based on two calixarenes from adjacent bi-layers, with these cations taking on different orientations, depending on the nature of the phosphonium cation, and whether the metal also binds to sulfonate moieties.