Ultrasound-induced gelation of fluorenyl-9-methoxycarbonyl-l-lysine(fluorenyl-9-methoxycarbonyl)-OH and its dipeptide derivatives showing very low minimum gelation concentrations

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• 作者：Huimin Geng^a ; ^b ; ^{genghuimin1003@163.com} ; Lin Ye^a ; ^b ; ^{yelin@bit.edu.cn} ; Ai-ying Zhang^a ; ^b ; ^{zhay@bit.edu.cn} ; Ziqiang Shao^a ; ^c ; ^{shaoziqiang@263.net} ; Zeng-guo Feng^a ; ^b ; ^{sainfeng@bit.edu.cn}
• 关键词：Ultrasound-induced gelation ; Organogels ; Self-assembly ; Lysine-based short peptides
• 刊名：Journal of Colloid and Interface Science
• 出版年：2017
• 出版时间：15 March 2017
• 年：2017
• 卷：490
• 期：Complete
• 页码：665-676
• 全文大小：4511 K
• 卷排序：490

文摘

Four l-Lysine(Lys)-l-glutamic acid(Glu) dipeptide derivatives (1–4) and their precursor–a single fluorenyl-9-methoxycarbonyl(Fmoc)-l-Lys(Fmoc)-OH amino acid (5) were demonstrated as gelators to gelate a variety of alcohols and aromatic solvents under the sonication conditions. Compared to the routine heating-cooling protocol, the ultrasound substantially brought down the minimum gelation concentrations (MGCs) of the resulting organogels. The Fourier transform infrared spectroscopy (FT-IR) and fluorescence studies revealed that the π-π stacking and hydrogen bonding act as major driving forces for the self-assembly of these lysine-based gelators into supramolecular fibrous three dimensional (3D) network, where the more the Fmoc protecting groups, the gelators are more responsive to ultrasound-stimulus and more conducive to an ordered molecular arrangement reinforcing the intermolecular forces. Moreover, the ultrasound-triggered organogels of 5 exhibited the thixotropic property. Upon imposing a mechanical shear, its gels with the fibrous 3D network structure were unraveled into sols. However, after standing quiescently over time, these sols returned to the gels showing a more ordered lamella-like packing structure as evidenced by scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses.