ORGANOGELS FORMED BY N-BENZYLOXYCARBONYL-L-ALANINE 4-HEXADECANOYL-2-NITROPHENYL ESTER AND RELATED-COMPOUNDS

Organogels of low molecular weight compounds, N-benzyloxycarbonyl-L-al anine 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 s ol-to-gel phase transition which gave the thermodynamic parameters for the transition. The FT-IR spectroscopic results suggested that the in termolecular hydrogen bonding between N-H and C=O of urethane bond pla yed a vital role in gelation. The aggregates for gelation were mainly assembled by pi-pi interaction, dipole-dipole interaction, and the hyd rophobic interaction as well as hydrogen bonding for BLAHN. The compar ison of CD spectra of BLAHN, N-benzyloxycarbonyl-D-alanine 4-hexadecan oyl-2-nitrophenyl ester (BDAHN), and related molecules indicated that the self-aggregation of gelator molecules gradually proceeds and the c omponent molecules are cooperatively organized to form a chiral aggreg ate. The three-dimensional interlocking structures and tree-branched s tructures responsible for the immobilization of fluid were observed by TEM and SEM. (C) 1997 Academic Press.