Keplerates

Keplerates are a class of coordination polymers with a specific structural motif. They are named after Johannes Kepler due to their structural resemblance to the Kepler conjecture, which describes the densest packing of spheres. In keplerates, metal ions are linked by polyoxometalate (POM) clusters, typically those based on tungstate or molybdate. These POM clusters, often polyhedra themselves, are arranged in a way that mimics the close packing of spheres.

The structure of keplerates can be quite complex, involving intricate three-dimensional networks. The POM units act as building blocks that self-assemble around central metal atoms or ions. This assembly process often leads to the formation of cavities or channels within the framework, which can encapsulate guest molecules. The size and shape of these cavities are determined by the specific POM units and the coordination geometry of the metal ions.

Keplerates have garnered interest for their potential applications in various fields. Their porous nature makes them candidates for gas storage and separation. The ability of the framework to host guest molecules also suggests applications in catalysis, where the encapsulated species can act as active sites. Furthermore, the optical and electronic properties of keplerates can be tuned by the choice of metal ions and POM clusters, opening possibilities for use in sensing and optoelectronic devices. Research continues to explore new synthetic routes and functional properties of these fascinating materials.