Supporting Electrolyte Solution

The electrochemical reduction reactions of the central metallotetraphenylporphyrin moieties are, fortunately, much more straightforwardly analyzed (1,2). With few exceptions, when transferred to a fresh supporting electrolyte solution, films formed from ECP reactions like Fig. 2A exhibit electrochemical reduction waves at or very near the potentials observed for reductions of the corresponding monomers dissolved in solutions. For example, a film formed oxidatively as in Fig. 2A gives in fresh electrolyte the reductive gyclic voltammogram of Fig. 2B. 

Before starting any experiment, the potential of the test electrode Ej is measured with reference to a saturated calomel electrode which is connected to the experimental cell through a bridge containing the same supporting electrolyte solution. Such measurements are taken whenever the concentration of the metal ion is changed. The cell is kept immersed in a thermostated bath maintained at a known temperature. 

Obtained in acetonitrile containing 0.2 mol dm 3 Bu NBF4 as supporting electrolyte. Solutions... 

Obtained in acetonitrile solution containing 0.2 mol dm 3 BuJNBF4 as supporting electrolyte. Solutions were —2 x 10"3 mol dm"3 in compound, and potentials were determined with reference to SCE. One-wave shift in oxidation potential produced by presence of metal cation (4equiv) added as perchlorate salts. New wave evolved. 

Data were obtained in aqueous solution containing 0.2 mol dm"3 KC1 as supporting electrolyte. Solutions were 3 X 10 3 mol dm"3 in compound and potentials were determined with reference to SCE at 21 1°C at 50 mV s"1 scan rate. The solution pH was adjusted with 0.5 mol dm"3 KOH and 0.1 mol dm"3 HC1. 6For [28], [29], [30] and [31] the CVs were reversible one electron oxidations at pH < 6. At pH = 11, an EC mechanism was observed for [28], [29] and [31]. Minor oxidation waves of the amino groups appeared after that of the Fc+/Fc couple at slow scan rate. The CV of [32] was a one-electron reversible oxidation wave, less dependent on the solution pH, and showed no oxidation of the amino groups in the pH range explored. Anodic shifts of anodic current peak potential of the Fc+/Fc couple produced by the presence of metal cations (1 or 2 equiv added as their perchlorate salts). 

Obtained by both cyclic (100 mV s-1) and square-wave (10 Hz, Osteryoung-type) voltammetry in acetonitrile solution containing 0.1 mol dm-3 BuJNBF4 as supporting electrolyte. Solutions were 1 x 10-3 mol dm-3 in compound with reference to an Ag/Ag+ electrode (330 10 mV vs SCE) at 21 1°G b Anodic shift of the reduction waves of [57] in the presence of 1.0 equiv of the respective cationic species added as their perchlorate or hexafluorophosphate salts. "Anodic shift in the presence of 2.0 equiv of the respective cations. The second reduction wave of [57] became obscure or disappeared in the presence of more than 1 equiv of the respective cations. 

Obtained in MeCN solution containing 0.1 mol dm 3 Bu°NBF4 as supporting electrolyte. Solutions were 1 x 10 3 mol dm 3 in compound and potentials were determined with reference to an Ag/Ag+ electrode at 21 1°C, 50 mV s scan rate. > p, and represent the anodic and cathodic peak potentials. Cathodic shifts in the metallocene redox couples produced by the presence of anion (5 equiv) added as their tetrabutylammonium salts. As the concentration of the anion increased, the cathodic current peak potential of the ferrocene/ferTOcenium redox couple began to exhibit the features of an EC mechanism. 

Figure 8.11 Electrochemistry of nanotubes solubilized by direct sodium reduction. Background of the supporting electrolyte solution is shown with dashed line. The star indicates the irreversible anodic peak due to the oxidative stripping of the reduced alkali metal film. 2 mM tetrabutylammonium hydroxide/DMSO working electrode Pt disk (r = 25 pm) data recorded at 298K scan rate 1 V/s. Potentials are referenced to SCE. Reproduced with permission from Ref. 122. Copyright 2008 American Chemical Society.

In 2006, electrochemically induced synthesis of (3-lactams, by cyclization of haloamides, has been achieved in suitable solvent-supporting electrolyte solutions previously electrolyzed under galvanostatic control [166, 167]. The yields and the stereochemistry of the process were influenced by the nature of the R -R4 substituents, by the solvent-supporting electrolyte solutions, and by the electrolysis conditions (Scheme 69). 

Transfer of the sensor to blank supporting electrolyte solution... 

Case b in Scheme 6. Here, the MIP-film-coated electrode is equilibrated in solution containing both the electroinactive analyte and electroactive competitor. Then the electrode is rinsed with a solvent and transferred to a blank supporting electrolyte solution. Next, the concentration of the MIP-bound electroactive competitor is determined. Procedures for determination of a range of herbicides have been developed based on this approach. 

Obtained in acetonitrile solution containing 0.2 mol dm"3 Bu4NBF4 as supporting electrolyte. Solutions were 1 X 10 3 mol dm"3 in ligand and potentials were obtained with reference to Ag/Ag+ electrode. "Cathodic shift in reduction potential produced by presence of anions (up to 10 equiv) added as their tetrabutylammonium salts. 

Bismuth nitrate (analytical grade) lppm high-purity standard solutions of the nitrate salts of Pb and Cd prepared using supporting electrolyte solutions and acetate buffer (0.1 M, pH 4.5) as supporting electrolyte prepared in Milli-Q water. 

The following table lists the polarographic half-wave potentials (E1/2, in volts, vs. SCE, the standard calomel electrode) of inorganic cations and the supporting electrolyte used during the determination.1 5 All supporting electrolyte solutions are aqueous unless noted. See page 629 for a description of the concentration nomenclature. 

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