Cyclic voltammetry copper

In the five-coordinate [Cu(Tp )L]C104 (L = 1-methylcarbal-dimino-3,5-dimethylpyrazole) characterized by IR, UV-Vis, EPR, and cyclic voltammetry, copper is in a distorted square-pyramidal geometry coordinated by tridentate K3-Tp and two N atoms from L.543... 

Porphyrin, octaethyl-, copper complex cyclic voltammetry, 4, 399 <73JA5140)... 

M.F.S. Teixeira, A. Segnini, F.C. Moraes, L.H. Marcolino, O. Fatibello, and E.T.G. Cavalheiro, Determination of vitamin B-6 (pyridoxine) in pharmaceutical preparations by cyclic voltammetry at a copper(II) hexacyanoferrate(III) modified carbon paste electrode. J. Brazilian Chem. Soc. 14, 316-321... 

The oxidation of hydroxide ion in acetonitrile at copper, silver, gold, and glassy-carbon electrodes has been characterized by cyclic voltammetry. In the absence of bases the metal electrodes are oxidized to their respective cations (Cu+, Ag+, and Au+) at potentials that range from -0.2V vs. SCE for Cu to +1.3 V for Au. At glassy carbon OH is oxidized to 0 - (+0.35 V vs SCE) and then to... 

Nanocarbons can also be deposited onto surfaces via electrochemistry, such as electrophoretic deposition described earlier. A method for one-step electrochemical layer-by-layer deposition of GO and PANI has been reported by Chen et al. [199]. A solution of GO and aniline was prepared and deposited onto a working electrode via cyclic voltammetry. GO was reduced on the surface when a potential of approx. -1 V (vs. SCE) was applied compared to the polymerization of aniline which occurred at approx. 0.7 V (vs. SCE). Repeated continuous scans between -1.4 to 9 V (vs. SCE) resulted in layer by layer deposition [199]. A slightly modified method has been reported by Li et al. who demonstrated a general method for electrochemical RGO hybridization by first reducing GO onto glassy carbon, copper, Ni foam, or graphene paper to form a porous RGO coating [223]. The porous RGO coated electrode could then be transferred to another electrolyte solution for electrochemical deposition, PANI hybridization was shown as an example [223]. 

Oxidation peak potentials of phenol derivatives were measured with cyclic voltammetry 0.53, 0.47, 0.47, 0.28, and 0.77 V vs. Ag/ AgCl for phenol, 2,6-dimethyl-, 2,6-diphenyl-, 2,6-dimethoxy-, and 2,6-dichlorophenol respectively. The oxidation potential of phenol and 2,6-dichlorophenol are relatively high and this high potential is one of the reasons why phenol and dichlorophenol could not he polymerized by the oxidation with copper catalyst or lead dioxide. On the other hand, for the electro-oxidative polymerization the potential can he kept slightly higher than the oxidation potential of phenols and the polymerization proceeds. 

Kowal, A. and Domianowski, A., 1973. Cyclic voltammetry of ethyl xanthate on a natural copper sulphide electrode. Electrocnal Chem. Interf. Electrochem., 46 411 - 420 Laajalehto, K., Nowak P., Pomianowski, A., Suonien, E., 1991. Xanthate adsorption at the PbS/aqueous interface comparison of XPS, infiared and electrochemical results. Colloids Surf., 57 319-333... 

Cyclic voltammetry was employed to determine the nature of the anodic and cathodic reactions of bare and coated copper in aerated 0.1M HClOjj (pH=1) and phosphate buffer (pH=5.6) solutions. Steady-state measurements were made in air to obtain a more... 

The reaction between A-chlorobenzotriazole and l-methyl-2-phenylindole involves formation of the indole radical cation and benzotriazole radical via an initial electron transfer <82JOC4895, 91JCS(P2)1779>. Chemical reactions of benzotriazole on a freshly etched surface of metallic copper are studied by surface-enhanced Raman scattering, x-ray photoelectron spectroscopy, and cyclic voltammetry. The surface product is (benzotriazolato)copper(-l-), which covers the surface in the shape of polymeric material and shows good anticorrosion effects for copper <91JPC7380>. 

Scheme 3 accounts for the various products formed, and it is consistent with known transformations in organometallic chemistry. In the first step, CO2 is reduced in a proton-coupled two-electron process to form adsorbed CO. That CO is an intermediate in the reduction of CO2 to hydrocarbons is supported by the following observations. (1) Reduction of CO at copper electrodes under the same conditions gives a similar distribution of hydrocarbon products. Reduction of formate, on the other hand, gave no hydrocarbon products [98, 102]. (2) CO on the electrode surface could be detected by cyclic voltammetry measurements. Fourier transform... 

A series of pubKcations was devoted to the electrocatalytic reduction of nitrate by the Eindhoven group [50-54]. On the basis of these works, a comparative study was performed to determine the reactivity of nitrate ions in 0.1 mol dm concentration on eight different polycrystaUine electrodes (platinum, palladium, rhodium, ruthenium, iridium, copper, silver, and gold) in acidic solution using cyclic voltammetry, chronoamperometry, and differential electrochemical mass spectroscopy (DEMS) [50]. 

Farias etal. [197] have presented cathodic adsorptive stripping voltammetry of guanine in the presence of copper at static mercury electrode. Cyclic voltammetry was also employed to characterize the interfacial and redox mechanisms. 

Redox potentials for copper systems have been based on a variety of approaches including (i) redox titrations, (ii) potentio-static methods involving spectral monitoring, (iii) cyclic voltammetry (CV), and (iv) pulsed methods. Of these, CV measurements are by far the most prevalent. No effort has been made in this treatise to identify the method used for a specific reported potential value unless the method itself appeared to be pertinent. 

The occurrence of the redox-driven reversible assembling-disassembling process involving copper complexes of 16 has been verified through cyclic voltammetry experiments at a platinum electrode in a MeCN solution. Figure 2.17 shows the CV profile obtained with a solution of the double-strand helicate complex [ Cu 21 (16)212 +. 

The cyclic voltammetry behavior of the Cu(II) rotaxane, 4(5)2+ (Fig. 14.8b), is very different from that of 4, t l +. The potential sweep for the measurement was started at - 0.9 V, a potential at which no electron transfer should occur, regardless of the nature of the surrounding of the central Cu(II) center (penta- or tetracoordinate). Curve i shows two cathodic peaks a very small one, located at + 0.53 V, followed by an intense one at —0.13V. Only one anodic peak at 0.59 V appears during the reverse sweep. If a second scan ii follows immediately the first one i, the intensity of the cathodic peak at 0.53 V increases noticeably. The main cathodic peak at —0.15 V is characteristic of pentacoordinate Cu(II). Thus, in 4(5)2+ prepared from the free rotaxane by metalation with Cu(II) ions, the central metal is coordinated to the terdentate terpyridine of the wheel and to the bidentate dpp of the axle. On the other hand, the irreversibility of this peak means that the pentacoordinate Cu(I) species formed in the diffusion layer when sweeping cathodically is transformed very rapidly and in any case before the electrode potential becomes again more anodic than the potential of the pentacoordinate Cu2 + /Cu+ redox system. The irreversible character of the wave at —0.15 V and the appearance of an anodic peak at the value of + 0.53 V indicate that the transient species, formed by reduction of 4(5)2 +, has undergone a complete reorganization, which leads to a tetracoordinate copper rotaxane. The second scan ii, which follows immediately the first one i, confirms this assertion. 

The results obtained by cyclic voltammetry clearly show that upon oxidation or reduction of the central metal copper, the macrocycle is set in motion. Upon oxidation of 6(4)+, the resulting tetrahedrally coordinated Cu(II) is unstable as Cu(II) forms stable square planar complexes or higher coordination (five or six). Therefore, the macrocycle pirouettes around the axle permitting the restoration of a stable coordination, that is pentacoordination by the 2,2, 6 2"-terpyridine and 2, 2 -bipyridine... 

The redox properties of dinuclear copper(II) complexes have received extensive attention using cyclic voltammetry measurements, and it was recognized in the early literature that the two copper(II) ions could be reduced to copper(I) at the same potential or at different potentials (Section 53.3.7).30,934,1021,1022 In either case the reduction requires a two electron process and if the E° values are well separated may result in the observation, under favourable circumstances, of a two-peaked cyclic voltammogram (Figure 61b), as in... 

At the end of this section on the relationship between the electronic properties and the stereochemistry of complexes of the copper(II) ion, it is worth summarizing the most useful physical techniques which offer a criterion for the presence of a polynuclear copper(II) complex rather than a mononuclear complex. These are (i) magnetic susceptibility measurements down to near absolute zero, for the determination of O or / values (ii) ESR spectra of magnetically dilute systems, in the solid state or in solution, to obtain hyperfine data and (iii) cyclic voltammetry to show evidence for a one-step reduction process in a Cu2 species. 

The irreversibility of the reduction peak of 16 2+, combined with the appearance of a reversible peak corresponding to tetracoordinated copper, suggests that the reorganization of the rotaxane in its pentacoordinated form 16(S)+ (i.e., with the copper coordinated to terpy and to dpp units) to its tetracoordinated form (16 +, in which the copper is surrounded by two dpp units) occurs within the timescale of the cyclic voltammetry. Indeed, the cyclic voltammetry response located at -0.15 V becomes progressively reversible when increasing the potential sweep rate, as expected for an electrochemical process in which an electron transfer is followed by an irreversible chemical reaction (EC). Following the method of Nicholson and Shain, 9S the rate constant value, k, of the chemical reaction, i.e., the transformation of pentacoordinated Cu(i) into tetracoordinated Cu(i), was determined. A value of 17 s 1 was... 

BASIL CIS CV CVD DSSC ECALE EC-STM EDX, EDS, EDAX EIS EMF EQCM FAB MS FFG-NMR Biphasic Acid Scavenging Utilizing Ionic Liquids Copper-indium-selenide Cyclic Voltammetry Chemical Vapor Deposition Dye Sensitized Solar Cell Electrochemical Atomic Layer Epitaxy Electrochemical in situ scanning tunnelling microscopy Energy Dispersive X-ray analysis Electrochemical Impedance Spectroscopy Electromotive Force Electrochemical Quarz Crystal Microbalance Fast atom bombardment mass spectroscopy Fixed Field Gradient Nuclear Magnetic Resonance... 

Tohnan and Lee constructed a type 1-like site linked to a type 2-like site and investigated the potential for intramolecular electron transfer between the two. Their coordination scheme is illustrated in Figme 6(a) the structure of their complex in shown in Figure 6(b). Cyclic voltammetry showed the two Cu(II) atoms to undergo quasi-reversible, independent reduction with 1/2 values consistent with the two copper atoms coordination -0.911 V for the CuSR site, -0.112 V for the CuPyr one. These studies did not address the question of intramolecular electron transfer between the two sites, however. 

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