1421930-92-8Relevant academic research and scientific papers
Intra- and intermolecular hydrogen bonds enhance the fluoride- responsiveness of functionalized glycolipid-based gelators
Tsai, Cheng-Che,Chuang, Wei-Tsung,Tsai, Yow-Fu,Li, Jyun-Ting,Wu, Yu-Fa,Liao, Chun-Chen
, p. 819 - 827 (2013/07/05)
We propose a facile approach toward enhancing the efficiency of fluoride-responsive gels through the positioning of functionalized receptor units, allowing tunable intra- and intermolecular hydrogen bonding, in the gelator molecules. We prepared the new glycolipid-based gelator 2 and its hydroxy and methoxy derivatives 2a and 2b, respectively, to study the effects of three types modes of supramolecular assembly: solely intermolecular hydrogen bonding in 2, solely intramolecular hydrogen bonding in 2b, and both inter- and intramolecular hydrogen bonding in 2a. 1H NMR spectra confirmed the self-assembly interactions of these glycolipid-based gelators. We measured the minimum gel concentrations and sol-gel transitions and recorded X-ray diffraction patterns and electron micrographs to characterize the gelation behavior and structural organization of each of these supramolecular gels. Among these three gelators, only 2 and 2a could form organogels in the test solvents, indicating that intermolecular hydrogen bonding plays a determinant role in the supramolecular assemblies leading to gelation. The self-assembly of 2 resulted in a bilayer-packed lamellar structure within ribbon-like fibers, whereas that of 2a resulted in hexagonally packed cylindrical micelles within tree-like fibers. A minimum amount of 0.3 equivalent of F- was required for complete disruption of the gel formed from 2a, which was approximately four times lower than that required for the gel formed from 2. Thus, the incorporation of a β-hydroxy motif - the only difference in the chemical structures of 2 and 2a - led to interesting variations in the resulting gel morphologies and enhanced the gel's fluoride-responsiveness. The Royal Society of Chemistry 2013.
