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    Abstract Solute descriptors characterizing major interactions in solution are accessible based on quantitative structure-property relationships (QSPR). Parameters of such relationships should be additive for functional groups. Because added parameters of monools describing molecular interaction do not meet the experimentally found intermolecular interaction parameters of diols and triols, it is assumed that intramolecular hydrogen bonding is responsible for these deviations. In this paper the intramolecular interactions in several diols are illuminated by IR measurements. Particularly, the influence of intramolecular hydrogen bonding on the absorbances of the OH groups is subject of investigation. Two conclusions can be drawn from the results: The terminal OH groups, which underlie an OH–OH interaction, also change their absorbance intensity in comparison to the free OH band. Secondly, the intermolecular interaction potential is strongly affected by intramolecular hydrogen bonding. The first observation is tentatively quantified as well as the position of the equilibrium between intramolecularly bonded and free diols.
    Absorbance
    Intermolecular interaction
    Mixed monolayers consisting of 4-fluorobenzenethiolate and 1-octadecanethiolate on Au surfaces were formed by immersing in an ethanol solution of 4-fluorobenzenethiol (FBT), and subsequently by immersing in that of 1-octadecanethiol (ODT). To obtain systematically a mixed monolayer, the formation of FBT- and ODT-monolayers was investigated with respect to the reaction time and concentration of the solution. The monolayer formed on a Au surface was evaluated based on the work function, the water contact angle, and the X-ray photoelectron spectroscopy (XPS) spectra measured. The XPS measurement of substrates prepared for formation of a mixed monolayer exhibited F 1s and C 1s spectra supporting the presence of a mixed monolayer consisting of 4-fluorobenezenethiolate and 1-octadecanethiolate.
    Self-assembled monolayer
    Citations (8)
    The electrostatic binding and metal coordination between metal ions and Langmuir monolayers or LB films are discussed, and their effects on the monolayer 2D structure and related phase behavior are analyzed. The interfacial recognition and sensing for metal ions by Langmuir monolayers are also shown. Langmuir monolayers and LB films as 2D template to induce the 2D-oriented crystal growth via metal/monolayer binding is especially demonstrated. The abnormal catalytic characteristics, the functions and devices of metal-incorporated Langmuir monolayers and LB films are displayed by some examples. The review also shows the application of metal-chelating lipid monolayers on the interfacial study of bio-macromolecules. The review suggests the great roles of metal/monolayer binding in alternating monolayer structures and the assembly of functional metal complexes.
    Citations (0)
    The molecular interactions of monolayers composed of cyclic and linear forms of surfactins (SFs) were evaluated through atomic force microscopy (AFM) together with a Langmuir monolayer technique. The surface pressure (π)-area per molecule (A) isotherm of a pure cyclic surfactin (CSF) monolayer exhibited a liquid expanded (Le) monolayer, while that of a pure linear surfactin (LSF) monolayer exhibited a liquid condensed (Lc) monolayer, demonstrating that the CSFs are in a rather loose molecular packing state owing to its bulky heptapeptide ring. The plots of the mean area per molecule of the CSF/LSF monolayers were well fitted to the ideal curves, suggesting that ideal mixing occurs, or that the two components are immiscible in a monolayer. The AFM images of the CSF/LSF monolayers transferred at 25 mN/m gave phase-separated microdomain structures, indicating that the CSFs and LSFs are almost immiscible and separated into a CSF-rich and LSF-rich phases, as suggested from the analysis of the mean area per molecule of the monolayers. Our results clearly demonstrated that the cleavage of the cyclic heptapeptide headgroup of CSF drastically changes its molecular packing state in a monolayer and that AFM observation combined with the Langmuir monolayer technique is quite useful to explore the manner of self-assembly of a binary system of microbial products such as CSFs and LSFs.
    Surface pressure
    Citations (12)