title: Evaluation of hydrogen-bond acceptors for redox-switchable resorcin[4]arene cavitands.
abstract: 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.
authors.affiliation: Laboratorium für Organische Chemie, ETH Zürich , Hönggerberg, HCI, 8093 Zürich, Switzerland.
authors.forename: Igor
authors.initials: I
authors.lastname: Pochorovski
authors.forename: Jovana
authors.initials: J
authors.lastname: Milić
authors.forename: Dušan
authors.initials: D
authors.lastname: Kolarski
authors.forename: Cornelius
authors.initials: C
authors.lastname: Gropp
authors.forename: W Bernd
authors.initials: WB
authors.lastname: Schweizer
authors.forename: François
authors.initials: F
authors.lastname: Diederich