Metal Actuated Ring Translocation Switches in Water

Among a series of metal ions in water, silver is the only one to remotely and reversibly switch cucurbit[7]uril (CB[7]) movements (translocation or uptake) on a rigid and linear three-station viologen–phenylene–imidazole (V–P–I) derivative, avoiding undesired pH actuation. 1H NMR, UV–vis spectroscopy, mass spectrometry, ITC, and modeling were combined to show that ring translocation or uptake along a molecular thread is possible in water by Ag+ as a metal stimulus.