一种含芘葡萄糖衍生物的合成及其胶凝行为

合成并表征了一种荧光活性小分子胶凝剂——芘磺酰基-丙二胺-葡萄糖(PSDAPG), 考察了其在36种常见溶剂中的胶凝行为. 结果发现, PSDAPG可使其中16种溶剂胶凝. 对癸醇, PSDAPG表现出罕见的超级胶凝能力, 室温下最低胶凝浓度(MGC)达7.0×10-4 g·mL-1. 此外, PSDAPG还是一种既可胶凝水又可胶凝有机溶剂的双性胶凝剂. 扫描电镜(SEM)、傅立叶变换红外光谱(FTIR)、核磁共振(1HNMR)和荧光光谱研究表明,在不同溶剂中, PSDAPG具有不同的聚集结构, 除了芘基之间的疏水π-π堆积作用外, 氢键作用是PSDAPG自发形成三维网络结构的重要驱动力. 实验研究还表明, 溶液态和凝胶态的PSDAPG荧光光谱均同时呈现芘的单体荧光和激基缔合物荧光光谱特征, 但两者的光谱形貌差异显著. 随凝胶的形成, 体系单体荧光发射增强, 激基缔合物荧光发射减弱,表明形成的三维网络结构阻碍了PSDAPG中芘单元的运动性, 使得以Birks途径形成激基缔合物的效率降低.

Synthesis and Gelation Behavior of a Pyrene-Containing Glucose Derivative

Apyrene-containing glucose derivative (PSDAPG) was synthesized and characterized. Its gelation behavior in 36 solvents was evaluated and the compound geled 16 of the solvents tested. Interestingly, PSDAPGwas a super gelator for 1-decanol and its lowest gelation concentration (LGC) was 7.0×10-4 g·mL-1. PSDAPG was found to behave as a “bifunctional gelator”as it gels in both water and organic solvents. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), nuclear magnetic resonance (1H NMR) spectroscopy and fluorescence spectroscopy reveal that the gelator adopts different supramolecular network structures in different solvents. Additionally, hydrophobic and π-π stacking interactions exist between the pyrene structures of the gelator molecules. Hydrogen bonding between the glucose residues also plays a crucial role in the spontaneous  formation of gel networks. Fluorescence emission spectra of PSDAPG in the solution state and in the gel state were characterized by monomer emission and excimer emission. Profiles of the two types of spectra were quite different. We found that the monomer emission increased and the excimer emission decreased as the gelation process proceeded. This  indicates that formation of gel networks greatly suppresses the mobility of pyrene units in the gelator and results in lower excimer formation efficiency via Birks' scheme.