In this depiction of the structure of PCN-61, a metal-organic framework, copper atoms (blue) sit in “paddlewheel” structures with oxygen (red) and carbon (black) atoms. The paddlewheels link together to form cuboctahedra enclosing volumes about 13 Å across (large red spheres). Three-armed ligand molecules then connect the cuboctahedra into a larger structure enclosing cavities 15 Å (yellow spheres) and 23 Å (blue) across. (Credit: Zhou et al.)
The ChemMatCARS advanced crystallography station was used to determine the structure of a metal-organic framework compound with a unique stucture that combines large cavities (> 20 Å) and small openings (< 20 Å). The structure is achieved by a novel synthesis strategy. Porous materials frameworks with open structures are potentially useful for a wide range of applications, such as gas storage, catalysis, and drug delivery.