Laboratory for Chemistry and Life Science, Institute of Innovative Research, Tokyo Institute of Technology, 4259 Nagatsuta, Midori-ku, Yokohama, 226-8503, Japan.
Faculty of Engineering, Yamanashi University, 4-3-11 Takeda, Kofu, 400-8511, Japan.
Angew Chem Int Ed Engl. 2017 Sep 11;56(38):11360-11364. doi: 10.1002/anie.201703357. Epub 2017 Aug 9.
In spite of wide-ranging previous studies on synthetic macrocycles, the installation of open-close functions into the frameworks remains a challenge. We present a new polyaromatic macrocycle capable of switching between open and closed forms in response to external stimuli, namely, base and acid. The macrocycle, which is prepared in three steps, has a well-defined hydrophobic cavity with a length of around 1 nm, surrounded by four pH-responsive acridinium panels. The open and closed structures were confirmed by single-crystal X-ray analysis. The cylindrical cavity can bind long hydrophilic molecules up to 2.7 nm in length in neutral water and then release the bound guests through a reversible open-to-closed structural change upon simple addition of base.
尽管之前已经有广泛的关于合成大环化合物的研究，但在框架中安装开-关功能仍然是一个挑战。我们提出了一种新的多环芳烃大环化合物，它能够对外界刺激（即碱基和酸）做出响应，在开环和闭环两种形式之间切换。该大环化合物通过三步合成，具有约 1nm 长的明确疏水空腔，周围环绕着四个对 pH 敏感的吖啶基团。开环和闭环结构通过单晶 X 射线分析得到证实。在中性水中，圆柱形空腔可以结合长达 2.7nm 的长亲水分子，然后通过简单地加入碱基实现开环到闭环的结构可逆变化，从而释放结合的客体。
