@article { ISI:000232725900025,
	title = {Temperature-dependent and friction-controlled electrochemically induced shuttling along molecular strings associated with electrodes},
	journal = {CHEMPHYSCHEM},
	volume = {6},
	year = {2005},
	month = {OCT 14},
	pages = {2179-2189},
	abstract = {The temperature and solvent composition dependence of the electrochemically stimulated rate of shuttling of the redox-active cyclophane, cyclobis(paroquat-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 on electrode, and stoppered on the other side with on adamantane unit. The cyclophone rests on the pi-donor site, owing to stabilizing pi-donor-acceptor interactions. Electrochemical reduction of the cyclophone units, to the bis-radical cation cyclophone, 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 rote 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{\textquoteright} 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.},
	issn = {1439-4235},
	doi = {10.1002/cphc.200500162},
	author = {Katz, E and Baron, R and WILLNER, I and Richke, N and LEVINE, RD}
}
