Dynamics of Magnetic Isolation and Nano-Vacuum State in Endohedral Fullerene Li + @C 60

High Resolution Image Download MS PowerPoint Slide The realization of isolated quantum systems within solid-state matrices is a pivotal challenge in quantum information science. This study demonstrates the existence of a “nano-vacuum” state in lithium-ion endohedral fullerene (Li + @C 60 ·PF 6 – ), where the encapsulated ion exhibits extreme magnetic isolation. Using ultrahigh field (18.79 T) solid-state NMR, we observed a 7 Li line width of ∼50 Hz that remains invariant under magic angle spinning (MAS), indicating that the ion undergoes ultrafast isotropic motion (τ c ≪ 10 –5 s), which completely averages quadrupolar interactions. Most significantly, we report a record-breaking spin–lattice relaxation time ( T 1 ) of approximately 1068 s. This extraordinary lifetime is rationalized by a “relaxation blockade” mechanism: the absence of spin–orbit coupling prevents phonon scattering, while the rapid “roaming” of Li + and the cooperative “plastic” rotation of external PF 6 – anions synergistically suppress dipolar and quadrupolar relaxation channels. These findings establish Li + @C 60 as a ″thermodynamically open but magnetically closed″ system, offering a robust platform for quantum sensing.