Magnetic endohedral metallofullerenes with floppy interiors

It is shown that Gd₃N@C₈₀ is a highly magnetic and very stable motif that allows enhanced contrast magnetic resonance imaging and electric dipole moment with potential for cancer treatment. Using a synergistic approach combining Stern-Gerlach experiments in beams and first-principles electronic structure studies, it is demonstrated that an isolated Gd₃N has a ground state spin moment of 23μ_B followed by a noncollinear state of 17.2μ_B only 88 meV above the ground state. The large moment is largely due to localized f electrons. As a Gd₃N is embedded inside a C₈₀ cage, the localized f electrons maintain the magnetic character while the hybridization between the s, d states of isolated Gd₃N and p states of C₈₀ leads to a strongly bound motif with an interaction energy of 13.63 eV and a large highest-occupied-molecular-orbital–lowest-unoccupied-molecular-orbital gap of 1.48 eV. Gd₃N@C₈₀ is further shown to possess two isomers corresponding to the location of the N atom on either side of the Gd₃ triangle with an appreciable electric dipole moment and a low barrier of 91 meV for transition between them offering potential for a fluctuating dipole.