N-cholyl amino acid alkyl esters - A novel class of organogelators

Several N-cholyl amino acid alkyl esters were found to act as novel, potent organogelators for aromatic solvents and cyclohexene. These novel organogelators afford stable, transparent, and thermoreversible gels. Modification of the molecular structure and IR measurements show that gelation takes place by means of a hydrogen-bonded network and involves at least the amide bond and several hydroxy groups of the cholic acid component. The chiral center of the amino acid component seems to play an important role in gelation. Although a wide variety of derivatives display gelation behavior, a small change in molecular structure can have a dramatic effect on the gelling capability. Electron microscopy reveals a fibrous structure in the gels. Differential scanning calorimetry shows several transitions in the melting behavior of the gels.