Redox electrochemical properties

Besides its widespread use for investigating the mechanism of redox processes, spectroelectrochemistry can be usefiil for analytical purposes. In particular, the simultaneous profiling of optical and electrochemical properties can enhance the overall selectivity of different sensing (30) and detection (31) applications. Such coupling of two modes of selectivity is facilitated by the judicious choice of the operating potential and wavelength. 

When the second-site revertants were segregated from the original mutations, the bci complexes carrying a single mutation in the linker region of the Rieske protein had steady-state activities of 70-100% of wild-type levels and cytochrome b reduction rates that were approximately half that of the wild type. In all these mutants, the redox potential of the Rieske cluster was increased by about 70 mV compared to the wild type (51). Since the mutations are in residues that are in the flexible linker, at least 27 A away from the cluster, it is extremely unlikely that any of the mutations would have a direct effect on the redox potential of the cluster that would be observed in the water-soluble fragments. However, the mutations in the flexible linker will affect the mobility of the Rieske protein. Therefore, the effect of the mutations described is due to the interaction between the positional state of the Rieske protein and its electrochemical properties (i.e., the redox potential of the cluster). 

Because of the exposed histidine ligands of the [2Fe-2S] cluster, the Rieske is capable of binding quinones in a redox-dependent manner. The variation of the hydrogen bond strength and of the electrostatic properties will control the movement of the catalytic domain of the Rieske protein. Therefore, the function depends on the unique structural and electrochemical properties of the Rieske cluster. 

The redox properties of complexes with hexaaza monocyclic ligands (e.g., (568)-(570)) are similar to those of the cyclam complex, indicating that the electrochemical properties of the complexes are only slightly affected by the presence of uncoordinated tertiary nitrogen atoms,... 

The electrochemical properties of redox-active moieties of a dendrimer can be influenced by other species added to the solution. This may open the way to... 

In conclusion, the electrochemical data offer a fingerprint of the chemical and topological structure of these dendrimers. Furthermore, the knowledge of the electrochemical properties of the mononuclear components and the synthetic control of the supramolecular structure allow the design of dendrimers with predetermined redox patterns. 

Electrochemical oxidation of X produces a polymer film with polythiophene as the backbone and viologen centers as pendant redox groups. The electrochemical properties of the polymer are the combination of polythiophene and viologen. Using viologen subunits as the internal standard (one per repeat unit of the polymer), the "doping level" of the oxidized polythiophene backbone at its maximum conductivity can be measured and is about 25%. The charge transport via the pendant V2+/+ of poly(l) has been studied by... 

The electrochemical properties of [14] and [15] were studied using CV. Each compound exhibited a reversible one-electron oxidation wave. Anodic redox potential perturbations of the CV oxidation waves were observed (due to a through space interaction as the methylene linkage is insulating) on addition of excess amounts of Na+, K+, Mg2+ and Ba2+ cations. 

CV and SWV were used to investigate the electrochemical anion recognition properties of these species in acetonitrile and the results are summarized in Tables 21 and 22. With reference to the known electrochemical properties of [Ru(bipy)3][PF6]2, the respective reversible oxidation and reduction redox couples exhibited by the receptors can be assigned to the metal-centred... 

It is difficult to obtain reliable measurements of En and hence pe in soils. Strictly, only measurements made with the electrodes in soil solution extracts rather than directly in soil are thermodynamically meaningful, and these are also subject to various errors, particularly due to the presence of mixed redox systems. Nonetheless it is a useful parameter and is the only single electrochemical property that can distinguish submerged soils from well-drained ones. 

Although the hybridization of single-stranded DNA to its complement results in detectable changes in electrochemical properties, particularly in support of non-Faradaic current, the DNA bases may also demonstrate redox behavior that gives rise to Faradaic currents. The electrochemical behavior of DNA has been studied over the past few decades. Differential pulse voltammograms show clearly defined peaks for the reduction of cytosine and adenosine. Electrochemical characterization of guanine by cyclic voltammetry has shown... 

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