Extended Data Fig. 2: Calculated PES of the reduced [2]catenane [2]C^5+4•.

a, The potential energy for the CBPQT^2(+•) ring as a function of its position on the loop in the reduced state of the [2]catenane [2]C^5+4•. The numbered atoms on the loop are used to define the position of the CBPQT^2(+•) ring. b, Graphical representation of the reduced state of [2]catenane [2]C^5+4• in its lowest-energy co-conformation in which the CBPQT^2(+•) ring encircles the V^+• unit, position 10. c, Graphical representation of calculated potential energy of the CBPQT^2(+•) ring as it moves around the loop, shown in a rollercoaster manner for the radical state [2]C^5+4•. d, Quantum mechanical minimized structures (M06-2X/6-31G* basis set) for the CBPQT^2(+•) ring located at positions 10, 21 and 27, respectively.