芴酮為橋聯之雙芳杯衍生物合成及其膠體研究

Abstract

利用點擊反應合成以芴酮、二苯甲酮為橋聯之雙芳杯化合物20、 21，和控制化合物22、23。經一系列膠體性質測試發現化合物20 在 大部分醇類溶劑下會形成膠體，且在異丙醇裡有最低臨界膠體濃度 0.13 w/w % 屬一超級凝膠。雖然控制化合物22、23 在部分溶劑下也 會形成膠體，但CGC 多高於2 w/w %，由此證明芳杯在自組裝過程 扮演重要角色。而化合物21 不會形成膠體表示π-π 堆疊具一定的重 要性。 由掃描式電子顯微鏡可知化合物20 於異丙醇中，濃度為10-5 M 時呈直徑10-20 nm 的球狀，隨濃度升高至10-3 M 呈珊瑚狀。此外利 用核磁共振光譜儀、紫外可見光光譜儀、螢光放射光譜儀、紅外光譜 儀、和粉末X 光繞射儀探討分子自組裝之機制，結果顯示芳杯提供凡 得瓦、氫鍵作用力，三唑提供偶極-偶極力，芴酮提供π-π 作用力進而 形成膠體。 由於化合物20 含有芴酮，具有氧化還原的性質，嘗試以化學氧 化還原劑調控其相轉變，結果顯示當加入氧化還原試劑會使膠體進行 不可逆之反應。此外嘗試加入17 種金屬離子，並觀察膠體相變化， 發現銀離子、汞離子及鐵離子會造成膠體崩解，此表示化合物20 可 應用於金屬離子感測。化合物21 無法形成膠體，故以照光進行奪氫 反應增加作用官能基，但產物均無法形成膠體。

A 9-fluorenone bridged and a benzophenone bridged biscalix[4]arene, 20, 21 and their control compound 22, 23 were synthesized through click reaction. Their gelation behavior in twenty one organic solvents were investigated. CGC (critical gelation concentration) tests showed compound 20, 22, and 23 can form gel. However, the compound 21 can not gelate in any solvents. Only the compound 20 can gelate in isopropanol at 0.13 w/w %, such low concentration called ”supergelators”. On the basis of these results, indicating the calix[4]arene and π-π stacking play important role in their self-assembling process. The SEM images showed the aggregates of 20 in isopropanol can form spheres between 10-20 nm in diameter at 10-5 M. As the concentration increase, the spheres gradually become coralloid fiber. In addition, self-assembling process was investigated via nuclear magnetic resonance (NMR) spectroscopy, ultraviolet-visible spectroscopy (UV), fluorescence spectroscopy (PL), infrared spectroscopy (IR), and powder X-ray diffraction technique (PXRD). The gelation results of compound 20 can be rationalized due to the van der Waals interation and H-bonding from calix[4]arene, dipole-dipole interaction from triazole, and π-π stacking form 9-fluorenone. It is known that the 9-fluorenone can be redox, so gel-to-sol transition by adding redox agent was conducted; however, the gelator 20 was suffered irreversible reaction. Furthermore, considering the fact that the weak interaction based self-assembly, evaluating the 17 metal-ion sensing abilities of gel were proceeded. Gel collapsed only after the addition of 1 eq. of Ag+, Fe3+, and Hg2+ perchlorates, while the rest of the metal ions had no effect. It may provide new routes for preparing a metal-ion sensing system. Since the compound 21 had no gelation behavior, a H-abstraction via UV irradiation was utilized to increase the interactions, (e.g., van der Waals, H-bonding). But, the desired results still can not be obtained.