Calculations on ionic solvation. Part 1.—Free energies of solvation of gaseous univalent ions using a one-layer continuum model

Abstract

The electrostatic free energy of solvation of an ion has been calculated using a model in which su1 ion of radius u and dielectric constant Ci = 1 is surrounded by a solvent layer of thickness (b-a) and dielectric constant EI, immersed in the bulk solvent of dielectric constant go. The electrostatic energy is combined with the nonelectrostatic free energy of solvation, obtained from experimental data on the free energy of solution of gaseous non-polar solutes, to yield the total free energy of solvation of a gaseous ion in a solvent. It is found that when a is taken as the ionic crystal radius, (b-a) as the solvent radius and EI = 2 there is excellent agreement with experiment for the solvation of gaseous univalent cations and anions in the solvents, 1,l-dichloroethane, 1,2-dichloroethane, tetrahydrofuran, lY2-dimethoxyethane, ammonia, acetone, acetonitrile, nitromethane, 1-propanol, ethanol, methanol and water. Limited data suggest that the method can also be applied to solution of ions in benzene, bromobenzene, chlorobenzene, ethyl benzoate, ethyl acetate and nitrobenzene.* The ionic radius a is usually taken as the ionic crystal radius. Lawrence and Krue 25 have shown that in aqueous solution the distance from the centre of an ion to the centre of a surrounding water molecule is indeed the sum of the ionic crystal radius and the radius of a water molecule (about 1.4 A).

Solvation of monovalent anions in acetonitrile and N,N-dimethylformamide: Parameterization of the IEF-PCM model

“…We combined these data with the aqueous free energy of solvation from Pliego and Riveros [33] for F À , Cl À , Br À , I À , N À 3 , CN À and CH 3 CO À 2 , the hydration free energy data for I À 3 and SCN À anions from Marcus [34], the NO À 3 anion hydration free energy from Florian and Warshel [35], and the aqueous solvation free energy value for the picrate (Pic À ) anion from Kusakabe and Arai [36]. For the ClO À 4 anion, we have taken the solvation free energy in water from the work of Abraham and Liszi [37]. These experimental data are all corrected, when necessary, to the recently obtained standard value for the experimental solvation free energy for the proton in water, DG solv ðH þ Þ ¼ À264 kcal=mol [38], corresponding to the process of transfer of the proton from ideal gas at 1 atm to ideal diluted solution at 1 mol/l.…”

Selection of Appropriate Training Set of Chemicals for Modeling Dermal Permeability Using Uniform Coverage Design

“…In order to identify descriptors for solvation process, the steps involved in solvation process must be known. A cavity model has been proposed by Abraham and Liszi [11] to describe solvation which involve 3 steps: (1) Formation of suitable size of cavity proportional to solute size, in the solvent which is a endoergic process (breakage of solvent-solvent bond), (2) Insertion of solute into cavity and reorganization of solvent molecules around solute, and (3) Exoergic solute solvent interaction. Based on solvation process, five solvatochromic (involved in solvation process during permeation) descriptors (E, S, A, B, V) were found to be most relevant to the passive diffusion process [12] (Table 1).…”

The Ion Transfer From Aqueous(w), Formamide(fa) or W-Fa Mixtures to Organic Solution Studied by Polarography at the Electrolyte Solution Dropping Electrode

“…4G °tr for 0104-, BF4-and I-from FA to NX are less positive than those from W to NX, and, hence, these anions are considered to be solvated more weakly with formamide molecules than water molecules. The results could not be explained by the Born equation or Abraham-Liszi equation [12,13], in which OG °soly is calculated using c and based on the long distance force working on the ion in a solvent. The discrepancy indicates the existence of specific short distance interactions such as ion-dipole interaction in addition to the non-specific coulombic interaction.…”