Related Experiment Video
Updated: Aug 15, 2026

Electric-field Control of Electronic States in WS2 Nanodevices by Electrolyte Gating
Published on: April 12, 2018
Temperature-dependent and friction-controlled electrochemically induced shuttling along molecular strings associated
Eugenii Katz1, Ronan Baron, Itamar Willner
1Institute of Chemistry, The Hebrew University of Jerusalem, Jerusalem 91904, Israel.
Abstract:
The temperature and solvent composition dependence of the electrochemically stimulated rate of shuttling of the redox-active cyclophane, cyclobis(paraquat-p-phenylene), on a molecular string has been studied. The molecular string includes a pi-donor diiminebenzene-site that is associated on one side with an electrode, and stoppered on the other side with an adamantane unit. The cyclophane rests on the pi-donor site, owing to stabilizing pi-donor-acceptor interactions. Electrochemical reduction of the cyclophane units, to the bis-radical cation cyclophane, results in the shuttling of the reduced cyclophane towards the electrode, a process that is driven by the removal of the stabilizing donor-acceptor interactions, and the electrostatic attraction of the reduced product by the electrode. The latter process is energetically downhill, and is temperature-independent. Upon oxidation of the reduced cyclophane that is associated with the electrode, the energetically uphill shuttling of the oxidized cyclophane to the pi-donor site proceeds. The rate of this translocation process has been found to be temperature-dependent, and controlled by the solvent composition. The experimental results have been theoretically analyzed in terms of Kramers' molecular friction model. The theoretical fitting of the experimental results, using solutions of variable composition, reveals that the rate-constants for the uphill reaction in a pure aqueous solution follow the temperature-dependence of the viscosity of water. The results demonstrate the significance of friction phenomena in shuttling processes within molecular machines.
Related Concept Videos
Electrochemical Systems
Processes at Electrodes
The Electrical Double Layer
Electrolysis
Interfacial Electrochemical Methods: Overview
Electromotive Force

