CVSIM in the Literature

Links to papers that used the program CVSIM and/or CVFIT

Redox Mediation and Photomechanical Oscillations Involving Photosensitive Cyclometalated Ru(II) Complexes, Glucose Oxidase, and Peroxidase Intact photosensitive cyclometalated RuII derivatives of 2-phenylpyridine or N,N-dimethylbenzylamine cis-[Ru(C∼N)(LL)X2]PF6 [C∼N = o-C6H4-py or o-C6H4CH2NMe2; LL = 1,10-phenanththroline (phen), 2,2‘-bipyridine (bpy), or 4,4‘-Me2-2,2‘-bipyridine (Me2bpy); X = MeCN or pyridine (py)] are efficient mediators of glucose oxidase (GO) from Aspergillus niger and horseradish peroxidase (HRP). Their redox potentials in an aqueous buffer are in the range 0.15−0.35 V versus SCE, and the rate constants for the oxidation GO(red) (where red indicates reduced) by the electrochemically generated RuIII species equal (1.7−2.5) × 106 M-1 s-1 at pH 7 and 25 °C. The redox potentials of all complexes decrease cathodically by 0.4−0.6 V upon irradiation by visible light because of the photoinduced solvolysis of acetonitrile or py ligands. These in situ generated species display an even better mediating performance with HRP, although their behavior toward GO is different. The loading of a ruthenium unit into the protein interior brings about large catalytic currents in a self-assembled system GO−Ru−d-glucose. The estimated rate constant for intramolecular electron transfer from FADH2 of the active site at RuIII, kintra, equals 4.4 × 103 s-1. This suggests that the distance between the redox partners is around 19 Å. The value of 21 Å was obtained through the docking analysis of a possible closest-to-FAD localization of a Ru-containing fragment derived from the irradiated complex cis-[Ru(o-C6H4-py)(phen)(MeCN)2]PF6. The operational stability of the GO−Ru assemblies depends on the nature of complex used, the highest being observed for cis-[Ru(o-C6H4-py)(Me2bpy)(MeCN)2]PF6 (2). UV−vis studies of interaction of 2 with GO revealed photomechanical oscillations in the system GO−Ru−d-glucose. When irradiated complex 2 is mixed with GO and d-glucose, the absorbance at 510 nm increases because of the enzymatic reduction of RuIII to RuII. The absorbance drops rapidly and then increases as in the first cycle after shaking the reaction solution. Many cycles are possible, and the rate of absorbance increase does not depend on a cycle number. A plausible mechanism of the oscillations is presented.
UV-Visible Spectrooelectrochemistry of the Reduction Products of Anthraquinone in Dimethylformamide Solutions: An Advanced Undergraduate Experiment The redox properties of anthraquinone (AQ) may be used to model the behaviour of quinones in biological systems. AQ undergoes two successive one-electron reductions in aprotic solvents to form a stable radical anion (AQ.-) and a stable dianion (AQ2-) but this behaviour is altered in the presence of a proton donor. This advanced undergraduate experiment shows how cyclic voltammetry, digital simulations of cyclic voltammograms, and UV-visible spectroelectrochemistry may be used to examine the reduction behaviour of AQ in dimethylformamide (DMF), both in the absence and presence of benzoic acid.The cyclic voltammetry of AQ in DMF shows two reversible one-electron reductions. This allows the UV-visible spectra of AQ.- and of AQ2- to be determined using an optically transparent thin layer electrode (OTTLE) cell. AQH- may also be detected in the spectra if there are proton impurities. When benzoic acid is added to the DMF, the cyclic voltammograms are markedly altered with almost all the reduction occurring near the AQ/AQ.- potential and the corresponding oxidation at rather more positive potentials. The UV-visible spectroelectrochemistry shows AQH2 as the stable reduction product under these conditions while digital simulations of the cyclic voltammograms support a mechanism involving protonation of AQ.- followed by AQH. disproportionation.
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Electron-transfer kinetics and ternary equilibria of the nitrogen dioxide(1+)/nitrogen dioxide/dinitrogen tetraoxide system by transient electrochemistry.pdf
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