Molecular magnetic switch for a metallofullerene

The endohedral fullerenes lead to well-protected internal species by the fullerene cages, and even highly reactive radicals can be stabilized. However, the manipulation of the magnetic properties of these radicals from outside remains challenging. Here we report a system of a paramagnetic metallofullerene Sc₃C₂@C₈₀ connected to a nitroxide radical, to achieve the remote control of the magnetic properties of the metallofullerene. The remote nitroxide group serves as a magnetic switch for the electronic spin resonance (ESR) signals of Sc₃C₂@C₈₀ via spin-spin interactions. Briefly, the nitroxide radical group can 'switch off' the ESR signals of the Sc₃C₂@C₈₀ moiety. Moreover, the strength of spin-spin interactions between Sc₃C₂@C₈₀ and the nitroxide group can be manipulated by changing the distance between these two spin centres. In addition, the ESR signals of the Sc₃C₂@C₈₀ moiety can be switched on at low temperatures through weakened spin-lattice interactions.