Thermodynamics and X-ray studies of 2-alcohol monolayers: Two-dimensional phase diagrams

Alonso, Coralie; Artzner, Franck; Lajzérowicz, J.; Grübel, G.; Boudet, Nathalie; Rieutord, F.; Petit, J. M.; Renault, Anne

doi:10.1007/s101890070042

Cited by 4 publications

(3 citation statements)

References 21 publications

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“…Whatever the ratio of ( R ) and ( S ) enantiomers, monolayers present the same hexagonal phase but with different lattice parameters. Our method of preparing monolayers allows the molecules to diffuse freely from the reservoir to the film and vice-versa; thus, the concentration in the monolayer is not necessarily the same as that of the reservoir drop . Our results demonstrate that the interface does not favor one single ratio of enantiomers.…”

Section: Monolayersmentioning

confidence: 88%

Two- and Three-Dimensional Stacking of Chiral Alcohols

et al. 2001

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An investigation of bulk single crystals and crystalline monolayers at the air-water interface of secondary alcohols bearing 16 and 17 carbons has been carried out in order to investigate their molecular packing. These "simple" chiral molecules can be seen as model systems; therefore, their study might provide broader knowledge of how chirality affects the molecular arrangement. The bulk racemic mixtures exhibit racemate organization, i.e., ordered mixtures of left and right enantiomers, with a head to head packing, whereas the pure enantiomers present a head to tail arrangement. The former type of motif has been reported for many amphiphilic molecules, whereas the latter is more rare. In two dimensions, all compounds, pure enantiomers, racemic mixtures, as well as other mixtures, present a hexagonal rotator phase with lattice parameters close to 5 Å. The rotational motion suggests the formation of a two-dimensional solid solution. However, upon heating, monolayers of 2-heptadecanol present a peculiar evolution. For mixtures of the two enantiomers with ratios between 1:1 and 2:1, the hexagonal phase transforms to a centered rectangular one, due to an inclination of molecules of about 10°with respect to the vertical. The loss of hexagonal symmetry is attributed to the formation of a racemate.

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Section: Monolayersmentioning

confidence: 88%

Two- and Three-Dimensional Stacking of Chiral Alcohols

et al. 2001

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“…Surface pressure is a thermodynamic variable and permits systematic study of chiral forces in a membrane assembly. Monolayers at the air−water interface are an ideal example of physical systems where chirality has been studied in two dimensions . The asymmetry of intermolecular forces, the unique molecular structure, and the dynamic behavior make the interfacial region significantly different from a bulk liquid or a gas.…”

Section: Introductionmentioning

confidence: 99%

Equilibrium Structure and Dynamics of (2R, 3R)-(+)-bis(decyloxy)succinic Acid at the Air−Water Interface

Shankar

Patnaik

2008

Langmuir

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A twin-tailed, twin-chiral fatty acid, (2R,3R)-(+)-bis(decyloxy)succinic acid was synthesized and its two dimensional behavior at the air-water interface was examined. The pH of the subphase had a profound effect on the monolayer formation. On acidic subphase, stable monolayers with increased area per molecule due to hydrogen bonding and bilayers at collapse pressures were observed. Highly compressible films were formed at 40 degrees C, while stable monolayers with increased area were observed at sub-room temperatures. Langmuir monolayers formed on subphases containing 1 mM ZnCl2 and CaCl2 revealed two dimensional metal complex formation with Zn2+ forming a chelate-type complex, while Ca2+ formed an ionic-type complex. Monolayers transferred from the condensed phase onto hydrophilic Si(100) and quartz substrates revealed the formation of bilayers through transfer-induced monolayer buckling. Compression induced crystallites in 2D from monolayers and vesicle-like supramolecular structures from multilayers were the noted LB film characteristics, adopting optical imaging and electron microscopy. The interfacial monolayer structure studied through molecular dynamics simulation revealed the order and packing at a molecular level; monolayers adsorbed at various simulated specific areas of the molecule corroborated the (pi-A) isotherm and the formation of a hexagonal lattice at the air-water interface.

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“…It is simpler to study the chiral forces in two dimensions, as the degrees of freedom in the other two planes are restricted. Two-dimensional chiral films achieved through different noncovalent interactions help in understanding the phenomena at the molecular level. Monolayers at the air−water interface are an ideal example of physical systems where chirality is studied in two dimensions.…”

Section: Introductionmentioning

confidence: 99%

Chiral Discrimination of a Gemini-Type Surfactant with Rigid Spacer at the Air−Water Interface

Shankar

Patnaik

2007

J. Phys. Chem. B

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Spontaneous separation of chiral phases was observed in the monolayers of a racemate of gemini-type twin-tailed, twin-chiral amphiphiles, (2R,3R)-(+)-bis(decyloxy)succinic acid and (2S,3S)-(-)-bis(decyloxy)succinic acid. The pressure-area isotherms of the interfacial monolayers formed at the liquid-air interface, and the 2D lattice structures studied through surface probe measurements revealed that the racemate exhibits a homochiral discrimination of the enantiomers in two dimensions. An enantiomeric excess (e,e) of 20% was sufficient to break the chiral symmetry at the air-water interface for a homochiral interaction. Langmuir monolayers on ZnCl2 and CaCl2 subphases manifested chiral discrimination with Zn2+ evidencing homochiral interaction with a chelate-type complex, whereas Ca2+ resulted in a heterochiral interaction forming an ionic-type complex. For the chiral asymmetric units, oblique and rectangular unit cells of the racemic monolayer had exclusive requirements of homo- and heterochiral recognitions for Zn2+ and Ca2+ ions, respectively. Monolayers transferred from the condensed phase at 25 mN/m onto hydrophilic Si(100) and quartz substrates revealed the formation of bilayers through transfer-induced monolayer buckling. The emergence of homochiral discrimination was explained using the effective-pair-potential (EPP) approach.

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Thermodynamics and X-ray studies of 2-alcohol monolayers: Two-dimensional phase diagrams

Cited by 4 publications

References 21 publications

Two- and Three-Dimensional Stacking of Chiral Alcohols

Two- and Three-Dimensional Stacking of Chiral Alcohols

Equilibrium Structure and Dynamics of (2R, 3R)-(+)-bis(decyloxy)succinic Acid at the Air−Water Interface

Chiral Discrimination of a Gemini-Type Surfactant with Rigid Spacer at the Air−Water Interface

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