Ferrocene Analysis

Cyclic voltammetric measurements were made using well-characterized microcrystalline, boron-doped diamond thin-film electrodes to test the material s responsiveness for ferrocene as a function of scan rate, solvent. 

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One adverse effect of these additives on cell performance seemed to be related to their blocking of ionic paths on the surface of cathode materials, as indicated by the reduced power capabilities in the presence of ferrocenes. Analysis on the concentration changes of ferrocene additives in the electrolyte solutions before and after their exposure to cathode materials established that an adsorption of ferrocene species occurred on the cathode surface, 93% of which would be covered when as low as 0.3 M ferrocenes were present in the electrolyte solution.This surface deactivation resulted in the loss of both rate capability and capacity. 

The synthesis, chemical properties, and structural analysis of l,T-diphospha-ferrocene have been described [78JOM(156)C33 80AX(B)1344 80JA994 ... 

Due to the pronounced electron donating character of ferrocene, ot-ferrocenyl carbocations 3 possess a remarkable stability and can therefore be isolated as salts [16]. They can also be described by a fulvene-type resonance structure 3 (Fig. 4) in which the Fe center and the ot-center are significantly shifted toward each other as revealed by crystal stmcture analysis, indicating a bonding interaction [17]. 

Seiler P, Dunitz JD (1982) Low-temperature crystallization of orthorhombic ferrocene structure analysis at 98 K. Acta Crystallogr B 38 1741-1745... 

NFS spectra of the molecular glass former ferrocene/dibutylphthalate (FC/DBP) recorded at 170 and 202 K are shown in Fig. 9.12a [31]. It is clear that the pattern of the dynamical beats changes drastically within this relatively narrow temperature range. The analysis of these and other NFS spectra between 100 and 200 K provides/factors, the temperature dependence of which is shown in Fig. 9.12b [31]. Up to about 150 K,/(T) follows the high-temperature approximation of the Debye model (straight line within the log scale in Fig. 9.12b), yielding a Debye tempera-ture 6x) = 41 K. For higher temperatures, a square-root term / v/(r, - T)/T,... 

Azo-bridged ferrocene oligomers also show a marked dependence on the redox potentials and IT-band characteristics of the solvent, as is usual for class II mixed valence complexes 21,22). As for the conjugated ferrocene dimers, 2 and 241 the effects of solvents on the electron-exchange rates were analyzed on the basis of the Marcus-Hush theory, in which the t/max of the IT band depends on (l/Dop — 1 /Ds), where Dop and Ds are the solvent s optical and static dielectric constants, respectively (155-157). However, a detailed analysis of the solvent effect on z/max of the IT band of the azo-bridged ferrocene oligomers, 252,64+, and 642+, indicates that the i/max shift is dependent not only on the parameters in the Marcus-Hush theory but also on the nature of the solvent as donor or acceptor (92). 

Elimination of hydrogen halides from dihalogenoorganylboranes by reaction with ferrocene-1,1 -dithiol resulted in l,3-dithia-2-boryl[3]ferrocenophanes.170 These borylferrocenophanes were air sensitive, but were characterized by NMR, MS, and elemental analysis.170 A series of l,3-dibora-2-X-[3]fer-rocenophanes (X=S, Se, Te) were prepared and characterized and the crystal structure of [Se N Pr2)BC5Fl4 2Fe] has been reported.171... 

One example of a cocrystal containing BEDT-TTF and ferrocene has been reported [104]. The [(BEDT-TTF Cgob lferrocene) adduct was crystallized from a carbon disulfide solution. The unit cell has been determined by single crystal X-ray diffraction but the crystal structure was not reported. An infrared spectroscopic analysis indicates that the charge transfer between the BEDT-TTF and C6o molecules is quite small. It has been suggested that such complexes may offer a means to introduce iron into the fullerene lattice. 

The procedure may start with the reference experiment, which, in the case under analysis, involved a solution of ferrocene in cyclohexane (ferrocene is a nonphotoreactive substance that converts all the absorbed 366 nm radiation into heat). With the shutter closed, the calorimeter was calibrated using the Joule effect, as described in chapter 8, yielding the calibration constant s. The same solution was then irradiated for a given period of time t (typically, 2-3 min), by opening the shutter. The heat released during this period (g0, determined from the temperature against time plot and from the calibration constant (see chapter 8), leads to the radiant power (radiant energy per second) absorbed by the solution, P = /t. ... 

Interestingly Gokel has demonstrated the existence of a direct coordination coupling pathway between this ferrocene cryptand and a silver cation. Complexation studies were carried out with [24] and [25] (as well as other ferrocene cryptand-type species) by X-ray crystallography, FAB mass spectral analysis, nmr and UV/Vis spectroscopy. 

C4H6)Fe(CO)3. The elucidation of the structure of ferrocene eventually lead Hallam and Pauson2 to propose a jr-complex (1) for (C4H6)Fe(CO)3 and this was eventually confirmed by crystal structure analysis at low temperature3. Since that time interest in... 

The electrode processes on the voltammetric and the preparative electrolysis time scales may be quite different. The oxidation of enaminone 1 with the hydroxy group in the ortho position under the controlled potential electrolysis gave bichromone 2 in 68% yield (Scheme 4.) with the consumption of 2.4 F/mol [21], The RDE voltammogram of the solution of 1 in CH3CN-O.I mol/1 Et4C104 showed one wave whose current function, ii/co C, was constant with rotation rates in the range from 1(X) to 2700 rpm and showed one-electron behavior by comparison to the values of the current function with that obtained for ferrocene. The LSV analysis was undertaken in order to explain the mechanism of the reaction which involves several steps (e-c-dimerization-p-deamina-tion). The variation of Ep/2 with log v was 30.1 1.8 mV and variation of Ep/2 with logC was zero. Thus, our kinetic data obtained from LSV compare favorably with the theoretical value, 29.6 mV at 298 K, for a first order rate low [15]. This observation ruled out the dimerization of radical cation, for... 

One final issue remains to be resolved Of the portion of the AEpi that is due to resistance, what part is caused by solution resistance and what part is caused by film resistance To explore this issue we examined the electrochemistry of a reversible redox couple (ferrocene/ferricinium) at a polished glassy carbon electrode in the electrolyte used for the TiS 2 electrochemistry. At a peak current density essentially identical to the peak current density for the thin film electrode in Fig. 27 (0.5 mV see ), this reversible redox couple showed a AEpi of 0.32 V (without application of positive feedback). Since this is a reversible couple (no contribution to the peak separation due to slow kinetics) and since there is no film on the electrode (no contribution to the peak separation due to film resistance), the largest portion of this 0.32 V is due to solution resistance. However, the reversible peak separation for a diffusional one-electron redox process is —0.06 V. This analysis indicates that we can anticipate a contribution of 0.32 V -0.06 V = 0.26 V from solution resistance in the 0.5 mV sec control TiS2 voltammogram in Fig. 27. 

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