Following the same protocol employed for the previous cases, we built an AA model of trans-3 isomer of system 3 67 that was then equilibrated via a preliminary MD simulation in explicit CHCl 3 solvent (Fig. ). Starting from the resulting equilibrium structure, we performed a WT-MetaD simulation to explore the shuttling dynamics of the [10]CPP ring in rotaxane 3. To avoid spurious folding effects induced by the applied bias during the WT-MetaD simulation, the axle was kept extended during the simulation by softly restraining the position of the fullerene stoppers (see SI and Methods for details). Such a constrained condition is consistent with the typical application of similar structures, which have been tested as molecular wires in charge transport components or as molecular junctions in a setup where the axle is connected to two electrodes. As in the previous case, from a converged WT-MetaD simulation we could reconstruct the FES for the shuttling process, while multiple infrequent WT-MetaD simulations allowed us to reconstruct the height of the barriers and the characteristic kinetics for the involved transitions. In such an asymmetric variant of this specific system, the C 60 has only a single adduct, so that the CPP ring can be effectively released in solution directly from the bound state (see SI, Fig. , top). The kinetics of such a ring unbinding transition has been estimated experimentally to occur in the timescale of milliseconds. 67 Infrequent WT-MetaD simulations activating the ring unbinding from such an asymmetric system variant provided a comparable unbinding timescale, within the error that can be expected from such approaches (see Fig. and Methods section for details). On the one hand, such an agreement demonstrates the accuracy of the AA models and the appropriateness of the simulation setup adopted herein. On the other hand, this indicates that a direct ring unbinding event from a terminal fullerene group is ∼ 3 -4 orders of magnitude faster than the characteristic time required for the same macrocycle to leave the binding from the central fullerene and to diffuse along the axle in rotaxane 3 (Fig. ). This indicates a possible frustration of the CPP unbinding and diffusion processes in this rotaxane where, e.g., the ring can unbind and move from the fullerene only following specific directions determined by the substituents and the axle orientations (see bent axle orientation in, e.g., Fig. ). This reduces the accessible pathways toward unbinding and shuttling along the flexible linkers, which has a significant effect on the kinetics of such a transition.