Acetonitrile cyclic voltammetry experiment

Cyclic voltammetry experiments were controlled using a Powerlab 4/20 interface and PAR model 362 scanning potentiostat with EChem software (v 1.5.2, ADlnstruments) and were carried out using a 1 mm diameter vitreous carbon working electrode, platinum counter electrode, and 2 mm silver wire reference electrode. The potential of the reference electrode was determined using the ferrocenium/ ferrocene (Fc+/Fc) couple, and all potentials are quoted relative to the SCE reference electrode. Against this reference, the Fc /Fc couple occrus at 0.38 V in acetonitrile and 0.53 V in THF [30, 31]. 

The triple degeneracy of the LUMO of Cgo was confirmed experimentally in several steps between 1990 and 1992 with the detection of Cgo and Cgo [27], Cgo - [28], Cgo - [29], Cgo - [30], and finally Cgo [31]. Owing to limitations in the solvent potential window, the elusive hexaanion species was only detected when the experiment was carried out under vacuum, at low temperature (—lO C), and using a 0.1 M tetra-n-butylammonium hexafluorophosphate (TBAPFg) electrolyte solution in a solvent mixture consisting of toluene/acetonitrile (PhMe/MeCN) in a 4 to 1 ratio. Under these conditions, using cyclic voltammetry (CV)... 

The electropolymerization of ferrocene/thiophene conjugates [65] was conducted by oxidation on a Pt electrode and led to the deposition of a monolayer of poly (thiophene). The electropolymerization was performed from several solution systems, such as tetrabutylammonium hexafluorophosphate/acetonitrile and lithium perchlorate/acetonitrile, at a concentration of 0.1 M. Constant potential experiments (+ 2.0 V) for a definite time were used to effect polymerization. Polymerization was also attempted using cyclic voltammetry (repeatedly sweeping from 0.0 to + 2.5 V) and pulse potential (potential stepped from 0.0 to 2.0 V and back to 0.0 V). 

Stepwise anion coordination equilibria are also observed in the Cu(ll) complexes of ligands 113 and 114 [76]. UV/vis titrations in acetonitrile solution show that each Cu(II) complex binds two anions (chloride, bromide, iodide, nitrate or thiocyanate), the first at the Cu(ll) centre and the second in the bis-imidazoHum compartment. The Cu(I) complexes of these ligands are able to host only one nitrate anion (in the bis-imidazolium cavity), while other anions induce demetallation. Cyclic voltammetry and spectroelectro-chemical experiments showed that in the presence of one equivalent of nitrate the Cu(II)/Cu(I) redox change causes the anion to translocate quickly and reversibly from the metal-based binding site in the Cu(II) complex to the im-idazolium binding site in the Cu(I) system. 

Figure 1. Cyclic voltammetry resulls for a 0.001 M solution of Co(terpy)(bipy)]+ complex in acetonitrile with 0.10 M tetrabutylammonium hexafluorophosphate as supporting electrolyte. Scan rate was 0.10 Volts/sec in all experiments. Potentials are referenced vs. silver/0.010 M silver nitrate in acetonitrile, (a) Impure complex under nitrogen, (b) impure complex under oxygen, (c) purified complex under nitrogen, and (d) purified complex under oxygen.

The first redox potentials of ferryl complexes were measured by cyclic voltammetry in dry acetonitrile [48] but the instability of the reduced form [(L)Fe -O] leads to observed data that are not unambiguous. Two other types of experiments have been described more recently to obtain valuable information on the oxidation power of ferryl complexes (i) the spectropotentiometric oxidation of the Fe " - OH complex in acetonitrile with added water [49] and (ii) the titration of the ferryl complex with ferrocene derivatives (Fc) in dry acetonitrile to determine the Fc + Fe" =0/Fc -1- Fe -0 electron transfer equilibrium constant and, together with the kno wn redox potential of the Fc derivative used, the Fe =0/Fe -0 potential [48b]. Note that the two potentials (i) and (ii) describe two entirely different processes, both of importance for ferryl-catalyzed oxidation reactions, that is, (i) a H -coupled electron transfer and (ii) a pure electron transfer. That is. 

The small mass increase at the beginning of the reoxidation cycle was interpreted [24] as being due to the incorporation of both solvent and anion of the background electrolyte. However, no such trapping could be detected for the Cd(bpy)3(PF6)2 electrolyte using conventional cyclic voltammetry. In these experiments, the C60 film was continuously reduced and reoxidized in the Cd(bpy)3(PF6)2 electrolyte until a steady state was attained. The film (in the reoxidized state) was washed in a drybox with dry acetonitrile and... 

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