Synthesis and Organogel Properties of Bisisoxazolyaryl Biscalix[4]arenes

• Main Author: 鄭英材
• Other Authors: 鍾文聖
• Format: Others
• Language: zh-TW
• Published: 2011
• Online Access: http://ndltd.ncl.edu.tw/handle/60001735561202874382

碩士 === 國立交通大學 === 應用化學系碩博士班 === 99 === Biscalixarene is an important member of calixarene family, composed of two calixarene moieties linked at their lower rim through various spacers with more complicated structures and colourful properties as compared to monocalixarene. We have developed a method of attaching aryl isoxazole units onto the lower rims of calix[4]arenes by 1,3-dipolar cycloadditions to obtain a series of biscalix[4]arenes (50, 51, 52, 56 and 57) and our synthetic strategy for linking two calix[4]arenes involves a double cycloaddition between aryl dinitrile oxides and propargyl groups, yielded 22-35 % in four steps.The structures of all products were confirmed by spectral data including 1H-, 13C NMR, and MS. Organogels are usually assembled through self-aggregation of the small gelator molecules to form entangled supramolecular fibril networks via a combination of noncovalent interactions such as hydrogen bonding, ??? stacking, and van der Waals interactions. Serendipitously, we have observed the first example of thermoreversible organogel with biscalix[4]arene in the gelator framework. We have prepared a new fluorescence organogelator 59 with isoxazole based biscalix[4]arene framework without the assistance of long alkyl chain. Furthermore, we have explored their molecular assembly properties during the sol-to-gel phase transition by variable-temperature 1H-NMR. Moreover, we found that the gel suprastructure is sensitive to added metal ions which are known to coordinate with triple bonds like Ag+, Cu2+ and Hg2+. The gel matrix will collapse into a solution phase and quench its fluorescence in the presence of Ag+, Cu2+ and Hg2+. The organogel-based approach becomes quite attractive comparing to conventional metal ion sensors.