关键词: 水诱导, 超分子凝胶, N,N',N"-三(4-吡啶基)-均三苯甲酰胺, 自组装

N,N',N"-Tris(4-pyridyl)trimesic amide (4-btapa) was synthesized by chemical modification using 4-aminopyridine to benezene-1,3,5-tricarboxylic acid. The gelating ability of 4-btapa to different solvents and the effect of pH on gelating ability were studied in detail. The results indicated that a stable gel was obtained by adding a certain amount of water to a 4-btapa DMSO solution at room temperature. While adding a certain amount of water to solutions of 4-btapa in DMF, THF, methanol and so on, respectively, only flow turbid liquids with large viscosity were obtained. Upon heating the obtained turbid liquids to clear solutions and cooling them at room temperature, stable gels were also obtained. The structures of the aggregates in the gels were investigated using Fourier-transform infrared spectroscopy (FT-IR), nuclear magnetic resonance (NMR) spectroscopy, small angle X-ray scattering (SAXS) and scanning electron microscopy (SEM). The result of SEM shows that the 4-btapa can form fibrous self-assembly aggregates in different aqueous solvent, while 4-btapa shows the fiber cluster structure at pH=3.0 water-ethanol system, which is different from regular fibrous aggregate in pH=7.0, suggesting that the pH can affect the aggregation morphology of gelators. The results of nuclear magnetic resonance and infrared spectroscopy revealed that the molecular hydrogen bonds of N—H…Py and aromatic π-π stacking interactions were formed in gel state and water was a part of the gel. From the above observation and analysis of FT-IR, ¹H-NMR and XRD results, we can suggest the self-assembly arrangement of 4-btapa in gel state.

Key words: water induced, supermolecular gel, N,N',N"-tris(4-pyridyl)trimesic amide, self-assembly