We note that the proposed molecules have not been synthesized so far and serve as models here. Nevertheless, a few analogous systems have been experimentally observed. In particular, Hf@C84 has been isolated and Ti@Cn (n=28, 80, 90), as well as Zr@C28, have been detected in mass-spectroscopy experiments. Proof of concept; computations predict Ti@C70-D5h(1) to function as a molecular spinristor Density functional theory (DFT) computations using B97D3 functional predict the ground-state local minimum structure (LM1/LM1´) of Ti@C70 to be a closed-shell singlet, with the lowest triplet state at just 3.5 kcal.mol -1 above it, Fig. . The closed-shell singlet groundstate may seem to contradict the spin-filtering function. However, when connected to the electrodes the triplet is the ground state of the system. In LM1, the metal is connected to the interior of the fullerene cage in the electron-rich polar region. The position of the metal can switch between LM1 and LM1′ as the metal atom passes through the cavity of the cage to the other side. To switch between the local minima, the Ti@C70 has to pass through the respective transition state (TS) that is computed to be 16.6 kcal.mol -1 higher than LM1, Fig. . An intermediate, labeled LM2, 10.5 kcal.mol -1 above LM1 forms when the Ti is midway to the other side of the cage. The ground electronic state of the transition states between LM1/LM1′ and LM2, (TS/TS′), is a triplet in the gas phase for Ti@C70. Therefore, an intersystem crossing occurs while the metal switches its position, Fig. . For simplicity, we consider switching between LM1 and LM1′. It can be safely assumed that when the applied external electric field (EEF) is strong enough for LM1 to pass through TS, the system will not stop at LM2 as the barrier between LM2 and TS′ is notably smaller than the one between LM1 and TS on the potential energy surface (PES) of the molecule, Fig. . Controlling the position of metals inside EMFs by an EEF can be realized via scanning tunneling microscopy or, as recently reported, in a circuit. In principle, an increasing EEF reduces and eventually removes the energy barrier for switching by destabilizing the local minimum structures, in which the dipole moment vector of the structures are parallel to and along with the polarity of the applied field, Fig. . Simultaneously, the field stabilizes the local minima with a dipole moment vector against the direction of the externally applied field. Destabilization of one local minimum and stabilization of the other local minimum connected via a TS on a PES reduces the energy barriers between them as it is expected from the Hammond postulate. Additionally, the application of a quadrupolar field via the gate electrodes reduces the energy barrier further by manipulating the energies of TS/TS′ or the intermediate LM2, directly; see Fig. . We found that destabilizing LM2 is a more efficient way to achieve LM1′ from LM1 than stabilizing TS/TS′. We define the switching EEF as the field(s) (dipolar or quadrupolar) that is large enough to change the nature of a local minimum structure, e.g.LM1, on the PES, to a transition state or a non-stationary point so that the Ti relocates to another minimum position, e.g. LM1′.