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Partitioning of solutes in different solvent systems: the contribution of hydrogen-bonding capacity and polarity

el Tayar, Nabil
Tsai, Ruey-Shiuan
Testa, Bernard
Leo, A.
Published in Journal of pharmaceutical sciences. 1991, vol. 80, no. 6, p. 590-598
Abstract Published partition coefficient values of 121 solutes in five solvent systems (1-octanol-water, n-heptane-water, chloroform-water, diethyl ether-water, and n-butyl acetate-water) were correlated with solute properties, namely intrinsic molecular volume (indicator of cavity formation) and the solvatochromic parameters pi* (dipolarity/polarizability), beta (H-bond acceptor basicity), and alpha (H-bond donor acidity). While the cavity term and the H-bond accepting capacity played a comparable role in all solvent systems, the H-bond donor acidity was significant only in the alkane-water and chloroform-water systems. Comparison of the regression coefficients of pi*, beta, and alpha demonstrated the important role that water content at saturation in the organic solvents plays in the partitioning of solutes. Analysis of the differences between 1-octanol-water and n-heptane-water partition coefficients (delta log Poct-hep) and between 1-octanol-water and chloroform-water partition coefficients (delta log Poct-chf) showed that these values mainly quantitate the capacity of solute to donate hydrogen bonds. In contrast, the differences between 1-octanol-water and diethyl ether-water or n-butylacetate-water partition coefficients, (delta log Poct-dee and delta log Poct-ba, respectively) contain no structural information.
Keywords Chemistry, PhysicalHydrogen BondingPhysicochemical PhenomenaSolutions/*chemistrySolvents/*chemistry
PMID: 1941553
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EL TAYAR, Nabil et al. Partitioning of solutes in different solvent systems: the contribution of hydrogen-bonding capacity and polarity. In: Journal of pharmaceutical sciences, 1991, vol. 80, n° 6, p. 590-598. doi: 10.1002/jps.2600800619

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Deposited on : 2010-08-06

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