Encapsulation of a Cr-III Single-Ion Magnet within an Fe-II Spin-Crossover Supramolecular Host

Single functional molecules are regarded as future components of nanoscale spintronic devices. Supramolecular coordination chemistry provides unlimited resources to implement multiple functions to individual molecules. A novel coordination [Fe-2] helicate exhibiting spin-crossover is demonstrated to be ideally suited to encapsulate a [Cr(ox)(3)](3-) complex anion (ox = oxalate), unveiling for the first-time single ion slow relaxation of the magnetization for this metal. A possibility of tuning the dynamics of this relaxation as well as the performance of the Cr-III center as qubit arises from the observation that metastable high spin Fe-II centers from the host can be generated by irradiation with green light at low temperature.