Inclusion of a Cu2+ ion by a large-cavity crown ether dibenzo-24-crown-8 through supramolecular interactions.

A supramolecular copper-aqua-crown ether complex, [Cu(II)(H2O)4(dibenzo-24-crown-8]2+ (1c) is stabilized with a Lindqvist-type polyoxometalate anion, [Mo(VI)6O19]2- (1a), in an ion-pair compound [Cu(II)(H2O)4(dibenzo-24-crown-8][Mo(VI6O19] identical with [1c][1a] identical with 1. In the crystal, 1c and 1a assemble to a chainlike structure in which each polyoxoanion 1a is sandwiched by two 1c cations. 1c is a structurally characterized dibenzo-24-crown-8 (a larger-cavity crown ether) supramolecular complex that shows encapsulation of a small cation at the center of its internal cavity, and compound 1 represents a unique example of a first-row transition metal-crown ether inclusion complex that interacts with a polyoxometalate anion.