The hydration of anions in nonaqueous media

Inhibition by inorganic anions of glutathione S-transferases from insect and mammalian sources

“…The inhibition of the GSTs by these anions appears to be the same type of phenomenon. There is a strong relationship between the K, values reported here and the enthalpies of hydration determined by Arnett et al (1977) (see Fig. 3).…”

“…3. Apparent relationship between inhibition of GSTs by inorganic anions and the enthalpy of hydration of the ions K1 values for the inorganic anions acting on GSTs from G. mellonella (,0) and rat liver (A, A) are plotted against the enthalpies of hydration (AHh) of the ions in nitrobenzene (Arnett et al, 1977). the GSH thiol group (Chen et al, 1988).…”

“…Gibson & Weatherburn, 1972). Arnett et al (1977) proposed that all these phenomena derive directly from the ease of hydration or dehydration of the anions and may be related quantitatively to their enthalpies of hydration. The inhibition of the GSTs by these anions appears to be the same type of phenomenon.…”

Solvation energies of organic ions

“…Gas phase "titration" of many cations and anions is possible by successive additions of various solvents. Figure 5 shows a remarkable relationship between the incremental gas phase hydration energies of several isolated ions in the gas phase and the enthalpies of interaction of those same ions with added increments of water in the polar, but weakly basic, solvent propylene carbonate (53). Even though the condensed phase processes are undoubtedly much more complex, the ions seem to "remember" the gas phase energetics, although on a drastically attenuated scale.…”

Titrations in nonaqueous solvents

“…Previously proposed correlations between overvoltage and ion solvation energies in different solvents are not followed for the hydrogen ion in dimethylsulfoxide (299). The hydration of anions in low dielectric solvents such as nitrobenzene and o-dichlorobenzene has been studied by Arnett and co-workers (13). Isopiestie measurements have provided useful information on hydration of ions in low dielectric constant organic solvents (14).…”