Laboratorium für Organische Chemie, ETH Zürich , Hönggerberg, HCI, 8093 Zürich, Switzerland.
J Am Chem Soc. 2014 Mar 12;136(10):3852-8. doi: 10.1021/ja411429b. Epub 2014 Feb 25.
Various H-bond acceptor groups were evaluated for their propensity to induce conformational switching between the kite and vase forms of diquinone-diquinoxaline resorcin[4]arene cavitands upon redox interconversion. The H-bond acceptors were placed on the quinoxaline walls with the purpose of stabilizing the vase form only in the reduced hydroquinone state of the cavitand by forming H-bonds with the hydroquinone OH groups. Design guidelines for successful acceptors were derived. The carboxamide acceptor was shown to be the best candidate. Based on this moiety, a redox-switchable triptycene-based basket that can completely sterically encapsulate a guest in its closed vase conformation was prepared. The basket binds small molecule guests with association constants of up to 10(4) M(-1) in mesitylene-d12 and exhibits slow guest exchange kinetics with a half-life for guest release in the order of 10(4) s.
研究了各种 H-键受体基团在醌-二氢醌二嗪并[4,5-b]对苯二酚[4]芳烃主体空腔之间的构象转换倾向，这些受体基团被放置在喹喔啉壁上，目的是仅在主体空腔的还原氢醌状态下通过与氢醌 OH 基团形成 H-键稳定花瓶形式。得出了成功受体的设计准则。酰胺受体被证明是最佳选择。基于该部分，制备了一种基于三芴的氧化还原开关篮，可在其闭合的花瓶构象中完全空间位阻地封装客体。该篮在间二甲苯-d12 中与小分子客体的结合常数高达 10(4) M(-1)，并表现出缓慢的客体交换动力学，客体释放的半衰期约为 10(4) s。
