基于赖氨酸环二肽水凝胶因子的合成与凝胶化研究

在严格控制投料比的条件下，赖氨酸环二肽与Fmoc-OSu反应首先得到Fmoc单取代赖氨酸环二肽，进而再与环酸酐发生酰胺化反应得到一类具有热可逆性的小分子水凝胶因子.SEM和TEM显示凝胶因子在水中自组装成直径纤细的微纳米纤维结构，相互紧密缠绕形成三维网络结构；红外和荧光光谱分析表明在水凝胶形成的过程中π-π堆积和氢键共同发挥驱动力的作用.根据XRD测试结果，采用Rietveld法全谱图拟合精修得到了FL-Ga水凝胶干胶的晶体结构模型，表明凝胶因子以单分子层方式进行聚集. 

Study on Synthesis and Hydrogelation of Hydrogelators Based on Cyclo(L-Lys-L-Lys)

Fmoc mono-substituted cyclo(L-Lys-L-Lys) (FL-NH2) was fist synthesized under strict control of the feed ratio.Thereafter,FL-NH2 was further reacted with cyclic anhydrides,in which three thermo-reversible low molecular weight hydrogelators were obtained.A study on the impact of the aliphatic chain length of cyclic anhydrides on the gelation performance was carried out.In particular,the glutaric anhydride acrylated derivative (FL-Ga) shows a better hydrogel ability.The TEM and SEM observations reveal that the resulting hydrogelators are selfassembled into fibrous aggregates,which are further closely intertwined to form a 3D supramolecular network structure.The hydrogen bond and π-π stacking interactions play a cooperative role during the self-assembly of hydrogelators.Based on XRD patterns of the xerogel prepared from the hydrogel of FL-Ga and Rietveld method,a possible molecular packing model of single layer membrane was also deduced.