Transference number complex ions from

Radical anions are produced in a number of ways from suitable reducing agents. Common methods of generation of radical anions using LFP involve photoinduced electron transfer (PET) by irradiation of donor-acceptor charge transfer complexes (equation 28) or by photoexcitation of a sensitizer substrate (S) in the presence of a suitable donor/acceptor partner (equations 29 and 30). Both techniques result in the formation of a cation radical/radical anion pair. Often the difficulty of overlapping absorption spectra of the cation radical and radical anion hinders detection of the radical anion by optical methods. Another complication in these methods is the efficient back electron transfer in the geminate cation radical/radical anion pair initially formed on ET, which often results in low yields of the free ions. In addition, direct irradiation of a substrate of interest often results in efficient photochemical processes from the excited state (S ) that compete with PET. 

An EMF method has been used to study the interaction of ZnCl2 with chloride ion in methanol. It is found that Kx (7.76 x 103 M) is less than K2 (1.74 x 104 M), a finding which is interpreted in terms of passing from an octahedral [ZnCl(MeOH)5]+ species to a tetrahedral [ZnCl2(MeOH)2] complex.967 Related studies have shown that the solubility of cadmium halides in water decreases with increasing pressure.968 969 Anionic [ZnCl3] and [ZnCU]2-species are present in zinc chloride battery electrolyte, and are responsible for the observed negative transference numbers for zinc in aqueous acidic chloride medium.970 In neutral... 

Most M3+(aq) and a number of M2+(aq) cations behave in much the same way as Fe3+(aq). Evidently the viabilities of simple aquo-cations are restricted by the possibilities for hydrolysis, as well as the redox processes discussed in Section 5.4. The simplest explanation for the hydrolysis of Fe3+(aq) acknowledges the considerable polarising power of Fe3+. When surrounded by six water molecules, the cation will tend to attract electron density from the O atoms. This makes the coordinated O atoms less attractive to protons than those in the bulk solvent, and encourages the transfer of protons from the coordination sphere. If the bonding in the complex [Fe(H20)6]3+ is regarded as covalent, with the formation of coordinate bonds, we can arrive at the same conclusion the delocalisation of the positive charge over the complex ion [Fe(H20)50H]2+ will tend to discourage recombination of the coordinated OH- ion with a proton. 

We feel that the correlation between conductivity and number of initiated chains ought to be accepted with caution, unless the details of transfer and termination reactions are well understood and can be taken into account quantitatively, if necessary, to correct the original correlation. In other words, a given number of ions derived from the initiating complex does not necessarily lead to an equal or proportional amount of chain carriers, owing to possible complicating factors intervening in the actual polymerisation. 

We have also determined aG values for electron attachment to a number of neutral metal complexes by charge-transfer bracketing and equilibrium experiments with organic acceptors (Figure 2). One metallocene, Cp2Ni, was known to form a stable negative ion from early studies by Beauchamp and coworkers (20). Many aG values have also been determined for electron attachment to the first row transition metal tris(acetylacetonate) (M(acac)3) and tris(hexafluoracetylacetonate)... 

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