Prediction of the 1-Octanol/H2O Partition Coefficient, Log P, by Ab Initio MO Calculations: Hydrogen-Bonding Effect of Organic Solutes on Log P

Abstract

To predict the 1-octanol/H2O partition coefficient, log P, based on molecular structures, we calculated the solvent accessible surface area and the solvation energy difference of 166 organic molecules between 1-octanol and water environments with the ab initio molecular orbital self-consistent reaction field method, and then analyzed the relationships among the measured log P values with these two structural quantities by multiple linear-regression analyses. Physicochemically meaningful correlations were obtained, suggesting that non-hydrogen bonding and hydrogen-acceptor molecules behave similarly to each other in partitioning, but that hydrogen-donor molecules behave differently from the former molecules. The results provide a new computational approach for predicting log P.

Enhancement of phenanthrene solubilization and biodegradation by trehalose lipid biosurfactants

“…Edwards et al [25] observed that partitioning of three PAHs (naphthalene, PHE, and pyrene) to four nonionic, synthetic surfactants increased with decreasing solubility of the hydrophobic compounds. The results obtained in the present study indicate that trehalose lipid biosurfactants produced from R. erythropolis [40]. c Value obtained in the present study.…”

Analyses of the partition coefficient, log P, using ab initio MO parameter and accessible surface area of solute molecules

“…We analyzed experimental log P oct/w values measured with the n ‐octanol/water system using descriptors calculated by molecular orbital (MO) methods for various solute molecules 1. Descriptors considered initially were the difference in the electrostatic solvation energy, Δ E oct/w , between n ‐octanol and water phases and the “surface area” of solute molecules, ASA w , to which the water molecules are accessible.…”

Revisiting the Hansch–Fujita approach and development of a fundamental QSAR

“…(2), we formulated a semiempirical correlation Eq. (3) for log P sol (sol=chloroform (CL) and 1-octanol (oct)) [11][12][13] : (3) takes a value (a=−0.776) close to the expected one (−1/(2.303RT)=−0.734 at 298 K). However, for hydrogen-bonding donors, that is approximately half of the expected value (∼0.34).…”