Mercaptothiacalixarenes Steer 24 Copper(I) Centers to form a Hollow-Sphere Structure Featuring Cu2 S2 Motifs with Exceptionally Short Cu⋠⋠⋠Cu Distances.

Tetramercaptotetrathiacalix[4]arene (LH4 ) can be used as a coordination platform to bind four CuI ions at the thiolate and thioether S atoms. Donor ligands such as phosphanes can stabilize the resulting [LCu4 ] units, which then remain monomeric ([(Ph3 PCu)4 L]). In the absence of donor ligands, they aggregate, providing a hexamer ([LCu4 ]6 ) in high yields, with a hollow-sphere structure formed by an unprecedented Cu24 S48 cage that is surrounded by the organic framework of the calixarene chalices. Preliminary NMR experiments with regard to the host-guest chemistry in solution showed that the compound represents a polytopic host for acetonitrile and methane.