Imagerie par résonance magnétique dans le bilan des lombalgies et lombo-radiculalgies (indications et résultats)

LILLE2-BU Santé-Recherche (593502101) / SudocPARIS-BIUM (751062103) / SudocSudocFranceF

Lyotropic Lamellar Phase Formed from Monolayered θ-Shaped Carborane-Cage Amphiphiles

Lyotropic lamellar phases are ubiquitous on earth, they occur naturally and are a key architecture for life to appear as they enable closed cell topologies to occur1, 2, 3, 4, 5 . But in addition to the latter, enabling life means that the same solvent must be on both side of the cell membrane, hence a, at least, double layered membrane structure is necessary. For this a lamellar phase must be enabled. The present contribution shows, for the first time, that the formation of lamellar phases is not exclusive to alkyl chain based surfactants with a well-defined amphiphilic structure but that it can also be obtained with metalla-carborane clusters, described previously as θ-shaped amphiphiles6 . Similarly to phospholipids cell membranes the lamellae formed here can exist both in the liquid and in the solid states depending on temperature. The determination of the 2D molecular arrangement in the lamella proved that the formation of intermolecular dihydrogen bonds, such as -C-H+…-H-B-, is the driving force in the lamella self-assembly process. Compared to the common bilayer structure that originates from the hydrophobic effect7, θ-shaped amphiphiles form lamella with a peculiar monomolecular structure reminiscent of lamellar sheets observed in inorganic layered systems8 . Nano-scale ordering of planar organic-inorganic hybrid sheets is here controlled with temperature and concentration through a self-assembly process