Middle East Technical University, Department of Chemistry, 06800, Ankara, Turkey.
Sci Rep. 2019 Mar 20;9(1):4893. doi: 10.1038/s41598-019-41142-z.
The gelation of L-Tyr(tBu)-OH in tetrahydrofuran (THF) was discovered serendipitously. It was noted that this tremendously low molecular weight (LMW) compound has the ability to gel a wide variety of organic solvents (e.g., N,N-Dimetylformamide (DMF), THF, butanol, toluene), even in very low concentrations (i.e., 0.1 wt/v% in DMF). Addition of bases such as NaOH and piperidine enhanced the gel property. By changing the side-chain protecting group to tert-butyldimethylsilyl (TBDMS), a fluoride ion-responsive organogel was also acquired. This new organogelator responded fluoride ion concentration as low as 0.2 ppm. Characterization of microstructures and gel behaviours were studied by powder X-Ray diffraction spectroscopy (XRD), transmission electron microscopy (TEM), rheological measurements and molecular dynamics (MD) simulations. Experimental observations and theoretical simulations consistently show a fibre-like structure of the gel, in which the organogelator molecules are held together via a dense network of hydrogen bonds, and via van der Waals interactions between hydrophobic groups.
L-Tyr(tBu)-OH 在四氢呋喃（THF）中的凝胶化作用是偶然发现的。人们注意到，这种分子量极低（LMW）的化合物具有胶凝各种有机溶剂（例如 N，N-二甲基甲酰胺（DMF）、THF、丁醇、甲苯）的能力，即使在非常低的浓度下（例如在 DMF 中为 0.1wt/v%）也是如此。添加碱如 NaOH 和哌啶可增强凝胶性能。通过将侧链保护基改为叔丁基二甲基硅基（TBDMS），还获得了对氟离子响应的有机凝胶。这种新的有机凝胶剂对氟离子浓度低至 0.2ppm 有响应。通过粉末 X 射线衍射光谱（XRD）、透射电子显微镜（TEM）、流变学测量和分子动力学（MD）模拟研究了微观结构和凝胶行为。实验观察和理论模拟一致表明，凝胶具有纤维状结构，其中有机凝胶剂分子通过氢键的密集网络以及疏水分子之间的范德华相互作用结合在一起。
