Covalently bonded two spin centers of paramagnetic metallofullerene dimer

Paramagnetic endohedral metallofullerenes with well protected unpaired spin have potential applications in molecular-scale qubit processing and magnetoreception system. In this study, a paramagnetic metallofullerene Sc₃C₂@C₈₀ dimer with covalently bonded two spin centers was synthesized. Electron paramagnetic resonance (EPR) results further revealed the varied spin-nuclei couplings and paramagnetic property for Sc₃C₂@C₈₀ dimer. Briefly, the Sc₃C₂@C₈₀ dimer in toluene solution shows EPR hyperfine splittings originating from the spin-Sc couplings. However, the Sc₃C₂@C₈₀ dimer in solid state shows the disappearance of hyperfine structure and a single EPR signal caused by its two-spin-center structure. The transformation of EPR signals can be further finely modulated by controlling the dynamic motion of Sc₃C₂@C₈₀ dimer in chloronaphthalene. The Sc₃C₂@C₈₀ dimer with two spin centers possesses varied paramagnetic properties, demonstrating its potential as new magnetic material.