Department of Food, Aroma and Cosmetic Chemistry, Faculty of Bio-Industry, Tokyo University of Agriculture, 196 Yasaka, Hokkaido 099-2493, Japan.
Department of Physics, School of Science and Technology, Kwansei Gakuin University, Sanda 669-1337, Japan.
Molecules. 2022 Jul 7;27(14):4359. doi: 10.3390/molecules27144359.
Three-dimensional liquid crystal (LC) phases, cubic LC phases, have been extensively studied as fascinating molecular assembled systems formed by amphiphilic compounds. However, similar structures have only been seen in rare instances in lipid crystal states in glycolipid crystal studies. In this study, we prepared short-chain n-alkyl β-D-glucosides (CnG) with an alkyl chain length ranging from 4 to 6 and investigated their crystal structures. First, differential thermal analysis (DTA) and thermogravimetric analysis (TG) measurements showed the formation of hydrated crystals for C4G and C5G, respectively. Second, the crystal structures of CnG ( = 4, 5, 6) in both anhydrous and hydrated states were examined using a temperature-controlled powder X-ray diffraction (PXRD) measurement. Both hydrate and anhydrous crystals of C4G and C5G with critical packing parameters (CPPs) less than 0.33 formed cubic crystal phases. Bilayer lengths, calculated from the main diffraction peaks in each PXRD profile, depended on crystalline moisture for C5G, but no significant change was confirmed for C4G, indicating that the properties of each hydrophilic layer differ. However, C6G with a CPP of 0.42 formed a crystal structure with a modulated lamellar structure similar to C7G and C8G with similar CPP values. Thus, a glycolipid motif concept with a cubic crystal structure was demonstrated.
三维液晶 (LC) 相，立方 LC 相，已被广泛研究为由两亲化合物形成的迷人的分子组装体系。然而，在糖脂晶体研究中，仅在脂质晶体状态下的罕见情况下观察到类似的结构。在本研究中，我们制备了具有烷基链长为 4 至 6 的短链 n-烷基 β-D-葡萄糖苷 (CnG)，并研究了它们的晶体结构。首先，差示热分析 (DTA) 和热重分析 (TG) 测量表明 C4G 和 C5G 分别形成水合晶体。其次，使用控温粉末 X 射线衍射 (PXRD) 测量研究了 CnG ( = 4,5,6) 在无水和水合状态下的晶体结构。具有小于 0.33 的临界堆积参数 (CPP) 的 C4G 和 C5G 的水合和无水晶体均形成立方晶体相。从每个 PXRD 图谱的主要衍射峰计算出的双层长度取决于 C5G 的结晶水分，但对 C4G 未确认到明显变化，表明每个亲水层的性质不同。然而，CPP 为 0.42 的 C6G 形成了类似于 CPP 值相似的 C7G 和 C8G 的调制层状结构的晶体结构。因此，展示了具有立方晶体结构的糖脂基元概念。
