Switching redox switch

Goulle, V. Harriman. A. Lehn. J.M. An electro-photo-switch Redox switching of the lumineseenee of a bipyridine metal complex. J. Cheni. Soc., Chem. Commun. 1993, 1034-1036. 

Enclosure also changes the redox properties of a compound, its color, and other physical properties (1,2). On this basis nonlinear optical materials, luminescence markers, controlled light switches, and other high-tech devices might be designed and prepared (15,17,137). 

The second concept is to switch the reactivity of the complex by addition or substruction of one or two electrons to or from the complex applies the Umpolung principle. The effect of redox change is dramatic increase in the rate is often of the order of 109 for a given reaction [15-18]. These properties are summarized in the following Scheme I ... 

Redox switching, 126 Reference electrodes, 100, 105, 142 Reflectance spectroscopy, 44 Resistance, 22, 105 Resolution 50, 71 Reverse pulse polarography, 68 Reversible systems, 4, 31 Reticulated vitreous carbon, 114, 115 Riboflavin, 37... 

The redox processes responsible for the switching of the bridging redox polymer can also be brought about by redox processes induced by molecular species in solution Alternatively, the switching processes can be designed so that a solution component is essential for, or mediates the redox process. The array electrode can then be used as a sensor for those solution constituents. 

Therefore, the Rieske protein has to switch between the positional states during turnover. The following reaction scheme combines the movement of the catalytic domain of the Rieske protein with the redox-dependent stabilization of the intermediate semiquinone (Fig. 19) (42) ... 

Figure 19. Scheme describing the redox switch, which is based on a viologen redox center incorporated within the nanoclusters ligand shell. For simplification the counterelectrode is not shown. (Adapted with permission from Ref [34], 2000, Nature Publishing Group.)... 

Electrochemical redox studies of electroactive species solubilized in the water core of reverse microemulsions of water, toluene, cosurfactant, and AOT [28,29] have illustrated a percolation phenomenon in faradaic electron transfer. This phenomenon was observed when the cosurfactant used was acrylamide or other primary amide [28,30]. The oxidation or reduction chemistry appeared to switch on when cosurfactant chemical potential was raised above a certain threshold value. This switching phenomenon was later confirmed to coincide with percolation in electrical conductivity [31], as suggested by earlier work from the group of Francoise Candau [32]. The explanations for this amide-cosurfactant-induced percolation center around increases in interfacial flexibility [32] and increased disorder in surfactant chain packing [33]. These increases in flexibility and disorder appear to lead to increased interdroplet attraction, coalescence, and cluster formation. 

In recent years advances in the chemistry of leuco dyes have taken place particularly in the areas of structural identification by means of H- and 13C-NMR and selective syntheses of aminoquinones, etc. New applications of leuco quinones such as in electro-optical devices and information recording media have enhanced their importance. In these applications, the chemistry of leuco quinones is interesting mainly due to switching from a colored to a colorless system by a redox process. 

The incorporation of photoactive components into the molecular structure, which allows reversible switching of the output physical properties, such as light or redox potential, by an... 

The ability to switch a molecular unit on and off is a key component of an efficient molecular device, since it allows modulation of the physical response of such a device by external physical or chemical triggers. A molecular device, based on a trinuclear metal complex, shown in Figure 59, functions as an electroswitchable-photoinduced-electron-transfer (ESPET) device.616 Electrochemical switching of the redox state of a spacer intervening between a donor-acceptor pair can dictate the type of the observable charge separation and the lifetime of the resulting ion pair.616... 

Figure 14. Cyclic voltammograms of /<2c-Re(bpy)(CO)3Cl in acetonitrile-0.1 M Bu4NPF6 at a Pt electrode.144 Scan rate 0.2 V/s. The lower voltammograms show the switching potential characteristics A and F, reversible one-electron wave B and D, redox couple due to a dimer of the complex C, the second metal-based wave. The upper curves show the effect of C02 on the voltammogram. See also Figure 15.

Many chemical species exhibit different redox states with distinct electronic absorption spectra, usually in the UV/visible region of the electromagnetic spectrum. Where the switching of redox... 

Figure 3,55 Cyclic vollammograms of Re(Bipy)(CO)3CI in CH3CN/0.l M letrabutylammonium hexafluorophosphate as supporting electrolyte at a button Pt electrode, and with a sweep rate of 200 mV s (a) The switching potential characteristics of the coupled chemical reactions in the ahsence of C02. The lettered redox processes are discussed in the text. (b> The effect of saturating the solution with C02. From Sullivan et al. (1985).

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