Journal article
Monolayer behaviour of chiral compounds at the air-water interface: 4-hexadecyloxy-butane-1,2-diol
Monolayers of the pure S-enantiomer (x(S) = 1) and of two mixtures x(S) = 0.75 and x(S) = 0.5 (racemate) of 4-hexadecyloxy-butane-1,2-diol (C16H33-O-CH2-CH2-CHOH-CH2OH) (HOBD) have been studied at the air-water interface by thermodynamic measurements, fluorescence microscopy and X-ray diffraction. The isotherms depend only slightly on chirality.
Above the transition pressure pi(c) condensed domains with a polygonal shape are formed. In all cases the domains start to destabilize from the notch. The branches of the S-enantiomer turn only clockwise, whereas domains of the mixtures show branches which turn clockwise and counterclockwise. The number of the left- and right-handed arms depends on the mixing ratio.
At lower lateral pressures S-HOBD and the mixture with x(S) = 0.75 exhibit a chiral structure. At pressures above 25 mN m(-1) a centered rectangular structure with a tilt of the molecules towards their next-nearest neighbours (NNN) is formed, At lower surface pressures the racemate is packed in a centered-rectangular lattice with a tilt towards nearest neighbours (NN).
Above 14 mN m(-1) a transition to a NNN phase occurs.
Language: | English |
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Publisher: | Elsevier |
Year: | 1996 |
Pages: | 211-215 |
ISSN: | 18792731 and 00406090 |
Types: | Journal article |
DOI: | 10.1016/S0040-6090(95)08366-9 |
Chiral recognition Fluorescence microscopy Monolayers X-ray diffraction