Solvation parameters. 2. A simplified molecular topology to generate easily optimized values.

This paper describes a generalized method to establish the values of the five solvation parameters of solutes, which reflect, together with the five solvation parameters of solvents, the intermolecular forces involved in solutions and in some biological phenomena. The tool applied for this purpose is a simplified molecular topology (SMT), which principally takes into account, for each atom of a molecule, its nature, the nature of its bonds, and in some cases the nature of its first neighbors. The learning material used to weight the molecular features generated by SMT are two sets of experimentally determined solvation parameters, established in a previous work (Laffort et al. J. Chromatogr., A 2005, 1100, 90-107).

Solvation parameters Part 1. Mutual improvements of several approaches and determination of two first sets of optimized values.

An improvement in the characterization and the determination of the solvation parameters allows, not only a better knowledge of solutions, but also of some biological phenomena. In this paper, we test several published data and approaches in the field of solubility and solvation parameters in two ways: (i) the mutual independence of the parameters and (ii) their ability to take into account recently published gas-liquid chromatographic data. From this enquiry it arises that the most suitable published values are those of Abraham concerning 314 solutes. It also arises that the parameters of dispersion and orientation of this published data set are appreciably improved using two simple equations. In addition, a new set of optimized values for 133 solutes is given, by derivation from retention indices in gas-liquid chromatography (GLC) on five selected stationary phases, published by Kováts and co-workers and in the present study. The two sets have a total of 373 defined compounds.