Solvent window.

The coordination of redox-active ligands such as 1,2-bis-dithiolates, to the M03Q7 cluster unit, results in oxidation-active complexes in sharp contrast with the electrochemical behavior found for the [Mo3S7Br6] di-anion for which no oxidation process is observed by cyclic voltammetry in acetonitrile within the allowed solvent window [38]. The oxidation potentials are easily accessible and this property can be used to obtain a new family of single-component molecular conductors as will be presented in the next section. Upon reduction, [M03S7 (dithiolate)3] type-11 complexes transform into [Mo3S4(dithiolate)3] type-I dianions, as represented in Eq. (7). 

In the second category, SECMIT has been used to probe the relative permeability of oxygen between water and DCE or NB, with no supporting electrolyte present in any phase. Under the conditions employed, direct voltammetric measurements in the organic phase would be impractical due to the high solution resistivity (DCE or NB) or limitations of the solvent window available (NB). Figure 24 shows the steady-state current for the... 

The final choice is mainly driven by the solvent window potential size which, for the organic electrolyte, leads to a typical improvement of the energy and power density by five. 

Pons and co-workers [79] reported the first potentially modulated in-situ FTIR studies of the near-electrode region and they then developed the technique [24, 55, 56, 69] and eventually coined the acronym SNIFTIRS (subtractively normalised interfacial Fourier transform infrared spectroscopy). Corrigan et al. [81-83] and Bockris and co-workers [80, 84-88] have also reported studies employing the technique, or variations on it. These techniques all employ some form of potential modulation regime as with EMIRS, intended to cancel out all those absorptions that do not change with potential (bulk solvent, window, etc.), the spectra are again presented as (AR/R)v vs. v. However, the stepwidths (i.e. the time spent at each potential) in a SNIFTIRS experiment are much longer than those in EMIRS several tens of seconds instead of a tenth of second [89, 90]. 

The cyclic voltammogram (CV) of (C5gN)2 showed three overlapping pairs of reversible one-electron reductions within the solvent window ( i = -997 mV, E2 = -1071 mV, 3 = -1424 mV, 4=-1485 mV, E = -1979 mV, g = -2089 mV ferrocene/ferrocenium couple, internal standard) [7]. A combination of linear sweep voltammetry and chronoamperometry estabUshed that all overlapping waves were two-electron reductions [ 120]. There was also an irreversible two-electron oxidation with a peak potential at -i- 886 mV, that is 0.2 V more negative (easier to oxidize) than Cgo [121]. The appearance of closely spaced pairs of waves in the CV was interpreted in terms of two (identical) weakly interacting electrophores, similar to the dianthrylalkanes [122]. After the third double wave, the process is irreversible, this was interpreted as irreversible cleavage of the dimer bond. 

Device structure and energy level diagram of green phosphorescent OLED with mixed EML and TBADN Bphen ETL. HOMO energies were obtained as IPs by UPS spectroscopy or as electrochemical oxidation potentials by cyclic voltammetry. LUMO values were estimated from solution-determined redox data. Unless otherwise noted, redox processes were reversible. No reduction was observed for TCTA within solvent window, LUMO of TCTA is significantly higher than the shown value. Irreversible reduction was observed for Bphen LUMO may be up to 0.3 eV higher. ... 

PM-IRRAS exploits the different attenuation of s- and p-polarized light by adsorbed species at a reflective (electrode) surface to annul the unchanging contributions to the infrared signal at the detector from the solvent, window, and so on, and produces an absolute rather than difference spectrum at a particular potential. In this approach, a photo-elastic modulator is employed to modulate the polarization state of the incident infrared ray between s- and p-states. On the basis of Greenler s theory [81, 82], this polarization modulation gives rise to an AC signal at the detector, which is proportional (/p —7s)-the difference in intensity of the two polarizations. Since, in principle, /p is absorbed... 

There are several challenges associated with the synthesis of BDD suitable for electrochemistry. Since diamond is a semiconductor with exceptional properties, precise control of dopant impurities and extended defects is required to dope the diamond lattice with sufficient boron to make the material conduct. However, as the boron levels increase, it can be harder to maintain crystallinity and control the amount of nondiamond carbon (NDC) both within crystal defects and at grain boundaries. While NDC can increase material conductivity, it is be detrimental to a diamond electrochemist, as the widely recognized electrochemical properties of BDD (wide solvent window, low background currents, reduced susceptibility to electrode fouling, corrosion resistance) are impaired and the electrochemical response becomes more akin to glassy carbon. If the presence of NDC is unaccounted for, electrical resistivity measurements will mislead the user into believing that there is more boron than actually present in the matrix. 

The inertness of the surface raises interesting questions. The aqueous solvent window is pushed out as a result of water electrolysis being an inner-sphere mechanism. As a result, it is often stated in the literature that BDD can detect species which other electrodes cannot due to the extended solvent window. This is certainly true of outer-sphere species, but care must be taken when considering inner-sphere species. Heterogeneous ET will be retarded for many of these species on BDD, as there are no favorable adsorption sites, pushing out their electrochemical detection potential. Therefore, each species should be considered on a case-by-case basis, in combination with the effect of surface termination. For example, both oxidation [89] and reduction, in... 

The advantages of a pure sp surface, such as extended solvent window, low capacitatance, low background currents, and reduced electrode fouUng, also bring... 

Cyclic voltammograms of the heterobimetallic complexes 3-6 generally exhibit three redox waves (Table I) within the solvent window. In the presence of methanol, the Ru/Pd and Ru/Pt complexes all display a current increase at the Pd(II/IV) and Pt(II/IV) waves, indicating a catalytic methanol oxidation process similar to what was observed for complex 1 (Figure 2). Bulk electrolyses of methanol with complexes 3-6 were carried out for product identification and quantification. For comparison purposes, bulk electrolyses of methanol were performed at the same potential (1.70 V vs. NHE) as compound 1 (25). Therefore, the electrocatalysis with these complexes was performed at potentials positive of both the Ru(II/III) couple and the first oxidative wave of the second metal but before the Ru(III/IV) wave. 

In the CV of complex 7 a single reversible oxidation wave is observed at 1.44 V. A similar oxidation process has previously been assigned for CpRu(PPh3)2Cl (40) (Table 1) as the one electron oxidation of the Ru metal center. Based on this assignment and the fact that Sn is not redox active within the solvent window, the oxidation wave observed for complex 7 was assigned to the Ru(II/IlI) couple. In the presence of methanol, there is a significant increase in the current indicative of an electrocatalytic oxidation process (Figure 3). For... 

As can readily be seen from the chart of solvent windows (Figures 7-lA and 7-lB), there is no solvent that is completely transparent over the entire frequency range. In the areas where the solvent has bands that are totally absorbing, no information can be obtained about the sample (if the solvent absorbs all of the radiation, there is none left to interact with the sample), so that another solution, using a different solvent, must be made and scanned. The most useful pair of solvents is carbon disulfide and carbon tetrachloride (see Figure 7-1). 

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