Electrochemically Driven Motion

ELECTROCHEMICALLY DRIVEN MOTIONS IN COPPER-COMPLEXED CATENANES... 

The molecular axis contains a thin 2,2 -bipyridine motif, which is less bulky than a 1,10-phenanthroline fragment and thus is expected to spin more readily within the cavity of the ring. In addition, the bipy chelate does not bear substituents in -position to the nitrogen atoms. 5(4) + rearranges to the five-coordinate species 5(5)2+ after oxidation and vice versa. The electrochemically driven motions were studied by cyclic voltammetry. A lower limit for the rate constant of the... 

Lateral Translation of a Ring on the Molecular String on which it is Threaded Electrochemically-driven Motion... 

Electrochemically Driven Ring Gliding Motion in Catenanes I 271... 

The other examples of electrochemically driven ring motions in [2]catenanes are from the class of metal complexed catenanes (i.e., catenates) that have been synthesized and studied in our groups. These compounds, the synthesis of which relies on the ability of copper( I) to gather the bidentate phenanthroline ligand around its tetrahedral coordination sphere, are produced in remarkable yield [9, 28, 57f]. The principle of operation is essentially based on the different stereoelectronic requirements of copper(I) and copper(II). Whereas a coordination number of 4, with a tetrahedral or distorted tetrahedral arrangement is preferred by copper(I),... 

The mechanochemical rotatory motion of bacterial flagella, driven by electrochemical proton gradients across the peripheral membrane. Each complete turn requires... 

To produce membrane depolarization, a current stimulus of sufficient intensity to exceed the outward K+ current must be appUed to the cell. If the depolarizing stimulus raises the membrane potential above a threshold value, sodium channels within the sarcolemmal membrane change their conformation and open their ion-selective pore, allowing Na to enter the cell driven by the electrochemical gradient. The open sodium channels raise the membrane potential toward the equilibrium potential of sodium (-f65 mV) and set into motion the intricate and precisely coordinated series of ion channel openings and closings leading to the characteristic action potential. 

Catenanes in Motion Electrochemically and Photochemically Driven Machine-Like Molecules... 

Fig. 5 Controlled molecular motion in rotaxanes light-driven shifting of the wheel along the rotaxane axle (top) and contraction of a molecular muscle stimulated hy electrochemical Cu(I)-Cu(II) interconversion (bottom).

Electrochemical microsystem technology can be scaled down from macroscopic science to micro and further to nanoscale through EMST to ENT [1]. In ENT, electrochemistry involves in the production process to realize nanoproducts and systems which must have reproducible capability. The size of the products and systems must be in the submicron range. It considers electrochemical process for nanostructures formation by deposition, dissolution and modification. Electrochemical reactions combining ion transfer reactions (ITR) and electron transfer reactions (ETR) as applicable in EMST are also applied in ENT. Molecular motions play an important role in ENT as compared with EMST. Hence, mechanical driven system has to be changed to piezo-driven system to achieve nanoscale motions in ENT. Due to the molecular dimension of ENT, quantum effects are always present which is not important in the case of EMST. The double layer acts as an interface phenomenon between electrode and electrolyte in EMST, however, double layer in the order of few nanometers even in dilute electrolyte interferes with the nanostmcture in ENT. 

Gradients in surface (or interfacial) tension can accelerate the spreading of fluids, enhance the stability of surfactant-laden films of liquid, emulsions, and foams, and increase rates of mass transport across interfaces. The motion of fluid driven by a gradient in surface tension is referred to as a Marangoni flow . We have demonstrated that electrochemical reduction of IF to IF at an electrode that... 

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