Encapsulation of a CrIII single-ion magnet within an feII 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 [Fe2 ] 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 CrIII center as qubit arises from the observation that metastable high spin FeII centers from the host can be generated by irradiation with green light at low temperature.G.A. thanks the Generalitat de Catalunya for the prize ICREA Academia 2008 and 2013 and the ERC for a Starting Grant (258060 FuncMolQIP). The authors thank the Spanish MINECO for funding through MAT2014-53961-R, MAT2017-86826-R (O.R.) and CTQ2015-68370-P (G.A. and L.A.B.). M.D. thanks Avempace II Erasmus Mundus Action 2 program for a PhD scholarship. This research used resources of the Advanced Light Source, which is a DOE Office of Science User Facility under contract no. DE-AC02-05CH11231.Peer reviewe