Metal-organic frameworks (MOFs) have potential for catalysis, separations, and sensor technologies and are commonly investigated in crystalline powdered form. The combination of metal ions and organic ligands as well as their porosity and surface area give them useful properties. However, in thin layer form or as capsules they could be exploited in more specific ways because of the selective permeation of the micropores in the layer or capsule surface.

Dirk E. De Vos and colleagues, Katholieke Universiteit Leuven, Belguim, have reported the synthesis of capsules with a MOF structure. They suggest that a selective capsule might be used as a tiny reaction vessel in which highly selective catalytic processes could be performed.

• Interfacial synthesis of hollow metal-organic framework capsules demonstrating selective permeability
  R. Ameloot, F. Vermoortele, W. Vanhove, M. B. J. Roeffaers, B. F. Sels, D. E. De Vos,
  Nature Chem. 2011.
  DOI: 10.1038/nchem.1026