Electrochemical oxidation and reduction

A study of the electrochemical oxidation and reduction of certain isoindoles (and isobenzofurans) has been made, using cyclic voltammetry. The reduction wave was found to be twice the height of the oxidation wave, and conventional polarography confirmed that reduction involved a two-electron transfer. Peak potential measurements and electrochemiluminescence intensities (see Section IV, E) are consistent vidth cation radicals as intermediates. The relatively long lifetime of these intermediates is attributed to steric shielding by the phenyl groups rather than electron delocalization (Table VIII). 

Cation and anion radicals form from sulfoxides or sulfones by either chemical or electrochemical oxidation and reduction, respectively. The ability of compounds to accept... 

Koop, B., Schafer, H.J. and Straub, A., 2000, Steroselective interconversion of NaDH and NaDH" Analogues by Electrochemical Oxidation and Reduction , Paper presented at 197 meeting of the electochemical society . May 2000, Toronto, Canada, Abstract no. 1032. 

Rossmeisl J, Norskov JK, Taylor CD, Janik MJ, Neurock M. 2006. Calculated phase diagrams for the electrochemical oxidation and reduction of water over Pt(l 11). J Phys Chem B 110 21833-21839. 

These processes can be made to occur in a number of ways, for example with gas phase reagents such as AsF5 and I2, solution species such as FeCl3 or using electrochemical oxidation and reduction, but regardless of the method used the basic process is the same. If the material is to maintain overall electrical neutrality during and after doping, a counter ion is required, i.e., for p-doped materials,... 

I Iapiot, P., L. D. Kispert et al. (2001). Single two-electron transfers vs successive one-electron transfers in polyconjugated systems illustrated by the electrochemical oxidation and reduction of carotenoids../. Am. Chem. Soc. 123 6669-6677. 

At a terminal ac voltage of 4 V and a frequency of 30 Hz we observed a weak eel which was clearly identified as the IL emission of Pt(QO)2. It is+assumed that the ac electrolysis generates a redox pair Pt(QO)2 Pt(QO)2. The subsequent annihilation leads to the formation of electronically excited Pt(QO)2. The low eel intensity may be associated with the observation that the electrochemical oxidation and reduction of Pt(QO)2 is largely irreversible. CV measurements revealed an oxidation at E1. -... 

V.D. Neff, Electrochemical oxidation and reduction of thin films of Prussian blue. J. Electrochem. Soc. 128, 886-887 (1978). 

In this chapter we describe the use of polyelectrolytes carrying redox-active centers on electrode surfaces with particular emphasis on organized layer-by-layer redox polyelectrolyte multilayers (RPEM). In redox-active polyelectrolyte multilayers the polyion-polyion intrinsic charge compensation can be broken by ion exchange driven by the electrochemical oxidation and reduction forming extrinsic polyion-counterion pairing. In this chapter we describe the structure, dynamics and applications of these systems. 

In the liquid phase, the equivalents of IPs and EAs are the electrochemical oxidation and reduction potentials and analogous thermochemical cycles have been used in the literature to calculate pK values. However, oxidation and reduction potentials of RsSi radicals are not yet established experimentally and, therefore, the solution thermochemical cycles suffer from these limitations. 

One example of a tin porphycene has been reported, but as yet no organometallic derivatives have been reported." A small number of tin corrole complexes are known including one organotin example, Sn(OEC)Ph, prepared from the reaction of Sn(OEC)Cl with PhMgBr. A crystal structure of Sn(OEC)Ph shows it to have both shorter Sn—N and Sn—C bonds than Sn(TPP)Ph2, with the tin atom displaced 0.722 A above the N4 plane of the domed macrocycle (Fig. 6). The complex undergoes reversible one-electron electrochemical oxidation and reduction at the corrole ring, and also two further ring oxidations which have no counterpart in tin porphyrin complexes. " " ... 

Chapter 1 - Electrochemical Oxidation and Reduction of Organic Compounds,... 

In 1992, Kadish and coworkers [76] reported results for the first comprehensive study of the electrochemical oxidation and reduction of some metallocorroles, including (OMC)Co(PPh3) (16), where OMC denotes the trianion of 2,3,7,8,12,13,17,18-octamethylcorrole. 

Ferrocene has been widely investigated as an electron donor and its electron donating ability can be tuned by redox reactions. As anticipated, when a ferrocene unit is covalently connected to an electron acceptor moiety that shows intrinsic fluorescence, the fluorescence of the acceptor moiety would be largely quenched because of the photoinduced electron transfer between ferrocene and the fluorescent acceptor. For instance, triad 15 that contains perylene diimide flanked by two ferrocene moieties, shows rather weak fluorescence due to the photoinduced electron transfer between perylene diimide and ferrocene units. Either chemical or electrochemical oxidation of ferrocene unit lead to fluorescence enhancement. This is simply because the electron donating ability of ferrocene is reduced after oxidation and accordingly the photoinduced electron transfer is prohibited. In this way, the fluorescence intensity of 15 can be reversibly modulated by sequential electrochemical oxidation and reduction. Therefore, a new redox fluorescence switch can be established with triad 15.25... 

Stable disilenes are usually highly reactive toward oxidation and reduction because the 7i and n levels of disilene are much higher and lower than those of ethylene, as shown theoretically (Section III.A) and by the electrochemical oxidation and reduction potentials (Section III.E). Several stable disilenes are however stable in air for a long period. Disilene 27 undergoes very slow decomposition (half-life ca. 84 h) in wet THF solution at rt,60,61 and air oxidation of disilene 63 is completed in benzene at rt for a week.35 Disilene 27 survives for 4 months in the solid state. Since the oxidations and reductions of disilenes and their mechanisms have been extensively discussed in review OW, we mostly show herein the results of recent studies. 

In aqueous or aqueous-organic SSE s the accessible potential range is dependent on the electrochemical oxidation and reduction of water (or hydroxyl ions and protons in acid or alkaline media) with formation of oxygen and hydrogen, respectively. The potentials at which these processes take place are different for different electrode materials 9 in that the anodic limit for aqueous systems... 

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