Rapid capture of 4,13-diaza-18-crown-6 molecules by p-sulfonatocalix[4]arene in the presence of trivalent lanthanide ions

4,13-Diaza-18-crown-6 in the presence of aquated trivalent lanthanide ions and p-sulfonatocalix[4]arene results in a molecular capsule type arrangement with two 4– charge calixarenes and two water molecules shrouding the diprotonated crown ether with overall charged balance from two lanthanide ions. Analogous chemistry in the presence of 1-aza-18-crown-6 under the same conditions results in an unusual bi-layer structural motif devoid of the crown ether, the difference in chemistry being in part ascribed to any molecular capsule formed for the mono-aza crown ether taking on an overall 7– charge rather than a 6– charge, requiring fractional lanthanide ions for charge balance.