Organogels Formed by N-Benzyloxycarbonyl-l-alanine 4-Hexadecanoyl-2-nitrophenyl Ester and Related Compounds

Organogels of low molecular weight compounds, N-benzyloxycarbonyl-l-alanine 4-hexadecanoyl-2-nitrophenyl ester (BLAHN) and related compounds, in methanol and cyclohexane solvents were studied by FT-IR, circular dichroism (CD), transmission electron microscope (TEM), and scanning electron microscope (SEM). The gels exhibited a thermally reversible sol-to-gel phase transition, which gave the thermodynamic parameters for the transition. The FT-IR spectroscopic results suggested that the intermolecular hydrogen bonding between N-H and C=O of urethane bond played a vital role in gelation. The aggregates for gelation were mainly assembled by pi-pi interaction, dipole-dipole interaction, and the hydrophobic interaction as well as hydrogen bonding for BLAHN. The comparison of CD spectra of BLAHN, N-benzyloxycarbonyl-d-alanine 4-hexadecanoyl-2-nitrophenyl ester (BDAHN), and related molecules indicated that the self-aggregation of gelator molecules gradually proceeds and the component molecules are cooperatively organized to form a chiral aggregate. The three-dimensional interlocking structures and tree-branched structures responsible for the immobilization of fluid were observed by TEM and SEM. Copyright 1997 Academic Press. Copyright 1997Academic Press