Extended Data Fig. 3: Calculated PES of the reduced [3]catenane [3]CMM^7+6•.

a, Graphical representations of the redox process experienced by the [3]catenane in going from the oxidized state I (48, 19) to the reduced state II (28, 10). b, A two-dimensional position map describing the movement of the two reduced CBPQT^2(+•) rings (A and B) around the loop. Four hypothetical paths (R1–R4) during the reduction process are illustrated by diamond (grey), circle (light red), triangle (black) and square (red) symbols, respectively. The green arrow indicates the preferred direction of movement and the red arrow indicates the less preferred (nearly precluded) direction of movement. The green, purple, black, blue and magenta lines represent the positions of the IPP, V^+•, BPM, PY⁺ and T units, respectively. The dashed red diagonal lines represent barriers that cannot be crossed physically because doing so would require the two CBPQT^2(+•) rings to occupy the same space. c, The PESs of the two CBPQT^2(+•) rings moving around the loop in the reduced state, starting from point I (48, 19) and following paths R3 and R4, respectively. d, Structural formula of the loop with atoms numbered to define the positions of the CBPQT^2(+•) rings. e,f, Quantum mechanical minimized structures (M06-2X/6-31G* basis set, top-down and side-on views) for the CBPQT^2(+•) rings at positions (32, 10) and (2, 28), respectively.