Aroua Safwan, Lowell Andrew N, Ray Ankita, Trapp Nils, Schweizer W Bernd, Ebert Marc-Olivier, Yamakoshi Yoko
Laboratorium für Organische Chemie , ETH Zürich , Vladimir-Prelog-Weg 3 , CH8093 Zürich , Switzerland.
Department of Chemistry , University of Pennsylvania , 231 South, 34th Street , Philadelphia , PA19104-6323 , United States.
Org Lett. 2019 Jan 4;21(1):201-205. doi: 10.1021/acs.orglett.8b03660. Epub 2018 Dec 19.
A series of quinoxaline cavitands bearing pendant amide groups with various substituent sizes (Et, Pr, Bu) were synthesized, and their cavity size/structure were investigated by X-ray and NMR analyses. In the case of the Et or Pr amide cavitand, the conformation of the molecule was in the vase form, while the bulky Bu amide cavitand gave the kite conformation at room temperature. X-ray crystal structures of Et and Pr cavitands clearly showed the intramolecular H-bondings to influence the conformation and the cavity sizes dependent on the bulkiness of functional groups. The H NMR spectrum revealed that the Et cavitand can encapsulate an adamantane guest compound with slow exchange.
合成了一系列带有不同取代基大小（乙基、丙基、丁基）的酰胺侧基喹喔啉穴状配体，并通过X射线和核磁共振分析研究了它们的空腔大小和结构。对于乙基或丙基酰胺穴状配体，分子构象为花瓶状，而体积较大的丁基酰胺穴状配体在室温下呈风筝状构象。乙基和丙基穴状配体的X射线晶体结构清楚地表明，分子内氢键影响构象，空腔大小取决于官能团的体积。核磁共振氢谱表明，乙基穴状配体可以缓慢交换的方式包封金刚烷客体化合物。
