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 organoge lators afford stable, transparent, and thermoreversible gels. Modification of the molecular structure and IR measurements show that gelation takes pla ce by means of a hydrogen-bonded network and involves at least the amide bo nd and several hydroxy groups of the cholic acid component. The chiral cent er 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 cap ability. Electron microscopy reveals a fibrous structure in the gels. Diffe rential scanning calorimetry shows several transitions in the melting behav ior of the gels.