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Transferability of fragmental contributions to the octanol/water partition coefficient: An NDDO-based MST study

Posted September 5th, 2013 by ccurutchet
TitleTransferability of fragmental contributions to the octanol/water partition coefficient: An NDDO-based MST study
Publication TypeJournal Article
Year of Publication2003
AuthorsCurutchet, C, Salichs A, Barril X, Orozco M, Luque FJ
JournalJournal of Computational Chemistry
Volume24
Issue1
Pagination32 - 45
Date Published2003
ISBN Number0192-8651
Keywordsab-initio, aqueous-solutions, atomic charges, consistent reaction field, continuum models, cosmo-rs, electrostatic potentials, fractional solvation, free-energy perturbation, small organic-molecules, solvation, solvation model, solvent polarization
AbstractThis study examines the transferability of fragmental contributions to the octanol/water partition coefficient. As a previous step, we report the parameterization of the AM1 and PM3 versions of the MST model for n-octanol. The final AM1 and PM3 MST models reproduce the experimental free energy of solvation and the octanol/water partition coefficient (log P-ow) with a root-mean-square deviation of around 0.7 kcal/mol and 0.5 (in units of log P), respectively. Based on this parameterization, an NNDO-based procedure is presented to dissect the free energy of transfer between octanol and water in contributions directly associated with specific atoms or functional groups, Tire application of this procedure to a set of representative molecular systems illustrates the dependence of the log P-ow fragmental contribution due to electronic, hydrogen bonding, and steric effects, which cannot be easily accounted for in simple additive-based empirical schemes. The results point out the potential use of theoretical methods to refine the fragmental contributions in empirical methods. (C) 2002 Wiley Periodicals, Inc.