Combining the fields of single-molecule magnets (SMMs) and metal–organic frameworks (MOFs) can lead to new types of molecular magnetic materials. The organization of SMMs in a way that allows non-trivial interactions is a necessary step towards applications in molecular quantum devices. Guillermo Mínguez Espallargas, Eugenio Coronado, and their co-workers, Universidad de Valencia, Spain, have succeeded in finding an alternative approach to synthesize SMM–MOFs by simplifying the use of metal clusters typical of SMMs to single lanthanoid centers that present single-ion magnet (SIM) behavior.

Structural data show that the MOF [Ln(bipyNO)₄](TfO)₃ (bipy = bipyridine; Ln = Tb, Dy, Ho, Er) possesses a 3D organization of the Ln centers in a complex network, and magnetic measurements confirm the existence of slow magnetic relaxation typical of SMMs. They have also demonstrated how the properties of such complexes can be tuned, without interference of the slow magnetic relaxation, by the incorporation of bulky polyoxometalates (POMs) into the cavities of the SIM–MOF by anion exchange.

• A SIM-MOF: Three-Dimensional Organisation of Single-Ion Magnets with Anion-Exchange Capabilities,
  J. J. Baldoví, E. Coronado, A. Gaita-Ariño, C. Gamer, M. Giménez-Marqués, G. Mínguez Espallargas,
  Chem. Eur. J. 2014.
  DOI: 10.1002/chem.201402255