Correlation between Lewis acid-base surface interaction components and linear solvation energy relationship solvatochromic alpha and beta parameters

In this paper, we report our unexpected finding about the correlation between Lewis acid-base surface interaction components and linear solvation energy relationship (LSER) solvatochromic parameters alpha and beta. In 1987, van Oss, Chaudhury, and Good proposed to split the asymmetric acid-base parts of a bipolar system into separate surface tension components: Lewis acid (electron acceptor) gamma(+) and Lewis base (electron donor) gamma(-). It was assumed that the ratio of gamma(+) and gamma(-) for water at 20 degrees C was to be 1.0. With that ratio as a reference, the base components, gamma(-) for other liquids, biopolymers, polymers, and solids appeared to be overestimated. Recently, we unexpectedly found a correlation for liquids between gamma(+) and gamma(-), and a (solvent hydrogen-bond-donating ability) and beta (solvent hydrogen-bond-accepting ability) introduced since 1976 by Taft and Kamlet. From that correlation, we obtained a more realistic ratio for the normalized alpha and beta values for water at ambient temperature to be 1.8 instead of 1.0. Based on this new ratio, we calculated total surface tensions for related materials at 20 degrees C. They are generally unchanged as expected, despite the considerable, favorable change in the gamma(+) and gamma(-) values in the direction of lowering the Lewis basicity. The predicability of solubility with interfacial tension is also unaffected. For example, the sign of those negative interfacial tensions that favor solubility remains the same. In addition, the implications of other LSER parameters, e.g. Pi* and delta(H)(2), on surface properties will be briefly mentioned.