Study on the gel to crystal transition of a novel sugar-appended gelator.
4-(4'-Ethoxyphenyl)phenyl-beta-O-d-glucoside (1) was synthesized. A perfect crystal of 1 was obtained from an acetonitrile solution. In a mixture of water/1,4-dioxane (8/2, v/v), a gel formed at first and then collapsed into a needlelike crystal. The crystal and the gel were characterized by X-ray diffraction, UV-vis absorption, circular dichroism, Fourier transform infrared spectroscopy, and electron microscopy. It was found that the crystal formed from the gel had the same diffraction pattern as that of the single crystal from the acetonitrile solution, suggesting identical molecular packing. In a monoclinic cell containing two molecules, molecules took a "T" arrangement with an antiparallel direction. In contrast, the diffraction pattern of xerogel from water/1,4-dioxane (8/2, v/v) displayed a d-spacing ratio of 1:1/2:1/3 (2.39, 1.18, and 0.78 nm), indicating an interdigitated bilayer structure. A molecular packing model from gel to crystal where molecular sheets would insert into each other with a glide movement was suggested. On the basis of the understanding of the deformation mechanism, an additive was introduced to obtain a stable gel.
Cui
Jiaxi
J
Beijing National Laboratory for Molecular Sciences, Key Laboratory of Polymer Chemistry and Physics of Ministry of Education, College of Chemistry and Molecular Engineering, Peking University, Beijing 100871, China.
Shen
Zhihao
Z
Wan
Xinhua
X