Molecular organization of liquid n-octanol: an X-ray diffraction analysis.

We recorded X-ray diffraction patterns from n-octane, n-octanol, and fully hydrated n-octanol. These patterns were analyzed using a modified version of the Percus-Yevick hard-sphere theory for liquids. A model is presented for the molecular organization of n-octanol that accurately predicts the observed diffraction patterns. The octanol molecules are associated in aggregates, with their hydroxyl groups forming roughly spherical clusters and their hydrocarbon chains pointing outwards, almost fully extended. When n-octanol is hydrated, the overall organization does not change greatly, but water molecules coordinate the hydroxyl groups in the clusters. Estimates are made for the maximum number of octanol molecules in the aggregates.

[1]  G. W. Stewart,et al.  X-Ray Diffraction in Liquids: Primary Normal Alcohols , 1927 .

[2]  B. Warren.  X-Ray Diffraction in Long Chain Liquids , 1933 .

[3]  W. Pierce,et al.  X-ray Studies on Liquids: the Inner Peak for Alcohols and Acids , 1938 .

[4]  Reginald W. James,et al.  The Optical principles of the diffraction of X-rays , 1948 .

[5]  V. Luzzati,et al.  La structure des colloïdes d'association. I. Les phases liquide–cristallines des systèmes amphiphile–eau , 1960 .

[6]  D. Ives,et al.  311. The t-butyl alcohol–water system , 1962 .

[7]  D. Marquardt.  An Algorithm for Least-Squares Estimation of Nonlinear Parameters , 1963 .

[8]  Neil W. Ashcroft,et al.  Structure and Resistivity of Liquid Metals , 1966 .

[9]  A. Fletcher,et al.  Self-association of alcohols in nonpolar solvents , 1967 .

[10]  A. Lawrence,et al.  Molecular association in liquid alcohol-water systems , 1969 .

[11]  A. Leo,et al.  Partition coefficients and their uses , 1971 .

[12]  B. Lippold,et al.  Molekülassoziation in n‐Octanol und n‐Octanol‐Wassergemischen , 1972 .

[13]  V. Luzzati,et al.  Order-disorder conformational transitions of the hydrocarbon chains of lipids. , 1974, Journal of molecular biology.

[14]  O. Bonner,et al.  A spectroscopic investigation of the structure of alcohol-water solutions , 1975 .

[15]  C. Hansch,et al.  Selection of a reference partitioning system for drug design work. , 1975, Journal of pharmaceutical sciences.

[16]  J. Barker,et al.  What is "liquid"? Understanding the states of matter , 1976 .

[17]  E. Caponetti,et al.  The static dielectric constant of solutions of water inn-alcohols at 15, 25, 35, and 45°C , 1979 .

[18]  David W.L. Hukins,et al.  X Ray Diffraction by Disordered and Ordered Systems , 1981 .

[19]  R. Cramer,et al.  Measurement of correlation of partition coefficients of polar amino acids. , 1981, Molecular pharmacology.

[20]  D. Engelman,et al.  Conformation of liquid N-alkanes. , 1981, Biophysical journal.

[21]  G. Stell,et al.  Polydisperse systems: Statistical thermodynamics, with applications to several models including hard and permeable spheres , 1982 .

[22]  B. Gestblom,et al.  Dielectric relaxation studies of aqueous long-chain alcohol solutions , 1984 .

[23]  A. Hopfinger.  Computer-assisted drug design. , 1985, Journal of medicinal chemistry.

[24]  A. Leo,et al.  Hydrophobicity and central nervous system agents: on the principle of minimal hydrophobicity in drug design. , 1987, Journal of pharmaceutical sciences.

[25]  Y. Marcus.  Structural aspects of water in 1-octanol , 1990 .