Stoddart et al. 1989

molecular shuttles: gliding of a ring along the axle on which it is threaded signal 1 signal 2

pp.1172-1175

(A) Molecular drawing of the bistable [2]catenane used in this work (A) Molecular drawing of the bistable [2]catenane used in this work. The voltage-driven circumrotation of co-conformer [A0] to co-conformer [B+] is the basis of the device.

(B) Proposed mechanism for the operation of the device (B) Proposed mechanism for the operation of the device. Co-conformer [A0] represents both the ground-state structure of the [2]catenane and the “switch open” state of the device. When the [2]catenane is oxidized, the TTF groups (green) are ionized. The coconformer [B+] is formed. When the voltage is reduced to a near-zero bias, the co-conformer [B0] is formed, and this represents the “switch closed” state of the device. Partial reduction of the cyclophane (+2 V) is necessary to regenerate the [A0] co-conformer. The reduced co-conformer [AB#] is indicated with an unknown oxidation state.

Science, Vol. 294, 21 December 2001, p.2442

Controllable dethreading–rethreading processes, based on a (E)– (Z) photoisomerisation reaction, of the pseudorotaxanes formed by selfassembly of (E/Z)-1 with 24+. The structures shown are energy-minimised MM2 (CS Chem3D Pro) geometries of pseudorotaxanes [(E)-1·2]4+ and [(Z)-1·2]4+ (hydrogen atoms have been omitted for clarity).

Acid/base control of the wheel position on the axle